Holliday et al.'s Gish Gallop: Nanodiamonds
Holliday et al.'s "comprehensive refutation" of the Younger Dryas impact hypothesis (YDIH) is a highly misleading Gish gallop.
An earlier blog post addressed the presence of impact melts and microspherules in the YDB. By themselves, they confirm a cosmic impact at Abu Hureyra near the YD onset. Due to the similarity of debris at the YDB across a wide range of sites, it's likely there were cosmic impacts across a wide area within a short timespan, indicating a singular event.
The remaining topics to be discussed are, therefore, the presence of nanodiamonds and platinum at the YDB, and the apparently synchronous timing of this evidence across ~ 50 sites on several continents. This blog post, therefore, focusses on the nanodiamond evidence. This corresponds to section 12 of Holliday et al.. Given the clear presence of nanodiamonds in the Abu Hureyra YDB, it is very likely they too are products of a cosmic impact.
The main paper on nanodiamond abundances at the YDB is Kinzie et al. (2014). Their main result is shown below.
The horizontal grey bands are the expected positions of the YDB at many different sites, while the dots (connected by lines) are measured nanodiamond abundances. The agreement is superb, and effectively rules out any significant problems with experimental methods, since they would tend to eliminate any signal. Clearly, Kinzie et al. (2014) are able to locate nanodiamonds at the YDB across several continents.
My comments below are in italics.
12. Purported YDIH evidence of impact: Nanodiamonds
Impact proponents enthusiastically describe nanodiamonds at the YDB and claim that they
are impact markers apparently basing this on their presence in Cretaceous-Tertiary (KT)
boundary sediments (e.g., Kennett et al., 2009a,b; Kurbatov et al., 2010; Israde-Alcántara et al.,
2012; Bement et al., 2014; Kinzie et al., 2014) and their dubious synthesis experiments (Kimbel
et al., 2008).
Nanodiamonds are also known to be produced by high-energy carbon-rich explosives. Indeed, Daulton (a co-author of Holliday et al.) has published on this. And, in any case, their presence in the debris layer at Abu Hureyra, where the microspherule evidence alone confirms a cosmic impact, means it is almost certain that nanodiamonds in the YDB layer are also produced by the impact.
The presence of nanometer-sized diamond of the cubic 3C polytype in sediments is
not necessarily an indicator of an impact. Diamond is chemically inert, highly resistant to
weathering (e.g., decomposition and transformation) and will persist in the surface environment.
Erosion of diamond-bearing source rocks and transportation by wind or water could widely
redistribute nanometer- to submicron-sized diamonds into distant alluvial deposits and sediments
that bear little resemblance to the diamond source rocks (Section 12.1).A similar case could be
made for micron-sized host grains containing nanodiamond inclusions, and those inclusions
would be released when the host grains weather. Also, those inclusions would be extracted from
their host minerals during laboratory acid dissolution as has been applied to study YDB
sediments
This mechanism is implausible across several continents, especially when there are obvious alternatives, such as cosmic impact. And we know from Abu Hureyra, where an impact is confirmed, that nanodiamonds and impact microspherules occur together.
The use of the rare hexagonal 2H polytype of diamond as an impact marker can be
questioned as well, but for different reasons (Section 12.2).
We shall see.
Impact proponents further claim that at multiple sites across the Northern Hemisphere, there
is a peak in nanodiamond concentration at the YDB usually in the hundreds of ppb range (Kinzie
et al., 2014), but upwards of 190 ppm (e.g., Bement et al., 2014), with the absence (or near
absence) of nanodiamonds immediately above and below that horizon. Such a spike in the
concentration of nanodiamonds at the YDB would represent a strong indicator that a highly
unusual event occurred at that time horizon.
Exactly.
However, the measurement of ppm/ppb
concentrations of nanodiamonds in sediments is technically very challenging, and the methods
used by the impact proponents have numerous problems with both identification and
quantification that render their approach impractical (Section 12.6).
We shall see.
Consequently, published
nanodiamond concentrations from purported YDB sediments are completely unreliable and
scientifically meaningless.
So far, no evidence has been presented against the presence of nanodiamonds at the YDB.
12.1. Cubic Nanodiamonds
In arguing that nanodiamonds are impact markers, Sweatman (2021, p 8) claimed, “Almost
all terrestrially formed diamond is microscopic or larger, >1 μm, and of cubic form. Naturally
formed terrestrial nanodiamonds, 2 nm to 100 nm, are extremely rare…,” which echoed earlier
unsupported claims of LeCompte et al. (2018, p 165) (see Table 2). The distribution of
nanodiamonds in terrestrial sediments and rocks remains largely unknown due to the severe
experimental challenges that have limited their study (e.g., Daulton et al., 2017a,b). Because of
this, the rarity/abundance of nanometer-sized diamond relative to the total terrestrial diamond
population across their entire size range is unknown.
And yet we see an abundance peak at the YDB across several continents that must be explained. It is clear the peak far exceeds background values.
Nevertheless, recent studies have begun to
examine natural terrestrial diamond of nanometer to submicron-size, and various formation
conditions/mechanisms (including those exclusive of shock transformation) have been proposed
based on their petrological context (e.g., see Simakov et al., 2015; Farré-de-Pablo et al., 2018;
Pujol-Solà et al., 2020 and references within Daulton et al., 2017a). However, the literature is
complicated by the varying strength of the published data due to the difficulty in
micro/nanoanalysis of nanodiamonds.
None of this can explain a layer of nanodiamonds across several continents in the same YDB layer as microspherules either known (at Abu Hureyra) or strongly suspected to also be generated by cosmic impact.
Sweatman (2021) cites only several select studies and only those he claims support the
YDIH. Nanometer- to submicron-sized diamonds were reported within 0.1-1.5 mm-sized
carbonaceous particles, similar in description to carbon spherules reported in YDB sediments,
but from modern forest soils in Germany and Belgium (Yang et al., 2008). Sweatman (2021, p
9) wrote, “Yang et al. (2008) suggest these nanodiamonds are likely to have been produced by
another cosmic impact or detonation of explosives during modern wars.” The origin of these
nanodiamonds remains undetermined, however.
And no other explanation is provided here either.
Sweatman (2021, p 9) also wrote that Tian et al.
(2011) “confirmed the existence of abundant cubic nanodiamonds at the Ussello horizon, often
thought to be the continuation of the YDB…”. These claims were repeated from his book where
he wrote (Sweatman 2019, p. 102), “nanodiamond abundance peak was also confirmed…in the
Ussello layer” and (p. 155) “the Younger Dryas black mat is found in Belgium, where it is called
the Ussello Horizon.”
The Usselo soil suffers the same confused interpretation by YDIH proponents as does the
black mat, however, being perceived to be the impact debris layer (i.e., the YDB) or not (see
Sections 5.6, 6).
It is clear the impact debris should be found at or near the bottom of the YD black mat. Although bioturbation and other forms of re-working could redistribute this debris to nearby sediments. Figure 1 from van Hoesel et al. (2012) below shows the Ussello Horizon at Geldrop-Aalsterhut in the Netherlands. It is not obvious where the YDB layer is in relation to the Ussello horizon. This can be established only through experiments and is likely the cause of any confusion.
For example, Firestone et al. (2010a, p. 40) wrote, “magnetic grains and
spherules, charcoal, iridium, and rare earth elements peak beneath the Usselo layer, the
European analog to the black mat [emphasis added].” In subsequent papers coauthored by
Firestone inconsistencies and contractions regarding the Usselo soil abound (Kennett et al.,
2015a; Wolbach et al., 2018b, 2020). Kennett et al. (2015a, p. E4351) wrote, “The charcoal-rich
YDB layer occurs at the top of the Usselo horizon … and contains peaks in impact-related
spherules, carbon spherules, and nanodiamonds [emphasis added].” Wolbach et al. (2018b,
supplemental, caption figure A6) wrote, “Charcoal-rich black layers…, or ‘black mats,’ lie at the
boundary between the underlying Usselo Formation and overlying sandy sediment.” Wolbach et
al. (2020, p. 99) wrote, “impact material fell on and mixed into the top of the Usselo [horizon],
which existed before the impact event [emphasis added].” Regardless of this confused
interpretation, Usselo soils are not uniquely linked to the YDB, and their formation neither began
nor ended at the YDB. Rather, they formed before and during the YD/GS-1 (Section 5.6). This
fact may contribute to the YDIH proponents confused interpretation.
Nevertheless, it is clear what is intended. At some point in this sequence the YDB impact debris layer is found near the Ussello Horizon. Still, no arguments are provided to dispute this evidence.
Furthermore, the main
conclusion of Tian et al. (2011) is prominently emphasized in the title of their paper
“Nanodiamonds do not provide unique evidence for a Younger Dryas impact.” Tian et al. (2011,
p 44) wrote that this conclusion was reached because, “… the present variety of crystalline
structures observed in the black [presumed] Younger Dryas boundary in Lommel does not
provide sufficient evidence to conclude an exogenic impact as the origin of these structures.”
Clearly, the title of their paper is a contortion. In fact, despite their wordplay, their positive identification of nanodiamonds at the YDB at Lommel strongly supports the YDIH. This is very obvious.
Furthermore, as pointed out by van Hoesel et al. (2012, p. 7648), “no age control was presented”
by Tian et al. (2011) to support the identification of the black layer in the Usselo soils as the
YDB.
The YDB at Lommel is dated in Kennett et al. (2015) and is consistent with the YDIH. The issue of dating the YDB is dealt with separately.
12.2. Hexagonal Nanodiamonds (Lonsdaleite)
The hexagonal (2H polytype of) diamond, lonsdaleite, was first discovered by laboratory
shock synthesis and then subsequently found in shocked meteorites as well as within impact
structures. This lead to the perception that its formation was exclusively associated with shock
processes. However, the literature also contains reports of natural lonsdaleite with no direct
connection to shock processes (see references within Daulton et al., 2017a). It is difficult to
evaluate that literature, because some (but not all) published data identifying natural lonsdaleite
is not rigorous or convincing, with identifications sometimes based on several diffuse X-ray lines
or a few Transmission Electron Microscopy (TEM) electron diffraction patterns. In some studies
(e.g., Koeberl et al., 1997; Masaitis et al., 1999; Titkov et al., 2001), no data are presented to
support the lonsdaleite identification. Lonsdaleite is almost always reported intergrown with
cubic 3C diamond, which complicates microanalysis, and literature reports often lack details of
the nano/microstructure (e.g., stacking-domain size and volume/mass fraction of hexagonally
and cubic stacked layers). Whether a specimen reported in a study is best described as an
intergrowth of discrete cubic and hexagonal polytypes, a highly stacking disordered tetrahedral diamond
layer structure, or a microstructure in between (e.g., see Murri et al., 2019) can be
indeterminate. Moreover, stacking faults in diamond, e.g., {ABABC}, can form several unit-cell
thick lamellae with the 2H or 3C polytype structure. In nanocrystals, whether these thin lamellae
constitute a phase a particular polytype or disorder can be a matter of definition, perhaps
dependent on which stacking sequence is more prevalent. In fact, Németh et al. (2014) have
gone as far to speculate that lonsdaleite does not exist as a discrete phase and is merely fine-scale
stacking faults and twinning in cubic diamond, but this has been challenged with contrary
evidence (e.g., see Kraus et al., 2016; Daulton et al., 2017a; Turneaure et al., 2017; Volz et al.,
2020; Volz and Gupta 2021; Tomkins et al., 2022). Nevertheless, speculation by some that
lonsdaleite does not exist reflects the lack of sufficient nano/micro-characterization of lonsdaleite
in the literature due to the experimental difficulty.
No problem with any of this. Distinguishing nanodiamond polymorphs is certainly not easy and research continues.
Still no evidence is presented against the YDIH.
Therefore, in the literature on specimens obtained from sites either exhibiting or lacking
shock indicators where details of the micro/nano-structure are lacking, presence of lonsdaleite is
uncertain in the specimens studied. Consequently, it is also uncertain if lonsdaleite in nature is
exclusively (or predominantly) associated with impact structures and, in turn, the extent and
circumstances under which it can be used as an impact marker are uncertain.
A recent study of
ureilite meteorites further reinforce the questions of if and when lonsdaleite can be used an
impact marker. In that study, Tomkins et al. (2022, abstract) proposed lonsdaleite formation “by
psuedomorphic replacement of primary graphite, facilitated by supercritical C-H-O-S fluid
during rapid decompression and cooling”, and described the “process is akin to industrial
chemical vapor deposition but operates at higher pressure.” They wrote (p. 6), “Shock-induced
conversion of graphite to lonsdaleite or diamond produces a large volume decrease reflecting
their respective densities (graphite = 2.26 g/cm3, lonsdaleite and diamond = 3.52 g/cm3), so the
observed volume increase requires addition of carbon, such as by fluid-mediated
pseudomorphism” and “In the meteorites examined here, polycrystalline lonsdaleite tends to
occur in fully annealed ureilites (NWA 5996, NWA 7983), or in domains of annealing associated
with smelting (NWA 2705, NWA 11755), which formed after the primary shock event.”
It's not clear how any of this helps. Clearly, if any Lonsdaleite does exist in the YDB it was not formed in a lab. But the above suggests it might exist in some meteorites.
Whether or not lonsdaleite can be used as in impact marker is a moot point, however, given
that there is no viable evidence of the presence of lonsdaleite in YDB sediments (Daulton et al.,
2010, 2017a,b; van Hoesel et al., 2012; van Hoesel, 2014). The published YDB data is thus
inconclusive for lonsdaleite, inconsistent with lonsdaleite, and/or a misidentification as
lonsdaleite (Daulton et al., 2010; 2017a,b).
Let's see. Still no evidence is provided against the YDIH.
In response to Daulton et al. (2017a) regarding the misidentification of lonsdaleite in YDB
sediments, Sweatman (2021, figure 8 caption) declared “Daulton et al., [(2017a)] focus on the
single [emphasis added] missing diffraction ring between the 100 and 110 rings…”, and (p 11)
“the key issue identified by Daulton et al., [(2017a)] is that the diffraction patterns of Kennett et
al. (2009b), Kurbatov et al. (2010) and Kinzie et al. (2014) appear to be missing diffraction rings
at 0.15 nm expected for Lonsdaleite. By scaling these diffraction patterns by a factor of 1.054,
Daulton et al., [(2017a)] claim a better match is obtained to an assembly of graphene/graphene
[/graphane] layers. But this is a matter of judgment based on a rather fuzzy diffraction image
(see Fig. 8).” These statements are only marginally correct. Contrary to Sweatman (2021),
Daulton et al. (2017a) did not rule out the lonsdaleite identification of Kurbatov et al. (2010)
based on the lack of a (102) reflection at 0.15 nm. The only diffraction pattern supporting a
lonsdaleite identification presented by Kurbatov et al. (2010) is their figure 6. That figure
contains structural data from two nanocrystals isolated from residues of ice sampled at a
purported YDB-dated margin site east of Kangerlussuaq, West Greenland. In figure 6c of
Kurbatov et al. (2010), a diffraction pattern of the first nanocrystal is shown. As discussed later
in this section, a single zone axis diffraction pattern from a nanocrystal is insufficient to base
conclusive mineral identification. Thus, the identification of this nanocrystal is undetermined.
The figures 6b and d of Kurbatov et al. (2010) display a high-resolution (HR)-TEM lattice image
of the second nanocrystal and presumably its fast Fourier transform (FFT). The lattice image
and FFT are unquestionably inconsistent with the crystal structure of lonsdaleite. Daulton et al.
(2017a, p 12) wrote, “No crystallographic zone axis of lonsdaleite exists that can display two
differently oriented sets of 2.06 Å -spaced {002} planes because there is only one such set of
planes in the structure (Fig. 3).” In other words, there is only one unique {00ℓ} direction in the
hexagonal system. Thus, this nanocrystal cannot be lonsdaleite. Furthermore, there is reason to
believe that the identification of nanodiamonds in Greenland ice could not be reproduced by the
Kurbatov group (Section 13.4).
Sweatman’s (2021, p 11) remark above about “scaling diffraction patterns” misleadingly
implies the scaling was performed to achieve a better match of the pattern to graphene/graphane
than lonsdaleite. Daulton et al. (2010, p 16044) clearly wrote in the caption of their figure 3,
“Peaks measured from the doubled diffraction lines in Fig. S2B of Kennett et al., [(2009b)] are
shown (we calibrated the reported {100} reflection to 2.189 Å, and the line widths represent the
error in our measurement).” The length scale of the diffraction pattern was calibrated by
assuming the diffraction ring labeled {110} by Kennett et al. (2009b) was the (110) reflection of
lonsdaleite at 1.260 Å (Table 9). This ring was selected because it had the strongest intensity of
those rings that did not overlap with other rings. This calibration set the ring labeled {100} at
2.189Å, very close to its predicted value (Table 9). Despite calibrating the pattern with the
initial assumption that the diffraction lines were from lonsdaleite, the diffraction lines more
closely matched that of graphene/graphane.
One point Sweatman (2021) correctly stated is that the polycrystalline diffraction pattern
shown in figure 8 of Sweatman (2021) (originally from Kennett et al., 2009b, and Figure 4 of
this review) does appear “fuzzy”. However, it contains a wealth of structural information.
Specifically, the diffraction pattern is azimuthally asymmetric with partial and double rings of
variable width (i.e., “fuzzy”), which indicates heterogeneity in the form of texturing. Texturing
(defined as a distribution of crystallographic orientations of polycrystalline grains, in which all
possible orientations do not occur with equal probability) can produce asymmetric ring intensity.
Sweatman (2021, figure 8 caption) attributes the pattern to texturing of lonsdaleite by stating,
“The axial asymmetry in this diffraction pattern, highlighted by the ellipses can be explained by
a non-uniform distribution of crystal grain orientations.” However, texturing of single-phase
lonsdaleite can be ruled out because this diffraction pattern completely lacks intensity from many
(not just one) lonsdaleite reflections including, but not limited to, the (101) at 0.193 nm, (102) at
0.150 nm, and (202) at 0.096 nm. Furthermore, the lonsdaleite (202) reflection is predicted to be
similarly as intense as the (200) reflection (Table 9). Kennett et al. (2009b) indexes a diffraction
ring as lonsdaleite (200) (Figure 4 and original source). If the grain is lonsdaleite, and the (200)
diffraction ring has sufficient intensity to be visible, so should the (202) diffraction ring have
sufficient intensity to be visible. There is no hint of diffraction intensity from the lonsdaleite
(202) (Figure 4). The (203) lonsdaleite reflection is predicted stronger than the lonsdaleite (210)
and Kennett et al. (2009b) identify a visible diffraction ring as lonsdaleite (210). If this
identification is correct, the lonsdaleite (203) reflection should have sufficient intensity to be
visible as well, but it is missing. However, Sweatman (2021) misleadingly implies Daulton et al.
(2017a) claims only one reflection, the (102), is missing despite Daulton et al. (2017a, p 15)
stating, “there are many missing lonsdaleite reflections.” The set of missing reflections indicate
the grain cannot be lonsdaleite unless a highly fortuitous and improbable texturing geometry is
present (and further implausible that this is the case for every aggregate that was examined). On
the other hand, the observed diffraction lines more closely match that of a mixture of graphene
and graphane having an unremarkable texturing geometry.
Figure 4. [COLOR] A) The transmission electron diffraction pattern from figure S2 (part B) of
Kennett et al. (2009b). We modified the diffraction pattern from the original published by
Kennett et al. (2009b) by inverting its contrast to aid in visual clarity (white – no diffraction
intensity, darker grey scale indicates higher intensity) and by superimposing additional
annotations on the pattern. A scale bar in units of d-spacing (nm) is superimposed over the
needle blocking the non-diffracted beam. Two rings indicate a region of interest (ROI) defined
between 0.9937 to 0.9381 nm (d-spacing) where the (202) lonsdaleite reflection would occur.
That region is devoid of any detectable diffraction peaks/intensity. All adjustments of the
brightness, contrast, and gamma of the image’s grey-scale look up table (LUT) did not reveal
any intensity features within the ROI. B) The same diffraction pattern displayed using a
topological unroll mapping where the polar coordinates (r, ) are mapped to Cartesian
coordinates (x = r, y = ). To take into account the large dynamic range across scattering angles,
the gamma of the LUT varied with scattering radii following a power law with exponent 2.5 (see
lower scale bar). Newton rings in the diffraction pattern image, presumably created when the
original TEM film negative was scanned, appear visible after the LUT enhancement. The
predicted lonsdaleite reflections are denoted by the vertical lines (see Table 9). No discernable
diffraction peaks are present at the radii corresponding to (101) or (202) lonsdaleite reflections.
Sweatman (2021, p 11) subsequently stated, “one potential resolution of this data is that
lonsdaleite-like crystals in question have a disordered sequence of AB and ABC layers.” A
disordered diamond polytype stacking structure would have diffraction contributions from 2H
diamond lamellae as well as 3C diamond lamellae. Thus, it would have more reflections than
expected for 2H diamond, not less. Consequently, a disordered diamond stacking structure
would be inconsistent with figure 8 of Sweatman (2021) since that diffraction pattern is missing
many 2H diamond reflections.
Kinzie et al. (2014, p 492) perplexingly conclude after discussing their measurement of the
purported (100) lonsdaleite spacing of the same grain Daulton et al. (2010) demonstrated was
missing 2H diamond reflections, “Although the lonsdaleite-like crystals may be some other
unknown carbon-based mineral, there is no current evidence that excludes the possibility that it
is lonsdaleite.” However, this is because Kinzie et al. (2014) also ignore and fail to address the
missing 2H diamond reflections. Further, we object to the term “lonsdaleite-like” first used by
Kinzie et al. (2014) and subsequently used by Sweatman (2021) to replace the word
“lonsdaleite” when describing certain materials in the purported YDB (see also Section 12.7);
either the mineral phase is hexagonal 2H diamond or it is not. The term “lonsdaleite-like” by
definition would encompass any material with similarities to lonsdaleite. To demonstrate the
absurdity of the term “lonsdaleite-like,” consider that electron diffraction and elemental
composition are among the primary observables in electron microscopy. Thus, in the context by
which the “lonsdaleite-like” is used by Kinzie et al. (2014) and Sweatman (2021), that of phase
identification by electron microscopy, graphene/graphane aggregates can certainly be termed
“lonsdaleite-like.”
Independent studies (including those of impact proponents) have confirmed
graphene/graphane aggregates that resemble lonsdaleite are present in YDB sediments (Madden
et al., 2012; van Hoesel et al., 2012; Kinzie et al., 2014; Bement et al., 2014; van Hoesel, 2014)
and these studies (with the exception of Kinzie et al., 2014) have also failed to observe
lonsdaleite. Furthermore, if one accepts Sweatman’s (2021) argument that the diffraction pattern
of the purported lonsdaleite grain shown in Kennett et al. (2009b, figures 2a-2c, S2b), Kinzie et
al. (2014, figure 15), and Sweatman (2021, figure 8) is too “fuzzy” to definitively identify the
specimen as a polycrystalline aggregate of graphene/graphane, then conversely it must be too
“fuzzy” to definitively identify the specimen as lonsdaleite. This is an example of the selfinconsistent
arguments frequently presented by impact proponents.
Sweatman (2021, p 11) also wrote, “Moreover, Kinzie et al. (2014) provide further evidence
of Lonsdaleite-like crystals from two caves, Sheriden and Daisy, in North America, and this data
is not contested by Daulton et al., [(2017a)].” As discussed in Daulton et al. (2010, 2017a), a
single zone axis diffraction pattern (or high-resolution phase-contrast image) from a nanocrystal
is insufficient to base conclusive mineral identification. In fact, Kinzie et al. (2014, p 485)
wrote, “By themselves, SAD [selected area diffraction] patterns are insufficient to identify NDs”
and this statement is quoted in Daulton et al. (2017a). Therefore, the Sheriden and Daisy data is
inconclusive for the identification of lonsdaleite.
Regarding the identification of Lonsdaleite, Kinzie et al. (2014) state;
"Because many new, very hard forms of carbon have been discovered within the past few decades, these crystals may be some unidentified, diamond-like carbon allotrope. Therefore, we consider the identification of lonsdaleite to be provisional, pending further work.”
and
"Multiple measurements with a calibrated beam (diamond standard) attained an accuracy of approximately 1%, producing a range of ≈2.16–2.20 A° for the 2.18-A° d-spacing. We also measured d-spacings for commercial graphene and were able to easily distinguish between the d-spacings of 2.18A° for the lonsdaleite- like crystal and 2.13 A° for graphene, eliminating both graphene or graphane as candidates."
and
"The EDS analysis indicates that the ball is composed almost solely of carbon, while HRTEM confirms that the matrix is amorphous and studded with a mix of NDs, including one n-diamond star-twin (2.06 A°) and one lonsdaleite-like crystal (2.18- and 1.93-A° d-spacings). We compared that 2.18-A° spacing to the similar 2.13-A° d-spacing for graphene and found that we were able to distinguish them, making it highly unlikely that any of these lonsdaleite-like crystals are graphene."
Thus, these samples are clearly not graphene, but Daulton et al. (2017) argue they could still be a mix of graphane and graphene, since the layer spacing for graphane is increased relative to graphene. Ultimately, to definitively show the lonsdaleite samples are correctly identified, an EELS spectrum or EFTEM is needed to distinguish sp3 from sp2 bonding. This was the conclusion in Sweatman (2021).
See also section 12.3 below.
12.3. Controversial ‘n-diamond’ and ‘i-carbon’
One important point to clarify is that the majority of the reported YDB nanodiamonds is
not diamond, but rather are a controversial modified form of diamond termed “n-diamond”
(Kennett et al., 2009a,b; Kurbatov et al., 2010; Israde-Alcántara et al., 2012; Kinzie et al., 2014;
Bement et al., 2014) and another controversial form of carbon, termed “i-carbon” (Israde-
Alcántara et al., 2012; Kinzie et al., 2014). While neither is a diamond polytype, and their
existence, identification, as well as structure are debated, impact proponents describe them as
nanodiamonds (Kennett et al., 2009a,b, Kurbatov et al., 2010, Israde-Alcántara et al., 2012,
Kinzie et al., 2014, Bement et al., 2014). In YDB sediments, n-diamonds are usually reported at
significantly higher abundances than diamond (Israde-Alcántara et al., 2012, Bement et al., 2014;
Kinzie et al., 2014), and occur at 22 out of 24 purported YDB sites (see table D2 of supplemental
materials of Kinzie et al., 2014). In fact, at 14 of those 24 purported YDB sites, n-diamonds but
not diamonds are reported. Following n-diamond, i-carbon is reported as the next most
abundant. In all but two purported YDB sites where n-diamonds are reported, i-carbon is also
reported. To emphasize our point, we will use ‘nanodiamond’ to refer to predominantly ndiamond
and i-carbon along with minor amounts of diamond, if any.
Nemeth et al. (2016) show that it is likely all these different nanodiamond polymorphs are actually just twinned cubic diamond or cubic nanodiamond with finite thickness. So, once again, no evidence is provided here against the identification of nanodiamonds in the YDB.
The next section, 12.4, in Holliday et al. focusses on carbon spherules rather than the identification of nanodiamonds, and is therefore irrelevant and omitted.
12.5. ‘Nanodiamond’ misidentifications
Daulton et al. (2010, 2017a) examined acid residues of YDB sediments and YDB carbon
spherules for nanodiamonds and did not observe diamond (or C phases consistent with the
debated n-diamond and i-carbon). Sweatman (2021) attempted to discredit these critical studies
by erroneously claiming the wrong specimens were collected and wrong locations were sampled.
Let's see.
Regarding the samples Sweatman (2021, p 9) wrote, “Daulton et al. (2010) were unable to
reproduce these results [observation of nanodiamonds] but this was very likely due to collection
of incorrect samples. Kennett et al. (2009b) reported nanodiamonds inside or adhered to specific
kinds of glassy carbon particles, such as carbon spherules and glassy carbon ‘elongates’.
However, Daulton et al. (2010) analyzed microcharcoal aggregates from Murray Springs, which
are not expected to contain any nanodiamonds.” Microcharcoal was not the only material
studied by Daulton et al. (2010). They also examined carbon spherules as well as glassy carbon,
and later acid residues of YDB dated sediment (Daulton et al., 2017a); microcharcoal was
examined to be thorough given that impact proponents claim YDB nanodiamonds were formed
through a process “identical to the commercial process for producing activated charcoal”
(Kimbel et al., 2008, see also Kinzie et al., 2014; Wolbach et al., 2018b).
Nevertheless, Daulton et al. (2010) still failed to collect the correct samples from the YDB. Let's see.
Regarding the field
sites, Sweatman (2021) wrote, “…Wittke et al. (2013b) and Kinzie et al. (2014) show… that
Daulton et al. (2010) did not, in fact, sample the same site as Kennett et al. (2009b) at Arlington
Canyon.”
The same AC003 site of Kennett et al. (2009b) was sampled (Section 4.1), and no ‘nanodiamonds’
were observed by Daulton et al. (2010, 2017a,b) in YDB-dated materials from Arlington Canyon.
This seems to be deliberate obfuscation. The same AC003 site was sampled by Daulton et al., but only in later papers (Daulton et al. 2016/2017). And while Daulton et al. (2010) might have sampled a site in Arlington Canyon, it is clear they did not sample the same AC003 site as Kennett et al. (2009b). So the above text seems to be phrased deliberately to be misleading.
This matter is discussed in detail in section 4.1 of Holliday et al. which is inserted here for convenience.
-----------------------------------------
4.1. Arlington Canyon Confusion
Wolbach et al. (2020, p 97) falsely allege, "[Daulton et al., 2017a] claim to have analyzed
samples [for nanodiamonds and found none] from the YDB layer provided by Pinter et al.
(2011). However, figures 3 and 4 of Pinter et al. reveal that not a single sample was acquired
from 12,800-y-old strata and instead, samples were acquired up to thousands of years younger
and older, completely missing the YDB-age layer." Pinter et al. (2011) show sediment logs of
Sauces Canyon and Verde Canyon in their figures 3 and 4, respectively, to demonstrate magnetic
grains and spherules are present throughout those sequences rather than only at the YDB. They
clearly state on p 258 that microcharcoal from Murray Springs and carbon spherules from
Arlington Canyon (both dated to the YDB) were examined for nanodiamonds.
Ok, let's look at the details of Pinter et al. (2011) to see where those "carbon spherules from Arlington Canyon ... examined for nanodiamonds" were obtained. Actually, Pinter et al. (2011) is a review article;
"The reports of nanodiamonds in YDB sediments (Firestone et al., 2007a; Kennett et al., 2009a,b) lacked a number of key details (e.g., see above) and left many unanswered questions regarding the nature and occurrence of the nanodiamonds. For this reason, Daulton et al. (2010) performed a detailed TEM microcharacterization of carbonaceous materials (carbon spherules, microcharcoal, and glassy carbon) from YDB black mats and other dated sources (see Table 1) to independently address the question of nanodiamonds in YDB sediments and in sediments of other ages. In that work, microcharcoal aggregates were isolated from the base of black mat sediment layer at the same locality (Murray Springs) reported to contain cubic nanodiamonds (Kennett et al., 2009a), and carbon spherules were isolated from the same area (Arlington Canyon, Santa Rosa Island, CA) reported to contain hexagonal nanodiamonds (Kennett et al., 2009b)."
Clearly, we need to read Daulton et al. (2010) to find out where those Arlington Canyon samples were obtained. In fact, this is dealt with by Holliday et al. next...
Wittke et al. (2013a, supplemental materials) incorrectly assert that Scott et al. (2010; 2017)
and Daulton et al. (2010; 2017a,b) sampled the wrong localities at Arlington Canyon.
This is clearly obfuscation. How can Wittke et al. in 2013 incorrectly assert that Scott et al. in 2017 and Daulton at al. in 2017 sampled the wrong localities. After all, they are not time travellers!
This
flawed assertion was echoed by Kinzie et al. (2014), Sweatman (2021), and Powell (2020, 2022).
Let's see.
Kinzie et al. (2014, p 477) wrote, “Their incorrect stratigraphic locations apply to all those
investigations, explaining their inability to detect YDB NDs [nanodiamonds], cosmic- impact
spherules, and ND-rich carbon spherules at Arlington Canyon.” In Sweatman (2021) much of
the ‘discussion’ of the non-reproducibility of the nanodiamonds focuses on this incorrectly
perceived misidentification of sampling localities rather than addressing any of the substantive
criticism (similar to the approach taken in dismissing the many critical problems of dating
documented by Meltzer et al., 2014; Section 5.3).
Still no evidence is provided against nanodiamonds at the YDB. Will we ever get to the point?
Impact proponents make much of the spatial
coordinate problem that was in fact due to a failure by Kennett et al. (2009b) to state the
associated Datum. For example, Sweatman (2021, p 9) not only reproduces criticisms that had
already been addressed but failed to understand what was said.
They had not been addressed. Let's see.
“Wittke et al., [2013a] and Kinzie
et al. (2014) show… that Daulton et al. (2010) did not, in fact, sample the same site as Kennett et
al. (2009b) at Arlington Canyon – instead their samples with labels SRI-09 were obtained from
several different locations separated by up to 7000 m from the site sampled by Kennett et al.
(2009b). Scott et al. (2017), with Daulton as co-author, later refuse to admit this error, pointing
to photographs that show that they did indeed sample the same sediment bank as Kennett et al.
(2009b).”
Just so that it is clear what is being debated here, the original samples are described in Daulton et al. (2010). "Carbon spherules were isolated from the same locality (Arlington Canyon, Santa Rosa Island, CA) reported to contain hexagonal nanodiamonds (16). Kennett et al. (14, 16) dated the entire basal 5 m of the Arlington YD sequence within the 1σ range 13,100–12,830 cal yr B.P. and reported nanodiamonds in the deepest meter thick layer (16). In contrast, we obtained calibrated radiocarbon dates spanning >5;000 years over that same 5-m sequence. From that sequence, we examined two specimens for nanodiamonds (from the lowest meter) dating to 12,766–13,044 and 13,379–13,560 cal yr B.P. (1σ range)."
The table below is also provided by Daulton et al. (2010)
From this, it is clear that the only Arlington Canyon samples examined for nanodiamonds by Daulton et al. (2010) are those labelled SRI-09-028 and SRI-09-29c.
The precise location of those samples is given in the supplementary information of Scott et al. (2010). Note that Scott et al. (2010) does not examine any samples for nanodiamonds - they are interested only in the identification of carbon spherules. Precise UTM coordinates for these two samples examined for nanodiamonds in Daulton et al. (2010) are provided.
Wittke et al. (2013) provide a map of the location of all the samples in Daulton et al. (2010) and Scott et al. (2010) (above). Note this map uses the specified coordinates and projection for each paper. The ones examined for nanodiamonds in Daulton et al. (2010) are points C and D above. Clearly, they are not the same location as the Kennett site. Nevertheless, Holliday et al. try to explain this discrepancy next.
Scott et al. (2017, p 44-45) clearly explained the situation, which we further clarify for emphasis.
“Arlington Canyon has featured centrally in results suggesting a global-scale
impact drove broad changes at the onset of the Younger Dryas (the YDIH). Wittke
et al., [2013a] assert that we did not study the same section as theirs (AC003).
This lacks precision. Specifically, Wittke et al. (2013) and others assert that Daulton et al. (2010) did not examine the same section as theirs (AC-003) for nanodiamonds.
This is not true.
Yes it is.
While Kennett et al. ([2008a], 2009b) gave UTM coordinates without
specifying the associated datum or map projection, we were able to navigate to [the
general area which we searched and found] their published location using the North
American Datum 1983 (NAD83) and found there the largest, best exposed, and
most accessible outcrop in Arlington Canyon. Later we surmised that Kennett et al.
([2008a], 2009b) had used NAD27 (confirmed in Wittke et al., [2013a]). We
subsequently measured, sampled, and dated the small section at that location.”
This is very vague. Which samples are they referring to here? We are only interested in the location of samples SRI-09. Perhaps I can suggest what happened. First Daulton et al. used the incorrect map projection (NAD83) to navigate to the Kennet et al. (2008,2009) site. But the coordinates for the Kennett et al. site were instead expressed in terms of the NAD27 projection. Therefore, the original samples, labelled SRI-09, obtained by Daulton et al. (2010) were from the wrong location. Then, later, Scott et al. (2010) used the correct map projection to locate the same site as Kennett et al. (2008,2009). But none of these new samples (with labels SRI-10 to SRI-13 etc) were examined for nanodiamonds - they simply examined carbon microspherules instead.
Further, Scott et al. (2017, p 37) explained:
“Wittke et al., [2013a] claim that ‘coordinates, photographs, stratigraphic
descriptions, and radiocarbon ages presented in their papers… conclusively
demonstrate that none of their samples collected were taken from the same
stratigraphic section studied by Kennett et al., [2008a].’ On the contrary, our
Locality III is identical to their locality AC003…
This is more obfuscation. Wittke et al. (2013) and Sweatman (2021) are clearly only interested in the samples labelled SRI-09 used by Daulton et al. (2010). We can agree that Locality III is identical to locality AC003, but no samples taken from Locality III were examined for nanodiamonds by Daulton et al. (2010).
Furthermore, material from AC 003 was sent to the
senior author in March 2007 by G. James West (via John
Johnson) with a request to report on the charcoal. Lithological logs of other
Arlington sections and radiocarbon data are given in Hardiman et al. (2016).”
This is not very clear, but presumably, we can interpret that samples from Kennett's AC003 site, which we know is the same as Locality III in Scott et al. (2010), were sent to the "senior author" (but who is this?) by G. James West (is this Allen West, a member of the Kennett et al. team?)
Sweatman may not be familiar with sedimentary logs nor their interpretation in a
geologic context. Sweatman’s (2021, p 9) misconceived argument is that explanation “is
misleading, as the site and samples depicted in these photos are all labelled SRI-10 to
SRI-13, whereas the relevant samples in Daulton et al. (2010) all have labels SRI-09. So
it is quite clear the nanodiamond samples in Daulton et al.… did not, in fact, come from
the same sediment bank sampled by Kennett et al. (2009b).” These comments show a
misunderstanding of sample numbering. ENDNOTE 5
Presumably, SRI stands for "Santa Rosa Island", the island from which these samples are taken. The designators 09, 10, 13, etc presumably indicate the year the sample was taken or analysed. Whatever, the sample name is less specific about the sample location than a grid coordinate. So this is yet more obfuscation.
Sweatman (2021, p 20) also asserts, “when attempting to reproduce purported evidence for a
cosmic impact, it is important that similar samples from exactly the same stratum at the same site
are taken. Daulton et al.’s (2010) search for nanodiamonds appears to be hamstrung by this issue,
an error these researchers seem determined not to admit…” (emphasis added). Scott et al. (2017,
figure S1) unambiguously establish that Scott et al. (2010; 2017) and Daulton et al. (2010;
2017a,b) sampled precisely the same section as field site AC003 of Kennett et al. (2009b).
First, let's be clear. Sweatman (2021) was specifically referring to Daulton et al. (2010), just like Wittke et al. (2013). But the above also refers to Scott et al. (2017) and Daulton et al. (2017a,b), muddying the water. Nevertheless, this is Holliday et al.'s best evidence for showing that the location of Daulton et al. (2010) SRI-09 samples is the same as the Kennett site. They suggest this evidence is in Figure S1 of Scott et al. (2017). In fact, that figure is just a smaller part of Figure 2 from the main text of their paper, shown below.
While this IS clearly the same location as the Kennet site, it does NOT list any of the samples SRI-09. Therefore, they do not provide any evidence that the samples examined for nanodiamonds in Daulton et al. (2010) came from the same site as the Kennett site. In fact, we know they didn't, because their coordinates show they didn't.
However, on the issue of other nanodiamond samples, Scott et al. (2017) also state "We examined three different specimen sets of carbonaceous spherules for the presence of nanodiamonds: (i) five spherules/fragments from SRI 09-28A; (ii) eight spherules/fragments from AC003; and (iii) 13 acid-washed spherules/fragments from AC003. For a detailed discussion on the interpretation of this evidence please refer to Daulton et al. (2016)."
We already know the samples SRI-09-28A are not from the Kennett site. But what are the other samples "from AC003" that they analysed? Presumably, these are the ones sent by G. James West (Allen West?), mentioned above. But which ones exactly are they? They refer to Daulton et al. (2016) for details, so let's look in there.
In Daulton et al. (2016) we read "Millimeter-scale carbonaceous spherules and/or their fragments were isolated from Arlington Canyon, Santa Rosa Island, California, sediments AC-003 (Kennett et al., 2008, 2009b) and SRI 09-28A from Locality III (Scott et al., 2016, 2010) that were dated to the YDB (12 800–13 100 and 12 718–13 079 cal a BP, respectively). Full details describing the collection/acquisition of those sediments are provided in Scott et al. (2016). Three different specimen sets were separately crushed between sapphire discs: (i) five spherules/fragments from SRI 09-28A; (ii) eight spherules/fragments from AC-003; and (iii) 13 acid-washed spherules/fragments from AC-003."
First, note that Daulton et al. (2016) are claiming that sample SRI-09-28A is from locality III, when the map coordinates given by Scott et al. (2010) show clearly that it is not. Either Daulton et al. (2010) is mistaken or this statement in Daulton et al. (2016) is wrong. A correction from Daulton et al. is needed to clarify this point.
Also, we must now read Scott et al. (2016) to find out the correct label and location for the "AC-003" samples. However, Scott et al. (2016) is the same as Scott et al. (2017); they are the same paper!
So, it seems that Scott et al. (2017) refers to Daulton et al. (2016), which in turn refers to Scott et al. (2016), which is the same as Scott et al. (2017). Thus, we have a circular cycle of references in which the sample names and locations for their "AC-003" samples examined for nanodiamonds are not identified, other than being sent by G. James West (Allen West?). Notably, Scott et al. (2016/17) does not discuss nanodiamonds further. So, let's look at Daulton et al. (2016) to see if it can enlighten us. In fact, Daulton et al. (2016) does not provide any further details of the sample names or locations for its samples.
So what does Holliday et al. or Daulton et al. (2016) have to say about nanodiamonds in these "AC-003" samples from Kennett et al. (2008,2009b)? Nothing interesting apparently, as it's not discussed further by Holliday et al.. However, Daulton et al. (2016) claim that they could not find any nanodiamonds in these samples. But it should be noted that they could also not find any nanodiamonds in the same samples from Lommel, Belgium, investigated by Tian et al. (2010) where definitive evidence via EFTEM is provided for their existence. To explain this discrepancy they state they did not perform an exhaustive search. Most likely, then, is that there is a flaw in Daulton et al.'s methodology, and this is the reason the could not find any nanodiamonds in any of their samples, either from Arlington Canyon or Lommel.
The main conclusion from we can draw from all this is that Daulton et al. (2010) did not sample the same site as Kennett et al. (2008,2009), just as Wittke et al. (2013) and Sweatman (2021) claimed. This is very clear. It is also clear that some statements in Daulton et al. (2016) are false, and that Holliday et al. are deliberately engaging in obfuscation to hide their error. It also seems that their analysis methods are suspect.
Daulton et al. (2016) should therefore be corrected and the original Daulton et al. (2010) paper should be retracted.
But even if it was not the “exactly the same stratum”, Sweatman’s (2021) assertion is ridiculous
because impact proponents claim that at the YD/GS-1 onset a layer of impact markers was
deposited across North America to Europe. If this were the case, then certainly an YDB-dated
layer containing those markers would have covered the entire island of Santa Rosa.
This is false. YDIH proponents have never claimed the YD boundary layer is continuous across several continents, and no evidence is provided to support this claim. Probably, Holliday et al.'s misunderstanding here is caused by their own misinterpretation of comments made by various authors that the YDB stretches across or "spans" several continents etc., but at no time has any YDIH proponent claimed the YDB is perfectly continuous. Of course, no such claim could ever be made, since the presence of the YDB will be influenced by a variety of local conditions. Thus, it is Holliday et al. who are being ridiculous.
Sampling methods used by YDIH advocates at the Arlington Canyon section are also
problematic. Clearly the proponents are unfamiliar with sampling in fluvial sediments or the
potential pitfalls in the interpretation of the data obtained from such sediments. All the sections
studied by the YDIH proponents are represented by a single set of vertical samples. There are no
lateral duplicates. In lacustrine sections this may be satisfactory as sediments are deposited in
horizontal layers. However, several observations may be made concerning the sampling at
Arlington Canyon in particular. 1) The section shows considerable facies variation, both
vertically and laterally (see Scott et al., 2017, figure 2). 2) Samples only 1m lateral to those
sampled would have given quite different results. This is clearly shown by the lateral duplicate
sampling performed by Scott et al. (2017, figure S4).
Nevertheless, this is not evidence against the presence of nanodiamonds in these sediments.
3) Obtaining quantitative data on the
carbonaceous material by quoting particles per unit weight is meaningless as the facies range
from pebble conglomerates to silty sands.
This is pedantry. What units would Holliday et al. prefer? The presence of nanodiamonds has still not been refuted.
In addition, charcoal particles break up during
processing making number-based quantification meaningless (Scott et al., 2017, figure S6).
Ok, so what units would Holliday et al. prefer? Are there any units at all they would be happy with?
4) No samples were obtained below the so-called YDB layer so the position of its base cannot be
fully determined. In addition, the “YDB layer” was not clearly documented to be a layer as no
lateral samples were collected nor was the layer unique in the section.
Again, this is Holliday et al.'s misunderstanding, as YDIH proponents do not claim a continuous layer. Presumably, the YDB "layer" at this location is highly re-worked due to turbulent flows of water (streams) down the canyon bed, which will tend to focus debris along the bottom of the stream bed. Also, the presence of nanodiamonds in these YDB-consistent sediments is still not refuted.
5) Some of the organic material was concentrated by fluvial processes (see figure S4 of Scott et al., 2017).
Exactly.
6) There are
many sections within Arlington Canyon that could have been studied (see Hardiman et al., 2016)
besides the one by Kennett et al. (2009b), but none of the other sections were examined by the
YDIH proponents. None of the features mentioned, therefore can be demonstrated to be unique
to the proposed “horizon”.
It's true, the YDB and other cosmic impact boundary layers might exist elsewhere on the island. But more extensive sampling requires a larger research project, which would require much more funding. But I expect such funding requests would be rejected by proposal reviewers such as Holliday et al. who would likely consider them frivolous. Moreover, do Holliday et al. expect Kennett et al. to sample the whole island? Or the whole continent? They are being ridiculous.
[End of inserted section 4.1]
---------------------------------------
Rather, within carbon spherules extracted from Arlington Canyon YDB-dated sediments,
Daulton et al. (2017a,b) observed graphene/graphane aggregates previously discussed, as well as
Cu and CuO2 nanocrystals that have identical diffraction lines as ascribed to n-diamonds and icarbon,
respectively, with plane spacing differing by ≈1%. Copper is present in sediments at
relatively high concentrations relative to those reported for ‘nanodiamonds’. Trace Cu is present
at 5-9 ppm in several-thousand-year old (preindustrial era) sediment deposits (DeLaune et al.,
2016), presumably in a range of minerals. In comparison, the ‘nanodiamond’ peak
concentrations in purported YDB sediments are claimed to have a smaller range of 66 - 493 ppb
(Kinzie et al., 2014 and supplemental materials). Sclerotia-forming fungi, such as Botrytis
cinerea and Sclerotinia sclerotiorum, utilize Cu to assist in infecting host plants (Saitoh et al.,
2010; Ding et al., 2020), and sclerotia are efficient biosorbents of Cu(II) (Long et al., 2017). The
mean concentration of Cu reported in sclerotia is between 43 and 152 ppm (Nyamsanjaa et al.,
2021). Impact proponents have reported carbon spherules containing as high as 600 ppm to 0.06
wt.% Cu (Firestone, 2009a; Firestone et al., 2010a). In comparison, the ‘nanodiamond’ peak
concentration in purported YDB carbon spherules is again claimed smaller, 10 to 3680 ppb
(Kinzie et al., 2014 and supplemental materials). Since the purported n-diamond and i-carbon in
YDB carbon spherules and sediments can be easily confused for the relatively more abundant Cu
minerals (Daulton et al., 2017a,b), the identification of the controversial n-diamond and i-carbon
is necessarily placed into question.
To further demonstrate that impact proponents most likely misidentified Cu and its oxides
as ‘nanodiamonds’ in sediments and carbon spherules (i.e., sclerotia), consider the international
patent application (Provisional US application No. 61/062,350 filed on Jan. 25, 2008; Patent
Cooperation Treaty No. PCT/US09/31731 filed Jan. 22, 2009), e.g., West and Kennett (2011,
2009a,b,c) to name a few. This patent is mentioned in Kimbel et al. (2008) and was submitted
by two major coauthors of the key papers on purported YDB ‘nanodiamonds’ (Kennett et al.,
2009a,b; Kurbatov et al., 2010; Israde-Alcántara et al., 2012; Kinzie et al., 2014; Moore et al.,
2020).
In addition to claiming a process for forming nanodiamonds during charcoal production,
the patent (West and Kennett, 2011, p 6) also claims the following process:
“[0070] A 3-mm-wide grid for observing samples in a transmission electron
microscope (TEM) was used. The grid was constructed of a thin copper support
structure with about 90-micron-square holes in it, and which supported an
approximately 50-nm-thick amorphous carbon film. Neither the copper nor film
contained diamonds originally. Next, a drop of dilute hydrochloric acid (HCl) with
a pH of 0.5 was deposited on the grid and immediately afterward, dried it at
atmospheric pressure and room temperature over a span of several minutes. [0071]
Upon viewing the grid by TEM, diamonds had grown as nanometer-sized fibers at
the junction of the copper and the carbon film. In some cases, the HCl had not dried
completely, and in those cases, the active diamond growth process was observed by
TEM. As observed, the diamonds writhed as if living, grew longer, became wider,
and some times several fibers coalesced into one large fiber. Within a few minutes,
the HCl dried and the diamond synthesis ceased. The process produced a large
number of nanodiamonds on a 3-mm-wide grid within minutes.”
Nanodiamonds were similarly claimed to form through the same process using a slightly
different solution (West and Kennett, 2011, p 6), “Carbon dust from charred coconut shells was
collected and tested to determine that it did not contain diamonds. Next, slurry was made by
combining the carbon with 0.5-pH HCl. Then, a drop of the carbon-HCl solution was added to a
3-mm-wide copper grid without a carbon film.”
Rather than forming diamond under nonsensical, by any standard, formation conditions for
diamond, it is far more likely the Cu of the TEM grid and its surface oxides were dissolved by
HCl, which then precipitated out as the solution evaporated. The reported nanowire growth
under the electron beam of the TEM instrument by West and Kennett (2011) may have involved
mechanisms similar to that investigated for Cu by van der Meulen and Lindstrom (1956), Glad et
al. (2020), and Hamdan et al. (2020). The West and Kennett (2011) patent application, now
apparently abandoned by its authors and based on experiments reported in Kimbel et al. (2008),
certainly place into question the credibility of all the results claimed in Kimbel et al. (2008).
Consequently, the identification of ‘nanodiamonds’ in key YDB ‘nanodiamond’ papers sharing
coauthors of Kimbel et al. (2008) are also placed into question: Kennett et al. (2009a,b),
Kurbatov et al. (2010), Israde-Alcántara et al. (2012), Kinzie et al. (2014), and Moore et al.
(2020).
The purpose of the lengthy section above in Holliday et al. is to suggest that YDIH proponents have mistaken copper or copper oxide crystals for nanodiamonds in all their samples. This is quite ridiculous because YDIH proponents use a range of experimental methods to confirm their samples are pure carbon. Moreover, their criticism has already been dealt with. For example, in Kinzie et al. (2014) we read "Some earlier ND work (Kennett et al. 2009a,2009b; Kurbatov et al. 2010) was conducted on copper grids, which were discontinued because of the similarity between the spacings of crystallographic planes (d-spacings) of copper and some NDs (Daulton et al. 2010). Those early samples on copper grids were subsequently reanalyzed on gold or molybdenum grids and with additional analytical techniques, such as EDS and energy-filtered TEM (EFTEM) that can differentiate carbon from copper particles. The results confirmed that the use of copper grids, although suboptimal, did not lead to the misidentification of YDB."
Did Holliday et al. not read this part of Kinzie et al.? It is very clear. It seems that Holliday et al. are very selective in their reading of YDIH proponent papers.
Thus, Holliday et al. have not provided any arguments that call the YDIH nanodiamond evidence into question. On the contrary, in Kinzie et al. (2014) we read "In summary, abundant NDs within or near the YDB layer have been reported by four independent groups (Redmond and Tankersley 2011; Tian et al. 2011; van Hoesel et al. 2012; Bement et al. 2014). In addition, NDs have been reported independently in three conference presentations (at Indian Creek, MT, by Baker et al. 2008; at Newtonville, NJ, by Demitroff et al. 2009; and at Bull Creek, OK, by Madden et al. 2012). These investigations independently confirm the presence of an ND abundance."
That is, nanodiamonds within the YDB have been confirmed by many independent research groups. This is the gold standard in science. If Holliday et al. (via Daulton et al.) cannot find them, they must be doing something wrong (e.g. using the wrong samples or not performing an "exhaustive search").
12.6. ‘Nanodiamond’ Concentration Spike at YDB
A compilation of all the available ‘nanodiamond’ evidence claimed to support the YDIH was
presented by Kinzie et al. (2014).
Yes, this is a key paper.
This included measurements of the ‘nanodiamond’
concentration at purported YDB sites using techniques based on electron microscope estimations
of implied modal abundances of diamond in crushed spherules, acid dissolution residues, and
melted ice. Kinzie et al. (2014) purport a spike in the nanodiamond concentration at the YDB at
multiple sites across the Northern Hemisphere. Sweatman (2021, p 9) wrote, “A coetaneous
abundance of nanodiamonds dispersed across a large area at Earth’s surface, therefore, is an
excellent proxy for a cosmic impact, especially in the absence of evidence for volcanism, such as
sulphate and tephra abundances.” Accurate dating of the stratigraphic record of the purported
YDB sites is problematic in many cases and reported ages have been questioned (see Section 5
and ENDNOTE 10). Thus, there is no clear indication that the YDB layer was sampled in many
of those sites.
The issue of site dating is dealt with separately. Still no evidence against an abundance of nanodiamonds at the YDB is provided.
More importantly, in a critical review, Daulton et al. (2017a) describe in detail the
microanalytical difficulties of identifying nanoparticles in acid residues of sediments and in
crushed carbon spherules (see also Section 12.4) and the difficulties in their quantification.
These experimental challenges render electron microscopy estimations of modal abundances of
diamond within those materials, as performed by impact proponents, technically
impractical/impossible (Daulton et al., 2017a).
This is false, for reasons that are given in Kinzie et al. (2014) and emphasized in Sweatman (2021). See also below.
Consequently, the reported high concentrations of ‘nanodiamonds’ at the YDB and complete (or near
complete) absence immediately above and below this level are completely unsupported.
Wrong. Let's see below.
The material recovered from crushed spherules or acid dissolution residues of sediments
contains a wide range of mineral species. Kinzie et al. (2014, p 480) state, “Typically, NDs
represent <50% of the residue, and the remaining non-ND residue can mask the NDs, thus
making them difficult to identify." The greatest limitation of the approach of Kinzie et al. (2014)
and others is that detailed laborious measurements must be performed on each individual
nanoparticle in order to correctly identify whether it is diamond or not.
This is absurd. A statistical method will suffice. Sampling every nanoparticle is not necessary at all.
Kinzie et al. (2014, p
480) acknowledge the experimental challenge of identifying nanodiamonds by writing, "In
addition, there are inherent difficulties and uncertainties in correctly identifying tiny crystals <2
nm in diameter.” They further state (p 485), “By themselves, SAD patterns are insufficient to
identify NDs, and so further investigations, such as those using HRTEM, FFT, EDS, and EELS,
were performed on these nanoparticles to confirm that they are NDs and not some other
mineral.” In their conclusions, Kinzie et al. (2014, p 500) specifically described their
methodology as “The identification of the isolated NDs involves two main methods, electron
microscopy imaging and electron spectroscopy, using up to nine imaging, analytical, or
quantification procedures: scanning electron microscopy, STEM, TEM, HRTEM, EDS, SAD,
FFT, EELS, and EFTEM. The entire procedure is labor-intensive and technically demanding.
Even so, it has proven to be effective and replicable by skilled independent groups based on the
processing of more than 100 samples.” However, Kinzie et al. (2014) perplexingly describe in
their supplemental materials (p 9), “. . . for the purpose of estimating abundances, we assumed
that all rounded particles were NDs. We also observed abundant amorphous carbon
nanoparticles, but almost none were rounded, and therefore, we discounted them. This
estimation procedure focused solely on the presence or absence of rounded particles.” The
methodology actually employed was stated only in the less accessible supplemental materials
and starkly contradicted the methodology Kinzie et al. (2014) described in their main text, which
is a troubling contradiction.
There is no contradiction here at all. All these statements are in accord with each other.
In this light, one could interpret the Kinzie et al. (2014) paper as deceptive.
Not at all. Only in your mind.
We reiterate that Kinzie et al. (2014) measured projected areal densities of “rounded
particles,” not necessarily nanodiamonds, and they certainly did not measure modal mass
abundances. This is a critical flaw, given that the acid-dissolution residues and crushed
spherules are not pure diamond and contain a multitude of different minerals.
Holliday et al. have omitted a crucial passage in the supplemental materials of Kinzie et al. (2014), one that was highlighted by Sweatman (2021), so they should be aware of it. In the section "Quantification of NDs" Kinzie et al. (2014) state "Base on multiple analyses, we observed that nearly all rounded nanocrystals are NDs (>99%) and are not other minerals, such as quartz, zircon and rutile. Therefore, for the purpose of estimating abundances, we assumed that all rounded particles were NDs." Thus, Kinzie et al. use a statistical method to ensure they almost always (>99%) count nanodiamonds and not other kinds of crystal. Moreover, given the very large numbers of nanodiamonds counted in each frame, using a statistical average for their mass abundance is fine. Only if their samples were small would such a statistical approach result in significant errors (which could still be quantified). So there is no basis to Holliday et al.'s criticism. Indeed, more perplexing is why Holliday et al. omitted this crucial sentence in Kinzie et al. (2014) when it was emphasized by Sweatman (2021).
For measuring ‘nanodiamond’ abundances Kinzie et al. (2014, supplemental materials p
10-11) estimated the area fraction of TEM grids that contained “rounded particles” in mounted
sediment acid residues and crushed carbon spherules. This is neither a measurement of mass or
even volume fraction of “rounded particles” in those specimens (see Daulton et al., 2017a).
It is when a sample of nanoparticles are used to define an average mass or volume per particle. See above.
Mass or volume fraction is needed to accurately determine abundance in the source specimen.
Of course, and this can be measured statistically using a sample. Are Holliday et al. claiming that a full suite of measurements must be made on every individual nanoparticle observed in their scans, presumably numbering in the 10s of thousands. This is just absurd. Holliday et al. seem to have no conception of how sampling can be used to obtain reliable estimates for a population, a basic scientific method.
Instead, the area fraction on TEM grids was normalized by the mass fraction of recovered
residue from processed sediment and the mass fraction of carbon spherules from 1 kg of
sediment, respectively. Using the latter must necessarily assume that all carbon spherules
contained “rounded particles”, but the fraction claimed to contain ‘nanodiamonds’ significantly
changes in different impact proponent publications (Section 12.7).
Kinzie et al (2014) use a consistent sampling method throughout.
It is worthwhile noting that nanodiamonds isolated by acid dissolution from sediments at
the KT boundary and inferred associated with the Chicxulub impact, are not reported rounded.
Carlisle and Braman (1991, p 708) wrote, “3-5 nm in size and, wherever any morphology could
be discerned, octahedral in form”. Gilmour et al. (1992, p 1624) wrote, “~6 nm in size and
vary in morphology from irregular to near -cubic crystals.” Hough et al. (1997, p 1020)
wrote, “polycrystalline diamond aggregates ranged from 1–30 μm and some displayed a
hexagonal platy shape (Fig. 2A), which may indicate that graphite was the precursor carbon
material. Individual diamond crystals in these aggregates, have grain sizes in the range 0.1 to 1
μm.” In contrast to these descriptions, Kinzie et al. (2014, p 491) wrote, “in most cases, YDB
NDs [consisting mostly of n-diamond and i-carbon, Section 12.3] are rounded to subrounded”,
which by the way is consistent with the rounded morphology of Cu nanocrystals observed in
carbon spherules by Daulton et al. (2017a, figure 9).
As already stated, they sampled the rounded nanoparticles using a suite of diagnostic measurements to confirm they are nearly all (> 99%) nanodiamonds.
Of all the YDB sites, three sites should, by all reason, potentially offer the most compelling
‘nanodiamond’ concentration profile measurements: two with the highest purported
‘nanodiamond’ concentrations (Bull Creek, Oklahoma and Lubbock Lake, Texas), and one with
the most detailed concentration measurements (Arlington Canyon, California). Instead, the
results published by the YDIH proponents further illustrate that those measurements are
unreliable.
Let's see.
Bull Creek, Oklahoma was one of the early sites where ‘nanodiamonds’ were purported, with
a spike in the ‘nanodiamond’ concentration of 100 ppb at the YDB (Kennett et al., 2009a). In a
subsequent study of the same section, Bement, a coauthor of Kennett et al. (2009a), purported a
three order-of-magnitude larger 'nanodiamond' spike of 190 ppm (Bement et al., 2014) that was
higher than that purported at or around the YDB of all other sites (see Kinzie et al., 2014).
However, this ‘nanodiamond’ peak was purported in sediments older than the YDB (Table 5,
also Section 5.5).
It is not statistically older, i.e. it is within error bounds, so this is fine.
Nevertheless, subsequent attempts by the Bement group to further study the
YDB ‘nanodiamonds’ at Bull Creek were unsuccessful because – in the same ‘nanodiamond’
sediment isolate previously purported to contain ‘nanodiamonds’ (Bement et al., 2014) – the
‘nanodiamonds’ could not be found (Sexton, 2016). Sexton (2016) is a thesis where L. Bement
and A. Madden, coauthors of Bement et al. (2014), were thesis advisors.
This is a short Masters thesis that, with all due respect to Rebecca Sexton, would probably not meet the required standards for publication in a refereed journal. All academics will appreciate the considerable resource issues of supervising MSc projects, so this can hardly be counted as strong evidence. Even so, Sexton's conclusions have been misrepresented by Holliday et al.. Regarding the detection of nanodiamonds using Raman spectroscopy, Sexton could not observe nanodiamonds at all, either in any samples from Bull Creek or in a commercial sample of nanodiamonds. Clearly, the failure of the calibration experiment with commercial nanodiamonds indicates these experiments are not reliable for detection of nanodiamonds. Regarding her analysis with TEM and the absence of nanodiamonds in a YDB sample that had previously been shown to contain nanodiamonds by Bement et al. (2014), Sexton's account is lacking in many of the usual details in published work, and the absence of nanodiamonds is explained in terms of storage of the sample for 5 years in ammonia hydroxide. Bement et al. clearly showed in 2014 that the sample did contain nanodiamonds originally.
Following publication
of Sexton (2016) and citation of that study by Daulton et al. (2017b), impact proponents (e.g.,
LeCompte et al., 2018; Wolbach et al., 2018b supplemental; Wolbach et al., 2020; West et al.,
2020a; Powell, 2020, 2022; Sweatman, 2021) continue to claim the results of Bement et al.
(2014) support the YDIH. No impact proponent has cited Sexton (2016), including Powell
(2022) who cites Daulton et al. (2017b) and thus, must clearly be aware of Sexton (2016) and yet
he still cites the irreproducible results of Bement et al. (2014).
Probably, this is because Sexton (2016) is a short MSc thesis probably not of publishable quality with many short-comings, not a peer-reviewed article. However, it seems this is the best evidence Holliday et al. can muster.
The Bull Creek results also illustrate a characteristic shared among many YDIH proponent
papers: self-inconsistency and circular arguments. Bement et al. (2014) also reported a high 190
ppm concentration of nanodiamonds in each of two adjacent levels in modern to Late Holocene
sediments, which must be viewed as unreliable in light of Sexton (2016) and, as discussed, the
inappropriate TEM methodologies utilized.
Rather, the results of Sexton (2016) are likely unreliable. We should be discussing high quality evidence. Remember, nanodiamonds at the YDB have been reported independently by many research groups.
Nevertheless, Kinzie et al. (2014, p 478) accepts
these concentration peaks as accurate and wrote, “In addition, Bement et al. (2014) observed an
ND abundance peak of similar amplitude to their YDB peak in two contiguous samples of late
Holocene surface sediments (0–10 and 10–20 cm below surface). They suggested that this
younger ND peak may have been produced by a nearby cosmic-impact event within the past
several thousand years.” In an example of self-inconsistency Kinzie et al. (2014, p 483)
misleadingly wrote “our group and others have measured marker abundances [including
‘nanodiamonds’] in several stratigraphic profiles that span as much as the past 30,000 yr. These
proxies reached maximum abundances only in the YDB layer and are not known to peak
individually or collectively anywhere else in that span [emphasis added], making the YDB
highly unusual.”
It is not clear how this refutes the presence of a nanodiamond abundances in the YDB? Do Holliday et al. actually have any good evidence for their case at all?
In an example of circular reasoning LeCompte et al. (2018, p 165) claimed, “If
nanodiamonds could be produced in natural fires, they should be common and ubiquitous in
sediments of all ages, but instead, they range from nonexistent to extraordinarily rare, being
found in high abundances only in known or proposed [emphasis added] impact-related
sedimentary layers…” The flawed logic is that if one assumes any ‘nanodiamonds’ in sediments
were formed by impact, then one will misconstrue ‘nanodiamonds’ are only found in known or
proposed impact-related sediments, and hence the ‘nanodiamonds’ must be formed by impact.
The issue here is whether nanodiamonds are produced by natural wildfires. LeCompte et al.'s (2018) argument, which is very sensible, is that if they were, then they would be ubiquitous since wildfires are very common. Instead, nanodiamonds are extremely rare, thus ruling out wildfires. Indeed, they are limited to discrete boundary layers typically associated with cosmic impacts, including the K-Pg boundary. Given we already know that an impact occurred at Abu Hureyra where microspherule evidence alone confirms an impact, and nanodiamonds also appear in the YDB there, we should conclude that nanodiamond abundances are also a good diagnostic for cosmic impact at the YDB.
A further indication of the unreliability of the nanodiamond concentration measurements is
found in a study of the Lubbock Lake archaeological site in northwest Texas (Johnson, 2012;
Holliday et al., 2016). In 2007, a blind study of a stratigraphic section sampled across the YDB
at Lubbock Lake was performed by two independent groups (Surovell and Kennett) for joint
publication (see Sections 10 and 14). Only the Kennett group attempted the measurement of
‘nanodiamond’ concentrations, reported by Holliday et al. (2016). They reported a dramatic
‘nanodiamond’ spike with near complete absence of ‘nanodiamonds’ in other levels they
analyzed. Again, the concentration purported for the ‘nanodiamonds’ was no less extremely
high (3000 ppb) relative to that at all other global YDB sites (66 - 493 ppb) where
‘nanodiamonds’ had been measured (Kinzie et al., 2014), and second only to Bull Creek
(Bement et al., 2014). Given that the Bull Creek measurements were not reproducible (Sexton,
2016), Lubbock Lake then becomes the highest purported ‘nanodiamond’ concentration of all
YDB sites. However, the concentration spike at Lubbock Lake occurred at a stratigraphic level
dated ≤11.5 cal ka BP, at least 1300 years younger than the YDB.
I agree, this is the only study, among hundreds, with evidence that contradicts YDIH. It should be repeated, as stated in Sweatman (2021).
As noted previously, Sweatman (2021, p 9) claimed that coetaneous YDB nanodiamonds
“across a large area at Earth’s surface…is an excellent proxy for a cosmic impact.”
Correct.
However, in
addition to numerous unresolved issues of dating purported YDB layers (Section 5),
We shall come to this in another blog post.
‘nanodiamond’ concentrations as reported by impact proponents are not coetaneous even at the
local scale of a single purported YDB site. Arlington Canyon is the one site where the
concentrations of n-diamonds, 3C polytype nanodiamonds, and 2H polytype nanodiamonds were
individually purported (Kennett et al., 2009b, table S1). The concentrations of n-diamonds in
carbon spherules and in ‘elongated’ variety of carbon spherules were separately measured. They
are not reported with broad distributions that overlap, but rather entirely different with well defined,
disparate peak positions. In carbon spherules, n-diamond concentrations peak at 480-
485 cm and at 493-498 cm below surface. In elongated carbon spherules, n-diamond
concentrations peak at 392-396 cm and at 498-503 cm below surface. Also in elongated
spherules, nanodiamonds of the 3C polytype are purported only at 383-386 cm below surface.
The 2H polytype nanodiamonds peak at 459-463 cm below surface. If these nanocrystals were
all formed by a single impact event, why would their concentrations peak at different
stratigraphic levels, and why do the n-diamonds have different bimodal peaks depending on
slight variations in their host grains?
As already mentioned, Arlington Canyon is expected to have experienced considerable turbulence and re-working of sediments. The issue is whether the samples from the purported YDB layer are of YDB age. This will be covered in a later blog post.
Sweatman (2021) also makes coetaneous claims for other
purported impact markers, but many do not overlap in their stratigraphic levels (see Daulton et
al., 2017a).
No evidence is provided here that refutes the YDIH at all. Of course, different impact proxies can take different routes through the environment to their final resting place.
12.7. Redefinitions of ‘nanodiamond’-related markers
In response to challenges to their results and claims, YDIH proponents progressively
redefine (see also Section 10) and then draw back the evidence in subsequent publications.
Firestone et al. (2010a, p 35) first wrote, “Many carbon spherules contained nanodiamonds
which are clear evidence of production during an impact.” After the identification of
‘nanodiamonds’ (including lonsdaleite) was challenged by Daulton et al. (2010), the relative
proportion of carbon spherules containing ‘nanodiamonds’ was significantly reduced.
This is not inconsistent, since "many" is not numerically defined.
Kinzie et
al. (2014, p 483) wrote, “For carbon spherules, 111 of 153 samples investigated (73%) contained
no detectable NDs.” However, the supplement materials of Kinzie et al. (2014, p 5) reduced
without explanation the fraction of carbon spherules with nanodiamonds further, “only a small
fraction of carbon spherules contains NDs (average ≈5%; range ≈2% to 19%).”
Yes, I agree, this seems to be inconsistent and an explanation is needed. But it also seems a bit pedantic. It certainly does not refute the existence of nanodiamond abundances in the YDB.
In addition,
Kinzie et al. (2014, p 475) redirected discussion of lonsdaleite to a vaguely-redefined
hypothetical mineral.
This criticism is itself too vague to be of interest.
In their abstract they wrote, “Observed ND polytypes include cubic
diamonds, lonsdaleite-like crystals [emphasis added], and diamond-like carbon nanoparticles,
called n-diamond and i-carbon.”
Indeed they did. It is true that the identification of specific nanodiamond polymorphs is challenging, and this is an active research area. As already stated, Nemeth et al. (2016) show that all these "different" polymorphs are probably just twinned cubic nanodiamond.
In addition to carbon spherules, Kennett et al. (2008a; 2009b) claimed similar but
morphologically distinct carbonaceous materials, termed carbon elongates, were also present in
YDB sediments at greater concentrations than carbon spherules. Carbon elongates were also
purported to host ‘nanodiamonds’ at over an order of magnitude higher ppb concentrations than
carbon spherules (Kennett et al., 2009b). One difficulty with the YDIH is that if ‘nanodiamond’-
containing carbon spherules and carbon elongates were formed by the same event, why were
they reported with disparate concentration profiles in the sediments (Section 12.6).
Perhaps because they formed through different mechanisms? It would be helpful to know why this was done, but still no evidence against an abundance of nanodiamonds in the YDB is presented.
Scott et al.
(2010) challenged the identification of carbon elongates and carbon spherules by YDIH
proponents. Afterwards, Kinzie et al. (2014) made no reference to carbon elongates in the main
text, but discussed carbon spherules at length. Based on a comparison of purported
concentrations in supplemental table D of Kinzie et al. (2014) and table 3 of Kennett et al.
(2009b) it appears Kinzie et al. (2014), with Kennett as coauthor, reclassified the purported more
abundant and more ‘nanodiamond’-enriched carbon elongates as carbon spherules. However, no
explanation is provided for this reclassification. The reclassification seemingly removes the
problem that several markers have different concentration profiles in the sediments. However,
the new, redefined singular marker has a problematic purported bimodal distribution in the
sediments. More importantly and despite that reclassification, impact proponents still purport
that differences in the morphology of these carbonaceous materials correlated to differences in
their purported ‘nanodiamond’ concentrations as well as their concentration profiles within the
sediments (Kennett et al., 2008a; 2009b), and this is difficult to reconcile with them all being
formed by a single abrupt event.
No evidence is provided to support this statement. As stated above, they could be formed from different but related impact processes or different initial materials with different pathways through the environment. Still no evidence is provided against an abundance of nanodiamonds in the YDB.
The section on 'diamondoids' that follows does not concern nanodiamond abundances at the YDB boundary, and so is omitted. It is irrelevant.
Summary
This section of Holliday et al. is a perfect example of a Gish gallop. Their arguments invariably depend on many kinds of absurd or spurious reasoning including;
1. Omission of important information from Kinzie et al. (2014) that refutes their arguments.
2. Use of low-quality data, like Sexton (2016).
3. Wordplay based on the least charitable interpretation of various YDIH texts.
4. Failure to understand that sampling is a reliable method for estimation of particle properties.
5. Diversions based on, for example, identification of diamondoids or carbon spherules.
Moreover, it is clear that Holliday et al, like other papers from Daulton et al. and Scott et al., engage in rampant obfuscation in order to hide a critical error, which is that Daulton et al. (2010), one of the earliest papers to claim refutation of YDIH data, did not sample the same site as Kennett et al. (2008,2009) at Arlington Canyon for nanodiamonds. Daulton et al. (2010) should now be retracted and related papers should be corrected.
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Németh, P., Garvie, L. & Buseck, P., (2016). Twinning of cubic diamond explains reported nanodiamond polymorphs. Sci Rep 5, 18381.
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