Holliday et al.'s Gish gallop: the YD black mats
We have already established that Holliday et al. is a Gish gallop, i.e. a (very)
long series of weak or fallacious arguments. Now let's look at another of their
less interesting chapters that are quite superfluous, but it nevertheless
illustrates the kind of rhetorical tactics that Holliday et. al are prepared to use.
In this case, Section 6 concerns interpretation of the Younger Dryas (YD) black
mat. It's a superfluous section because any misunderstanding of the YD black
mat by YDIH proponents is irrelevant - it makes no difference whatsoever to the
case for the YD impact as it's not evidence for or against the YD impact nor is it a predicted
secondary effect of the impact. So this whole section is just pedantry.
Before we start, let's remind ourselves of what Haynes (2008) had to say about the YD
black mat. His abstract reads
"Of the 97 geoarchaeological sites of this study that bridge the Pleistocene-Holocene transition (last deglaciation), approximately two thirds have a black organic-rich layer or “black mat” in the form of mollic paleosols, aquolls, diatomites, or algal mats with radiocarbon ages suggesting they are stratigraphic manifestations of the Younger Dryas cooling episode 10,900 B.P. to 9,800 B.P. (radiocarbon years). This layer or mat covers the Clovis-age landscape or surface on which the last remnants of the terminal Pleistocene megafauna are recorded. Stratigraphically and chronologically the extinction appears to have been catastrophic, seemingly too sudden and extensive for either human predation or climate change to have been the primary cause. This sudden Rancholabrean termination at 10,900 ± 50 B.P. appears to have coincided with the sudden climatic switch from Allerød warming to Younger Dryas cooling. Recent evidence for extraterrestrial impact, although not yet compelling, needs further testing because a remarkable major perturbation occurred at 10,900 B.P. that needs to be explained."
Haynes (2008) appeared ~ 1 year after the YDIH was first scientifically
described by Firestone et. al (2007). My comments in italics.
-------------------------------------------------------
6. Misinterpreted black mats
Firestone et al. (2007, p 16016) begins their introduction, "A carbon-
rich black layer, dating to 12.9 ka (12,900 calendar years B.P.)
…, has been identified by C. V. Haynes [2008], at 50 sites across
North America as black mats… …the base of this black layer coincides
with the abrupt onset of Younger Dryas (YD) cooling, after
which there is no evidence for either in situ extinct megafaunal
remains or Clovis artifacts.” Firestone et al. (2007, p 16017) clamed,
“Directly beneath the black mat, where present, we found a thin,
sedimentary layer“ that contains impact markers and “[w]e identify
this [sedimentary] layer as the YD boundary.”
Correct
Prior to Firestone et al.
(2006, 2007), Brakenridge (1981) proposed a Late Quaternary supernova
event in which he speculated black mats “are terrestrial records
of the Vela supernova” (p 90) and included a photo of one at the YDIH
Murray Springs site.
Irrelevant. This is not the YDIH.
Cosmic-catastrophe proponents focus considerable
attention on the “black mat” (e.g., Brakenridge, 1981; Firestone et al.,
2006, 2007; Wittke et al., 2013a, 2013b; Mahaney et al., 2010a, 2010b,
2013, 2017, 2022; Kennett et al., 2008a; Firestone et al., 2010a, 2010b;
LeCompte et al., 2012, 2013; Pigati et al., 2012; Kinzie et al., 2014;
Israde-Alc´antara et al., 2012, 2018; Wolbach et al., 2018b; Sweatman,
2021; Powell, 2020, 2022; and many others).
True, but we should only be interested in peer reviewed papers since 2007 which
contain the scientific evidence for the YDIH.
A black, organic-rich
stratum covering the Lehner Clovis site in Arizona was first described
by Haury et al. (1959) and termed “black swamp soil” (Antevs, 1959).
Similar organic-rich layers are known by other names (see Quade et al.,
1998) including the “black mat” (Haynes, 1968, 2008; Haynes and
Huckell, 2007), which has become the dominant term used for these
stratigraphic entities.
Powell (2022, p 5) refers to the black mat as “enigmatic.” The only
thing “enigmatic” about the black mat is its attribution to an impact.
Nothing is particularly unique about the black mat other than its
appearance in some stratigraphic sections along drainages in southeast
Arizona, and the High Plains of Texas and New Mexico.
This clearly contradicts Haynes (2008). Holliday et al. make their claim
with far too much certainty, which is not good science.
Discussions of
the black mat by impact proponents are grossly oversimplified with
critical data misstated or ignored as repeatedly pointed out by Meltzer
and Holliday (2010) and Holliday et al. (2014, 2020).
Which critical data? None is specified here.
Some YDIH
proponents claim the black mat lies directly above the YDB, while others
assert, as discussed below, that it represents a layer of purported impact
debris (i.e., the YDB).
Both claims can be true depending on the situation. This is because the YD
black mat has very different characteristics in different locations. No YDIH
proponent claims the YD black mat is the same everywhere. So this is just
word play that is missing important context.
For example, Kennett et al. (2009b, p 12623)
erroneously state “This biostratigraphic marker dates to ~12.9 ± 0.1
ka (10,900 ± 100 14C years).” However, dating by Haynes (2008)
clearly shows that many are not unique to the YD/GS-1 or the YDB for
that matter. Some started forming far earlier than the YD/GS-1, others
persisted beyond the YD/GS-1, and yet others have no clear dating to the
YD/GS-1.
Here, Holliday et al. clearly contradict Haynes' (2008) abstract (see above). Haynes
interpreted those radiocarbon dates in a different way. He, like many YDIH proponents,
does not simply take radiocarbon dates at face value. We have already seen that
doing so is bad science because the intrinsic radiocarbon measurement error is
not a good estimator for the true sample age uncertainty. Anyway, just to be sure,
let's look at Haynes' (2008) data.
Above is Figure 5 from Haynes (2008). He clearly interprets the base
of the YD black mat as synchronous across all the sites he studied - located at the Z2-beta_2a contact.
This is what Haynes (2008) says about stratum beta_2a, the YD black mat.
"Stratum beta_2a represents YD black layers (black
mats) at 70 localities (Fig. 1 and SI Table 2) and reflects more
mesic conditions in the form of wet-meadow soils or a rise of
water tables (6, 7, 17) to either emergence as ponds or saturation
of lowland surfaces (Fig. 4, position 1). In eolian deposits on
uplands, black mats take the form of cumulic mollisols (aggrading
A horizons) (Fig. 4, positions 2 and 3). The Z2 contact with
1 is conformable in most areas, deflational in a few, and merges
with Z1 at the edges of the 1 channel to form the Z1–2 surface
(Fig. 2). This surface, covered by the YD black mats, demarks the
topography of the Clovis-age landscape (SI Fig. 6). At 27 sites
mammoth bones are blanketed by YD black mat deposits (Table
1). Six of these have Clovis artifacts on the same surface (Z1–2)
on which the bones rest. Bioturbation across the Z1–2 contact at
several sites resulted in a mixture or reversals of radiocarbon ages
with ages of 11,000 B.P. in lower 2a and younger, 10,000
B.P., for strata on which 2a is resting. Hell Gap and the Jim Pitts
sites are examples (SI Table 2, nos. 9 and 17a) (SI Fig. 7a and
SI Fig. 8b).
The 2a black mat deposits are devoid of in situ megafauna
other than bison (Bison bison antiquus) but contain the earliest
post-Clovis archaeological evidence represented by in situ
Paleoindian artifacts, e.g., Folsom-Midland, Plainview-Goshen,
and Agate Basin (Figs. 3 and 5), commonly in direct association
with the bones of extinct bison in the Great Plains and Southwest
(18). In the eastern United States post-Clovis fluted-point
making cultures dominated during the YD (19, 20), whereas the
Dalton technocomplex appeared in the Southeast (21). The YD
black mats blanket the Clovis-age Z1–2 surface (Fig. 4, 2a) and
provide a marker horizon for exploration for Paleoindian sites.
The manifest increase in cultural diversity and bison kill sites
(18) following Clovis suggests a significant population increase
during YD time.
Of the 70 sites in SI Table 2, 56 (80%) have skeletal elements
of the Rancholabrean megafauna directly underlying the YD
black mat (Table 1). Approximately 38.6% have mammoth
remains, 37.1% bison, 8.6% horse, 7.1% camel, 2.9% mastodon,
and 8.6% other extinct-species remains, all on the Clovis-age
surface, and only bison remains appear in the overlying YD
black mat.
The 27 sites of SI Table 3 that do not have black mats per se
have strata that are manifestations of YD climate. Of these, 19
(70%) have Rancholabrean megafauna remains all in contact
with the YD-age sediments (Table 1). Of the total, 18.5% have
mammoth bones on the Clovis age surface, 11.1% have mastodon,
37% have bison, and 3.7% have horse remains on the Z1–2
contact.
Twenty-three sites lack a documented extinct fauna. Fifteen,
or 65%, have either Clovis artifacts on the Clovis-age surface
and/or post-Clovis Paleoindian artifacts in the overlying YD
sediments. All of the sites in SI Tables 2 and 3 have either
radiocarbon ages indicating YD ages for the black mat and/or
have a Clovis-age (Z1–2) contact. Therefore, the Z1–2 contact
appears to be the same age everywhere, essentially isochronous,
in this study (Fig. 5)."
Later, Haynes (2008) states; " The black mat at a few
locations may have begun accumulating during the Allerød
period (28) or perhaps the IACP, based on older radiocarbon
ages. However, these ages may have been affected by
contamination with older carbon. In any case the major deposition
began with the onset of YD cooling."
Thus, it is clear that Holliday et al.'s interpretation misrepresents Haynes (2008).
They must know this. Haynes (2008) essentially agrees with Kennett et al. (2009b),
but Holliday et al. try to make it seem like they are in disagreement.
In other words, the YD black mat is thought to be consistent with a synchronous
event at most sites. Black mat sites where the dating is currently not obviously consistent
with synchroneity could, in fact, be synchronous due to problems with the radiocarbon dating.
Another key mischaracterization by YDIH proponents is that it
is essentially a continuous stratigraphic entity: a “stratigraphic marker
that covers much of the Clovis-age landscape of N. America”
(Sweatman, 2021, p 2) and describes it as “spanning the entire
continent” of North America (p 3).
This is false. I don't say it is "continuous". The word "span" does not mean "continuous".
They are different words with different meanings.
If I had meant it was "continuous", I would have said "continuously spanning". So this
is simply a misinterpretation on Holliday et al.'s behalf.
Haynes (2008) does not say that.
Nor do I.
A close reading of his text and tables show that the black mat is not
continuous (and certainly does not span the continent) and represents a
variety of geologic processes in a variety of landscape settings.
This is a strawman fallacy, criticising something I did not say or mean.
The genesis of these soils and deposits varies significantly from location to
location (Haynes, 2008; see also Harris-Parks, 2016). Some are algal
mats, others aggrading wetland deposits or lowland soils, or lacustrine
deposits including white to light gray diatomites, and still others are
well-drained upland soils (see also Meltzer and Holliday, 2010).
The notion among some YDIH proponents of a continent-wide black
mat with origins linked to an impact that spans the YD/GS-1 also
directly contradicts the concept of an environmental catastrophe at a
specific time of ~12.9 cal ka BP.
How so?
The black mat as conceived by those
YDIH proponents is a kind of soil horizon spread across the continent
and which should therefore indicate continent-wide landscape stability.
But there is no such indicator of regional stability, nor any evidence of
geomorphic disruption across the continent at the YDB or through the
YD/GS-1 (Meltzer and Holliday, 2010; Holliday and Miller, 2013) (see
Section 13.7).
This seems to be another strawman fallacy, with Holliday et al. inventing
an interpretation which they then criticise. It is actually quite simple. The
YD black mat is often a good guide to the position of the YDB, which is often
found at its base. The YDB defines the time-position of the impact, not the
black mat. According to radiocarbon dating, the base of the YD black mat
might not be synchronous everywhere, although (as stated by Haynes)
where this occurs the problem is likely in the radiocarbon date. This would
not be surprising - we have already seen how the intrinsic uncertainty of
a radiocarbon measurement is not often a good guide to the true sample age
uncertainty.
Like today and throughout the Quaternary, a broad variety
of both local and regional geomorphic systems driven by their
respective environmental processes affected the landscapes of North
American as well as elsewhere. Specific geomorphic processes and the
rates at which they operated varied spatially and through time. No evidence
shows a single continent-wide geomorphic event at the YDB or
through the YD/GS-1 (e.g., papers in Gillespie et al., 2004; Straus and
Goebel, 2011; Eren, 2012).
Again, Haynes (2008) interpreted the origin of the YD black mat
as probably synchronous. However, this is all besides the point. It is the
YDB, not the black mat, which defines the YD impact. As we have
seen in an an earlier blog post, Holliday et al. fail to show
that the YDB is not synchronous. They failed because they relied heavily on
Meltzer et al. (2014). But Meltzer et al. (2014) failed to report the uncertainty
in their age-depth models at each YDB site. Holliday et al. support
Meltzer et al. (2014) by arguing that such uncertainty estimates are an
"irrelevant technicality", but no competent scientist would omit uncertainty
estimates in their measurements, calling them irrelevant.
Sweatman (2021, p 2) comments, “Around one hundred black mat
sites across N. America have been discovered. Most in-situ Clovis
sites are found directly under the black mat.” Kennett and West
(2008, p E110) and Wolbach et al. (2018b, table 1) make similar assertions.
Both statements are wrong. Haynes’s (2008) supplemental
table 2 lists 72 sites with black mats and supplemental table 3 lists
another 27 without YD/GS-1 black mats. Haynes’ supplemental table 2
includes 13 Clovis occupations buried by “black mats” (including white
diatomite). ENDNOTE 11. His supplemental table 3 also describes 13
Clovis occupations without black mats. The number of “black mat localities”
rises notably if the localities reported by Holliday (1995) and
Mandel (2008) (further discussed below) are included. With the
exception of the Clovis type site and the Lubbock Lake site, no Clovis
sites are reported from any of the scores of sections they report,
however.
Nevertheless, Haynes states that; "This layer or mat covers the Clovis-age landscape or surface on which the last remnants of the terminal Pleistocene megafauna are recorded".
See also the direct quotes and Figure 5 from Haynes above. Holliday et al. are
disingenuous or mischievous by mispresenting Haynes' conclusions in this way.
To my knowledge, no Clovis artefacts have ever been found above the YDB
which is often found at the base of the YD black mat.
The radiocarbon age variation of black mats is also well documented
by Quade et al. (1998) and Pigati et al. (2012) who identified black algal
mats in North and South America ranging in age from 40,000 cal yr BP to
modern.
We are only interested in the YD black mat. The existence of other black
mats says nothing about the origin of the YD black mat.
Further, Quade et al. (1998) clearly document and state that
the most common age range for black mats in southern Nevada centers
on 10,000 14C yr BP (~11.5 cal ka BP, i.e., post-YDB).
Quade et al. (1998) is out of date today, and is superseded by Haynes (2008).
Nevertheless, let's look at Figure 5 from Quade et al. (1998) below.
It shows a distinct radiocarbon peak during the Younger Dryas, which shows there is a distinct YD
black mat. Note that Quade say nothing about whether they take their samples from the bottom,
middle or top of each respective black mat. So Quade et al. (1998) can say nothing about the
timing of the beginning of the YD black mat. Nevertheless, their data is not inconsistent with
the more up-to-date view of Haynes (2008) that the base of the YD black mat is likely synchronous.
Nevertheless, this is all besides the point. The YD black mat only serves as a guide
to the likely position of the YD boundary, which is defined by geochemical impact proxies.
The YD black mat is not generally the YDB itself which is shown to be almost certainly
synchronous in an earlier post.
Sweatman (2021, p 20) dismisses the conclusions of Pigati et al. (2012) but on the same
page asserts that their work “actually supports” the YDIH (Table 8).
There is no contradiction here. It is entirely consistent to dismiss their
conclusions while arguing that their data supports the YDIH. In other words,
I'm disputing their interpretation of their data. That
Holliday et al. find fault with this nicely illustrates the kind of
rhetoric that they are prepared to engage in.
Some YDIH papers identify a generic black or gray layer (i.e., an organic rich
or otherwise dark colored zone) as the YD-aged black mat with no
evidence that it is in fact a YD-age zone (Tables 6 and 7). Impact markers
are purported below, at the base, or even within this perceived black mat
and taken as prima facie evidence by many YDIH proponents that this
dark layer represents the YDB (Table 2).
The 'perceived' black mat is clear where it exists (there are many, many
very nice pictures of it at many different locations) and it generally serves as a
good guide to the likely position of the YDB. Radiocarbon dating shows the
YDB is consistent with synchroneity and statistical reasoning shows it
almost certainly is synchronous. See an earlier post.
The YDIH is rife with further contradictions regarding the black mat.
These perceived contradictions are mainly wordplay by Holliday et al.
Note that the YD black mat varies in character considerably between sites.
This is entirely expected, because we would not expect local conditions
at each site to be identical. Partly, this is because of local geography,
and partly its because the favoured YD impact model consists of a
multitude of separate impacts, and each would have its own separate
consequences. Most are thought to have been airbursts, but some ground
impacts are not yet ruled out.
Firestone et al. (2010a) wrote (abstract, p 30), “At many locations the
impact layer is directly below a black mat” and (p 57) “The black
mat which overlays the YDB layer at many sites… … was not
formed by the impact and appears to consist mainly of algal material
produced by dying organic matter and burned material.”
There is no contradiction here at all.
Bunch et al. (2012, p E1903) and Moore et al. (2017, p 7) also describe
the black mat as overlaying the YDB layer.
Likewise, no contradiction.
Pino et al. (2019) wrote,
“Most classic black mats in the United States do not contain much
charcoal…, but it is sometimes [i.e., not often] abundant immediately
below the black mat…, where the YDB layer typically is
found…”
Still no contradiction.
However, that is at odds with Firestone et al. (2007) because
Pino et al. (2019) described weak evidence of wildfire in the YDB and
weaker evidence in the black mat.
How is it at odds? This seems entirely consistent. They are all saying the
YDB is often found at the base of the YD black mat. Clearly, characteristics of the
YD black mat can vary between sites, as expected.
In contrast, others describe the black mat as both the YDB and an
impact debris layer. Mahaney et al. (2013, p 100) claimed “Recent
analyses of black mat beds in the northwestern Venezuelan Andes
… show conclusive micrographic and chemical evidence … that
could only be produced by an ET airburst/impact” and (p 103–104)
“The black mat beds, dated to 12.8 ± 0.2 calibrated ka, have yielded
aerodynamically modified Fe spherules that most likely
formed in a local airburst, resulting from a fragmented asteroid or
comet.” Mahaney et al. (2017, p 68–69) further claimed, “The airburst
often produced a dark layer sometimes called the ‘black mat’,
which in the Alps is represented by carbon encrusted grains in
rinds and in paleosols. As elsewhere, the affected sediment typically
contains high-temperature carbon (charcoal, soot, carbon
spherules, glass-like carbon, melted, welded and quenched grains)
and is common across Europe and western North America, but less
common across eastern North America.”
There is no inconsistency here. Characteristics of the YD black mat can vary
between locations, as expected. Context matters.
Wolbach et al. (2018b, p
195) assert “YD onset is marked by the widely distributed deposition
of black-mat layers across North America… The presence of
these organic-rich sediments is consistent with an abrupt episode
of large-scale biotic degradation that resulted from YD climate
change and a major increase in biomass burning…” For the Sheriden
Cave site, Wolbach et al. (2018b, p 200–201) purports, “A charcoal rich
black mat dates to the YD onset and contains peak abundances
of charcoal, AC/soot, carbon spherules, and nanodiamonds
[repeatedly claimed by YDIH proponents to form by impact and not by
wildfire] that are closely associated with the last known Clovis artifacts
in the cave. The black-mat layer is in direct contact with the
wildfire-charred bones of two megamammals… … the last known
examples anywhere in the world of those extinct species.”
Again, there is no inconsistency. Characteristics of the YD black mat
can vary between locations. Clearly, we should not expect the same conditions
in the Andes as at Sheriden Cave (Ohio). And we have seen that it is Haynes' (2008)
view as well that the base of the black mat (where the YDB is often found)
is likely synchronous. His view is that radiocarbon measurements that are
inconsistent with synchroneity could be problematic.
Essentially, Holliday et al. prefer to take radiocarbon measurements at face value
while YDIH proponents, and Haynes (2008), accept that this can be
very misleading. In any case, it is the date of the YDB and not the black mat that
really matters, and the YDB is shown to be almost certainly synchronous in a previous post.
Wolbach et al. (2018b, SI fig. A6) consider a charcoal zone associated with the
Usselo soil (Section 5.6) an equivalent to the black mat and of YDB age
(Table 6).
This debate is covered in detail in Section 5.7. Wolbach et al. (2018b)
and rebutted line-by-line in an earlier blog post.
Israde-Alc´antara et al. (2018, p 60) claimed, “at several Clovis
Palaeoindian sites in the USA (Murray Springs, Arizona and
Topper, South Carolina) [although there is no black mat at Topper] …,
the black mat forms a distinctive stratigraphic marker at the onset
of the YD climate change and is marked by peak abundances of
charcoal fragments from a major episode of biomass burning.”
I agree, charcoal fragments are not obvious in the YD black mat at the sites
investigated by Haynes (2008). However, charcoal is abundant in the YDB at
other YD black mat sites such as the Usselo/Finow horizon. Charcoal is
also abundant in a lacustrine layer (see an earlier blog post)
that could represent the YDB at the site examined by Gill et al. (2009).
So it all depends how the stratigraphy is interpreted.
There are probably many US sites where charcoal is abundant in the YDB, but
the YDB has been missed or misinterpreted.
Israde-Alc´antara et al. (2018, p 76) concluded, “An anomalous black
sediment layer, produced during the YD interval, was recognized
in three different lake sites from central Mexico (Lakes Acambay,
Cuitzeo, and Chapala)… These black mat layers contain large
amounts of organic material, charcoal, soot, nanodiamonds (only
studied at the Lake Cuitzeo site, Israde-Alc´antara et al., 2012),
magnetic Fe-rich microspherules (some with aerodynamic shapes
and evidence of high-velocity collisions) are a common feature in
four of the five sites analysed. These unusual materials were not
observed above or below the black mat sediments at these sites [emphases
added].” Only one of the sections described in that work could be
YDB age, however (Table 4).
This is yet again misleading and covered by an earlier blog post. I repeat
that discussion here.
"The five lakes are; Tocuila, Acambay, Cuitzeo, Chapala and Cedral. The dates of the claimed YDB impact debris are as follows. The Tocuila black mat is consistent with a YDB age (10,800,+- 50 BP uncalibrated radiocarbon age). The Acambay black mat is undated, but lower sediments are older than the YD onset, as expected. The Cuitzeo black mat from the main core has a single radiocarbon date inconsistent with the YD onset, but a detailed age-depth model from another core from the same lake with the same stratigraphy does have a consistent YD age (12,897 +- 187 cal BP). This is described in Kinzie et al. (2014). The Chapala microspherules are in a black mat layer that has a single radiocarbon date inconsistent with the YD onset. This core would benefit from a higher resolution age-depth model, like Cuitzeo. Cedral has no microspherules, but several black mats, although none are thought to be of YD age."
Confusingly, Firestone (2020, p 3358) contradicts his previous work
when he cites, “YD impact layer is precisely dated to the onset of the
YD, exists only within the black mat, and consists of PGE elements,
spherules, nanodiamonds, aciniform carbon, and other impact indicators
observed at over two dozen sites on four continents
(Firestone et al., 2007…) [emphasis added].” Firestone et al. (2007, p
16017) purported, “six of 10 [sites] have a black mat overlying the
YDB. At Blackwater Draw and Murray Springs, the YDB is found
directly beneath the black mat [emphasis added].”
I have no time for such pedantry.
Carbon is a ubiquitous component of sediments and soils across the
Earth’s surface and has been since plant life first appeared. As such,
sediments and soil horizons high in organic carbon (i.e., “black mats” in
a literal sense) are ubiquitous in late Quaternary stratigraphic records (e.
g., Quade et al., 1998; Pigati et al., 2012; Israde-Alc´antara et al., 2018;
Holliday et al., 2007; Haynes, 1968; Mandel, 2008; Holliday, 1995;
Rachal et al., 2016) and most have no connection to the YD/GS-1.
This statement is obviously wrong - see above. It is made with far too
much certainty, which is poor science. The correlation between the YD black
mat the onset of the YD period is clear. To say that most have "no connection" is an
outright falsehood.
Charcoal can induce dark coloration, but it is not a significant component
of black mats.
It is in some places, e.g. the Ussello/Finow horizon. Characteristics of the YD
black mat can vary between locations, obviously.
Evidence for burning is mentioned nowhere by
Haynes (2008). Subsequently, Haynes et al. (2010, p 4014) noted, “Over
the past four decades the lead author has chemically pretreated
hundreds of black mat samples for multifraction 14C dating…. Very
few YD-age black mats were found to contain adequate charcoal”
for dating (see also Table 6). Furthermore, Harris-Parks (2016, p 102)
studied black mats microscopically at YDIH sites Murray Springs,
Blackwater Draw, as well as Lubbock Lake and reported, “the absence
of ash and near-complete absence of charcoal in all of the samples
do not support the idea that black mats formed by regionally
extensive fires caused by an extraterrestrial impact.”
As already stated, characteristics of the YD black mat can vary by location,
as expected.
On the other hand, a wide array of sites and settings with YDB- and
YD/GS-1-age deposits have no “black mats” (Meltzer and Holliday,
2010; Holliday, 1995; Holliday and Miller, 2013). Of the 29 localities
with claimed evidence for impact proxies tabulated by Holliday et al.
(2014, SI table S1), independent of the reliability of the dating or
stratigraphic context, only about half exposed a “black mat.”
Agreed. This is not a problem for the YDIH.
Local environmental conditions likely control their genesis. In what inadvertently
became a search for black mats inspired by the geoarchaeological
record at the Blackwater Draw Clovis site (a YDIH “type section” of
sorts) and the Lubbock Lake site, Holliday (1995) reports on a study of
“draws” (dry valleys) on the High Plains of northwest Texas and eastern
New Mexico as part of the Brazos and Colorado drainage systems. These
valleys aggraded through the latest Pleistocene and Holocene. Among
110 localities (representing >400 exposures and cores) along >1400 km
of draws, only 16 sites contain black or gray organic-rich deposits that
overlapped the YD/GS-1. A number of sections contained black mats
that persisted into the early Holocene. Their occurrence was apparently
controlled by the presence of seeps or springs.
Again, this is not a problem for the YDIH. The YD black mat serves as a guide
only to the likely location of the YDB. It's really simple. That a YD-age black mat
exists is shown by Haynes (2008) and also Quade et al. (1998) above.
Similarly, late Holocene
wetland muds, constituting another sort of “black mat” are common
along the draws in proximity to historic springs.
In contrast, Mandel (2008) reports a variant of the black mat from
the Central High Plains, based on work at 49 dated localities from 37
stream valleys, draws, and fans in the Kansas and Arkansas drainage
systems. At the close of the late Pleistocene the meandering streams
stabilized except for incremental additions of flood deposits. The result
was development of an over-thickened (up to 2 m) black-to-dark gray
soil A-horizon forming a distinct stratigraphic marker. Stabilization and
soil cumulization began as early as ~15,600 cal yrs. BP but was underway
in most sections between 13,300 and 12,900 cal yr BP; hence the
onset of this process was time-transgressive and largely pre-YDB.
This may well be true at some sites. But there clearly is also a distinct
YD-age black mat in may places. This is shown by Haynes (2008) and
Quade et al. (1998)
The cumulic soils were buried by flood deposits in a likewise time transgressive
process varying from ~11,400 to ~10,200 cal yr BP, post- YD/GS-1.
This is stated with far too much certainty, which is bad science.
The period of alluvial stability and concomitant soil
cumulization includes the YD/GS-1 but is not synchronous.
It might not be synchronous in all locations, but its formation does
appear to be synchronous in most places. See Haynes (2008).
Formation of this stratigraphic marker was due to localized changes in floodplain
geomorphic process, not to any sort of ET process.
Again, this is stated with far too much confidence and is bad science.
This stratigraphic research by both Holliday (1995) and Mandel (2008) is well published
and widely known except by YDIH proponents. ENDNOTE 12.
Mandel (2008) takes samples from very irregular intervals at every site investigated,
and few, if any, correspond to the base of the YD black mat. Like Quade et al. (1998),
Mandel (2008) does not have high enough resolution to show that the base of the YD black
mat is inconsistent with synchroneity with the YD impact. Nor are any age-depth models
generated by them, so it is impossible to dispute the age of the base of the YD black mat
using this evidence. Holliday et al. must realise this. In any case, we are interested mainly
in the YDB which is shown to be consistent with synchroneity.
Other inconsistencies abound in using the black mat as some sort of
proof of a YDB impact (see also Section 13.3).
Haynes (2008) clearly thought it indicates an extraordinary event.
Sweatman (2022, p 22)
notes problems with dating soil organic matter in an attempted rebuttal
to Jorgeson et al. (2020) but wholly accepts dating of black mats by
Haynes (2008), which includes dating such material.
The issue here is whether the dates are inconsistent with a synchronous event.
Holliday et al. seem to lack the required logic to understand this.
Wolbach et al.
(2018b, table 1) claim a direct link between sites with black mats and
extinct fauna immediately below.
Haynes (2008) alludes to this too.
Sweatman (2021, p 2), following
Haynes (2008), states “at 27 black mat sites mammoth bones are
blanketed directly by the black mat.” Powell (2022, p 3) and other
YDIH proponents make similar claims. A look at supplemental table 2 in
Haynes (2008) clearly contradicts that interpretation and linkages between
black mats and extinct fauna (Table 7).
This is very repetitive. We have dealt with this already.
The only sites where an
organic-rich layer directly covers mammoth or other megafauna are in
the San Pedro Valley of Arizona.5 At many sites elsewhere the “layer” in
question is the A-horizon of a soil. Such zones are superimposed into
sediment, i.e., they are not layers of sediment. ENDNOTES 8, 13.
This seems to contradict Haynes (2008).
One observation is clear; YDIH proponents have never been in
consensus regarding the role of the black mat in the hypothesis.
No, the thing that is clear is Holliday et al.'s misrepresentation of the words
of others. And their insistence on taking radiocarbon dates at face value without
acknowledging the true sample age uncertainty can be much greater.
Some
believe it is in the impact debris layer (e.g., Mahaney et al., 2013, 2017,
2022; Israde-Alc´antara et al., 2018; Wolbach et al., 2018b; Firestone
2020)
... it may well be in some places - the context matters.
while others believe it is not (e.g., Firestone et al., 2007, 2010a;
Bunch et al., 2012; Moore et al., 2017; Pino et al., 2019). Some believe it
is unique to the YD/GS-1 onset and is a global stratigraphic layer (e.g.,
Firestone et al., 2007; Mahaney et al., 2013) while others believe black
mats form at different times within different regions but only those that
contain YDB-aged impact markers are associated with the YDB impact
(e.g., Israde-Alc´antara et al., 2018; Wolbach et al., 2018a, SI).
The problem is caused by radiocarbon dating. It is not yet clear whether
it is a global stratigraphic layer. But there is clearly a distinct layer
in many places that began at the YD onset.
Most YDIH proponents, but not all (e.g., Pino et al., 2019), claim the black mat
is rich in charcoal, but that has been refuted by independent studies
(Haynes et al., 2010; Harris-Parks, 2016).
In some places it does contain abundant charcoal, e.g. the Ussello/Finow horizon.
Authors common to YDIH proponent
papers with opposing black mat interpretations appear
confused and lacking in credibility.
Summary
Holliday et al.'s acceptance of radiocarbon dates without recognising the true
sample age uncertainty can be much greater along with their many over-confident
statements about the YD black mat and their support of Meltzer et al.'s (2014)
omission of uncertainty estimates in their age-depth models are obvious flaws in their
arguments. Moreover, they rely on work like Mandel (2008) and
Quade et al. (1998) that don't have sufficient resolution to refute the age of
the base of the YD black mat at any of the sites they investigate (nor do they
generate age-depth models to estimate the age of base of the YD black mat).
Ultimately, however, this debate about the YD black mat is a waste of time.
Interpretation of the YD black mat is a distraction from the important issue of
dating the YDB. In fact, very often the YDB is found near the base of the YD
black mat which therefore serves as a good guide to the YDB's location.
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