[meteorite-list] Holocene Start Impact Event Controversy Continues

[Paul H.]

In “Holocene Start Impact Event Controversy Continues” at
http://www.mail-archive.com/meteorite-list@meteoritecentral.com/msg110580.html
E.P. Grondine wrote,

“What Boslough did not mention or is not being reported 
is several recent possible major astroblemes, such as (sic)
Ilturalde Crater and the Lloydminster Structure. Nor that 
the layer of impactites has been independently confirmed 
by others.”

First, if you would read Boslough et al. (2012) you will
find that the so-called “layer of impactites” and their 
allegedly being “independently confirmed by others” is 
discussed in detail their paper. Your complaint about
“layer of impactites” not being discussed is completely
groundless and wrong.

Second, although the Ilturralde Structure has the 
appearance of a real impact structure, the best estimate 
of it age seems to be 10,000 to 30,000 BP according to 
Campbell et al. (1988, 1998). The older range of the 
structure is based upon radiocarbon dates from "fossil
tree trunks" in permeable fluvial sediments in a tropical
climate. Given my experience with radiocarbon dates 
from similar samples and matrix, their dates in the 30,000 
BP range could very well be much older, even "dead" 
samples contaminated by modern carbon in the 
groundwater. In fact, Campbell et al. (1985) reports
dates of greater than 40,500 years BP for these deposits. 
Thus, the maximum age of the sediment in which the 
Ilturralde Structure, and the structure itself, is 
developed could be considerably older than 30,000 BP, 
even back to the last interglacial or more.

Thus from what little I can find, it is unknown exactly 
how old this proposed crater might be. There is a lack 
of any solid evidence for claiming that this feature 
is contemporaneous with and part of a hypothesized 
Younger Dryas impact event. Until such evidence is 
published, it is premature to criticize anyone for not 
discussing this hypothetical structure in association 
with a hypothetical Younger Dryas event. If you want 
the Ilturralde Structure discussed in a paper about the 
Younger Dryas, you need to provide and formally publish 
definitive evidence that it is an impact structure and 
it is contemporaneous with the start of the Younger Dryas.

Even if the Ilturralde Structure is an impact “crater” 
and dates to the Younger Dryas, any impact that forms an 
8-km in diameter impact crater in soft sediments within 
the Lower Amazon jungle of Bolivia very likely will not have 
any significant effect in North America. Being soft-sediment, 
the original transient crater, unlike Meteor Crater, which 
is in rock, has completely collapsed. Thus, the diameter of 
the original transient crater was significant smaller (by  
kilometers ) in diameter than the current structure that 
has only 3 meters of relief.  Also, there are numerous 
pollen sites and other documented and published 
paleoenvironmental records lying between this circular 
structure and North America that show a complete lack of 
any environmental effects from any impact during the 
Younger Dryas. It is highly implausible that an impact 
associated with a structure of this size in soft sediment 
is going to create the havoc that is argued to have occurred 
in North America at the start of the Younger Dryas. 

Boslough et al. (2012) did not need to mention the 
Iturralde Structure because 1. it is not yet determined
to be an impact structure, 2. it is unknown if it is 
contemporaneous with the start of the Younger Dryas, 
3. it is unproven that this feature has any association with 
a hypothetical Younger Dryas impact event and 4. it is 
much too small to have been an impact that would have 
had any effect on North America. 

Some web pages are: "Iturralde Crater"
http://en.wikipedia.org/wiki/Iturralde_Crater

And "Araona Crater (Iturralde Structure)"
http://svs.gsfc.nasa.gov/vis/a000000/a000900/a000925/index.html

Third, petroleum and other geologists have studied in 
great detail the geology of the Lloydminster Heavy Oil Area, 
which apparently what you have repeatedly referred to
as your so-called "Lloydminster  Structure," in east-central 
Alberta and west-central Saskatchewan. If a person looks 
though what has been published about it, including 
structural maps, a person finds a complete absence of 
any geological evidence that it either is an impact 
structure or its development is associated with the start 
of the Younger Dryas in any fashion. There is even a 
complete lack of either any ring faulting or any other 
circular structure(s) that can be used to define or 
postulate the existence of an extraterrestrial impact in 
within the Lloydminster Heavy Oil Area. According 
interpretations made from the an abundance of available 
geophysical logs, cores, and cuttings from oil and gas 
wells and innumerable seismic lines, the geological 
structures are clearly the result of irregular collapse of 
Cretaceous and overlying strata because of the subsurface 
dissolution of thick Middle Devonian Prairie Evaporite 
rock salt that underlie these strata rest. If this is the so-
called "Lloydminster  Structure," then enough has been 
published about its origin to completely discredited this
 alleged "structure" as a possible impact crater. There
is no need, in this case, to discuss an imaginary "crater"
that has never been formally proposed judging from 
what I have so far found. For more details, consult 
Gregor (1997), Kohlruss et al. (2010), and Orr et al. (1977)

It is nonsensical for Boslough et al. (2012) to have to 
discuss every lake, “paleolagoon,” ring igneous intrusion, 
other geologic structure, or other feature that someone, 
often on the basis of a quite vivid imagination, speculates 
to be an Younger Dryas impact crater without offering a 
single shred of hard evidence. The circular and even 
noncircular lakes, structures, and other features that 
people interpret to be impact craters are seemingly 
endless and uncountable. In fact, Boslough et al. (2012) 
did take the time and space to discuss the geologically 
illiterate claim that the Great Lakes are in part impact 
craters.

Fourth, I will disregard the details of ill-tempered and 
imaginary Vogon Poetry about another impact researcher 
personal motivations. As with various Young Earth 
creationists, some people obviously need to understand 
that stating such fiction for mudslinging, and character 
assassination involving other people's motivation and 
character because they disagree with you is definitely 
not a productive technique to win friends and positively 
influenced people. They also need to understand that 
fictional ad hominem attacks about personal motivations 
are not an acceptable part of scientific discourse. 
[Besides Boslough et al. (2012) has 16 coauthors. Are 
you implying that they all have some sort personal 
axes to grind?  :-)  :-) ]

Finally you, stated:

“"Denial" is a strange psychological mechanism, and 
undoubtedly we will hear stories about how an 
"asteroid impact did not kill the dinosaurs" for many 
years to come.”

>From what I have found, complaints about people, who 
disagrees with a specific point of view, being in “denial” 
is the standard silly, scientifically illiterate, and just 
plain stupid psychobabble that I hear from Young Earth 
creationists; supporters of Rand Flem-Ath’s / Charles 
Hapgood’s ideas about Earth Crustal displacement; Ed 
Conrad’s Carboniferous human bones; and supporters 
of many other fringe pseudoscientific claims. This 
whining about people being in “denial” at its most basic 
level, an ad hominem attack on any person, who 
disagrees with a specific pet idea or theory. I consider
it an ad hominem attack  because it insinuates that their 
disagreement is based, not on the facts, but on some
mental impairment. Again, such complaints about other 
people being in "denial" neither wins friends and 
positively influences people nor has anything to do 
with scientific discourse. 

Judging from what you argue about the Ilturralde 
Structure and your imaginary "Lloydminster Structure," 
I suspect that if the age of the Chicxulub impact 
structure was unknown that either you or someone else 
would be arguing that it was also an Younger Dryas 
impact structure as well. :-) :-) :-)

References Cited:

Boslough, M., K. Nicoll, V. Holliday, T. L. Daulton, D. 
Meltzer, N. Pinter, A. C. Scott, T. Surovell, P. Claeys, J. Gill, 
F. Paquay, J. Marlon, P. Bartlein, C. Whitlock, D. Grayson, 
and A. J. T. Jull, 2012, Arguments and Evidence Against a 
Younger Dryas Impact Event. , in Climates, Landscapes, 
and Civilizations, Geophysical. Monograph Series, vol. 198, 
edited by L. Giosan et al. 13–26, AGU, Washington, 
D. C., doi:10.1029/2012GM001209. 
http://www.agu.org/books/gm/v198/2012GM001209/2012GM001209.shtml

Campbell, K. E., Jr., C. D. Frailey, and L. J. Arrelano, 1985, 
The geology of the Rio Beni: further evidence for Holocene 
flooding in Amazônia. Contributions in Science. vol. 364,
pp. 1-18.

Campbell, K. E., Jr., R. A. F. Grieve, Z. Pacheco, and J. B. 
Garvin, 1988, A Possible Impact Structure in Amazonian 
Bolivia. Abstracts of the Lunar and Planetary Science 
Conference, vol. 19, p. 163-164.

Campbell, K. E., Jr., R. A. F. Grieve, Z. Pacheco, and J. B. 
Gavin, 1989, A newly discovered probable impact 
structure in Amazonian Bolivia. National Geographic 
Research. vol. 5, no. 4, pp. 495-499.

Gregor, V. A., 1997, Mannville Linear in the Lloydminster 
Heavy Oil Area and Their Relationship to Fractures and 
Fluid Flow in the Western Canada Sedimentary Basin. 
In S. G. Pemberton and D. P. James, ed., pp. 428-474. 
Petroleum Geology of the Mannville Group. Memoir no. 18, 
Canadian Society of Petroleum Geology, Calgary, Alberta,
Canada.

Kohlruss, D. A. Marsh, G. Jensen, P. Pedersen, and G. 
Chi, 2010, Lower Cretaceous Mannville Group 
Sandstones in the Clearwater River Valley, Northwestern 
Saskatchewan: Preliminary Observations, Bitumen 
Sampling, and Mapping. In Summary of Investigations 
2010, Volume 1, Miscellaneous Report 2010-4.1, 
Paper A-1. Saskatchewan Geological Survey, Regina,
Saskatchewan, Canada.

Orr, R. D., J. R. Johnston, and E. M. Manko, 1977, Lower 
Cretaceous Geology And Heavy Oil Potential Of The 
Lloydminster Area. Journal of Canadian Petroleum 
Technology. vol. 17, no. 1, pp. 1187-1221.

Best wishes,

Paul H.