Including Original "Paul H. Letters" Copyright © 1996-2024 Paul V. Heinrich / website © 1996-2024 Dirk Ross - All rights reserved.



Tuesday 21 September 2010

Radiometric Dating Still Reliable

Radiometric Dating Still Reliable

Monday, September 20, 2010 10:41 PMRadiometric Dating Still Reliable (Again), Research Shows,
Science News, September 18, 2010,
http://www.sciencedaily.com/releases/2010/09/100915171534.htm

http://www.physorg.com/news203788993.html

http://www.terradaily.com/reports/Research_Shows_Radiometric_Dating_Still_Reliable_999.html


The paper is:

Lindstrom, R. M. E. Fischbach, J. B. Buncher, G. L. Greene,
J. H. Jenkins, D. E. Krause, J. J. Mattes, A. Yue, 2010,
Study of the dependence of 198Au half-life on source
geometry. Nuclear Instruments and Methods in Physics
Research Section A: Accelerators, Spectrometers, Detectors
and Associated Equipment. vol. 622, no. 1, pp. 93-96.

Abstract at: http://dx.doi.org/10.1016/j.nima.2010.06.270


Yours,

Paul H.

Saturday 18 September 2010

New Paper on Lunar Impact Cratering History Saturday, September 18, 2010 4:27 AM

New Paper on Lunar Impact Cratering History

Saturday, September 18, 2010 4:27 AM
byThe Hole Thing: Lunar Topographic Map Provides Rich
Record of Impacts on the Moon: Laser altimetry data from
NASA's Lunar Reconnaissance Orbiter have provided a
comprehensive look at the cratering history of the inner
solar system, National Geographic, spet. 16, 2010.
http://www.scientificamerican.com/article.cfm?id=lro-moon-craters


The paper is:

Head, J. W., III, C. I. Fassett, S. J. Kadish, D. E. Smith, M. T. Zuber,
G. A. Neumann, and E. Mazarico, 2010, Global Distribution
of Large Lunar Craters: Implications for Resurfacing and
Impactor Populations. Science. vol. 329, no. 5998,
pp. 1504-1506. [DOI: 10.1126/science.1195050]
http://www.sciencemag.org/cgi/content/abstract/329/5998/1504


Other Papers:

Greenhagen, B. T., P. G. Lucey, M. B. Wyatt, T. D. Glotch,
C. C. Allen, J. A. Arnold, J. L. Bandfield, N. E. Bowles, K. L.
D. Hanna, P. O. Hayne, E. Song, I. R. Thomas, and D. A.
Paige, 2010, Global Silicate Mineralogy of the Moon
from the Diviner Lunar Radiometer. Science. vol. 329,
no. 5998, pp. 1507-1509. [DOI: 10.1126/science.1192196]
http://www.sciencemag.org/cgi/content/abstract/sci;329/5998/1507


Glotch, T. D. P. G. Lucey, J. L. Bandfield, B. T. Greenhagen,
I. R. Thomas, R. C. Elphic, N. Bowles, M. B. Wyatt, C. C.
Allen, K. L. D. Hanna, and D. A. Paige, 2010, Highly Silicic
Compositions on the Moon. Science. vol. 329, no. 5998,
pp. 1510-1513. [DOI: 10.1126/science.1192148]
http://www.sciencemag.org/cgi/content/abstract/sci;329/5998/1510


Yours,

Paul H.

Saturday 4 September 2010

Young volcanism on Mercury

Young volcanism on Mercury

Saturday, September 4, 2010 11:14 AM
byYoung volcanism on Mercury
http://www.psi.edu/pgwg/images/sep10.html


MErcury Surface, Space ENvironment, GEochemistry,
and Ranging (MESSENGER) spacecraft
http://messenger.jhuapl.edu/index.php

http://messenger.jhuapl.edu/the_mission/gallery.html


Yours,

Paul H.

Debate Over Younger Dryas Impact Hypothesis Continues

Debate Over Younger Dryas Impact Hypothesis Continues

Saturday, September 4, 2010 3:39 AM
On the side of people disputing the Younger Dryas Impact
hypothesis there is:

Kerr, R. A., 2010, Mammoth-Killer Impact Rejected.
Science Now, August 30, 2010
http://news.sciencemag.org/sciencenow/2010/08/mammoth-killer-impact-rejected.html


Dalton, R., 2010, Comet theory carbonized: Sediment
studies rule out impact as cause of ancient cold spell.
Nature News. August 31, 2010.
http://www.nature.com/news/2010/100831/full/news.2010.441.html


Impact hypothesis loses its sparkle, Physorg.
August 30, 2010,
http://www.physorg.com/news202382634.html

http://www.physorg.com/news195979458.html


Kerr, R. A, 2010, Mammoth-Killer Impact Flunks Out.
Science, vol. 329, no. 5996, pp. 1140 - 1141
DOI: 10.1126/science.329.5996.1140
http://www.sciencemag.org/cgi/content/summary/329/5996/1140


The paper is:

Daulton, T. L., N. Pinter, and A. C. Scott, 2010,
No evidence of nanodiamonds in Younger–Dryas
sediments to support an impact event. Proceedings
of the National Academy of Science of the United
States. Published online before print August 30, 2010,
doi: 10.1073/pnas.1003904107
http://www.pnas.org/content/early/2010/08/26/1003904107.abstract?sid=f62eef7c-9d13-48e9-a003-ddd93d93d75b


On the other hand, the BBC Article stated:

“Allen West said further nanodiamond evidence in support
of the impact theory would be published in the coming weeks.”

One of these papers is:

Kurbatov, A. V., P. A. Mayewski, J. P. Steffensen, A. West, D. J.
Kennett, J. P. Kennett, T. E. Bunch, M. Handley, D. S. Introne,
S. S. Que Hee, C. Mercer, M. Sellers, F. Shen, S. B. Sneed, J. C.
Weaver, J. H. Wittke, T. W. Stafford, J. J. Donovan, S. Xie, J. J.
Razink Jr., A. Stich, C. R. Kinzie, W. S. Wolbach, Discovery of
a nanodiamond-rich layer in the Greenland ice sheet. Journal
of Glaciology, v. 56, n 199, 749-759.

PDF file at :
http://cci.siteturbine.com/facultystorm/profile/research/publication.php?publicationId=7406

http://www.climatechange.umaine.edu/people/profile/andrei_kurbatov


Thus, the debate continues.

Yours,

Paul H.

Thursday 2 September 2010

Known Tektite Strewn Fields - North American Strewn Field

Known Tektite Strewn Fields - North American Strewn Field

Thursday, September 2, 2010 12:07 PM
In the thread “[meteorite-list] Known Tektite Strewn Fields?”
http://six.pairlist.net/pipermail/meteorite-list/2010-August/068400.html
,
Sterling K. Webb asked:

“So, I have a question for the geologists on the List
(I know you're there), where do I go in the Eastern U.S.
to find Top-O-The-Eocene exposures (beside Georgia
and Texas)?”

First, figure 1 of Heinrich(2009) shows the approximate
distribution of the North American strewn field and
locations from where tektites and microtektites of
the North American strewn field has been reported.

Microtektites have been reported from St. Stephens Quarry
in Alabama from two levels in the North Twistwood Creek
Formation. This suggest that microtektites, possibly even
tektites, can be found within the outcrops within exposures
of the Moodys Branch Group from Georgia to Texas that
expose sediments which are contemporaneous with the
Chesapeake Bay Impact (King and Petruny 2008). The exact
outcrop belt in which find exposures, can be found in local
and regional geologic maps, county geologic reports, field trip
guidebooks and other publications. In Louisiana, the entire
Moodys Branch Group is still somewhat exposed at
Montgomery Landing Bluff on the Red River.

Reference Cited:

Heinrich, Paul V., 2009, Reevaluation of Tektites Reported
from Rapides Parish, Louisiana. Louisiana Geological Survey
NewsInsights. vol. 19, no. 1, pp. 10-14.

The PDF file of this article can be either requested from
the author of downloaded from either:
http://www.scribd.com/doc/18698759/Alleged-Tektites-From-Rapides-Parish-Louisiana
or
http://www.lgs.lsu.edu/deploy/uploads/Summer_09_LGS_Newsletter.pdf


King, D. T., Jr., and L. W. Petruny, 2008, Impact stratigraphy
of the U.S. Gulf coastal states: Gulf Coast Association of
Geological Societies Transactions. vol. 58, pp. 503-516.

Georgia Deposits

In Georgia, the source bed of Georgiaites has been located.
It is "a patchy coarse-grained sand layer up to 10 cm thick that
lies at the boundary between the Twiggs Clay and the underlying
Middle Eocene Huber Formation.” It contains shocked quartz
from the Chesapeake Bay impact. This sand layer, which is the
basal layer of the Twiggs Clay, is a transgressive sheet sand
consists of sand that has been redeposited, reworked, and
bioturbated,

Published papers and abstracts are:

Harris, R. C., M. F. Roden, P. A. Schroeder, S. M. Holland, M. S. Duncan,
and E. F. Albin, 2004, Upper Eocene impact horizon in east-central
Georgia. Geology. vol. 32, no. 8, pp. 717-720; DOI: 10.1130/G20562.1
http://geology.geoscienceworld.org/cgi/content/abstract/32/8/717


Harris, R. S., M. S. Duncan, S. M. Holland, M. Steven, M. F. Roden,
Michael, and P. A, Schroeder, 2002, Probable shocked quartz as
evidence of for an Upper Eocene Impact Horizon in Coastal Plain,
Warren County Georgia. Geological Society of America Abstracts
with Programs. vol. 34, no. 6, pp. 402.
http://gsa.confex.com/gsa/2002AM/finalprogram/abstract_41931.htm

http://gsa.confex.com/gsa/2002AM/finalprogram/session_3270.htm


Schroeder, P. ., and Harris, R. S., 2004, X-ray powder diffraction
evidence for shocked quartz in an upper Eocene sand deposit,
Warren County, Georgia, U.S.A. Southeastern Geology. vol. 42,
pp. 145–150

Schreoder, P. A., R. S. Harris, M. F. Roden, M. Duncan, S. Mack,
and S. M. Holland, 2002, 100% X-Ray Diffraction Evidence for
Shocked Quartz in an Upper Eocene Sand Deposit, Warren
County, Georgia. Geological Society of America Abstracts with
Programs. vol. 34, no. 6, pp. 544.
http://gsa.confex.com/gsa/2002AM/finalprogram/abstract_38959.htm

http://gsa.confex.com/gsa/2002AM/finalprogram/session_3270.htm


In addition, multi-lithic conglomerates and breccias, which
are one to two meters thick have been reported from Georgia.
These enigmatic conglomerates, occur between the middle
Eocene Hawthorne Group and middle Miocene Altahama
Formation. Although their origin is unknown, it has been
suggested that they might be deposits related to the Chesapeake
Bay impact. If so, they might contain ejecta from this impact
(Cocker 2007, King and Petruny 2008). Additional studies of
these conglomerates are definitely needed.

References Cited:

Cocker, M., 2007, Possible impact-related conglomeratic
sediments in the upper coastal plain of southwestern Georgia.
Geological Society of America Abstracts with Programs.
vol. 39, no. 6, p. 311.
http://gsa.confex.com/gsa/2007AM/finalprogram/abstract_131779.htm


King, D. T., Jr., and L. W. Petruny, 2008, Impact stratigraphy
of the U.S. Gulf coastal states. Gulf Coast Association of
Geological Societies Transactions. vol. 58, pp. 503-516.

Yours,

Paul H.