AMN 33,2 Program News

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Home Antarctic MeteoritesAntarctic Meteorite NewslettersAMN 33,2 Program News
Volume 33 No. 2 – September 2010

Program News

Curator Comments

Kevin Righter, NASA-JSC

New meteorites

This newsletter reports 255 new meteorites from the 2007, 2008 and 2009 ANSMET seasons from the Miller Range (MIL), Dominion Range (DOM) and the Allan Hills (ALH) regions. The first new samples from the 2009-2010 ANSMET season at the Miller Range are reported here and the region is continuing to yield many interesting and diverse samples. Included are four new lunar meteorites - two of which are paired - and three additional masses paired with the MIL 03346 nakhlite, bringing the combined total of MIL nakhlite material to 1.87 kg. Other achondrites in this newsletter are a howardite, 4 diogenites (3 paired), an acapulcoite/lodranite, and a ureilite. There is also a large pairing group of CO3 chondrites from the Miller Range 2007 and 2009 seasons. Other carbonaceous chondrites include a CB chondrite (paired with two other previous MIL CBs), two CK chondrites, a CM chondrite, a CR chondrite, and 5 CV3 chondrites. One of the CV3 chondrites is a 6.29 kg sample bestowed with the number MIL 090001.

A reminder about guidelines for destructive analysis on thin sections

Several recent incidents have compelled us to write a reminder to all PIs who have thin sections on loan from our collection. With the advent of new techniques that utilize thin sections for micro-analytical techniques, we have many more requests for thin and thick sections. On the other hand, some of our samples are small and rare, and protected by the Meteorite Working Group guidelines. One of those guidelines is to reserve only a few sections for destructive analysis so that as much sample as possible is preserved for study and observations. As a result, any destructive analyses that a scientist would like to perform on a thin section must first be approved by the meteorite working group. Destructive analyses include (but are not limited to) Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS), Focused Ion Beam extractions (FIB), Secondary Ion Mass Spectrometry or ion probe (SIMS), microdrilling or micro-coring, and high sample current techniques used for some imaging such as X-ray mapping with Field Emission Guns (FEG). If you have not been specifically approved to carry out analysis on a thin or thick section with one of these techniques you must first contact the meteorite curation group for permission. Requests are usually handled faster (between meetings) if the section(s) in question is (are) already in the possession of a PI.

If you have completed your destructive analysis and are ready to return the section to us, please fill out a short form that allows us to understand what techniques were used on the section and what the extent of damage has been: http://curator.jsc.nasa.gov/antmet/returns.cfm. This form does not need to be filled out if you have undertaken standard SEM or electron microprobe analysis.

We oversee one of the largest research collections in the world, which has grown every year for over thirty years, so we thank you in advance for your cooperation in helping to maintain the integrity of the collection.

Cutting Plan and Photo of Howardite EET 87513

Cutting Plan and Photo of Howardite EET 87513

Lunar Meteorite Compendium

The Lunar meteorite compendium was initially completed in May 2007 by the Antarctic meteorite group. The number of lunar meteorites was 42 then, and now it has grown to 62. The compendium has now been updated (for a third version) and includes research published up to January 2010. The web pages has also been given a new design and look, thanks to the efforts of Judy Reustle and Nancy Todd:

http://curator.jsc.nasa.gov/antmet/lmc/index.cfm

If you know of research that is not mentioned or covered in the chapters, please let us know. Kevin is updating them as frequently as he can.

HED (Howardite-Eucrite-Diogenite) Meteorite Compendium

We are working on an HED meteorite compendium given the anticipated interest in the DAWN mission encounter with 4 Vesta in 2011. As part of the compendium we will feature some samples that have been in the collection for some time and analyzed more extensively than others. For example the paired howardites EET 87503 and EET 87513 were slabbed and studied extensively. The photos have not been available online, but we will include as much information as possible.

We would also remind people studying HEDs that we have many howardites and polymict eucrites that are large (> 200 g) and relatively unstudied, especially those recovered since 1991. Please check our database if you are interested in finding out which samples those are.

2010-2011 ANSMET Field Season Report

Ralph Harvey, Principal Investigator, ANSMET

One of our sayings in the Antarctic Search for Meteorites (ANSMET) program is that a successful ANSMET field team member has five distinct qualities:

  1. Incredible stamina
  2. A high tolerance for pain
  3. A poor memory
  4. ....And I forget the other three..........

This comes to mind because as I started writing this piece, I couldn't think of anything new to say — yet in hindsight it's been a very active summer. The ANSMET program remains healthy and active, and we're about one year away from the program's 35th anniversary. Through the last decade we've often had two parties in the field during each austral summer; we took a break from that for a few years recently, but for the the 2010-2011 field season we'll once again have two field teams, courtesy of an infusion of funding from NASA. Our 8-person systematic searching team will travel to the icefields surrounding the Davis Nunataks and Mt. Ward (affectionately known as Davis-Ward), the home of many of the DOM meteorites. One previous season of systematic searching and two shorter reconnaissance visits have recovered more than 600 meteorite specimens from these icefields. A large region of blue ice remains unsearched, and the 10–11 ANSMET field team will attempt to cover as much of this as possible through overlapping systematic transects.

A second research objective for this team will be short first–ever visits to two icefields in the central Transantarctic Mountains (near Buckley Island and Moody Nunatak) using helicopter support from the CTAM camp located at the old Beardmore South site this season. Attempts to reach these two icefields in past seasons have been unsuccessful using fixed–wing aircraft, so the helicopter–based support available this season is a unique opportunity. The four-person reconnaissance team has an ambitious schedule that includes visits to a number of promising sites in the "Atlantic" parts of the East Antarctic plateau. The expedition will start at some icefields a few km off the eastern extremities of the LaPaz icefields and later visit two or three other sites spread out all the way to the Omega nunataks (so named because it was the last rock seen for 2000 miles by an early traverse of the continent). Many of these distant sites were located by careful perusal of abundantly-available satellite imagery on the internet, but in spite of the digital era we live in, in the end it takes boots on the ground to establish whether or not meteorites are present. As we have done on a number of previous expeditions, we plan to update a weblog on the ANSMET website, so if you're interested, please tune in!

Photo showing weather conditions experienced at the Davis-Ward Icefields

Weather conditions experienced at the Davis-Ward Icefields. Photo courtesy of Joe Boyce.

Report from the Smithsonian

Cari Corrigan, Geologist (Dept. of Mineral Sci.)

This newsletter announces the classification of all but ~150 of the '07 meteorites and continues working through the newly received ALH and MIL '09's. Things continue to look up here in the Division of Meteorites at the Smithsonian. We have a new post doc, Karen Stockstill-Cahill, who began in January, and another, Yulia Goreva, who began in August. Karen comes to us from the University of Hawaii and Yulia from the University of Arizona. Both Karen and Yulia will be assisting in the Antarctic meteorite classification process. Jonathon Cooper survived his first year at the museum, and has picked up the fine art of thin section making very quickly, making well over half of the thin sections we probed for this newsletter, including dozens of carbonaceous chondrites, which are tricky to make. One sad bit of news this past year was the passing of Brian Mason, the first curator of Antarctic Meteorites. Among other significant career achievements, Brian secured the Smithsonian's role in the classification and curation of the Antarctic collection. While we mourn the loss of such an esteemed colleague as Brian, we are extremely pleased to welcome Karen and Yulia, and will continue to make sure the high level of service that you have come to expect from the Smithsonian continues.