Antarctic Meteorite NewsletterNewsletter Volume 28, Number 2 August 2005 A periodical issued by the Meteorite Working Group to inform scientists of the basic characteristics of specimens recovered in the Antarc- Curator’s Comments tic. Edited by Cecilia Satterwhite and Kevin Righter, NASA-JSC Kevin Righter, NASA Johnson Space Center, Houston, Texas 77058 New Meteorites This newsletter contains classifications for 274 new meteorites from the 2003 and 2004 ANSMET collections. They include samples from the Cumulus Hills, Larkman Nunatak, LaPaz Ice Field, MacAlpine Inside this Issue Hills, Dominion Range, Miller Range, Roberts Massif, and Sandford Curator’s Comments..................1 Cliffs. Petrographic descriptions are given for 33 of the new meteorites; New Meteorites.........................3 19 pallasites, 2 ureilites, 1 anomalous ureilite, 1 unusual aubrite, a Location Abbreviations mesosiderite clast, 1 unbrecciated eucrite, 2 CK, 2 CM, and 1 CO3 and Map...............................3 chondrites, 2 type 3 ordinary chondrites, and a small iron. Several of Table 1: Newly Classified these new meteorites are paired with samples from previous Antarctic Meteorites...............4 newsletters (see Table 3). The two new CK chondrites bring the number Table 2: Newly Classified of US Antarctic CK’s to a total of 77 (20 unique meteorites with pairings). Meteorites by Type...............10 Pallasites are rare among Antarctica meteorites. Previously Notes to Tables 1 & 2..............11 Table 3: Tentative Pairings.......12 there have been only 8 recovered: PCA 91004, PCA 91005, PCA 91388, Petrographic Descriptions........ 13 QUE 93544 (ANSMET), GRV 020099 (PRIC collection), Thiel Mountains Sample Request Guidelines......18 (main mass at NMNH) and Y74044, and Y8451 (NIPR collection). CMS Antarctic Meteorite Laboratory 04069 (44.7 kg) and its 18 pairs from Cumulus Hills total 170.55 kg, by Contacts............................. 18 far the largest pallasite yet recovered from Antarctica. Meteorites On-Line..................19 CMS 04049 is a beautiful unbrecciated eucrite. Its coarse grained nature is similar to a few other unbrecciated eucrites in the collection, including PCA 91245 and GRA 98098. Pictures of each of these have recently been added to our website, and are shown here for comparison to the images of the new sample CMS 04049. Finally, we have two very unusual achondrites in the newsletter. LAR 04315 is an anomalous ureilite that contains many interesting features described within by Tim McCoy, and LAR 04316 is an aubrite that contains a rare basaltic vitrophyre clast similar to those described by Fogel (GCA 69, 1633-1648) in Khor Temiki and LEW 87007. continued on p.2 Sample Request Deadline MWG Meets Sept. 15, 2005 Sept. 29-30, 2005 1 Requesting samples Report on the 2005-2006 Field In light of several requests we have received, we have decided to reiterate a few Season points when writing sample requests. First, Ralph Harvey, Principal Investigator the Meteorite Working Group (MWG) meets Antarctic Search for Meteorites (ANSMET) program twice a year to make recommendations regarding requests for scientific study of meteorites. The MWG members can most In about 8 weeks we’re going to be starting a new effectively judge the merits of a study when ANSMET season that promises to be one of the most the descriptions are concise yet informative. challenging and potentially rewarding in a long time. But For example, when someone states “I need because of problems getting funding delivered and people this meteorite for my research”, that is not very put in the right places at the right times, preparations helpful, because the research is not haven’t been where they should be and there’s still too mentioned, nor is the reason given for the much left to do. Only in the last few days has it been need. Please give a brief description of the clear how many field parties we’d have, and field team research, along with an explanation of why membership is still in flux. these particular samples are of interest. As in recent past seasons, ANSMET will send out Second, sometimes we receive multiple two field parties. The first, a party of eight, will deploy to requests from one investigator for the same the Miller Range to begin systematic searching of the ice deadline. Although we realize that sometimes fields. This place has a lot of potential. It’s been visited this is unavoidable, please try to keep all three times before, and each time field party members requests on one form. found meteorites in their path no matter the direction they were traveling. It’s also where ANSMET found its most Lunar Meteorite Compendium recent martian meteorite, the nakhlite MIL 03346, during Work is continuing on the Lunar a reconnaissance visit in 2003. I can’t wait to see what Meteorite Compendium. Draft chapters have else is out there! been completed for six of the US Antarctic The second team, dedicated to reconnaissance, meteorites - ALHA81005 (the first recognized has what can only be described as a “Groovy Retro-style” lunar meteorite), MAC 88105, LAP 02205 (and trip ahead of them (and here I feel obligated to add the their pairings) QUE 93069/94269, QUE phrase “Right On”). In a throwback to the very first days 94281, and EET 87521/96008. Processing of ANSMET, the reconnaissance team of four will be sketches and genealogy charts have been conducting a snowmobile traverse southwards from the prepared for these meteorites, and will soon southern end of the Allan Hills region, visiting a number be posted on our website. In addition, of modest-sized ice fields scattered along the ice sheet chapters are underway for the other lunar above the Dry Valleys. Some of these sites were among meteorites in our collections –MET 01210 and the very first looked at by Bill Cassidy and colleagues 30 PCA 02007, as well as others such a Y86032 years ago; and since those days there have been some and it’s paired masses (Y82192 and 82193). serendipitous discoveries and advances in our In the meantime if you have some lunar understanding of meteorite concentrations that strongly meteorite publications that you think may be encouraged us to have another look. Moving camp every relevant to such a project, please send them 5 to 7 days, the goal of the recon team will be to give us to [email protected]. A few of you the final word on the ice fields easily reached from have done this already, and it has been very McMurdo, cleaning up all the recoverable specimens they beneficial - thank you! can. There’s even a third field team this year! I’ll be leading a group of four returning to the Lewis Cliff Ice Tongue to study local evaporites as a potential martian analog. While this third team is not really a part of ANSMET, we are sharing logistics and expertise and of course, keeping our eyes open for meteorites. 2 New Meteorites 2003-2004 Collection Pages 4-19 contain preliminary Macroscopic descriptions of stony me- Meteorite descriptions contained in descriptions and classifications of teorites were performed at NASA/JSC. this issue were contributed by the meteorites that were completed These descriptions summarize hand- following individuals: since publication of issue 28 (1), specimen features observed during inital Feb. 2005. Specimens of special examination. Classification is based Kathleen McBride, Cecilia Satterwhite petrologic type (carbonaceous chon- on microscopic petrography and recon- Antarctic Meteorite Laboratory drite, unequilibrated ordinary chon- naissance-level electron microprobe NASA Johnson Space Center drite, achondrite, etc.) are repre- analyses using polished sections pre- Houston, Texas sented by separate descriptions un- pared from a small chip of each mete- less they are paired with previously orite. For each stony meteorite the Tim McCoy, Linda Welzenbach, described meteorites. However, sample number assigned to the prelimi- Cari Corrigan, and Allison Gale some specimens of non-special pet- nary examination section is included. Department of Mineral Sciences rologic type are listed only as single In some cases, however, a single mi- U.S. National Museum of Natural line entries in Table 1. For conve- croscopic description was based on History nience, new specimens of special thin sections of several specimens be- Smithsonian Institution petrological type are also recast in lieved to be members of a single fall. Washington, D.C. Table 2. Antarctic Meteorite Locations ALH — Allan Hills OTT — Outpost Nunatak BEC — Beckett Nunatak PAT — Patuxent Range BOW — Bowden Neve PCA — Pecora BTN — Bates Nunataks Escarpment CMS — Cumulus Hills PGP — Purgatory Peak CRE — Mt. Crean PRA — Mt. Pratt DAV — David Glacier PRE — Mt. Prestrud DEW — Mt. DeWitt QUE — Queen Alexandra DOM — Dominion Range Range DRP — Derrick Peak RBT — Roberts Massif EET — Elephant Moraine RKP — Reckling Peak FIN — Finger Ridge SAN — Sandford Cliffs GDR — Gardner Ridge SCO — Scott Glacier GEO — Geologists Range STE — Stewart Hills GRA — Graves Nunataks TEN — Tentacle Ridge GRO — Grosvenor Mountains TIL — Thiel Mountains HOW — Mt. Howe TYR — Taylor Glacier ILD — Inland Forts WIS — Wisconsin Range KLE — Klein Ice Field WSG — Mt. Wisting LAP — LaPaz Ice Field LAR — Larkman Nunatak LEW — Lewis Cliff LON — Lonewolf Nunataks MAC — MacAlpine Hills MBR — Mount Baldr MCY — MacKay Glacier MET — Meteorite Hills MIL — Miller Range ODE — Odell Glacier 3 Table 1 List of Newly Classified Antarctic Meteorites ** Sample Weight Number (g) Classification Weathering Fracturing % Fa % Fs DOM 03180 ~ 219.9