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Volume 40 No. 1 – February 2017

Curator Comments

Kevin Righter, NASA-JSC

This newsletter reports 180 new meteorites from the 2012, 2013, and 2015 ANSMET seasons from Larkman Nunatak (LAR12), and the Miller Range (MIL13 and MIL15). Meteorites include 3 CK, 3 CM1, 15 CM2, 2 CV3, 1 CO3, 1 CR2 carbonaceous chondrite, 6 enstatite chondrites, 1 eucrite, 1 mesosiderite, and 1 ureilite.

With this newsletter, characterization and announcement of the 2012 (382 meteorites total) and 2013 (320 meteorites total) seasons are complete. The 2012 season collection is from GRA, GRO, GDR, LAR, PAT, SCO, and SZA and features large CO, CK, CR and CV chondrites (SZA 12430, SZA 12431, LAR 12247, and LAR 12002, respectively), EH3 chondrite (LAR 12001), diogenites (LAR 12010, 12248, 12320), howardite (LAR 12326), 3 irons (LAR 12059, 12204, and 12138), 3 shergottites (LAR 12011, 12095, and 12240), and the collections second winonaite (GRA 12510).

The 2013 season collection from the Miller Range (MIL13) features a lunar meteorite (MIL 13317), IAB iron (MIL 13013), aubrite (MIL 13004), CM1/2 chondrite (MIL 13005), and an unbrecciated eucrite (MIL 13019), as well as many others.

The diversity of materials from these two seasons is astounding and reflected in the large and steady number of requests we have received in the past several years. Speaking of numbers, with the recent field team collecting ~220 specimens, the total collected by ANSMET teams is ~22,013. Why the "~" you ask? During most field seasons, there are terrestrial samples collected and we slowly discover them as we classify all the samples. Therefore, we cannot give a specific number until all samples are classified (for example, the 2013 MIL season included 12 terrestrial samples). As of the Spring 2017 (this) newsletter, we have classified and announced 20,540 samples. And finally, just for more numbers – we have received >3,400 sample requests since 1978.

Reclassification

Over the last several years, we have been measuring magnetic susceptibility during the initial characterization of meteorites (see AMN vol. 39, no. 1). To make that data useful, and to verify what looked like a LL shower in the Dominion Range, we recently made thin sections of 15 large chondrites classified as LL, to compare to the magnetic susceptibility data. As it turns out, all 15 samples had olivine Fa contents of 24-25, which means these samples are L chondrites, not LL chondrites (see LPSC 2017 abstract # 2396). In fact, among the ~60 samples from Larkman Nunatak and Dominion Range that are part of the calibration of magnetic susceptibility versus X_Fa (probe data), all H chondrites had log c values > 4.9, and no LL chondrites had log c values > 4.4.

As a result, and using MS data published in AMN 39, no. 1, we have reclassified the samples listed below. We also note that there are ~140 ordinary chondrites from the 2003 season and ~990 from the 2008 season from the Dominion Range whose classification may be suspect and should be treated with caution until we verify these as well. There may be a large L shower associated with the Dominion Range and so the statistics from this region may be skewed from a regular distribution (see LPSC 2017 abstract # 2396).

Re-classified to H using magnetic susceptibility:

Sample	AMN classification	M₀ (10^-3)	Mass (g)	Log _χ(10^-9 m³/kg)	Revised classification
DOM 10030	L5	109	67.75	5.09	H5
DOM 10039	L5	189	95.23	5.25	H5
DOM 10051	L5	225	197	5.22	H5
DOM 10052	L5	189	147.72	5.14	H5
DOM 10055	L5	115	67.84	5.11	H5
DOM 10056	L5	62.7	43.15	4.96	H5
DOM 10072	L6	39.8	17.86	5.04	H6
DOM 10074	L6	43.2	14.37	5.15	H6
DOM 10076	L6	41.6	18.5	5.04	H6
DOM 10078	L5	39.2	14.13	5.12	H5
DOM 10086	L6	46.2	23.61	4.99	H6
DOM 10089	LL5	84.5	21.95	5.28	H5
DOM 10149	L5	110	61.01	5.12	H5
DOM 10160	L6	16.3	5.94	5.07	H6
DOM 10164	L6	27.6	11.31	5.05	H6
DOM 10167	L6	5.6	2.49	4.94	H6
DOM 10217	L5	35.7	18.61	4.97	H5
DOM 10228	L6	71.5	59.28	4.94	H6
DOM 10234	L6	28	13.72	4.98	H6
DOM 10235	L6	19.4	9.07	4.98	H6
DOM 10237	L6	22.4	10.18	5	H6
DOM 10246	LL6	143	79.4	5.17	H6
DOM 10247	L6	75.9	43.8	5.04	H6
DOM 10260	LL5	63.5	34.82	5.01	H5
DOM 10270	L6	4.85	2.06	4.95	H6
DOM 10293	L6	69.2	41.23	5.01	H6
DOM 10295	L5	73.2	42.19	5.03	H5
DOM 10298	L6	99.5	46.17	5.14	H6
DOM 10370	L6	68.1	18.33	5.26	H6
DOM 10371	L6	77.1	24.64	5.2	H6
DOM 10682	L6	84.2	40.44	5.1	H6
DOM 10686	L6	209	181.6	5.13	H6

Re-classified to L using magnetic susceptibility:

Sample	AMN classification	M₀ (10^-3)	Mass (g)	Log _χ(10^-9 m³/kg)	Revised classification
DOM 10032	LL6	36.7	56.31	4.66	L6
DOM 10033	LL6	95.3	124.11	4.88	L6
DOM 10035	LL6	66	87.78	4.81	L6
DOM 10036	LL6	47.5	81.3	4.68	L6
DOM 10037	LL6	40.5	48.46	4.74	L6
DOM 10038	LL6	57.5	79.29	4.77	L6
DOM 10053	LL6	48.9	93.24	4.66	L6
DOM 10054	LL6	48.2	77.71	4.7	L6
DOM 10057	LL6	42	67.03	4.68	L6
DOM 10058	LL6	62.3	67.88	4.84	L6
DOM 10060	LL6	26.9	42.31	4.59	L6
DOM 10061	LL6	21.4	40.63	4.5	L6
DOM 10062	LL6	22	21.37	4.71	L6
DOM 10063	LL6	22.9	20.48	4.74	L6
DOM 10065	LL6	28.3	26.98	4.73	L6
DOM 10066	LL6	29.3	28	4.73	L6
DOM 10067	LL6	14.4	19.62	4.56	L6
DOM 10068	LL6	17.8	23.95	4.57	L6
DOM 10070	LL6	8.6	12.63	4.5	L6
DOM 10073	LL6	8.88	8.88	4.65	L6
DOM 10075	LL6	15	22.046	4.53	L6
DOM 10079	LL6	16.7	23.25	4.56	L6
DOM 10081	LL6	36.2	36.26	4.76	L6
DOM 10082	LL6	32.7	33.95	4.73	L6
DOM 10083	LL6	26	28.31	4.68	L6
DOM 10084	LL5	14.6	17.16	4.62	L5
DOM 10087	LL6	30	45.15	4.62	L6
DOM 10140	LL5	55.3	223.77	4.6	L5
DOM 10143	LL6	58.3	124.56	4.67	L6
DOM 10144	LL6	45.4	80.66	4.67	L6
DOM 10145	LL6	33.5	71.35	4.56	L6
DOM 10146	LL6	27.9	42.44	4.61	L6
DOM 10148	LL6	39.4	54.51	4.7	L6
DOM 10150	LL6	24.2	23	4.72	L6
DOM 10151	LL6	34.4	31.93	4.77	L6
DOM 10152	LL6	27.6	34.26	4.65	L6
DOM 10153	LL6	20.2	35.55	4.51	L6
DOM 10154	LL5	27.1	27.33	4.71	L5
DOM 10155	LL5	34.5	52.95	4.65	L5
DOM 10156	LL6	32.5	36.2	4.71	L6
DOM 10157	LL5	32.7	23.93	4.84	L5
DOM 10162	LL6	12.8	14.7	4.62	L6
DOM 10163	LL6	9.64	10.38	4.63	L6
DOM 10166	LL6	11.8	11.3	4.68	L6
DOM 10168	LL6	11.4	14	4.59	L6
DOM 10169	LL6	12.2	15	4.59	L6
DOM 10181	LL6	8.76	8.73	4.65	L6
DOM 10182	LL5	11.6	10.03	4.72	L5
DOM 10184	LL6	20.3	30.03	4.55	L6
DOM 10185	LL6	16.9	21.06	4.6	L6
DOM 10210	LL5	29.9	36	4.68	L5
DOM 10212	LL5	25.9	25.39	4.72	L5
DOM 10214	LL5	17	21.42	4.6	L5
DOM 10216	LL5	33.3	33.67	4.74	L5
DOM 10218	LL5	24.1	33.8	4.6	L5
DOM 10219	LL5	9.92	11.2	4.61	L5
DOM 10220	LL6	47	78.87	4.69	L6
DOM 10221	LL6	35.3	52.2	4.66	L6
DOM 10222	LL6	28.1	46.76	4.59	L6
DOM 10223	LL6	33.6	49.76	4.65	L6
DOM 10224	LL6	43.5	49.55	4.76	L6
DOM 10225	LL6	34	60.04	4.61	L6
DOM 10226	LL6	27.8	32.7	4.67	L6
DOM 10227	LL6	24.8	44.43	4.55	L6
DOM 10229	LL6	46.1	56.34	4.76	L6
DOM 10230	LL6	13.1	17.83	4.55	L6
DOM 10233	LL6	8.58	11.34	4.54	L6
DOM 10236	LL6	16.3	19.23	4.62	L6
DOM 10238	LL6	8.94	9.23	4.64	L6
DOM 10239	LL6	14.7	18.83	4.58	L6
DOM 10240	LL6	56.1	110.53	4.68	L6
DOM 10241	LL6	51.6	102.54	4.66	L6
DOM 10242	LL6	43.5	72.7	4.67	L6
DOM 10243	LL6	34.8	52.38	4.65	L6
DOM 10244	LL6	56.8	103.15	4.7	L6
DOM 10245	LL6	35.3	45.95	4.69	L6
DOM 10249	LL6	46.5	64.14	4.73	L6
DOM 10261	LL6	36.3	36.29	4.76	L6
DOM 10263	LL6	21.7	30.78	4.57	L6
DOM 10264	LL6	27.1	21.31	4.8	L6
DOM 10265	LL6	17	16.88	4.69	L6
DOM 10266	LL6	30.9	28.35	4.75	L6
DOM 10267	LL6	26.2	33.53	4.64	L6
DOM 10268	LL5	22.6	36.51	4.55	L5
DOM 10269	LL6	36.9	36.62	4.77	L6
DOM 10272	LL5	5.08	5.64	4.58	L5
DOM 10274	LL5	8.35	7.94	4.67	L5
DOM 10276	LL5	9.41	9.36	4.66	L5
DOM 10277	LL5	12.8	12.42	4.68	L5
DOM 10279	LL5	5.61	4.67	4.7	L5
DOM 10290	LL6	36.4	48.31	4.69	L6
DOM 10291	LL6	33.7	39.56	4.71	L6
DOM 10292	LL6	44.2	44.86	4.79	L6
DOM 10294	LL6	47.2	45.44	4.82	L6
DOM 10296	LL6	38.9	48.63	4.72	L6
DOM 10297	LL6	24.1	28.88	4.64	L6
DOM 10372	LL6	16.1	19.45	4.61	L6
DOM 10373	LL6	20.2	30.39	4.54	L6
DOM 10374	LL6	32.3	57.07	4.6	L6
DOM 10375	LL5	52.6	73.07	4.75	L5
DOM 10376	LL5	56.2	50.6	4.87	L5
DOM 10377	LL6	44.6	41.88	4.82	L6
DOM 10379	LL6	46.3	91.47	4.64	L6
DOM 10432	LL6	4.66	8.75	4.38	L6
DOM 10436	LL5	8.4	14	4.45	L5
DOM 10437	LL5	9.62	15.9	4.46	L5
DOM 10438	LL5	14	23.38	4.48	L5
DOM 10443	LL5	26.7	46.1	4.57	L5
DOM 10444	LL6	26.7	42.29	4.59	L6
DOM 10446	LL5	21.1	35.38	4.53	L5
DOM 10447	LL5	37.8	78.54	4.59	L5
DOM 10448	LL6	22.3	55.71	4.45	L6
DOM 10449	LL5	57.7	89.64	4.74	L5
DOM 10457	LL5	31	62.33	4.56	L5
DOM 10460	LL6	37.8	44.38	4.73	L6
DOM 10461	LL6	34.9	80.48	4.55	L6
DOM 10462	LL6	22.3	49.46	4.47	L6
DOM 10463	LL6	44.1	60.77	4.72	L6
DOM 10464	LL6	51	41.19	4.88	L6
DOM 10465	LL6	37	40.21	4.74	L6
DOM 10466	LL6	20.7	15.5	4.81	L6
DOM 10468	LL6	19.5	24.08	4.61	L6
DOM 10545	LL6	19.95	14.2	4.82	L6
DOM 10680	LL6	25.7	59.58	4.49	L6
DOM 10681	LL6	43.8	71.09	4.68	L6
DOM 10683	LL6	37.1	50.69	4.69	L6
DOM 10684	LL6	40.9	57.79	4.7	L6
DOM 10685	LL6	48.4	57.44	4.78	L6
DOM 10687	LL6	48.7	73.92	4.72	L6
DOM 10688	LL6	79.6	156.11	4.75	L6
DOM 10689	LL6	89.9	210.59	4.81	L6

Updates to JSC webpage:

The bibliography of US Antarctic Meteorites has been updated to reflect 59 new publications from 2016. In addition, search options have been added, including ability to search by author, text, or year; users also have an option to output the search to an excel file.

The structure of the webpage has changed slightly to reflect updates and additions. The collection excel sheet has been updated to include all samples through AMN 39, no. 2, the list of bandsawed samples has been updated, and portions have been updated to reflect our current request, review, approval, allocation, and loan agreement processes.

Reminder to acknowledge samples received from NASA-JSC

When publishing results of your research, please include the split numbers used in the research.

We also request that scientists use the following acknowledgement statement when reporting the results of their research in peer reviewed journals: “US Antarctic meteorite samples are recovered by the Antarctic Search for Meteorites (ANSMET) program which has been funded by NSF and NASA, and characterized and curated by the Department of Mineral Sciences of the Smithsonian Institution and Astromaterials Curation Office at NASA Johnson Space Center.” Such an acknowledgement will broaden the awareness of the funding mechanisms that make this program and these samples possible.

We suggest you find out how to acknowledge samples received from all the collections/museums from which you have received materials so that all the institutions making samples available to you receive proper credit and acknowledgement.

ANSMET 2016 – 2017 Field Season

Jim Karner, Ralph Harvey and John Schutt

The 2016–17 field season was marked by a major change in plans, and then a major delay getting into the field, ugh! ANSMET had planned to send a group of eight to work out of the Shackleton Glacier Camp (SHG) in the southern TransAntarctic Mountains. From there the group would split into two teams of four, and each team would search for and recover meteorites from nearby ice fields. That plan was not meant to be, however, because by mid-December the SHG was experiencing a serious shortage of fuel and logistical resources, and would be unable to support the ANSMET team. We quickly descoped our field season (so as to not be cancelled outright) and planned for a trip to the Elephant Moraine (EET) icefields, which could be supported out of McMurdo Station. ANSMET had recovered over 2000 meteorites from EET in the past, but the area had not been visited since 1999 due to extensive snow cover. The new season plan would allow ANSMET to recover meteorites from previously searched and unsearched areas of the vast icefields at EET (Figure 1).

The team was ready for put–in to EET on December 15, but a slew of bad weather at McMurdo and/or EET delayed John Schutt, Jani Radebaugh, Brian Rougeux, and Minako Righter until December 29. Another week of bad weather kept Jim Karner and Alex Meshik in McMurdo until Jan. 3. The full team was at EET from Jan. 4 to Jan. 19, but during that time the team was limited to only seven full days of searching out of a possible 14 working days. It turns out EET has a lot of bad weather - seriously windy, cold, lots of blowing snow! Anyway, the team worked hard when it could and employed recon and systematic searching throughout the vast EET icefields. The team recovered a total of 173 meteorites; that, added to Duck Mittlefelhdt and John Schutt's recon efforts earlier in the season, made for a grand total of 219 meteorites recovered for the 2016–17 field season. A smaller quantity than in most ANSMET seasons, but hopefully they will be of high quality!

Figure 1. ANSMET team members search for meteorites near their camp at EET.

Report from the Smithsonian

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

All is well in the Division of Meteorites at the Smithsonian. We are pleased to report that our new electron microprobe (a JEOL JXA 8530f Hyperprobe) arrived on November 1st, 2016, and is built and in the initial stages of testing. This new instrument will be used to classify the Antarctic Meteorites and will provide us with state of the art capabilities to do so. Here's hoping that all of the microprobe analyses in the Fall newsletter come to you from the new instrument!

We have two new volunteers on board with the Division of Meteorites. Greg Polley, who has a Masters Degree in Geology from the University of Maryland and has been working to complete the inventory of photographs of every Antarctic meteorite thin section in our collection. Doug Ross, a local musician and meteorite enthusiast, has recently come on board as well, and has been great about lending a hand while learning more about meteorites. We are happy to have them here, and appreciate their help and enthusiasm!