Cloppenburg (H4-5) – first results of a new find

Storz*, J., Bischoff, A., Degering, D., Ebert, S., Heinlein, D., Jull, T., Kontul, I., Li, X., Merchel, S., Oberst, J., Ott, U., Pack,, A., Peters, S., Petö, M.K., Rugel, G.

Paneth Kolloquium Nördlingen (2017), abstract #0075
October 11-13, 2017

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“The Cloppenburg meteorite of 141 g was found March 15, 2017 by the facility manager of a school while collecting rocks for the school garden. The rock with a mean density of (3.33 ± 0.03) g/cm3 is a brecciated H-group ordinary chondrite (H4-5) with mean olivine and low-Ca pyroxene of Fa18.5±0.3 and Fs16.4±0.6, respectively. The breccia containing shock veins is weakly shocked (S3) and heavily weathered (W3). The occurrence of vivianite, the oxygen isotopes, and the Ba-enrichment (by INAA) indicate strong weathering in a very wet environment. Radionuclide data evaluation is still ongoing: Accelerator mass spectrometry (AMS) of 14C, will reveal the terrestrial age. An upper limit of the terrestrial age is yet set by low-level gamma-spectrometry in the Felsenkeller underground lab. No 22Na (t1/2=2.6 a) nor 44Ti (t1/2=59 a) could been detected within a counting time of 27 days, whereas 26Al (t1/2=0.7 Ma) was clearly identified. AMS of 10Be (t1/2=1.4 Ma) of ~18 dpm/kg confirms the cosmic ray exposure age (CRE age) of (7.5 ± 0.4) Ma from noble gas mass spectroscopy.”