2,405 research outputs found

    Analysis of Moderately Siderophile Elements in Angrites: Implications for Core Formation of the Angrite Parent Body

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    Angrites are an enigmatic group of achondrites, that constitute the largest group of basalts not affiliated with the Moon, Mars or Vesta (HEDs). Chemically, angrites are exceptionally refractory element- enriched (e.g., Al, Ca) and volatile element-depleted (e.g., Na and K) achondrites. Highly volatile siderophile and chalcophile elements (Zn, Ge and Se) may be less depleted than alkalis and Ga taken to imply a fractionation of plagiophile elements. Core formation on the angrite parent body (APB) is not well understood due to the dearth of moderately siderophile element (Ga, Ge, Mo, Sb, W) data for angrites, with the exception of Ni and Co [2]. In particular, there are no data for Mo abundances of angrites, while Sb and W abundances are reported for only 3 angrites, and have not always been determined on the same sample. The recent increase in angrite numbers (13) has greatly increased our knowledge of the compositional diversity of the angrite parent body (APB). In this study, we report new Co, Ni, Ga, Mo, Sb and W abundances for angrites by laser ablation inductively coupled plasma mass spectrometry (ICP-MS) in order to place constraints on core formation of the APB

    The archaeology of the first farmer-herders in Egypt : new insights into the Fayum Epipalaeolithic and Neolithic

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    This book explores how and why farming and herding started in a particular time period in a particular region of Egypt. The earliest Neolithic farming in combination with herding in Egypt is known in the Fayum, which is a large oasis with a permanent lake in the Egyptian Western Desert. Farming and herding started at the transition from the Epipalaeolithic to Neolithic in the 6th millennium cal.BC owing to the arrival of Levantine domesticates. The Neolithic farmer-herders in the Fayum relied heavily on hunting and fishing, which had been the major subsistence activities since the Epipalaeolithic period. There are no remains of substantial dwellings to indicate that these farmer-herders lived a sedentary way of life. Previous researchers have thus asserted that the Fayum people were nomadic and moved seasonally. Lithic evidence obtained through new research suggests that the Fayum people were not nomadic but were tethered to lakeshores. The introduction of farming and herding would not have taken place in the Fayum without a lakeshore-tethered if not fully sedentary way of life. But the success of a farming-herding way of life in the Fayum would not have been possible without the reorganisation of mobility, which led to decreased moves of residential bases and increased logistical moves of individuals. Lithic evidence also suggests that the Fayum people kept exerting special efforts to make farming and herding a reliable subsistence and to maximise the yield. The introduction of farming and herding in the Fayum would have been a solution to mitigate growing population/resource imbalances when the climate became drier and more people had to aggregate around permanent water sources in the 6th millennium cal.BC.Netherlands Organisation for Scientific Research (NWO/WOTRO file number: W52-1038)UBL - phd migration 201

    Metallic partial melting processes on the acapulcoite-lodranite parent body.

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    第3回極域科学シンポジウム/第35回南極隕石シンポジウム 11月29日(木) 国立国語研究所 2階講

    Lithophile element characteristics of acapulcoite-lodranite.

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    第2回極域科学シンポジウム/第34回南極隕石シンポジウム 11月18日(金) 国立国語研究所 2階講
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