نتایج جستجو برای: lithic

تعداد نتایج: 1046  

Journal: :Archaeological and Anthropological Sciences 2018

2009
M. Ivarsson P. Lindgren A. Neubeck C. Broman N. G. Holm H. Henkel

Introduction: Impact-generated hydrothermal systems are often suggested as suitable habitats for primitive life [1,2], but fossil evidence of such colonization are rarely reported in the literature. Here, we report on the occurrence of putative microfossils in a hydrothermal system of the Dellen impact structure, Sweden. Impact-induced hydrothermal systems: Impacts in water-bearing targets can ...

2008
Hilary Downes David W. Mittlefehldt Noriko T. Kita John W. Valley

Ureilites are ultramafic achondrites that exhibit heterogeneity in mg# and oxygen isotope ratios between different meteorites. Polymict ureilites represent near-surface material of the ureilite parent asteroid(s). Electron microprobe analyses of >500 olivine and pyroxene clasts in several polymict ureilites reveal a statistically identical range of compositions to that shown by unbrecciated ure...

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