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Интеллектуальная Система Тематического Исследования НАукометрических данных |
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Endolithic (bio)weathering and rock varnish in East Antarctica as early Earth analogs of “protosoils”тезисы доклада
- Авторы: Sergey Goryachkin, Alex Cherkinsky, Nikita Mergelov, Ilia Shorkunov
- Сборник: Mineralogical Magazine
- Том: 76
- Тезисы
- Год издания: 2012
- Первая страница: 1777
- Последняя страница: 1777
- Аннотация: Rock varnish and endolithic organisms being quite informative as early-Earth analogs are very well studied apart however their interaction and possible cogenesis have never been particularly explored, as well as nobody has studied them as soils. Endolithic organisms of Antarctic Dry Valleys inhabit structural cavities in the superficial rock interior [1]. The other common feature of Antarctica is the red-brownish colour of solid rocks (rock varnish). Our explorations in coastal oases of East Antarctic at field and microscopic scales showed that such system as “endolithic organisms-granitoid rock-weathering products” has all features to be denominated as “protosoil”: (1) rock layer exposed to external abiotic factors; (2) this layer is inhabited by living organisms synthesizing and decomposing organic matter (OM); (3) induced by biotic and abiotic factors the initial lithomatrix is transformed in situ, the transformation products (e.g. fine earth) are retained and/or taken away, the vertical heterogeneity (microprofile) is formed. Organo-mineral horizons of endolithic soil contain 0,2-3,3% C and 0,02-0,47% N. 14C mean residence time of OM reaches 480±25 y BP, δ13C= -23,7- -21,0 ‰. Major pedogenic products are numerous Fe-C- Si-Al- S-Cl-Ca-Mg-containing bio-coatings which cover cavities in the rock. Main binding material are amorphous Si and Al with incorporated detritus. SEM morphology and composition of coatings correspond to those observed in varnish on rock. Thus, certain types of rock varnish could be the products of endolithic (bio)weathering exposed after exfoliation and transformed by external factors. This hypothesis can’t explain all rock varnishes (e.g. formed by accretion). However, this “endoliths-varnish” system may be recognized as an early-Earth “protosoil”.
- Добавил в систему: Мергелов Никита Сергеевич