کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
9526053 1636197 2005 24 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Facies-related diagenetic alteration in lacustrine-deltaic red beds of the Paleogene Ergeliin Zoo Formation (Erdene Sum area, S. Gobi, Mongolia)
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فرآیندهای سطح زمین
پیش نمایش صفحه اول مقاله
Facies-related diagenetic alteration in lacustrine-deltaic red beds of the Paleogene Ergeliin Zoo Formation (Erdene Sum area, S. Gobi, Mongolia)
چکیده انگلیسی
The prodelta/mud-sand flat deposits (unit I) were dolomitized and cemented by high-Mg calcite during evaporative pumping at times of low lake-stand under redox conditions greater than 0 and intrastratal solutions of strong alkalinity. Manganoan dolomite is fairly widespread in the delta front sediments (unit II), the Mn content of which is likely to have been derived from decomposition of vertebrate remains. The Mn/Fe ratio in the carbonate minerals was controlled by the redox conditions and the shallow burial depth. In the porous delta front sediments Eh values around zero and pH values slightly above 7 occurred as a result of basinward fluid movements (high-Mn dolomite, high-Fe dolomite, low-Mg calcite). Fluid movement was locally impeded by finer-grained delta plain deposits (unit III), intertonguing with arenaceous aquifers (low Mg-moderate Fe calcite, high-Mn calcite). Higher up on the delta plain with deposits laid down in an environment transitional between distal alluvial and deltaic (unit IV), closed lake basin conditions reappeared as fluids emerged from the distal alluvial-fluvial deposits or were driven by capillary force to ascend and form calcretes abundant in Mg-bearing calcite. The climatic conditions in the Erdene Sum area, Mongolia, are likely to have been semi-arid transitional into arid.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Sedimentary Geology - Volume 181, Issues 1–2, 1 November 2005, Pages 1-24
نویسندگان
, , , , , , ,