An Outline and New Aspects of the Regional Stratigraphy of Mongolia

Abstract

This paper concerns deals with the Mongolian regional stratigraphic classification of sedimentary, sedimentary-volcanogenic sediments, and metamorphic complex spread over the territory of Mongolia according to the new International Chronostratigraphic Chart [1]. The regional stratigraphy of Precambrian-Cenozoic rocks of the Mongolian territory was studied by Dorjnamjaa et al. [2]. So, this paper provides for the stratigraphy and correlation of key sections through the Archean-Proterozoic-Mesozoic-Cenozoic of various areas of Mongolia. In this paper, the author introduces the most important results indicating the key reference sections for the first time and put into a broad regional context. The characterization and geologic mapping of lithological units provided an essential basis for the lithostratigraphy, biostratigraphy and chemostratigraphy. Especially key biostratigraphic aspects are the phenomenon of faunal succession. The basic lithostratigraphic unit is the formations and groups which have been successful mapped. At present in Mongolia for Precambrian period (systems and series) 30 formations and groups, for Paleozoic-about 250 formations and groups, for Mesozoic-102 formations and groups, for Cenozoic-27 formations, members, and beds are distinguished. The auxiliary stratigraphic units are members, beds which should be mapped depending on great extent of detailed study. In the regional stratigraphical classification, there are two primary kinds of stratotypes [3]: a) unit stratotypes, which serve as the standard of definition for a stratigraphic unit, and b) boundary stratotypes, which serve as the standard of definition for a stratigraphic boundary. These aspects, in particular gradational boundaryas far as possible were examined for example for Archean-Paleoproterozoic (by geochronologic data), Ediacaran-Early Cambrian (by soft-bodied fossils, trace fossils and small shelly fossils), Ordovician-Silurian (by beyrichiidostracodes), Devonian-Carboniferous (by conodonds), Paleocene-Eocene (by mammals), Oligocene-Miocene (by small rodents) systems and series.

New scientific direction of the bacterial paleontology in Mongolia

“…All kinds of microbes, including prokaryotes and eukaryotes and their symbiotic associations with each other and higher organisms, can contribute actively to geological phenomena, and central to many such geomicrobial processes are transformations of metals and minerals. Indeed a diverse Proterozoic-Phanerozoic sedimentary stratigraphic rocks in Mongolia record and faunal, floral, and also bacterial localities (Mitrofanov et al, 1981;Bat-Ireedui, 1991, Bosak et al, 2011a, b;Barsbold and Byamba, 2012;Byamba, 2012;Dorjnamjaa, 2016;Dorjnamjaa et al, 2016;Dorjnamjaa, 2017;Anderson et al, 2017aAnderson et al, , b, 2018. In Mongolia the oldest microorganisms from the Paleoproterozoic were found in the iron-bearing quartzite.…”