Oligocene and early Miocene mammal biostratigraphy of the Valley of Lakes in Mongolia

Abstract

The Taatsiin Gol Basin in Mongolia is a key area for understanding the evolution and dispersal of Central Asian mammal faunas during the Oligocene and early Miocene. After two decades of intense fieldwork, the area is extraordinarily well sampled and taxonomically well studied, yielding a large dataset of 19,042 specimens from 60 samples. The specimens represent 176 species-level and 99 genus-level taxa comprising 135 small mammal species and 47 large mammals. A detailed lithostratigraphy and new magnetostratigraphic and radiometric datings provide an excellent frame for these biotic data. Therefore, we test and evaluate the informal biozonation scheme that has been traditionally used for biostratigraphic correlations within the basin. Based on the analysis of the huge dataset, a formalised biostratigraphic scheme is proposed. It comprises the Cricetops dormitor Taxon Range Zone (Rupelian), subdivided into the Allosminthus khandae Taxon Range Subzone and the Huangomys frequens Abundance Subzone, the Amphechinus taatsiingolensis Abundance Zone (early Chattian), the Amphechinus major Taxon Range Zone (late Chattian), subdivided into the Yindirtemys deflexus Abundance Subzone and the Upper Amphechinus major T. R. Z., and the Tachyoryctoides kokonorensis Taxon Range Zone (Aquitanian). In statistical analyses, samples attributed to these biozones form distinct clusters, indicating that each biozone was also characterised by a distinct faunal type.Electronic supplementary materialThe online version of this article (doi:10.1007/s12549-016-0264-x) contains supplementary material, which is available to authorized users.

Palaeo-environmental evolution of Central Asia during the Cenozoic: New insights from the continental sedimentary archive of the Valley of Lakes (Mongolia)

“…A younger basalt III group (13.2-12.2 Ma) dates back to the middle Miocene, but is not part of the sedimentary succession investigated here. Further details about the local nomenclature, the investigated profiles, profile correlation and lithostratigraphic relationships are provided in Harzhauser et al (2017 and Richoz et al (2017). Due to the complex architecture of the Valley of Lakes basin and adjacent areas, a mixed provenance has been proposed for the basin fill, however, detailed knowledge about the palaeo-depositional environment and source area relationships remain poorly constrained (Höck et al, 1999).…”

“…to normal grading, ripple marks, channel and scour fills and overbank fines (Richoz et al, 2017). Most horizons are highly fossiliferous (remains of small mammals and gastropods) and show signs of paleosol formation, such as calcite nodules and crusts incorporating plant debris, and burrow structures (Harzhauser et al, 2017).…”

“…An exception is the sedimentary archive of the Valley of Lakes (Mongolia), which hosts a ~34-21 Ma record of continental sedimentation in Central Asia. The biostratigraphy and the correlation between different outcrops in this basin are well established based on mammalian communities and gastropod records (Harzhauser et al, 2017), magnetostratigraphy (Sun and Windley, 2015) and radiometric age dating of different basalt horizons , rendering this https://doi.org/10.5194/cp-2021-32 Preprint. Discussion started: 25 March 2021 c Author(s) 2021.…”

“…Recently, Richoz et al (2017) have identified two aridification pulses in Central Asia, in the early and late Oligocene, which they assigned to global climatic events. To date, a correlation of the global marine record with the terrestrial record of Mongolia is barely developed (Harzhauser et al, 2016;Harzhauser et al, 2017;Richoz et al, 2017), which limits our understanding of the relative influences of climate change and regional tectonics on the evolution of hydroclimate and weathering conditions in Central Asia in the Cenozoic.…”

On the oldest Mongolian moschids (Mammalia, Ruminantia) and the early moschid evolution

“…Instead, the moschid males possess saber-like upper canines that are used both in display and for male-to-male combat. Today, the genus Moschus naturally occurs in Asia (from Afghanistan to Siberia) in mountainous and hilly areas (Groves, 2011;Groves and Grubb, 2011). All current musk deer populations are listed in Appendices I and II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES, 2017) and the IUCN Red List of Threatened Species.…”