T164 Evolution of Terrestrial Ecosystems: Community Assembly through Time I

Tuesday, 6 November 2018
8:00 AM - 12:00 PM
Room 143-144

CONSTRAINING ECOSYSTEM CHANGE IN THE TIEN SHAN OF KYRGYZSTAN

Paper number: T164-10
Program: Technical Sessions
Time: 10:15 AM – 10:30 AM

Authors

Abstract

Kyrgyzstan is the single most seismically active country in the world. Accessing the past, and therefore future hazard of faults, necessitates a high-resolution understanding of the timing of different geologic events. With no radiometrically datable rocks from the Neogene of Kyrgyzstan, biostratigraphy, coupled with magnetostratigraphy, offers a previously unutilized method of constraining the initiation of uplift, and when tectonic change in turn drove climatic and ecosystem changes. We herein present the first work formally describing Neogene vertebrate faunas from the Kochkor Basin of Kyrgyzstan. Utilizing a combination of biostratigraphy and magnetostratigraphy to constrain the timing of when the vertebrate assemblages were emplaced, and have dated the four investigated bone beds to all fall in the latest Miocene, spanning 9-5 million years ago. All four bone beds represent mass death assemblages, inferred to be from drought-caused mortality. The timing of the deposits corresponds to uplift in the Pamirs, Himalayan, and greater Tibetan Plateau, which would have blocked the Indian monsoon from reaching Central Asia, forever altering the climate and biota of the region. This change is reflected in the shifting mammal faunas, as evidenced by the novel rhinocerotid I describe in a phylogeographic context, as well as shifting faunas from those dominated by browsing ungulates indicative of semi-closed habitats to fauna associated with the high steppes of today. The emergence of steppe faunas is in line with the “Out of Tibet” hypothesis, where Central Asia and the greater Tibetan Plateau acted as an evolutionary nursery for modern alpine or cold-adapted faunas, as well as some of the most biogeographically widespread ungulates of today, the deer family.

Geological Society of America Abstracts with Programs. Vol. 50, No. 6

doi: 10.1130/abs/2018AM-324242

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