Tingjiang Peng

Late Tertiary reorganizations of deformation in northeastern Tibet constrained by stratigraphy and provenance data from eastern Longzhong Basin

The deformation of the Tibetan Plateau is central to unraveling the process and mechanism of continental tectonics. Although most agree that crust shortening and plateau growth were protracted throughout the Cenozoic Indo-Asian collision, particular deformation histories relating to tectonic kinematics and dynamics are still incomplete due to sparseness of diagnostic geological information from plateau margin. Here we present combined investigation of stratigraphy, magnetostratigraphy, and provenance for the eastern margin of Longzhong Basin to show two reorganizations of basin formation and tectonic regime during the late Tertiary. First, the depocenter migrated from the dispersed Paleogene sequences to the Wushan-Tianshui foreland sequence during the earliest Miocene (circa 22 Ma), accompanied by shift of sedimentary provenance from double sources including the eastern Qilian block and eastern West Qinling terrain to single source within the West Qinling. It suggests reorganization of deformation from NW-SE extension to NE-SW contraction and initial uplift of the eastern West Qinling. Second, massive coarse-grained fluvial beds were revived in the Wushan Basin during the late Miocene (circa 10 Ma), associated by eastward depositional expansion and another shift of sedimentary provenance toward northeast. It reflects thrusting up of the northern edge of the West Qinling and Liupan Shan Mountains linked with relocation of crust shortening from NE-SW direction to ENE-WSW direction and accelerated deformation of northeastern Tibet. These transitions of deformation regimes imply variation of geodynamic mechanisms during the process of plateau growth.

Diversity of Moschidae (Ruminantia, Artiodactyla, Mammalia) in the middle Miocene of China

Abstract. In this paper, we describe newly discovered and previously collected fossil moschid specimens from the middle Miocene of China. Besides the previously reported Hispanomeryx andrewsi, we recognize four additional fossil species in two genera of Moschidae in the middle Miocene of China based on dental morphology: Micromeryx cf. flourensianus, Micromeryx sp., Hispanomeryx sp. 1, and Hispanomeryx sp. 2. The specimens are of Tunggurian age (Neogene Chinese Land Mammal Age), corresponding to European MN6-MN7/8. The records show a diversity of fossil moschids in the middle Miocene of China comparable with the contemporaneous diversity in western European faunas.

Biomarkers Aid Paleoenvironment Studies of Asian Aridification

The broad, arid region of central Asia is one of the most important dust sources on Earth, its eolian dust output being critical to global biogeochemical cycles. For example, dust contains iron, and wind transport flings the dust to the ocean, where it serves as an important nutrient for phytoplankton. In turn, phytoplankton colonies fueled by dust uptake carbon dioxide (CO2), a key greenhouse gas, from the ocean, allowing the ocean to draw more carbon from the atmosphere. As such, dust availability helps determine how much carbon gets sunk into the ocean.