Middle to Late Miocene tectonic forcing of intensified humidity in the Xunhua Basin, NE Tibetan Plateau

Bowen Song; Fei Hu; Yu Liang; Kexin Zhang; Junliang Ji; Thomas J. Algeo; James C. Hower; Tinglu Yang; Xu Zhang

doi:10.1016/j.palaeo.2022.111268

Middle to Late Miocene tectonic forcing of intensified humidity in the Xunhua Basin, NE Tibetan Plateau

Bowen Song, Fei Hu, Yu Liang, Kexin Zhang, Junliang Ji, Thomas J. Algeo, James C. Hower, Tinglu Yang, Xu Zhang

Research output: Contribution to journal › Article › peer-review

3 Scopus citations

Abstract

The mechanisms and controls of the Middle-Late Miocene paleoenvironmental evolution of the northeastern Tibetan Plateau remain elusive. Here, we present an integrated multiproxy study of total organic carbon isotopes, lipid biomarkers, petrographic components and micropaleontological records in the well-dated Xigou section of the Xunhua Basin. Our data reveal a large decrease (−1.1 ‰) in bulk organic carbon isotopes (δ¹³C_org) at ∼12.7 Ma, a broad minimum at ∼12.7–8.0 Ma, and a large increase (+1.3 ‰) at ∼8.0 Ma. The decline in δ¹³C_org at 12.7 Ma was accompanied by pronounced changes in n-alkane indices, clay minerals, palynology, and ostracods, recording a major rise of lake level of paleo-Lake Xunhua due to increased precipitation in the regional catchment. Our inference of sustained elevated humidity in the Xunhua Basin at 12.7–8.0 Ma is contrary to previously reported cooling and drying trends on the NE Tibetan Plateau for the Middle-Late Miocene (∼14–8 Ma), thus precluding the role of global climate change as the dominant driver. Rather, we attribute the paleoenvironmental evolution of the Xunhua Basin to changes in regional rainfall patterns related to orogenic uplift. The Jishi Shan mountain range reached a critical threshold elevation at ∼12.7 Ma, becoming an orographic barrier to Westerlies-transported moisture and thus enhancing intensified precipitation within the Xunhua Basin. By ∼8 Ma, further uplift caused this orogen to become a barrier to the East Asian monsoon, resulting in aridification of the Xunhua Basin.

Original language	English
Article number	111268
Journal	Palaeogeography, Palaeoclimatology, Palaeoecology
Volume	607
DOIs	https://doi.org/10.1016/j.palaeo.2022.111268
State	Published - Dec 1 2022

Bibliographical note

Publisher Copyright:
© 2022 Elsevier B.V.

Funding

We thank Prof. Shucheng Xie for editorial handling and two anonymous reviewers for thorough reviews that considerably improved the manuscript. This work was funded by the National Natural Science Foundation of China (Nos. 42072141 , 41702118 ) and the Geological Survey of China (No. DD20221645 ). We are very grateful to Xiaohu Kou, Fenning Chen, Jianyu Zhang and Keke Ai for field assistance in the Xunhua Basin, to Huan Yang for his laboratory assistance with lipid analysis, and to Yibo Yang, Zhixiang Wang, Yan Zhao and Fang Han for helpful discussions.

Funders	Funder number
National Natural Science Foundation of China (NSFC)	41702118, 42072141
China Geological Survey	DD20221645

Keywords

Late Cenozoic
Micropaleontology
N-alkane
Organic carbon isotopes
Precipitation
Rain shadow

ASJC Scopus subject areas

Oceanography
Ecology, Evolution, Behavior and Systematics
Earth-Surface Processes
Paleontology

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1016/j.palaeo.2022.111268

Cite this

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title = "Middle to Late Miocene tectonic forcing of intensified humidity in the Xunhua Basin, NE Tibetan Plateau",

abstract = "The mechanisms and controls of the Middle-Late Miocene paleoenvironmental evolution of the northeastern Tibetan Plateau remain elusive. Here, we present an integrated multiproxy study of total organic carbon isotopes, lipid biomarkers, petrographic components and micropaleontological records in the well-dated Xigou section of the Xunhua Basin. Our data reveal a large decrease (−1.1 ‰) in bulk organic carbon isotopes (δ13Corg) at ∼12.7 Ma, a broad minimum at ∼12.7–8.0 Ma, and a large increase (+1.3 ‰) at ∼8.0 Ma. The decline in δ13Corg at 12.7 Ma was accompanied by pronounced changes in n-alkane indices, clay minerals, palynology, and ostracods, recording a major rise of lake level of paleo-Lake Xunhua due to increased precipitation in the regional catchment. Our inference of sustained elevated humidity in the Xunhua Basin at 12.7–8.0 Ma is contrary to previously reported cooling and drying trends on the NE Tibetan Plateau for the Middle-Late Miocene (∼14–8 Ma), thus precluding the role of global climate change as the dominant driver. Rather, we attribute the paleoenvironmental evolution of the Xunhua Basin to changes in regional rainfall patterns related to orogenic uplift. The Jishi Shan mountain range reached a critical threshold elevation at ∼12.7 Ma, becoming an orographic barrier to Westerlies-transported moisture and thus enhancing intensified precipitation within the Xunhua Basin. By ∼8 Ma, further uplift caused this orogen to become a barrier to the East Asian monsoon, resulting in aridification of the Xunhua Basin.",

keywords = "Late Cenozoic, Micropaleontology, N-alkane, Organic carbon isotopes, Precipitation, Rain shadow",

author = "Bowen Song and Fei Hu and Yu Liang and Kexin Zhang and Junliang Ji and Algeo, {Thomas J.} and Hower, {James C.} and Tinglu Yang and Xu Zhang",

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doi = "10.1016/j.palaeo.2022.111268",

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AU - Song, Bowen

AU - Hu, Fei

AU - Liang, Yu

AU - Zhang, Kexin

AU - Ji, Junliang

AU - Algeo, Thomas J.

AU - Hower, James C.

AU - Yang, Tinglu

AU - Zhang, Xu

PY - 2022/12/1

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N2 - The mechanisms and controls of the Middle-Late Miocene paleoenvironmental evolution of the northeastern Tibetan Plateau remain elusive. Here, we present an integrated multiproxy study of total organic carbon isotopes, lipid biomarkers, petrographic components and micropaleontological records in the well-dated Xigou section of the Xunhua Basin. Our data reveal a large decrease (−1.1 ‰) in bulk organic carbon isotopes (δ13Corg) at ∼12.7 Ma, a broad minimum at ∼12.7–8.0 Ma, and a large increase (+1.3 ‰) at ∼8.0 Ma. The decline in δ13Corg at 12.7 Ma was accompanied by pronounced changes in n-alkane indices, clay minerals, palynology, and ostracods, recording a major rise of lake level of paleo-Lake Xunhua due to increased precipitation in the regional catchment. Our inference of sustained elevated humidity in the Xunhua Basin at 12.7–8.0 Ma is contrary to previously reported cooling and drying trends on the NE Tibetan Plateau for the Middle-Late Miocene (∼14–8 Ma), thus precluding the role of global climate change as the dominant driver. Rather, we attribute the paleoenvironmental evolution of the Xunhua Basin to changes in regional rainfall patterns related to orogenic uplift. The Jishi Shan mountain range reached a critical threshold elevation at ∼12.7 Ma, becoming an orographic barrier to Westerlies-transported moisture and thus enhancing intensified precipitation within the Xunhua Basin. By ∼8 Ma, further uplift caused this orogen to become a barrier to the East Asian monsoon, resulting in aridification of the Xunhua Basin.

AB - The mechanisms and controls of the Middle-Late Miocene paleoenvironmental evolution of the northeastern Tibetan Plateau remain elusive. Here, we present an integrated multiproxy study of total organic carbon isotopes, lipid biomarkers, petrographic components and micropaleontological records in the well-dated Xigou section of the Xunhua Basin. Our data reveal a large decrease (−1.1 ‰) in bulk organic carbon isotopes (δ13Corg) at ∼12.7 Ma, a broad minimum at ∼12.7–8.0 Ma, and a large increase (+1.3 ‰) at ∼8.0 Ma. The decline in δ13Corg at 12.7 Ma was accompanied by pronounced changes in n-alkane indices, clay minerals, palynology, and ostracods, recording a major rise of lake level of paleo-Lake Xunhua due to increased precipitation in the regional catchment. Our inference of sustained elevated humidity in the Xunhua Basin at 12.7–8.0 Ma is contrary to previously reported cooling and drying trends on the NE Tibetan Plateau for the Middle-Late Miocene (∼14–8 Ma), thus precluding the role of global climate change as the dominant driver. Rather, we attribute the paleoenvironmental evolution of the Xunhua Basin to changes in regional rainfall patterns related to orogenic uplift. The Jishi Shan mountain range reached a critical threshold elevation at ∼12.7 Ma, becoming an orographic barrier to Westerlies-transported moisture and thus enhancing intensified precipitation within the Xunhua Basin. By ∼8 Ma, further uplift caused this orogen to become a barrier to the East Asian monsoon, resulting in aridification of the Xunhua Basin.

KW - Late Cenozoic

KW - Micropaleontology

KW - N-alkane

KW - Organic carbon isotopes

KW - Precipitation

KW - Rain shadow

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M3 - Article

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VL - 607

JO - Palaeogeography, Palaeoclimatology, Palaeoecology

JF - Palaeogeography, Palaeoclimatology, Palaeoecology

M1 - 111268

ER -

Middle to Late Miocene tectonic forcing of intensified humidity in the Xunhua Basin, NE Tibetan Plateau

Abstract

Bibliographical note

Funding

Keywords

ASJC Scopus subject areas

UN SDGs

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