Evidence of continuous Asian summer monsoon weakening as a response to global cooling over the last 8 Ma

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doi: 10.1016/j.gr.2017.09.003
Author(s): Miao, Yunfa; Warny, Sophie; Clift, Peter D.; Liu, Chang; Gregory, Mitchell
Author Affiliation(s): Primary:
Louisiana State University, Department of Geology and Geophysics, Baton Rouge, LA, United States
Volume Title: Gondwana Research
Source: Gondwana Research, Vol.52, p.48-58. Publisher: Elsevier on behalf of International Association for Gondwana Research, Amsterdam and Kochi, International. ISSN: 1342-937X
Note: In English. 66 refs.; illus., incl. 1 table, 3 plates, chart
Summary: The Asian Summer Monsoon (ASM) is the dominant climate system of South and East Asia. However, the history of monsoon intensification and the driving forces behind it are controversial. Wind-blown sediments in mid-latitude East Asia and fluvial-derived sediments in the northern South China Sea imply contrasting ASM patterns during the late Cenozoic. Here we use pollen records from the southwest South China Sea (International Ocean Discovery Program (IODP) Site U1433) to reconstruct the ASM evolution in low-latitude Southeast Asia. A slow increase in herbaceous plants since 8 Ma indicates a persistent weakening of precipitation in Indochina, which is dominated by the ASM. This signal is closely associated with a consistent coniferous plant record, indicating a continuous cooling trend that correlates well with Sea Surface Temperature (SST) decrease in the west Pacific Ocean. We propose that the monsoon weakening resulted in as much as a ∼ 25% reduction in precipitation over the past 8 Ma in response to the Northern Hemisphere glaciation/global cooling, with some of the increase in conifers being linked to uplift of the Vietnamese Central Highland and the SE flank of the Tibetan Plateau in Yunnan and northern Vietnam.
Year of Publication: 2017
Research Program: IODP Integrated Ocean Drilling Program
IODP2 International Ocean Discovery Program
ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Asia; Assemblages; Atmospheric precipitation; Cenozoic; China; Climate change; Coniferales; Cooling; Expedition 349; Far East; Glaciation; Global change; Gymnospermae; IODP Site U1433; Indochina; International Ocean Discovery Program; Leg 184; Microfossils; Miocene; Miospores; Monsoons; Neogene; North Pacific; Northwest Pacific; ODP Site 1144; ODP Site 1147; ODP Site 1148; Ocean Drilling Program; Okinawa Trough; Pacific Ocean; Paleoclimatology; Paleoecology; Palynomorphs; Plantae; Pollen; Pollen analysis; Pollen diagrams; Quaternary; Reconstruction; Sea-surface temperature; South China Sea; Southeast Asia; Spermatophyta; Tectonics; Tertiary; Tibetan Plateau; Tortonian; Uplifts; Upper Miocene; Vegetation; Vietnam; Vietnamese Central Highland; West Pacific; Yangtze Delta; Yunnan China
Coordinates: N125508 N125508 E1150251 E1150250
N200311 N200311 E1172508 E1172508
N185007 N185007 E1163317 E1163317
N185010 N185010 E1163356 E1163356
Record ID: 2018071144
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands