Variations in the radiolarian assemblages in the Bering Sea since Pliocene and their implications for paleoceanography

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doi: 10.1016/j.palaeo.2014.05.048
Author(s): Zhang Qiang; Chen Muhong; Zhang Lanlan; Hu Weifen; Xiang Rong
Author Affiliation(s): Primary:
Chinese Academy of Sciences, South China Sea Institute of Oceanology, Laboratory of Marginal Sea Geology, Guangzhou, China
Volume Title: Palaeogeography, Palaeoclimatology, Palaeoecology
Source: Palaeogeography, Palaeoclimatology, Palaeoecology, Vol.410, p.337-350. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0031-0182 CODEN: PPPYAB
Note: In English. 91 refs.; illus., incl. charts, 2 plates, 2 tables, sketch map
Summary: Radiolarian assemblages were analyzed using samples from the IODP Site U1340 to reconstruct the paleoceanographic conditions in the Bering Sea. Based on the characteristic faunal changes, the radiolarian evolution at Site U1340 was divided into four major intervals from Stages I to IV, with Stage IV divided into Substages IVa and IVb. The radiolarians in each stage recorded significant paleoenvironmental conditions. In general, the Bering Sea was governed by an ocean ecological environment with stable warm and saline surface water during Stage I (4.15 Myr to 3.91 Myr). The environment in the Bering Sea fluctuated strongly during Stage II (3.91 Myr to 2.75 Myr) and was controlled by the cold-water masses and sea ices during Stage III (2.75 Myr to 1.07 Myr) with the gradual development of cold and well-ventilated intermediate water. Stage IVa (1.07 Myr to 0.47 Myr) was a transitional period characterized by the enhanced formation of cold subsurface and intermediate water as well as of the oxygen-rich deep water. During Stage IVb (after 0.47 Myr), the Bering Sea was mainly characterized by enhanced warmth during interglacial episodes and well-developed water layers that were generally comparable to those of the modern Bering Sea. These conditions indicated that the vertical water-mass structure of the modern Bering Sea began to form since 0.47 Ma. Every Stage boundary in the studied core was marked by notable changes in the radiolarian assemblages. These changes corresponded to the climatic cooling event at ∼ 3.91 Ma, the intensification of Northern Hemisphere glaciation at ∼ 2.75 Ma, the beginning of the middle Pleistocene transition at ∼ 1.07 Ma, and the low-latitude radiolarian ecology event at ∼ 0.47 Ma. In addition, the relative abundance pattern of Cycladophora davisiana indicates that the Bering Sea was the main source of the past North Pacific Intermediate Water at ca. 0.85 Ma (MIS22), ca. 0.63 Ma (MIS16), and ca. 0.18 Ma (MIS6), just as it was during the last glacial maximum. Abstract Copyright (2014) Elsevier, B.V.
Year of Publication: 2014
Research Program: IODP Integrated Ocean Drilling Program
ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Assemblages; Bering Sea; Biogeography; Biostratigraphy; Bowers Ridge; Cenozoic; Cycladophora davisiana; Expedition 323; Holocene; IODP Site U1340; Ice; Integrated Ocean Drilling Program; Invertebrata; Leg 184; Marine environment; Microfossils; Nassellina; Neogene; North Pacific; Northwest Pacific; ODP Site 1143; Ocean Drilling Program; Osculosida; Pacific Ocean; Paleo-oceanography; Paleoecology; Paleotemperature; Pleistocene; Pliocene; Protista; Quaternary; Radiolaria; Sea ice; South China Sea; Tertiary; West Pacific
Coordinates: N092143 N092143 E1131707 E1131707
N532354 N532354 W1793113 W1793113
Record ID: 2014071607
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands