DOI: 10.1007/s00531-016-1309-0
论文题名: Steps in the intensification of Benguela upwelling over the Walvis Ridge during Miocene and Pliocene
作者: Hoetzel S. ; Dupont L.M. ; Marret F. ; Jung G. ; Wefer G.
刊名: International Journal of Earth Sciences
出版年: 2017
卷: 106, 期: 1 起始页码: 171
结束页码: 183
语种: 英语
英文关键词: Benguela upwelling
; Dinoflagellate cysts
; Eastern South Atlantic
; Miocene–Pliocene
Scopus关键词: biostratigraphy
; dinoflagellate cyst
; Miocene
; paleoceanography
; Pliocene
; upwelling
; Angola
; Atlantic Ocean
; Atlantic Ocean (North)
; Benguela
; Walvis Ridge
; Dinophyceae
英文摘要:
Upwelling is a significant part of the ocean circulation controlling largely the transport of nutrient-rich cold waters to the surface and therefore influencing ocean productivity and global climate. The Benguela upwelling system (BUS) is one of the major upwelling areas in the world. Previous reconstructions of the BUS mainly focused on the onset and intensification in southern and central parts, but changes of the northern part have been rarely investigated in detail. Using the Late Miocene to Pliocene organic-walled dinoflagellate cyst record of ODP Site 1081, we reconstruct and discuss the early upwelling history over the Walvis Ridge with a special focus on the movement of the Angola-Benguela Front (ABF). We suggest that during the Late Miocene the Angola Current flowed southwards over the Walvis Ridge more frequently than today because the ABF was probably located further south as a result of a weaker meridional temperature gradient. A possible strengthening of the meridional gradient during the latest Miocene to early Pliocene in combination with uplift of south-western Africa intensified the upwelling along the coast and increased the upwelling’s filaments over the Walvis Ridge. An intermediate period from 6.2 to 5.5 Ma is shown by the dominance of Habibacysta tectata, cysts of a cool-tolerant dinoflagellate known from the northern Atlantic, indicating changing oceanic conditions contemporaneous with the Messinian Salinity Crisis. From 4.3 Ma on, the upwelling signal got stronger again and waters were well-mixed and nutrient-rich. Our results indicate a northward migration of the ABF as early as 7 Ma and the initial stepwise intensification of the BUS. © 2016, Springer-Verlag Berlin Heidelberg.
URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84960429549&doi=10.1007%2fs00531-016-1309-0&partnerID=40&md5=09e540a0c5a3a712ab1172390fd4d91c
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/70095
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: MARUM - Center for Marine Environmental Sciences, University of Bremen, Leobener Str, Bremen, Germany; School of Environmental Sciences, University of Liverpool, Liverpool, United Kingdom
Recommended Citation:
Hoetzel S.,Dupont L.M.,Marret F.,et al. Steps in the intensification of Benguela upwelling over the Walvis Ridge during Miocene and Pliocene[J]. International Journal of Earth Sciences,2017-01-01,106(1)