| 北大西洋Hatton与Gardar沉积堤上等深线流活动的沉积学标志 |
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| 引用本文： | 王慧中.北大西洋Hatton与Gardar沉积堤上等深线流活动的沉积学标志[J].地质科学,1991,0(4):346. |
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| 作者姓名： | 王慧中 |
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| 作者单位： | 同济大学海洋地质系 上海200092 |
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| 摘 要： | 北大西洋东北部 Hatton 与 Gardar 沉积堤的早更新统沉积层分属两类不同的深海碳酸盐软泥。前者粗组份含量高,以有孔虫为主;后者明显变细,主要由超微化石组成。生物产率、水深、沉积速率及等深线流活动都有可能影响软泥的类型,但等深线流的改造作用最重要。本文进一步证实沉积堤是等深线流长期作用的产物,并自渐新世形成以来长期保持稳定。
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| 关 键 词： | 沉积堤 等深线流 深海碳酸盐软泥 冰期 北大西洋 |
| 修稿时间： | 1989-07-01; |
SEDIMENTOLOGICAL INDICATORS FOR CONTOUR CURRENT IN SEDIMENTS OF HATTON AND GARDAR DRIFTS, N. E. ATLANTIC OCEAN |
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| Wang Huizhong.SEDIMENTOLOGICAL INDICATORS FOR CONTOUR CURRENT IN SEDIMENTS OF HATTON AND GARDAR DRIFTS, N. E. ATLANTIC OCEAN[J].Chinese Journal of Geology,1991,0(4):346. |
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| Authors: | Wang Huizhong |
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| Institution: | Department of Marine Geology, Tongji University, Shanghai 200092 |
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| Abstract: | Samples taken from DSDP sites 552A and 553B on Hatton Drift and DSDP 611 on Gar-dar Drift in the Northeast Atlantic Ocean were examined by analyses of carbonate content, amount and composition of coarse fraction, grain size and composition of fine fraction, and oxygen isotopes. The age of sediments on both sections are early Pleistocene, from the end of the Jaramillo Normal Event to the boundary between the Matuyama and Drunhes epo-ches (about 0.77-0.96 Ma). Records of this time show a change from 23,000a to 100,000a with a periodicity about 0.818 Ma. This record is fully at site 552A, but less at site 611. Because of deficiency in the magnetic record at 553B, the section studied here is roughly placed in the same interval according to the nannofossil record and sedimentation rate.The grian size is predominated by coccoliths, foraminiferas and ice-rafted materials, all of which are related to glacialinterglacial changes. There are different types of carbonate oozes on Hatton and Gadar Drifts. Sedimentological results show that the sections 552A and 553B consist mainly of nanno-foraminiferal o ozes with minor interbeds of foraminiferal oozes, and are characterized by a higher content of the coarse fraction, abundant coarse terrigenous materials and grain size modes of both fragmented foraminifera and terrigenous materials in the fine fraction. The section at 611 consists mainly of foraminiferal-nannofossil oozes (or marls) with different size distribution from site 552A. Of several possible factors, such as productivity, depth, sedimentation rate and the action of contour current, influencing these, the current effects seem more significant than others, deduced from some sedimentological evidence.Results of this study further confirm that the sediment drifst are the product of contour current action in a long time. They have maintained their basic characteristics, including distribution pattern, individual feature and internal structure, at least since the early Pleistocene. |
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| Keywords: | Sediment drift Contour current Deep-sea carbonate ooze Glacial N E Atlantic Ocean |
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