Carbonate deposits on submerged seamounts in the northwestern Pacific Ocean
Carbonate deposits on submerged seamounts in the northwestern Pacific Ocean
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DOI：
10.1111/j.1440-1738.2007.00595.x
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发表时间：
2007-09
期刊：
影响因子：
1.5
通讯作者：
H. Takayanagi;Y. Iryu;Tsutomu Yamada;M. Oda;Kazuyuki Yamamoto;Tokiyuki Sato;S. Chiyonobu;A. Nishimura;T. Nakazawa;S. Shiokawa
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文献类型：
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作者：
H. Takayanagi;Y. Iryu;Tsutomu Yamada;M. Oda;Kazuyuki Yamamoto;Tokiyuki Sato;S. Chiyonobu;A. Nishimura;T. Nakazawa;S. Shiokawa
摘要介绍了利用深海钻探机系统在西北太平洋6个地区16座海山19个点采集的浅水碳酸盐岩岩性。这些地区包括奄美高原、大东海岭、冲大东海岭、乌尔达内塔高原、九州帕劳海岭和小笠原高原。钙质超微化石生物地层学、浮游有孔虫生物地层学、大有孔虫生物地层学和锶同位素地层学提供了年代学约束。在渐新世（一个相对较冷的时期），大量浅水碳酸盐沉积在海山上，而在早中新世（一个相对较暖的时期），形成了有限的碳酸盐沉积。这可能表明，西北太平洋海山上浅水碳酸盐的沉积不一定受气候条件的控制，而是与火山活动和构造有关，这些活动是珊瑚礁/碳酸盐台地形成的基础。白垩纪和新生代浅水碳酸盐岩生物组成存在显著差异。晚白垩世浅水碳酸盐岩的特征是出现了rudists、solenoporacean藻类和microencrusters。中始新世至早渐新世浅水碳酸盐岩主要由Halimeda或nummulitid和discocyclinid大型有孔虫组成。从渐新世开始，硬珊瑚变得很常见。非膝状体珊瑚藻和大型有孔虫在始新世至更新世之间普遍存在。在后白垩纪时期，浅水碳酸盐工厂中主要碳酸盐生产者的更替与先前的研究一致，并被认为反映了海水化学的变化。
Abstract The lithology of shallow‐water carbonates collected from 19 sites on 16 seamounts in six areas of the northwestern Pacific Ocean using the Deep‐sea Boring Machine System are described. The areas include the Amami Plateau, Daito Ridge, Oki‐Daito Ridge, Urdaneta Plateau, Kyushu‐Palau Ridge and Ogasawara Plateau. Chronological constraint is provided by calcareous nannofossil biostratigraphy, planktonic foraminiferal biostratigraphy, larger foraminiferal biostratigraphy and strontium (Sr) isotope stratigraphy. Large amounts of shallow‐water carbonates accumulated on the seamounts during the Oligocene, a relatively cool period, whereas limited carbonate deposits formed during the Early Miocene, a relatively warm period. This might indicate that deposition of shallow‐water carbonates on seamounts in the northwestern Pacific Ocean was not necessarily controlled by climatic conditions, but was related to volcanism and tectonics that served as foundations for reef/carbonate‐platform formation. Remarkable differences in biotic composition exist between Cretaceous and Cenozoic shallow‐water carbonates. Late Cretaceous shallow‐water carbonates are distinguished by the occurrence of rudists, solenoporacean algae and microencrusters. Middle Eocene to Early Oligocene shallow‐water carbonates are dominated by Halimeda or nummulitid and discocyclinid larger foraminifers. Scleractinian corals became common from the Oligocene onward. Nongeniculate coralline algae and larger foraminifers were common to abundant throughout the Eocene to the Pleistocene. The replacement of major carbonate producers in the shallow‐water carbonate factory during post‐Cretaceous time is in accordance with previous studies and is considered to reflect a shift in seawater chemistry.