Late Cretaceous stratigraphy and paleoceanographic evolution in the Great Australian Bight Basin based on results from IODP Site U1512
Late Cretaceous stratigraphy and paleoceanographic evolution in the Great Australian Bight Basin based on results from IODP Site U1512
复制标题
基于 IODP 站点 U1512 结果的大澳大利亚湾盆地晚白垩世地层学和古海洋演化
DOI：
10.1016/j.gr.2020.01.009
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发表时间：
2020
影响因子：
6.1
通讯作者：
et al.
中科院分区：
文献类型：
--
作者：
MacLeod;K. G.;L. T. White;C. C. Wainman;M. Martinez;M. M. Jones;S. J. Batenburg;L. Riquier;S.J. Haynes;D. K. Watkins;K. A. Bogus;H. -J. Brumsack;R. do Monte Guerra;K. M. Edgar;T. Edvardsen;M. L. G. Tejada;et al.
位于大澳大利亚湾Ceduna次盆地的国际海洋发现计划站点U1512的上白垩纪沉积序列代表了一个连续的、> 690 m厚的黑色粉质粘土和粘土岩层段，跨越了下土伦统至下坎帕尼亚统（约1000万年）。沉积物沉积在一个细长的，~E-W方向，~2500 km长的裂谷系统，该系统在澳大利亚和南极洲之间发展，西部与开放海洋连接，东部与大陆桥连接。现场U1512岩心提供了瓦拉鲁断层带上盘塞杜纳次盆地晚白垩世沉积的独特、连续记录。U1512样品的研究可以提供一个重要的高纬度，南半球的角度在白垩纪温室的高峰期和消亡的气候演变，并在冈瓦纳分裂的晚白垩世部分在盆地的沉积历史的近海记录。洞穴斑驳的块状粘土岩和粉质粘土岩构成了近700 m剖面的大部分，而罕见的（n = 28）孤立的2 - 21 cm厚的中细砂岩层是次要岩性。现存的大型化石包括常见的inoceramid和罕见的其他双壳类和菊石。微体化石包括常见的钙质超微化石、凝集和钙质底栖有孔虫、放射虫和有机壁甲藻孢囊，以及罕见的小型表面栖息有孔虫。碳酸盐（<7%）和有机碳（<1.5%）含量低。尽管岩性均匀，但磁化率和自然伽马辐射强度的节律性变化在大部分恢复部分中得到了很好的解决，并继续通过微小的取芯间隙（如井下测井记录所示）。来自站点U1512的数据为南极洲和澳大利亚之间的深水边界区域提供了新的视角。
The Upper Cretaceous sedimentary sequence at International Ocean Discovery Program Site U1512 in the Ceduna Sub-basin of the Great Australian Bight represents a continuous, > 690 m thick interval of black silty clay and claystone spanning the lower Turonian through Lower Campanian (~10 million years). Sediments were deposited in an elongate, ~E-W oriented, ~2500 km long rift system that developed between Australia and Antarctica with an open-ocean connection to the west and a continental bridge to the east. Site U1512 cores provide a unique, continuous record of Late Cretaceous deposition in the Ceduna Sub-basin on the hanging wall of the Wallaroo Fault Zone. Study of U1512 samples could provide both an important high-latitude, southern hemisphere perspective on climatic evolution during the peak and demise of the Cretaceous hothouse and an offshore record of the sedimentation history in the basin during the Late Cretaceous portion of the Gondwanan breakup.The Upper Cretaceous sequence at Site U1512 is notable for its lithologic uniformity. Burrow-mottled to massive claystone and silty claystone make up the majority of the almost 700 m section, while rare (n = 28) isolated, 2 to 21 cm thick medium to fine sandstone beds are a minor lithology. Macrofossils present include common inoceramids and rare occurrences of other bivalves and ammonites. Microfossils include common occurrences of calcareous nannofossils, agglutinated and calcareous benthic foraminifera, radiolaria and organic-walled dinoflagellate cysts as well as rare, small, surface dwelling planktonic foraminifera. Carbonate (<7%) and organic carbon (<1.5%) contents are low. Despite the lithologic uniformity, rhythmic alternations in the intensity of magnetic susceptibility and natural gamma radiation are well-resolved in much of the recovered section and continue through minor coring gaps (as documented by downhole logs). Data from Site U1512 provide new perspectives on the deep-water frontier region between Antarctica and Australia.