Late Cretaceous planktonic foraminifera from Kerguelen Plateau (ODP Leg 183): new data to improve the Southern Ocean biozonation
Late Cretaceous planktonic foraminifera from Kerguelen Plateau (ODP Leg 183): new data to improve the Southern Ocean biozonation
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凯尔盖朗高原的晚白垩世浮游有孔虫（ODP Leg 183）：改善南大洋生物区划的新数据
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发表时间：
2001
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通讯作者：
M. Petrizzo
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作者：
M. Petrizzo
摘要为了完善和整合以前提出的南大洋地区的分带方案，对新近在南印度洋科尔盖伦高原183航次期间发现的几乎完整的上白垩统沉积序列进行了浮游有孔虫分析。对1135A、1136A和1138A孔(晚白垩世S古纬度50°以北)进行了详细的生物地层学分析，识别出了有助于跨纬度对比的低纬度和中高纬度生物事件，以及已知的澳大利亚生物事件。由于Helvetoglobotruncana Helvetica的出现，标志着Whiteinella考古科和Helvetoglobotruncana Helvetica带之间的分界线，低纬生物分带可以应用于都罗纪沉积物。怀特伊尼拉古考古动物带的底部位于1138A孔最高的塞诺马尼亚-图罗尼亚黑色页岩水平内。利用在中高纬度地区识别的生物事件，可以确定从上图罗尼亚到最高桑托尼亚的地层间隔。它们在地层上的顺序分别是：科尼亚纪末最后一次出现的Maslakovae，科尼亚期/桑托期界线上首次出现的异形线虫Papula，桑东期晚期边缘类的灭绝，以及最近一次(？)桑托尼亚语。晚白垩世的其余部分与南纬向格局吻合得相当好，只是Globigerinelloids Imcount显示的地层范围与其在中高纬度地区的记录一致，并比以前在南部地点记录的更向下延伸。因此，尽管某些区段的恢复情况不佳，并且存在几个具有局部和区域重要性的间歇期，但已经获得了更详细的分区方案(主要针对分辨率较低的图罗尼亚-桑托尼亚区段)。还提供了一些文献中经常被忽视的物种的评论。
Abstract An almost complete Upper Cretaceous sedimentary sequence recently recovered on the Kerguelen Plateau (southern Indian Ocean) during ODP Leg 183 was analysed for planktonic foraminifera in order to refine and integrate the zonal schemes previously proposed for the Southern Ocean area. Detailed biostratigraphic analysis carried out on holes 1135A, 1136A and 1138A (poleward of 50°S palaeolatitude during Late Cretaceous time) has allowed recognition of low and mid–high latitude bioevents, useful for correlation across latitudes, in addition to known Austral bioevents. The low latitude biozonation can be applied to Turonian sediments, because of the occurrence of Helvetoglobotruncana helvetica , which marks the boundary between Whiteinella archaeocretacea and Helvetoglobotruncana helvetica zones. The base of the Whiteinella archeocretacea Zone falls within the uppermost Cenomanian–Turonian black shale level in Hole 1138A. The stratigraphic interval from upper Turonian to uppermost Santonian can be resolved using bioevents recognized in the mid–high latitude sections. They are, in stratigraphic order: the last occurrence of Falsotruncana maslakovae in the Coniacian, the first occurrence of Heterohelix papula at the Coniacian/Santonian boundary, the extinction of the marginotruncanids in the late Santonian, and the first occurrence of Globigerinelloides impensus in the latest (?) Santonian. The remainder of the Late Cretaceous fits rather well in the Austral zonal scheme, except that Globigerinelloides impensus exhibits a stratigraphic range in agreement with its record at the mid–high latitude sections and extends further downwards than previously recorded at southern sites. Therefore, despite the poor recovery in certain intervals and the presence of several hiatuses of local and regional importance as revealed by correlation among holes, a more detailed zonal scheme has been obtained (mainly for the less resolved Turonian–Santonian interval). Remarks on some species often overlooked in literature are also provided.