Collaborative Research: Late Cretaceous and Cenozoic Reconstructions of the Southwest Pacific

该奖项由极地方案办公室南极地质学和地球物理学方案以及海洋科学司海洋地质学和地球物理学方案联合提供，支持开展研究，为西南太平洋地区（太平洋、南极和澳大利亚板块之间以及新西兰、西南极洲、伊塞林浅滩、东南极洲和澳大利亚的大陆碎片）开发改进的板块旋转模型。改进后的旋转参数将用于解决与东南极洲和西南极洲之间的运动有关的构造问题，特别是主要热点群之间的相对漂移问题以及关于该区域可能缺失板块边界的争议。以前的工作已经记录了东南极洲和西南极洲之间的NNW走向中第三纪海底扩展磁异常，代表罗斯海以北的Adare槽开口约150公里。这还不足以解决板块运动与假设热点固定所推断的运动之间的明显差异。由于东南极洲和西南极洲之间的这种运动对应于一个非常小的旋转，它指出需要确定有限的旋转，以高精度描述这里各个板块的运动，特别是在较早的时候。现在，将在本项目中使用的数据集可以做到这一点。完成这项工作的方法是将现有数据与日本和意大利科学家最近在该区域进行的航行中提供的其他数据集的分析和解释相结合。 通过获取R/VI B Nathaniel B某些过境点的新海洋地球物理数据，将进一步加强这一工作。帕尔默 该项目的具体目标包括：1）改进东南极洲和西南极洲之间第三纪中期伸展的旋转模型，在计算澳大利亚-西南极洲运动时直接包括太平洋和澳大利亚板块之间的板块边界，2）改进晚白垩世和早第三纪时期的重建，包括对以前重建中未使用的几个边界的新限制，3）解决新的旋转模型对全球热点固定性问题的影响，4）根据中新生代大量伸展的模型重新审查西罗斯海海湾的地球物理数据。

This award, provided jointly by the Antarctic Geology and Geophysics Program of the Office of Polar Programs and the Marine Geology and Geophysics Program of the Division of Ocean Sciences, supports research to develop improved plate rotation models for the Southwest Pacific region (between the Pacific, Antarctic, and Australian plates, and the continental fragments of New Zealand, West Antarctica, Iselin Bank, East Antarctica, and Australia). The improved rotation parameters will be used to address tectonic problems related to motion between East and West Antarctica, and in particular, the questions of relative drift between major hotspot groups and the controversy regarding a possible missing plate boundary in this region. Previous work has documented NNW-striking mid-Tertiary seafloor spreading magnetic anomalies between East and West Antarctica, representing about 150 km of opening of the Adare Trough, north of the Ross Sea. This is not enough motion to resolve the apparent discrepancy between the plate motions and motions inferred from assuming hotspot fixity. Because this motion between East and West Antarctica corresponds to a very small rotation, it points to the need for determination of finite rotations describing motions of the various plates here with a high degree of accuracy, particularly for older times. This is now possible with the datasets that will be used in this project. The work will be accomplished by integrating existing data with analysis and interpretation of other data sets recently made available by Japanese and Italian scientists from their cruises in the region. It will be further augmented by acquisition of new marine geophysical data on selected transits of the R/VIB Nathaniel B. Palmer. Specific objectives of the project include the following:1) improve the rotation model for mid-Tertiary extension between East and West Antarctica by including the plate boundary between the Pacific and Australia plates directly when calculating Australia-West Antarctica motion,2) improve the reconstructions for the Late Cretaceous and Early Tertiary times by including new constraints on several boundaries not previously used in the reconstructions,3) address the implications of new rotation models for the question of the fixity of global hotspots,4) re-examine the geophysical data from the Western Ross Sea embayment in light of a model for substantial mid-Cenozoic extension.