Absolute Paleolatitude of Northern Zealandia From the Middle Eocene to the Early Miocene
Absolute Paleolatitude of Northern Zealandia From the Middle Eocene to the Early Miocene
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DOI：
10.1029/2022jb024736
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发表时间：
2022-09-01
影响因子：
3.9
通讯作者：
von Dobeneck, Tilo
中科院分区：
文献类型：
--
作者：
Dallanave, Edoardo;Sutherland, Rupert;von Dobeneck, Tilo
西兰洲北部在新生代的绝对位置是由全球板块运动模型推断出来的，因为当地的古地磁约束实际上是不存在的。西兰洲北部是一个90%以上被西南太平洋淹没的大陆。我们利用国际海洋发现计划在西兰迪亚北部的U1507地点和邻近塔斯曼海盆地的U1511地点钻探的古地磁数据，提出了新的古纬度约束。在校正倾角浅化后，5个古纬度估计提供了西兰洲北部从始新世中期到中新世早期的位置轨迹，跨越了C21n到C5Er（类似于48-18 Ma）的地磁极性年代。古纬度估计支持了先前关于全球绝对板块运动的研究，即西兰迪亚北部在早渐新世至早中新世期间向北迁移了6度，但绝对古纬度较低，特别是在巴顿纪和普里亚伯纪（C18n-C13r）。真正的极移（固体地球相对于自转轴的旋转）只能用古地磁数据来解决，这可能解释了这种差异。这种新的古地磁信息将西兰洲过去的纬度锚定在地球的自转轴上，不仅对全球地球动力学有意义，而且对解决古海洋学和古气候问题也有意义，这些问题通常需要精确的古纬度代用数据。
The absolute position during the Cenozoic of northern Zealandia, a continent that lies more than 90% submerged in the southwest Pacific Ocean, is inferred from global plate motion models, because local paleomagnetic constraints are virtually absent. We present new paleolatitude constraints using paleomagnetic data from International Ocean Discovery Program Site U1507 on northern Zealandia and Site U1511 drilled in the adjacent Tasman Sea Basin. After correcting for inclination shallowing, five paleolatitude estimates provide a trajectory of northern Zealandia past position from the middle Eocene to the early Miocene, spanning geomagnetic polarity chrons C21n to C5Er (similar to 48-18 Ma). The paleolatitude estimates support previous works on global absolute plate motion where northern Zealandia migrated 6 degrees northward between the early Oligocene and early Miocene, but with lower absolute paleolatitudes, particularly in the Bartonian and Priabonian (C18n-C13r). True polar wander (solid Earth rotation with respect to the spin axis), which only can be resolved using paleomagnetic data, may explain the discrepancy. This new paleomagnetic information anchors past latitudes of Zealandia to Earth's spin axis, with implications not only for global geodynamics, but also for addressing paleoceanographic and paleoclimate problems, which generally require precise paleolatitude placement of proxy data.