Paleomagnetic results from basement rocks from site 917 (east Greenland margin)
Paleomagnetic results from basement rocks from site 917 (east Greenland margin)
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917 号地点（格陵兰岛东部边缘）基底岩石的古地磁结果
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
J. Ali
中科院分区：
文献类型：
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作者：
D. Vandamme;J. Ali
在大洋钻探计划第152标段期间，在917A孔钻探了位于向海倾斜反射层序(SDRS)最古老部分的779米玄武岩熔岩。本文介绍了68个火成岩单元的150个古地磁标本的研究结果。我们试图使用地层显微扫描仪数据重新确定玄武岩碎片的方向，以便确定倾角，但尝试失败了。利用古强度实验，我们还试图测试几个可能记录了地磁短事件的单元的磁化热源。在加热过程中，样品中矿物质发生的化学变化阻止了任何结论的得出。然而，常规的古地磁实验允许我们直接或间接地确定92个火成岩单元中74个的倾角。整个层序的反转极性，以及由下层序中的三个(可能是五个)单元和中统中的一个单元记录的两个密码单元的存在，与磁性克莱恩24R、25R或26R期间917站点的火山序列的挤压一致，但排除了磁性Chron 27r。
During Ocean Drilling Program Leg 152, 779 m of basaltic lavas within the oldest part of the seaward-dipping reflector sequence (SDRS) was drilled in Hole 917A. We present the results of studies of 150 paleomagnetic specimens sampled from 68 igneous units. We tried to reorient basalt pieces using Formation MicroScanner data so that declinations could be determined, but the attempt failed. Using paleointensity experiments, we also tried to test the thermal origin of magnetization of several units that may have recorded a geomagnetic short event. Chemical changes that occurred in minerals in the samples during heating prevented any conclusions from being reached. Conventional paleomagnetic experiments, however, allowed us to determine the inclinations of 74 of the 92 igneous units, directly or indirectly. The reversed polarity of the entire sequence and the presence of two cryptochrons recorded by three (possibly five) units in the Lower Series and one unit in the Middle Series are consistent with an extrusion of the volcanic sequence of Site 917 during the magnetic Chrons 24r, 25r, or 26r, but exclude magnetic Chron 27r.