کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8908654 | 1636675 | 2018 | 19 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Remagnetization of the Lower Ordovician Hongshiya Formation of the southwestern Yangtze Block
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
فرآیندهای سطح زمین
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Large-scale block migration has been proposed based on Early and early Late Ordovician paleomagnetic data for the South China Block (SCB). However, this is anomalous in terms of the previously reconstructed affinity between the SCB and East Gondwana. A paleomagnetic and petrographic reassessment of the Lower Ordovician sedimentary rocks is therefore necessary to assess the reliability of the Early Ordovician paleopole of the SCB. Consequently, we obtained paleomagnetic data from 47 sites at five localities of the SCB. For most specimens, detailed thermal demagnetization experiments yielded viscous components at ~120â¯Â°C, while the stable characteristic remanent magnetization (ChRM) was isolated up to 680â¯Â°C. The ChRM passed the fold test and hematite is identified as the remanence carrier. The samples give the site-mean ChRM direction Ds/Isâ¯=â¯313.0°/61.9° (ksâ¯=â¯47.1, α95â¯=â¯3.2°) after tilt correction (five localities, 47 sites). Although the ChRM direction passed the fold test that was likely acquired before the Tertiary, petrographic studies reveal the occurrence of widespread secondary hematite in the specimens, indicating that the rocks were remagnetized after deposition. The average paleomagnetic direction overlaps with the Jurassic paleomagnetic direction from sampling areas of the southwestern SCB, implying that the remagnetization event occurred during the Jurassic. The Early Ordovician paleopole of the SCB is therefore urgently needed for plate reconstruction of the SCB within Gondwana.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Tectonophysics - Volumes 738â739, 25 July 2018, Pages 83-91
Journal: Tectonophysics - Volumes 738â739, 25 July 2018, Pages 83-91
نویسندگان
Liang Gao, Zhenyu Yang, Zhirui Han, Yabo Tong, Xianqing Jing, Shuan-Hong Zhang,