The latitudinal changes of Greater India and the paleogeographic evolution of the Tethys Ocean are controversial and depend strongly on determining the paleogeographic locations of the Tethyan Himalayas as a function of geological time. However, the lack of reliable paleomagnetic results from the Jurassic in the Tethyan Himalayas has cast a shadow on the above research. We conducted detailed paleomagnetic research on the Ningri Formation strata (Early–Middle Jurassic) of the Zanda area, Tethyan Himalayas. Positive fold and reversal tests and microscopic observations indicate that the characteristic remanent magnetization component (ChRM) is primary. Elongation/Inclination analysis of the ChRM of the Ningri Formation yields a best-estimated value of 35.8° for the mean inclination with a 95 % confidence interval between 29.2° and 42.3°. Our results constrain the Early–Middle Jurassic paleolatitude of the Tethyan Himalayas to 18.9 ± 4.3°S. The calculated paleopole is at 30.9°N, 277.1°E (A = 4.3°, K = 12.6). The Neo-Tethys Ocean had an N-S width of approximately 2300 km during the Early Jurassic and 4200 km during the Middle Jurassic by combining published paleolatitudes of the Lhasa Terrane and the Tethyan Himalayas.

中文翻译：

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特提斯喜马拉雅山早-中侏罗世岩石的古地磁结果及构造意义

大印度的纬度变化和特提斯洋的古地理演化是有争议的，并且在很大程度上取决于确定特提斯喜马拉雅山的古地理位置作为地质时间的函数。然而，特提斯喜马拉雅山侏罗纪缺乏可靠的古地磁结果，给上述研究蒙上了阴影。我们对特提斯喜马拉雅山扎达地区宁日组地层（早-中侏罗世）进行了详细的古地磁研究。正折叠和反转测试以及显微镜观察表明特征剩磁分量 (ChRM) 是主要的。对 Ningri 组 ChRM 的伸长/倾角分析得出平均倾角的最佳估计值为 35.8°，95% 置信区间在 29.2° 和 42.3° 之间。我们的结果将特提斯喜马拉雅山早-中侏罗世的古纬度限制在 18.9 ± 4.3°S。计算出的古极点位于北纬 30.9°，东经 277.1°（A = 4.3°，K = 12.6）。通过结合已公布的拉萨地体和特提斯喜马拉雅山的古纬度，新特提斯洋的南北宽度在早侏罗世期间约为 2300 公里，在中侏罗世期间为 4200 公里。