Karimi Kurosh, Kletetschka Gunther, Mizera Jiří, Meier Verena, Strunga Vladimír
Institute of Hydrogeology, Engineering Geology and Applied Geophysics, Faculty of Science, Charles University in Prague, Albertov 6, 128 43, Praha 2, Czech Republic.
Geophysical Institute, University of Alaska - Fairbanks, 903 N Koyukuk Drive, Fairbanks, AK, 99709, USA.
Sci Rep. 2023 Aug 8;13(1):12868. doi: 10.1038/s41598-023-40177-7.
The parent impact crater of Australasian tektites has not been discovered so far, but a consensus has been accepted on its location in a wider area of Indochina. Recently, an alternative location has been suggested in the Badain Jaran Desert (BJD), Northwest China. Employing gravity and magnetic data derived from satellites, possible presence of an impact structure in BJD is investigated. The gravity parameters include the free air gravity disturbance, its vertical derivative component and total horizontal gradient (THG), strike alignment (SA), and Bouguer anomaly with its first vertical derivative and tilt angle. The magnetic parameters include the anomalous total magnetic field (TMF), its reduced to the pole transformation (RTP), the first vertical derivative of the TMF vertical component (B), tilt angle (TA), and logistic total horizontal gradient (LTHG). Both the gravity and magnetic indicators support the presence of the impact structure. Gravity parameters display typical annular gravity highs circumscribing a gravity low. SA analysis reveals preferred parallel directions, implying the susceptibility of special zones to the impact shock waves, both within and beyond the rim. TMF reveals a large magnetic anomaly in the southern part of the proposed crater, and RTP displaces and restricts it further into the rim. B weakens the long wavelength anomalies, amplifies the superficial ones, and separates them horizontally. TA and LTHG delineate the deep-seated and shallow magnetic signals related to the peak and border magnetization, respectively.
迄今为止，澳大拉西亚玻璃陨石的母体撞击坑尚未被发现，但对于其位于印度支那更广泛区域的位置已达成共识。最近，有人提出在中国西北的巴丹吉林沙漠（BJD）存在一个替代位置。利用卫星获取的重力和磁数据，对BJD中可能存在的撞击结构进行了研究。重力参数包括自由空气重力扰动、其垂直导数分量和总水平梯度（THG）、走向排列（SA）以及布格异常及其一阶垂直导数和倾斜角。磁参数包括异常总磁场（TMF）、其化极变换（RTP）、TMF垂直分量的一阶垂直导数（B）、倾斜角（TA）和逻辑总水平梯度（LTHG）。重力和磁指标均支持撞击结构的存在。重力参数显示出围绕重力低值的典型环形重力高值。SA分析揭示了优选的平行方向，这意味着特殊区域对撞击冲击波敏感，无论是在边缘内部还是外部。TMF在拟议撞击坑的南部显示出一个大的磁异常，RTP将其进一步位移并限制在边缘内。B减弱了长波长异常，放大了表层异常，并在水平方向上分离它们。TA和LTHG分别描绘了与峰值和边界磁化相关的深部和浅部磁信号。
