Airborne electromagnetic characteristics and deep prospecting of a ringed molten rock mass in eastern Tianshan
YANG Bo1,2,3(), SUN Dong-Hua1,2,3
1. Airborne Survey and Remote Sensing Center of Nuclear Industry, Shijiazhuang 050002, China 2. Hebei Provincial Key Laboratory of Aerial Detection and Remote Sensing Technology, Shijiazhuang 050002, China 3. CNNC Uranium Resources Geophysical Exploration Technology Center (Key Laboratory), Shijiazhuang 050002, China
A ringed molten rock mass in eastern Tianshan, Xinjiang is closely related to Au-Pb-Zn mineralization. Since the mineralization occurs in the fault fracture zone near the outer contact zone between the rock mass and strata, it is necessary to find out the spatial distribution of the rock mass and the development of the fault structure. The processing and analysis of the 1∶25 000 high-resolution airborne transient electromagnetic and aeromagnetic data yielded the following airborne electromagnetic characteristics of the rock mass. The ringed molten rock mass displayed positive and negative alternating ringed aeromagnetic fields. There were four NWW-trending banded zones with strong electromagnetic responses along the ringed molten rock mass, with a time constant of generally 0.07~0.18 ms. Seven NWW-trending faults were inferred and interpreted using the high-value band of the electromagnetic response of the 23rd trace of the dB/dt X component and the aeromagnetic anomaly zone with amplitude of 5~10 nT. By combining the airborne electromagnetic characteristics and three-dimensional inversion results of magnetic vectors, the lithology and structures of the study area were inferred and interpreted again, roughly ascertaining the three-dimensional distribution characteristics of the diorites. Based on these results as well as the known metallogenic geological conditions and the airborne electromagnetic characteristics, two prospecting favorable areas were delineated in the areas with strong electromagnetic responses to the west and southwest of the ringed molten rock mass. This study provides important information on the deep prospecting of the rock mass.
杨波, 孙栋华. 东天山某环状熔融岩体航空电磁场特征及深部找矿研究[J]. 物探与化探, 2022, 46(4): 816-823.
YANG Bo, SUN Dong-Hua. Airborne electromagnetic characteristics and deep prospecting of a ringed molten rock mass in eastern Tianshan. Geophysical and Geochemical Exploration, 2022, 46(4): 816-823.
Wang Y L, Zhang Z W, Chen S B, et al. Petrogenesis and Metallogenic Potential Analysis of Mafic Intrusion in the Hongshigangbei Ni-Cu-Sulfide Mineralization in East Tianshan,Xinjiang[J]. Acta Geologica Sinica, 2017, 91(4):776-791.
Feng Y Q, Qian Z Z, Xu G, et al. Rock-forming mineral features of Permian mineralized mafic-ultramafic intrusions in East Tianshan Mountains and their implications for intrusion generation[J]. Acta Petrologica Et Mineralogica, 2017, 36(4): 519-534.
Ding J H, Xing S W, Xiao K Y, et al. Geological Characteristics and Resource Potential Analysis of the Dongtianshan-Beishan Cu-Ni-Au-Pb-Zn Metallogenic Belts[J]. Acta Geologica Sinica, 2016, 90(7):1392-1412.
Wang W, Meng Y, Wang K, et al. Zircon U-Pb ages, geochemical characteristics and petrogenesis of ringed pluton in the Hancaohu area,eastern Tianshan Mountains of Xinjiang[J]. Geological Bulletin of China, 2019, 38(5):777-789.
Yu J Y, Ji B, Wang G Q. Geochemistry of dioritic enclaves related to magmatic mixing in the concentrically zoned Alatage igneous complex, central Tianshan Mountains[J]. Geology in China, 2018, 45(4): 767-782.
Deng J H, Xu G Z, Wei K, et al. Metallogenic conditions and prospecting indicators of Yishan gold deposit in east Tianshan area, Xinjiang[J]. Inner Mongolia Science Technology & Economy, 2013(4):47-48,50.
Chen S M, Qin X, Zhao X X, et al. Geophysical field characteristics and deep ore prospecting prediction of the Zhaiwa concealed rock mass in Western Henan[J]. Geology and Exploration, 2019, 55(5):1117-1131.
Chen A G, Zhou T F, Liu J D, et al. Gravity and magnetic characteristics of Xuancheng ore concentration area along middle-lower Yangtze river valley metallogenic belt:Implications to ore prospecting[J]. Mineral Deposits, 2020, 39(5):879-892.
Zhang J T, Yu L, Liu C P, et al. Characteristics of regional gravity, magnetic anomalies and deep structural geological background of primary diamond deposits in the western Shandong Province[J]. Acta Geologica Sinica, 2020, 94(9):2783-2795.
Li H, Li Y J, Xu X Y, et al. Deep Structure and Texture of the Sartohay Ophiolite in West Junggar,Xinjiang:New Geological and Geophysical Evidence[J]. Geotectonica et Metallogenia, 2021, 45(4):634-650.
Letelier P, Napier S, Reid J, et al. Combined potential field and airborne electromagnetic interpretation to unravel the geological istory of the Curaca Valley Region, Bahia, Brazil[J]. ASEG Extended Abstracts, 2019 (1): 1-3.
Cheng G S, Liu W D, Chu Z Y, et al. Deep comprehensive geophysical characteristics and significance of the Xiyu kimberlites in the Mengyin County, Shandong Province[J]. Acta Geologica Sinica, 2020, 94(9):2772-2782.
Sun D H, Li H Y, Jiang M Z, et al. New evidence for the boundary of north China platform' north margin and its prospecting significance[J]. Geological Science and Technology Information, 2019, 38(2):25-30.
Ning Y L, Zhou Z Y, Jiang M Z, et al. Airborne anomaly characteristics and prospecting intention of the upper reaches of Xiagalai'aoyi river Pb-Zn deposit in Heilongjiang[J]. Progress in Geophysics, 2019, 34(3):1074-1080.
Shi L C, Luo Y, Jiang M Z, et al. Characteristics of aero-electromagnetic field and its prospecting significance in the Wulong gold deposit,Liaodong Peninsula[J]. Acta Geologica Sinica, 2020, 94(10):3106-3119.
Luo Y, Zeng Y, Shi Y, et al. The test of airborne transient electromagnetic technology in the volcanics-associated massive sulfide ore district[J]. Geophysical and Geochemical Exploration, 2014, 38 (4):840-845.
Prikhodko A, Geo P. EM time constant (TAU) analysis[M]. Geotech Ltd., 2010.
Ma G J, Zhang R, Zheng X L, et al. Application of VLF-EM method in the mineral exploration of Longtoushan Ag-Pb-Zn Deposit,Alukerqinqi,Inner Mongolia[J]. Progress in Geophysics, 2007, 22(5): 1627-1636.
蒋邦远. 实用近区磁源瞬变电磁法勘探[M]. 北京: 地质出版社, 1998.
Jiang B Y. Applied near zone magnetic source transient electromagnetic exploration[M]. Beijing: Geological Publishing House, 1998.