Tectonic affinity of the Khanka Massif in the easternmost Central Asian Orogenic Belt: evidence from detrital zircon geochronology of Permian sedimentary rocks
Abstract
The tectonic affiliation of the Khanka Massif, in the easternmost section of the Central Asian Orogenic Belt (CAOB) , is still a matter of debate. Here, we provide new constraints on the provenance and timing of deposition of Permian strata in the western margin of the Khanka Massif. The results, which include U-Pb dating of detrital zircon grains using laser ablation-inductively coupled plasma-mass spectrometry, provide evidence regarding the tectonic position of the Khanka Massif and its role in the late Palaeozoic evolution of the eastern CAOB. Detrital zircon grains from a sublitharenite (Pingyangzhen Formation), a litharenite (Liangzichuan Formation), and a metamorphic siltstone (Qinglongcun Group) yielded multiple age populations ranging from Neoproterozoic (~914 Ma) to Permian (~272 Ma). Combined with age constraints from overlying/latestage igneous rocks and other magmatism of the Khanka Massif, we conclude that the dated strata were deposited during the early-middle Permian and were sourced from the Khanka Massif. A comparison between the detrital zircon age populations and the history of magmatic activity in the neighbouring areas suggests that the Khanka Massif was tectonically linked to the Songnen- Zhangguangcai Range Massif. Based on tectonic discrimination diagrams, we conclude that the western margin of the Khanka Massif was positioned in a convergent-boundary basin during the early-middle Permian. Strike-slip faulting along the Dunhua-Mishan Fault, in response to ridge subduction of the Paleo-Asian Ocean Plate, resulted in a north-eastward movement of the Khanka Massif. The occurrence of Precambrian detrital zircon grains (with ages of 1900-1700 and 900-700 Ma) implies the presence of an ancient basement within the Khanka Massif.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.V31D0163X
- Keywords:
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- 1031 Subduction zone processes;
- GEOCHEMISTRY;
- 1037 Magma genesis and partial melting;
- GEOCHEMISTRY;
- 1115 Radioisotope geochronology;
- GEOCHRONOLOGY;
- 8104 Continental margins: convergent;
- TECTONOPHYSICS