Provenance Analyses of Lower Cretaceous Strata in the Liupanshan Basin: From Paleocurrents Indicators, Conglomerate Clas
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Proovenancce Anallyses of Lower Cretacceous Sttrata in the L Liupans shan Baasin: Frrom Palleocurreents Ind dicatorss, Coonglom merate Clast C Co omposittions, an nd Zirccon U-P Pb Geocchronollogy 2 Xiaaochen Zhaoo *1, Chiyang Liu *2, Jianqiang Wang W , Wei Luo L 3, Fangpeeng Du1, Li Ma M 4
1 College of Geeology and Envvironment, Xi’ann University off Science and Teechnology, Xi’aan 710054, Chin 1. na 2. Statee Key Laboratoory of Continenttal Dynamics, Department D of Geology, G Northwest Universityy, Xi’an 710069 9, China 3. BGP Inc., China National Petroleuum Corporationn Southwest Geo ophysical Reseaarch Institute, C Chengdu 61000 00, China 4. College off Energy Engineeering, Xi’an University U of Sciience and Technnology, Xi’an 7710054, China Xiiaochen Zhao: https://orcid.org h g/0000-0002-84404-9471; Ch hiyang Liu: httpps://orcid.org/00000-0003-1926 6-7947 AB BSTRACT: Th he Liupanshan n Basin constittutes a major portion p of the northern Norrth-South tecto onic beelt. The Lower Cretaceous strrata in the Liu upanshan Basin n recorded thee tectono-sedim mentary evoluttion prrocesses of thiss area and aree pivotal for understanding u the original sedimentary s appearance of the Liupanshan Bassin. In this worrk, we presentt a study of prrovenance and d tectono-sedim mentary evoluttion of the Liupanshaan Basin durin ng the Early Cretaceous. C Inttegrated-paleoocurrent directtions, gravel cllast compositions, an nd detrital zirrcon U-Pb isottopic analysis of the Lowerr Cretaceous S Sanqiao and HeH shangpu formatiions were applied to determ mine the proven nance. The gravel clast com mpositions of Sanqiaao Formation conglomeratess (mainly inclu uding magmattic rocks, metaamorphic rock ks and limeston nes) dissplay various features in diffferent places, revealing diffferent rock components of ssource areas. The T paaleocurrent dirrections of thee Sanqiao and d Heshangpu formations su uggest that thee sediments were w traansported from m the basin margin to the ceenter. Detrital zircons of twoo samples from m the Huoshizzhai Seection (northweestern Liupansshan Basin) yiield a dominan nt unimodal diistribution from m 420 to 500 Ma, M suggesting a sin ngle-sourced provenance. p Baased on the above a analysess, comparing to the magma atic reccords in the Qilian-Qinling orogenic o belt, the t detritus of the Sanqiao an nd Heshangpu u formations were w maainly from thee proximal meetamorphic and magmatic rocks of the Qiilian-Qinling oorogenic belt and a thee limestones off the archaic uplift. u Combin ned with sedim mentary characcteristics, we cooncluded that the Liupanshan Bassin experienced d multi-stage evolution e histo ory: (1) the earrly rifting exteension stage (Sanqiaao Period), (2) the middle spanning and deepression stagee (Heshangpu––Early Naijiahee Period), and (3) thee late extinctioon stage (Late Naijiahe Periood). The evoluttion of Liupan nshan Basin is closely related d to thaat of Ordos Basin B and it is further associiated with tecttonic transition n of the north hern North-South tecct
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