Basin evolution in the Subei Basin during the Pliocene-Quaternary based on provenance analysis of detrital heavy minerals
Since the Cenozoic era,a set of loose terrigenous strata has continuously deposited in the Subei Basin in a wide range,which contains abundant paleoenvironmental information.These strata are of great significance to the study of the evolution of large basin and the development of large river system under the control of the Neotectonics.In this paper,the wide-window particle size method was applied to conduct a quantitative analysis on the detrital heavy minerals in the sedimentary strata of the Pliocene in the Subei Basin to explore their provenance to reconstruct the basin evolution process.The results showed that during the Neogene period,the heavy minerals assemblage in the strata was epidote-limonite-ilmenite,with garnet as the characteristic minerals,indicating that the sediment mainly came from the surrounding areas of the Subei Basin(Jiangsu coastal uplift,Ningzhen Mountains)and the lower reaches of the Yangtze River(southern Anhui,Jianghuai,Zhejiang).Since the late Pliocene,the heavy min-erals in the Subei Basin underwent a sudden change,and the heavy minerals in the overlying Quaternary sediment showed obvious wide source characteristics,the sources of which were similar to those in the surface sediment of the modern Yangtze River.Therefore,it could be inferred that as the Neotectonics continued,the sedimentary center of the lower Yangtze River gradually shifted southward from the Subei Basin since the Pliocene,and the contemporary and modern delta sedimentary system gradually took shape as a consequence.
provenance analysisheavy mineralbasin evolutionchannel migration of the Yangtze River
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