广东海丰地区下侏罗统长埔组浅海沉积与前陆构造背景
- Publish Date: 2012-04-10
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Key words:
- retroarc foreland /
- shallowmarine sediment /
- Lower Jurrassic /
- Changpu Formation /
- Eastern Guangzhou province /
Abstract: Changpu Formation of lower Jurassic outcropped in Haifeng, Guangdong province is a set of shallow marine clastic deposits, composed of shoreface sandstones and turbidite deposits in the muddy shelf environment. The particle size analysis of sandstones shows that the probability cumulative curve of shoreface sandstone represents twostage and the frequency histogram is a single peak, and cumulative probability curve of turbidite represents threestage and the frequency histogram is bimodal. The lithofacies succession of Changpu Formation is a rock association indicating the transgressiveregressive processes with the thickening upward of sandstone layers. The transgressive regressive succession indicates that two eustatic sea level change occurred during development of Changpu Formation. The shallow muddy and turbidite deposits constitute a flysch succession. Markov chain analysis shows that it is a significant coarseningupward succession. Geochemical data reveal that sediments of Changpu Formation have features of both passive continental margin and active continental margin. The sediments were from the recycled orogen related to the magmatic arc orogen and subduction complex after analysis of the Dickinson Graphic of sandstone composition. Haifeng region was close to the thrust fault zone. The sedimentary basin developed under a tectonic setting of compressional retroarc foreland during the early Jurassic, and the basin provenances were both of recycled orogen zone and continental block.