山东地区早寒武世层序岩相古地理研究

【作者】 李国新；

【导师】 陈洪德； 侯明才；

【作者基本信息】 成都理工大学 ， 古生物学与地层学， 2006， 硕士

【摘要】 山东地区位于华北东南部及部分渤海海域。南北最长约400多公里，东西最宽约700多公里，总面积约15万平方公里。区内广泛发育下寒武统，累计厚度约100-300米。山东地区下寒武统沉积类型多样，生物化石较丰富，具有良好的岩石地层、生物地层、年代地层和沉积相研究基础，是进行层序地层学研究的理想地区和层位。通过本论文的研究，主要取得以下认识： 1、在大量前人研究成果的基础上，结合新的岩石地层清理意见，全面系统地对山东地区早寒武世地层进行了清理，主要将下寒武统划分为2阶：沧浪铺阶、龙王庙阶；3组：李官组、朱砂洞组、馒头组。并进行了全区的地层对比，使研究区下寒武统的岩石地层、生物地层、年代地层和层序地层得到了统一。 2、根据岩石类型、沉积构造、古生物、剖面结构和沉积旋回等特征，将山东地区早寒武世沉积体系划分为滨岸沉积体系、潮坪沉积体系，详细研究了各相、亚相和微相的特征，并建立了滨岸、潮坪沉积模式。 3、识别出4种层序界面的识别标志：①不整合面；②岩性、岩相转换面；③超覆面；④最大海泛面。以此为基础，将山东地区下寒武统划分为4个层序。讨论了各层序在不同相区内的特征及其变化，进行了区域上的对比，并建立了层序格架。层序在区内发育完整程度不同，反映了海平面变化、古气候及构造活动对层序发育的复合控制。 4、通过等时层序地层格架的建立和系统的层序岩相古地理编图，揭示了沉积盆地的古地理演化特征。结合区域构造演化的研究成果，讨论了早寒武世山东地区海侵方向变化的原因。更多还原

【Abstract】 Shandong zone is more than 400km at its length from south to north, about 700km at its width from east to west, and total area is about 1,500,000km~2, including east-south in the north-China and part of Bohai space. The region extensively develop early Cambrian series stratum whose accumulative thickness has about 100-300m. It has multiplicity sediment types and fruitful biological fossils. This region is ideal region and stratum study, in which has good base of the rock stratum, biology stratum, time stratum and sediment facies. This paper mainly gains following conclusions by this research.1. On the basis of the early study result as well as new rock stratum cleaning up mind, early Cambrian stratums in the Shandong region are studied completely. It is divided 2 stages: Changlangpu stage, Longwangmiao stage; 3 formations: Liguang formation, Zhushatong formation, Mantou formation. Lithostratigraphy, biostratum, and depositional sequence are consolidated by the whole region stratum contrast in research field.2. According to characters of the rock types, sediment structure, palaeocommunite, section structure, etc. early Cambrian sediment system is divided shore sediment system and tidal flat sediment system in the Shandong region. We traverse character of each sediment system, facies, sub-facies, tiny facies and erect sediment model.3. Four types of the sequence boundary wre recognized: unconformable surface, litholgy- lithofacies diversion surface, overlapping surface and maximum flooding surface, etc. Based on this, early Cambrian in the Shandong region is divided 4 sequences. This paper discuss each sequence character as well as change from different facies, contrast in the region, and erect sequence trellis. In short, each third sequence may contrast in the region. But sequences develop differently, it reflect that sequences upgrowth are controlled together by palaeoclimate, sea level change and regional tectonic activity.4. Lithofacies paleogeography characters were posted by upbuiding isochronous sequences frame and sequence-based lithofacies-paleogeography map working out. On the production of researching tectonic evolve, the author discussed the reason of transgression directional change.更多还原