沉积学报2024，Vol.42Issue(3)：892-911,20.DOI:10.14027/j.issn.1000-0550.2023.101
黔北地区下奥陶统沉积相与层序特征
Depositional Facies and Sequence Stratigraphy of the Lower Ordovician Successions in Northern Guizhou Province
摘要
Abstract
[Objective]The Great Ordovician Biodiversification Event(GOE)is the result of the interaction between marine environments and organisms.The analyses of sedimentary facies and depositional sequences of the Ordovician carbonate platform can reveal its development and evolution,as well as the history of sea level fluctuations,which can provide a sedimentary background and isochronous stratigraphic framework for exploring the spatiotemporal distri-bution characteristics and the evolution of coeval organisms.[Methods]Based on the measurement of the outcrop sec-tions and microscopic observation,the Lower Ordovician(Tongzi and Honghuayuan Formations)successions of the Piao'ertian section in northern Guizhou province were investigated to recognize the lithofacies types,construct the depositional model,identify the sequence stratigraphy,and explore the controls of depositional evolution.[Results and Conclusions](1)Ten types of lithofacies were identified and further grouped into two depositional belts(or associations)in a carbonate ramp system.The depositional system was further divided into non-skeletal and skeletal grain-dominated end members for the Tongzi and Honghuayuan formations,respectively.(2)These lithofacies are vertically stacked into asymmetrical,meter-scale,shallowing-upward open-marine depositional cycles for both Tongzi and Honghuayuan Formations.(3)Based on the vertical facies and cycle stacking patterns,three and one half third-order depositional sequences(Sq1-Sq4)were distinguished,which are defined by Ⅱ sequence boundaries(lithologic transition surfaces).Sq1-Sq3 are full sequences that consist of transgressive systems tract(TST)and upper regressive systems tract(RST)packages,but Sq4 only contains TST.(4)The depositional evolution and sequence development of the Lower Ordovician of the Piao'ertian section were controlled by relative sea-level oscilla-tions of different orders and paleogeographic configuration.The relative sea-level oscillations of different orders dictated the vertical development of facies;the paleogeographic configuration primarily defined the spatial distribution of depositional belts(or associations).关键词
碳酸盐岩/缓坡模式/沉积旋回/沉积层序/相对海平面变化/古地理格局Key words
carbonates/ramp model/depositional cycles/depositional sequences/relative sea-level fluctuations/paleogeographic configuration分类
天文与地球科学引用本文复制引用
郭川,张维圆,付勇,夏鹏..黔北地区下奥陶统沉积相与层序特征[J].沉积学报,2024,42(3):892-911,20.基金项目
贵州省科技计划项目(黔科合基础-ZK(2021)一般199) （黔科合基础-ZK(2021）
国家自然科学基金项目(42262019,92062221) （42262019,92062221）
贵州大学培育项目(贵大培育(2019)68号)[Foundation:Guizhou Provincial Science and Technology Projects,No.ZK(2021)ordinary 199 （贵大培育(2019）
National Natural Science Foun-dation of China,No.42262019,92062221 （）
Talent Project of Guizhou University,No.(2019)68] （2019）
