摘要
笔者基于一个完整的沙漠盆地内，各种地理景观、沉积环境与沉积作用、沉积类型间有机的密切联系，提出并使用沙漠盆地体系和沙漠盆地沉积体系的概念，结合将今论古的原理，在大量实际资料的分析、研究基础上，首次确定了在志丹群洛河组和罗汉洞组上段的沉积期间，有两期不同的古沙漠盆地体系和古沙漠盆地沉积体系的存在。根据各种沉积类型和剖面结构的古环境和古地理意义，对它们的次级环境和沉积体系进行了划分和讨论，重塑了这两期古沙漠盆地体系的古地理环境．依据保存的条件和地表的出露，笔者识别与恢复出洛河期古沙漠盆地体系从现盆地南部向北依次是砾模环境、丘外过渡环境和沙丘环境，而岩漠环境一般是不易被保存的，罗汉洞晚期的古沙漠盆地体系仅保存有沙丘环境和位于其南、北两侧的丘外过渡环境，而岩漠环境和现盆地市部的砾漠环境未被保存，现盆地北部的砾漠环境可能是未出露。对各种环境中的沉积类型和特征、剖面结构等均作了详尽地叙述和讨论。最后，并指出古沙漠相或古风成相的研究在沉积学的理论上和国民经济实践中的重要意义。
According to the data from the stLldy area, and through the detailed study, the existenceof the palaeodesert basins in the sedimentary period of Zhidan Group in Ordos Basin is identified. The palaeodesert basins are occurred in the sedimentary period of Luohe Formation andupper part of Luohandong Formation in Zhidan Group.On the basis of the sediment types and sectional texture, the palaeodesert basin in Luohe period is able to recover from soLlth to nortll gravel desert and outdune transition and duneenvironments, the rock desert environment is not preserved.In the gravel desert environment,it is mainly nltldflow and braided stream deposits,and a few eolian sand intercalationin the sectiontop.The sediments in dLlne environment consist mainly of dune deposits and intercalations of dry and damp interdune deposits.In the outdune transition environment, thesediments contain all sediment types in the gravel desert and dune environments.The palaeodesert basin in Luohandong late period is only able to distinguish dune andoutdune transition environments.The rock desert and gravel desert environments are notpreserved,the latter is also probably not exposed.The outdune transition environments are sitLlated at the soLlth and north both sides ofthe dune environment. The sediment types of dune environment are mainly dune depositsand intercalations of dry and damp intcrdLine deposits.In the outdune transition environmentat the north side of dune environment,the sedimentary sections are composed of alternatingbeds of the dune and wadi deposits. In the outdone transition environment at the south sideof dune environment I the sectional texture consist of sequence of alternating eolian and aqueous deposits.
出处
《西北地质科学》
1996年第1期63-90,共28页
Northwest Geoscience
基金
"鄂尔多斯盆地志丹群介形类生态环境"研究课题
关键词
志丹群
沉积时代
古沙漠
盆地体系
古地理
gravel desert environment outdune transitional environment dune environment sedimentary type sectional texts re
