华北地区奥陶纪岩相古地理

Sedimentary facies and palaeogeography of the North China region during the Ordovician

通过收集、吸收前人研究以及最新的大地调成果资料,以"构造控盆、盆地控相"为编图思路,在现今纬度下对中国华北地区开展岩相古地理的研究。本文认为,华北板块在早奥陶世和中-晚奥陶世处于不同的构造背景之下,不同的板块边界类型以及原始构造单元的基底形态控制着该时期古地理的展布。在此基础上,采用优势相以及压缩相的方法,总结划分出潮坪、局限台地、开阔台地、蒸发台地、浅(礁)滩、台地边缘斜坡、深水斜坡-盆地等7类沉积环境类型;梳理了华北克拉通沉积盆地在奥陶纪的古地理演化过程,编制了早奥陶世特马豆克期、早奥陶世弗洛期、中奥陶世大坪期-达瑞威尔期、晚奥陶世桑比期-凯迪期早期以及晚奥陶世凯迪期晚期-赫南特期等5个时期的华北地区古地理图。

The North China plate was situated in different tectonic settings during the Early Ordovician to the Middle and Late Ordovician, and different plate boundaries and basement topography of the original tectonic units tend to determine the distribution of the sedimentary facies and palaeogeography of the North China region. Seven sedimentary facies types have been distinguished in this study, including tidal fiat, restricted platform, open platform, evaporate platform, shoal （reef bank） , platform-margin slope and deep-water slope-basin facies. Five stages of the palaeogeographic maps have been reconstructed for the North China region, include the Tremadoeian （Early Ordovician ）, Floian （Early Ordovician）, Dapingian - Darriwilian （Middle Ordovician ）, Sandbian - Katian （ Late Ordovician） and late Katian - Hirnantian （ Late Ordovician） .