国内外红层分布及其地貌发育的对比研究

为了解全球红层的时空分布规律及其地貌发育的差异,对国内外红层的分布、形成年代、地质构造背景、古地理环境、岩性和地貌特征等进行了对比研究。结果表明：国内红层主要分布于东南、西南、西北等地区,形成年代主要为中生代,尤以白垩纪为主,构造环境主要为古陆块活化时形成的断陷/拗陷盆地;沉积环境几乎全部为陆相,形成于干旱或半干旱古气候条件;岩性复杂,兼具砾岩、砂岩、粉砂岩和泥岩,发育了丹霞地貌、红层高原、红层山地和红层丘陵等多种地貌类型。国外红层的形成年代跨度很大,从前寒武纪到新近纪均有发育,呈现出从老陆块向新陆块扩展的趋势;构造环境分为山前/山间拗陷堆积、地台拗陷堆积、裂谷盆地堆积和弧后盆地堆积;沉积环境以陆相为主,兼具滨-浅海相和海陆过渡相,也形成于干旱、半干旱气候;岩性以砂岩、粉砂岩和泥岩为主,砾岩较少;发育的地貌类型相对单一。

Comparative Study on the Global Distribution and Geomorphic Development of Red Beds

In order to advance our understanding on the temporal and spatial distribution law of red beds in the world and their differences in geomorphic development, a comparative study was conducted on the distribution, age, geological setting, paleogeographic environment, lithology, and geomorphic features of red beds in and outside China. It reveals that red beds in China are mainly distributed in southeast, southwest, and northwest China. They were mainly deposited in the Mesozoic Era, especially in Cretaceous. The major tectonic settings for the deposition of red beds in China are fault basins and depression basins in reactivated areas of paleo-landmass. Almost all red beds in China are continental deposits, which were formed in arid and semi-arid paleoclimate conditions, with a wide range of grain size, from coarse-grained conglomerates,through fine-grained sandstones and siltstones to mudstones. Various types of landform were developed on red beds in China, including Danxia landforms, red bed plateaus, red bed mountains, and red bed hills. By contrast, red beds outside China have a much wider range of age, from Precambrian to Neogene, indicating a trend of deposition from old landmass to young landmass. As for tectonic setting, it can be classified into four types: piedmont/intermountain depression deposition, platform depression deposition, rift basin deposition and back-arc basins. Most of them were continental deposits, with few littoral and transitional facies. The paleoclimate for the formation of these red beds was also arid and semi-arid climate. However, in lithology, most red beds outside China were composed of red sandstones, siltstones, and mudstones, with few coarse-grained deposits like conglomerates. Except in some piedmont/intermountain basins with complex tectonic setting, the types of red bed landforms developed in stable landmassesoutside China are relatively simple.