试论造山带层序地层的类型、特点和控制因素——以东昆仑三叠系为例

造山带地区的层序地层往往被视为禁区,以东昆仑三叠系为例,认为造山带除核部外,远离造山带核部地区基本具备了开展层序地层研究的条件,但造山带层序地层与克拉通相比具显著的不同:1)体系域的不完整;2)凝缩段常常缺乏;3)造山带海平面变化特征自始至终呈现剧烈的跳跃式。因而控制造山带海平面变化和层序地层的并不是全球海平面变化,而是区域构造作用和物源控制。从而对造山带层序地层不能套用稳定地区的层序地层模式,而需要从自身特征出发,因地制宜,建立起不同构造环境控制下的海平面变化模式。

THE OROGENIC SEQUENCE STRATIGRAPHIC TYPES AND THEIR CONTROLLING FACTOR TAKING THE TRIASSIC OF EASTERN KUNLUN AS EXAMPLE

Based on the Triassic of Eastern Kunlun, the area far from the orogenic core zone possesses the potential for studying the sequence stratigraphy. However, the sequence strata there are clearly different from the craton in the following aspects:1) System tract is not complete; 2) condensed member is lacking; 3) Fluctuation of sea-level of the orogenic zone remains sharply wavering throughout.Thus the factors controlling the fluctuation of sea-level of the orogenic zone and sequence stratigraphy are not the global eustatic fluctuation but are the regional tectonic process and the provenance control. We can not use the model of the sequence stratigraphy of the stable area for that of the orogenic zone and it is necessary to establish the model of the fluctuation of sea level controlled by different tectonic environments.