Study On The Characteristics Of Unconformity Development And Calculation Of Unconformity Denudation In The Region Of Central Tarim Uplift

The region of central Tarim uplift is a complex area where various structuressuperimpose each other.In this paper,we will focus on the unconformity development characteristics,unconformity types and plane distribution of unconformity interface in the region of central Tarim uplift,calculate the unconformity denudation quantity and analyze the spatial distribution characteristics of denudation quantity,so as to give some guidance for the development of the oil and gas exploration and exploitation.The research progress of this paper is as follows:?1?According to the lithology,depositional characteristics and period of tectonic activity,the tectonic sequence of the region of central Tarim uplift can be divided into four primary structural sequences,including the Upper Nanhua to Middle Devonian structural sequence;Upper Devonian to Permian structural sequence;Triassic to Cretaceous structural sequence;Paleogene to quaternary structural sequence.?2?There are many unconformities in the region of central Tarim uplift,with 10major unconformities.The levels of unconformity in the region of central Tarim uplift can be divided into three levels,the first of which is generally related to global or regional plate activities,including Nh/AnNh??/An??S/AnS?C-D₃/AnD₃?T/AnT?J/AnJ?K/AnK and E/AnE.The secondary unconformity generally corresponds to a number of strong regional tectonic activities,including Z₁/AnZ₁?D/AnD?P/AnP and N₂/AnN₂.Tier 3 unconformity is generally influenced by local tectonic activities,including O₃/O_1-2?O_3s/O_3l?P₂/P₁ and N₁/AnN₁.?3?By means of the method of layer extension,six major unconformity denudations are calculated and characteristics of spatial variation of denudation are analyzed.At the end of the Middle Ordovician period,denudation in most areas of the region of central Tarim uplift ranged from 100 to 200m.At the end of Ordovician period,the denudation was severe,and the largest denudation is over 1200m.At the end of the MiddleDevonian period,denudation was more than 1200m locally,and the thickness of denudation was more than 1000m in the Southwest region of the region of central Tarim uplift.At the end of the Permian period,the denudation thickness of the region of central Tarim uplift was small,and the maximum denudation was over 400m.At the end of the Triassic system,the denudation in the region of central Tarim uplift was small,about 400m.At the end of the Cretaceous period,denudation in the region of central Tarim uplift is generally between 100m and 200m.?4?In the region of central Tarim uplift,according to the structural sequence and the characteristics of unconformity,the evolution process of central Tarim uplift can be divided into:the developing period of central Tarim uplift:the Precambrian;the period of information of central Tarim uplift:Cambrian to Middle Ordovician;the stereotyping period of central Tarim uplift:late Ordovician to Middle Devonian;partial renovation period of central Tarim uplift:late Devonian to Triassic;tectonic activity stabilization period of central Tarim uplift:Jurassic to Cretaceous;burial settlement period of central Tarim uplift:palaeogene to quaternary.