西北地质
西北地質
서북지질
NORTHWESTERN GEOLOGY
2014年
2期
1-10
,共10页
张忠义%丁天柱%何鹏%祝新友
張忠義%丁天柱%何鵬%祝新友
장충의%정천주%하붕%축신우
赛什塘矿区%叠加褶皱%构造分析%劈理%印支期
賽什塘礦區%疊加褶皺%構造分析%劈理%印支期
새십당광구%첩가습추%구조분석%벽리%인지기
Saishitang mining area%superposed fold%structural analysis%cleavage%indosinian
新的资料揭示,青海赛什塘铜矿区是褶皱叠加变形区。为矿山勘探工作提供基础地质支撑,采用露头构造解析基础上的构造综合分析方法,在露头条件欠佳的矿区中下三叠统中首次厘定出4期褶皱组合样式,形成露头和区域尺度上的各类叠加构造。第二期褶皱(F2)叠加在第一期褶皱(F1)之上,主要形成 Ramsy(Ramsay et al.,1987)的第三类叠加,表明二者可能是同一构造事件中连续的2阶段变形作用的结果,代表了从分层剪切到横向缩短的地壳变形机制转换过程,其间同时发生了印支期岩浆杂岩的侵入就位,推测是对区域上印支期西秦岭地块与柴达木地块之间从俯冲向碰撞转换的远程效应的响应。褶皱构造对赛什塘铜多金属矿的形成、改造和保存都起了重要作用。
新的資料揭示,青海賽什塘銅礦區是褶皺疊加變形區。為礦山勘探工作提供基礎地質支撐,採用露頭構造解析基礎上的構造綜閤分析方法,在露頭條件欠佳的礦區中下三疊統中首次釐定齣4期褶皺組閤樣式,形成露頭和區域呎度上的各類疊加構造。第二期褶皺(F2)疊加在第一期褶皺(F1)之上,主要形成 Ramsy(Ramsay et al.,1987)的第三類疊加,錶明二者可能是同一構造事件中連續的2階段變形作用的結果,代錶瞭從分層剪切到橫嚮縮短的地殼變形機製轉換過程,其間同時髮生瞭印支期巖漿雜巖的侵入就位,推測是對區域上印支期西秦嶺地塊與柴達木地塊之間從俯遲嚮踫撞轉換的遠程效應的響應。褶皺構造對賽什塘銅多金屬礦的形成、改造和保存都起瞭重要作用。
신적자료게시,청해새십당동광구시습추첩가변형구。위광산감탐공작제공기출지질지탱,채용로두구조해석기출상적구조종합분석방법,재로두조건흠가적광구중하삼첩통중수차전정출4기습추조합양식,형성로두화구역척도상적각류첩가구조。제이기습추(F2)첩가재제일기습추(F1)지상,주요형성 Ramsy(Ramsay et al.,1987)적제삼류첩가,표명이자가능시동일구조사건중련속적2계단변형작용적결과,대표료종분층전절도횡향축단적지각변형궤제전환과정,기간동시발생료인지기암장잡암적침입취위,추측시대구역상인지기서진령지괴여시체목지괴지간종부충향팽당전환적원정효응적향응。습추구조대새십당동다금속광적형성、개조화보존도기료중요작용。
Recent geological studies have revealed that Qinghai Saishitang copper mining area is a deformation zone with several superimposed folds.To provide basic geological support for mine exploration programs,integrated tectonic analysis method drawn on outcrop structural analysis is adopted in this paper.Middle-Early Triassic rocks in mining area of poor outcrop condition are classified into four phases of fold association styles.All phases of folds are involved to produce various superimposed structures in light of outcrop and regional scale. In most cases, the presence of the Ramsy′s Type 3 superposition,which is formed by the overlay of F2 folds on earlier F1 ones,suggesting that the two may be result of two successive deformation phases in one tectonic cycle and representing a crustal deformation mechanism transition from delamination shear to horizontal shortening.The intrusion and emplacement of Indosinian magmatic complex also took place between two deformation phases,which is probably a response to the far field transition from subduction to collision of the west Qinling and Qaidam blocks in the Indosinian tectonic period.The fold structure plays an important role on the formation,reconstruction and preservation of the polymetallic deposit in Saishitang mining area.