地质科学
地質科學
지질과학
SCIENTIA GEOLOGICA SINICA
2010年
1期
278-291
,共14页
刘嘉庆%李忠%韩银学%彭守涛%韩登林%许承武
劉嘉慶%李忠%韓銀學%彭守濤%韓登林%許承武
류가경%리충%한은학%팽수도%한등림%허승무
Sedimentary facies%Trace elements%Carbonate%Lianglitag Formation%Tahe Oilfield
塔河油田上奥陶统良里塔格组下段以泥微晶灰岩、瘤状灰岩为主,上段以鲕粒灰岩、生屑灰岩、砂砾屑灰岩为主,纵向上构成了一个向上水体变浅的沉积序列.根据层序地层学研究结果,将良里塔格组划分为一个三级层序,细分为两个体系域.通过对各体系域地层单元的岩相学和地球化学分析研究,恢复了各时期的古地理面貌及沉积相带的空间展布.最终研究结果表明良里塔格组沉积相带具有开阔台地、台地边缘和斜坡3种类型,平面上由北向南顺序展布,走向近东西.微量元素分析进一步佐证和完善了该区沉积相带分析,V、Ni和Cr微量元素的含量显示从浅水到深水总体呈增加之势,Ce异常曲线对沉积环境也有良好反映,而台地边缘相的Sr/Ba比值表现出异常高值.
塔河油田上奧陶統良裏塔格組下段以泥微晶灰巖、瘤狀灰巖為主,上段以鮞粒灰巖、生屑灰巖、砂礫屑灰巖為主,縱嚮上構成瞭一箇嚮上水體變淺的沉積序列.根據層序地層學研究結果,將良裏塔格組劃分為一箇三級層序,細分為兩箇體繫域.通過對各體繫域地層單元的巖相學和地毬化學分析研究,恢複瞭各時期的古地理麵貌及沉積相帶的空間展佈.最終研究結果錶明良裏塔格組沉積相帶具有開闊檯地、檯地邊緣和斜坡3種類型,平麵上由北嚮南順序展佈,走嚮近東西.微量元素分析進一步佐證和完善瞭該區沉積相帶分析,V、Ni和Cr微量元素的含量顯示從淺水到深水總體呈增加之勢,Ce異常麯線對沉積環境也有良好反映,而檯地邊緣相的Sr/Ba比值錶現齣異常高值.
탑하유전상오도통량리탑격조하단이니미정회암、류상회암위주,상단이이립회암、생설회암、사력설회암위주,종향상구성료일개향상수체변천적침적서렬.근거층서지층학연구결과,장량리탑격조화분위일개삼급층서,세분위량개체계역.통과대각체계역지층단원적암상학화지구화학분석연구,회복료각시기적고지리면모급침적상대적공간전포.최종연구결과표명량리탑격조침적상대구유개활태지、태지변연화사파3충류형,평면상유북향남순서전포,주향근동서.미량원소분석진일보좌증화완선료해구침적상대분석,V、Ni화Cr미량원소적함량현시종천수도심수총체정증가지세,Ce이상곡선대침적배경야유량호반영,이태지변연상적Sr/Ba비치표현출이상고치.
The Upper Ordovician Lianglitag Formation,Tahe Oilfield,mainly consists of micrite,nodular limestone in the lower member and oolitic limestone,bioclastic limestone,calcarenite,calcirudite in the upper member,which constitutes a shallowing upward sedimentary sequence.Based on sequence stratigraphy research,the Lianglitag Formation is a integral three-order sequence,which is composed by two systems tracts.By means of detail investigation in petrographic and geochemical characteristics of stratigraphic units in every systems tract,the palaeogeographic and sedimentary facies distribution are recognized.There are three kinds of facies belts during upper Ordovician in Tahe Oilfield:platform,platform margin and slope facies,which is approximately east-west strike and distribute orderly from north to south in the plane.Analysis of trace elements and rare earth elements further support and improve the analysis of sedimentary facies.The content of V、Ni and Cr trace elements shows a overall increasing trend from shallow to deep water facies,as well as the abnormal curve of Ce is a good reflection about the sedimentary environment and the Sr/Ba ratio shows abnormally high values in platform margin.