松辽盆地南部火石岭组火山岩分布特征

Distribution characteristics of volcanic rocks in Huoshiling Formation in southern Songliao Basin

松南地区火山岩具有分布范围广、厚度大、岩性岩相特征复杂、地层穿时的特点,地层序列划分是地质研究的基础,对于后续相关地质研究及油气勘探开发部署具有重要意义,因此,明确不同区块的火山岩喷发时期与岩性组合差异尤为重要。应用以往的岩性岩相识别、地震地层接触关系分析方法,在火山岩年代学指导下,利用U-Pb、K-Ar、Ar-Ar等测年方法确定火山岩地质时期。通过取样分析测试得到松辽盆地火山岩的年代数据130个,明确松南地区火山岩时代归属。结合火山岩成分分类,确定松南地区火石岭组火山岩发育3个喷发旋回,由上至下分别为中性喷发旋回、中酸性喷发旋回以及中基性喷发旋回。中性喷发旋回分布范围较广,喷发次数多,在查干花、梨树、龙凤山地区均发育;中酸性喷发旋回分布范围较小,厚层酸性喷溢相为主,发育火山通道相,主要分布在查干花、梨树地区;中基性喷发旋回分布范围较小,仅在东岭地区发育,该旋回以中基性喷溢相和中基性爆发相为主。明确松辽盆地南部火石岭组火山岩喷发旋回划分,建立全区的火山岩地层格架,优选更利于勘探部署的喷发旋回开展研究工作,控制了勘探的时间成本,有利于松辽盆地南部火山岩研究的系统化。

The practice of deep oil and gas exploration in the southern Songliao Basin shows that volcanic oil and gas reservoirs have become an important field for oil and gas breakthrough.In recent years,the degree of oil and gas exploration for volcanic rocks has been significantly improved.The basin has abundant drilling,seismic,logging,volcanic rock chronology and geochemical data,which provides conditions for the study of deep volcanic rocks in the basin.Volcanic rocks in Songnan area have the characteristics of wide distribution,large thickness,complex lithology and lithofacies,and time-lapse of strata.Stratigraphic sequence division is the basis of geological research,which is of great significance for subsequent related geological research and oil and gas exploration and development deployment.In addition to the previous methods of lithology and lithofacies identification and seismic stratigraphic contact relationship analysis,this study also used U-Pb,K-Ar,Ar-Ar dating methods to determine the geological period of volcanic rocks under the guidance of volcanic chronology.Through sampling analysis and testing,130 age data of volcanic rocks in Songliao Basin are obtained,and the age of volcanic rocks in Songnan area is clarified.Further combined with the classification of volcanic rock composition,the volcanic rocks of Huoshiling Formation in Songnan area develop three eruption cycles,from top to top,they are neutral eruption cycle,intermediate-acid eruption cycle and intermediate-basic eruption cycle.The distribution range of neutral eruption cycle is wide,and the number of eruptions is large,which is developed in Chaganhua area,Lishu area and Longfengshan area.The distribution range of intermediate-acidic eruption cycles is small,and the thick-layer acidic effusive facies is dominant,and the volcanic channel facies is developed,which is mainly distributed in the Chaganhua and Lishu areas.The distribution range of the intermediate-basic eruption cycle is small,and it is only developed in the Dongling area.The cycle is dominated by intermediate-basic effusive facies and intermediate-basic explosive facies.The division of volcanic eruption cycle of Huoshiling Formation in southern Songliao Basin is clarified,the stratigraphic framework of volcanic rocks in the whole area is established,and the eruption cycle which is more conducive to exploration and deployment is selected to carry out research work,which controls the time cost of exploration and is conducive to the study of volcanic rocks in southern Songliao Basin.