| 四川盆地东部三叠纪含钾岩层古地磁及物性研究 |
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| 引用本文： | 姜枚,马开义,李普,张文治,林传律.四川盆地东部三叠纪含钾岩层古地磁及物性研究[J].物探与化探,1987,11(4):266-274. |
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| 作者姓名： | 姜枚 马开义 李普 张文治 林传律 |
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| 作者单位： | 中国地质科学院
(姜枚，马开义，李普，张文治)，地矿部第二地质大队(林传律) |
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| 摘 要： | 在四川合川地区沥鼻峡部面上进行了古地磁和岩石物性的研究工作,样品采自三叠系须家河组、雷口坡组、嘉陵江组和飞仙关组.共采集手标本500余块,对2200个样品测定了剩余磁化强度及方向、磁化率和密度.对样品进行了热退磁和交变退磁处理,并对部分样品作了镜下签定,确定了该区主要沉积岩石的磁性矿物是磁铁矿和少量磁黄铁矿.根据古地磁测量结果可知,四川盆地三叠纪时远离赤道由南向北漂移,在早三叠世时的古纬度为北纬18.72°附近,随后到达北纬26.68°附近,且后者相对于前者顺时针转动了30°.在此期间还发生了垂直升降作用.这些资料表明,本区在三叠纪时处于有利于成盐的中低纬度地区.我们还依据综合岩石物性资料,划分了本区的岩层.合川剖面的研究结果表明,将古地磁和岩石物性研究用于探讨盐矿生成环境,进行地层对比是非常有用的手段,应该得到广泛的应用.
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A STUDY ON PALEOMAGNETISM AND PHYSICAL PROPERTIES OF TRIASSIC POTASSIUM-BEARING STRATA IN EASTERN SICHUAN BASIN |
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| Institution: | 1. Chinese Academy of Geological Sciences;
2. No. 2 Geological Party, MGMR |
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| Abstract: | Researches on paleomagnetism and physical properties of rocks were carri-ed out along the Libixia profile in Hechuan area of Sichuan Province, withmore than 500 samples collected from Triassic Xujiahe Formation, LeikoupoFormation, Jialingjiang Formation and Feixianguan Formation. Remanent mag-netization and orientation, magnetic susceptibility and density were determinedfor 2200 samples. Heat demagnetization and alternation demagnetization wereperformed for all samples,and microscopic identification was conducted for partof the samples, indicating that magnetic minerals in major sedimentary rocksof this area axe magnetite and small amounts of pyrrhotite.The paleomagnetic measurements show that during Triassic the SichuanBasin continued to drift from south to north far away from the equator. AtEarly Triassic it was near 18.70°of Northern Latitude, and then reached26.68°, with the latter having a clockwise rotation of 30°relative to the form-er. It is noticed that vertical movement also took place during this period. Allthese data demonstrate that this area in Triassic lay in middle or low latituderegion favourable for formation of saline deposits, thus indicating an encouragingprospect for saline prediction in this area. In addition, strata in this area weredivided according to comprehensive data on physical properties of rocks.It is evident from the research work along the Hechuan profile that thestudy of paleomagnetism and physical properties of rocks is a very effectivemeans in the investigation of formation environment of saline deposits and incorrelation of strata, thus deserving of extensive application. |
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