地球物理学报
地毬物理學報
지구물이학보
2001年
1期
72-82
,共11页
塔里木地块%早白垩世%古地磁%磁倾角%压实作用
塔裏木地塊%早白堊世%古地磁%磁傾角%壓實作用
탑리목지괴%조백성세%고지자%자경각%압실작용
运用主成分分离及线性区段等方法,使早白垩世样品明显分离出二组磁组分.叠加剩磁为喜山期重磁化,特征剩磁明显偏离现代地磁场方向,经倾斜校正后,有很好的一致性并通过了倒转检验,给出塔里木地块库车坳陷早白垩世巴西盖组古地磁新数据.综合已有的古地磁结果,获得了塔里木地块早白垩世平均剩磁方向及平均古地磁极,阐明了塔里木地块早白垩世磁倾角明显偏低这一现象.分析导致磁倾角偏低的诸多因素,认为压实作用可能是导致磁倾角偏低的重要因素之一.
運用主成分分離及線性區段等方法,使早白堊世樣品明顯分離齣二組磁組分.疊加剩磁為喜山期重磁化,特徵剩磁明顯偏離現代地磁場方嚮,經傾斜校正後,有很好的一緻性併通過瞭倒轉檢驗,給齣塔裏木地塊庫車坳陷早白堊世巴西蓋組古地磁新數據.綜閤已有的古地磁結果,穫得瞭塔裏木地塊早白堊世平均剩磁方嚮及平均古地磁極,闡明瞭塔裏木地塊早白堊世磁傾角明顯偏低這一現象.分析導緻磁傾角偏低的諸多因素,認為壓實作用可能是導緻磁傾角偏低的重要因素之一.
운용주성분분리급선성구단등방법,사조백성세양품명현분리출이조자조분.첩가잉자위희산기중자화,특정잉자명현편리현대지자장방향,경경사교정후,유흔호적일치성병통과료도전검험,급출탑리목지괴고차요함조백성세파서개조고지자신수거.종합이유적고지자결과,획득료탑리목지괴조백성세평균잉자방향급평균고지자겁,천명료탑리목지괴조백성세자경각명현편저저일현상.분석도치자경각편저적제다인소,인위압실작용가능시도치자경각편저적중요인소지일.
The paleomagnetic results of Baxigai formation of earlyCretaceous in Kuche depression,Tarim block are reported. Two magnetic components were clearly isolated by means of principal component analysis method and Linefind method.Overprint component is a remagnetization of Himalayan,which is close to the present magnetic direction.Characteristic magnetic remanence shows obviously offset present magnetic direction.After tilted correction,ChRM shows well consistent and passed reversal test.Early Cretaceous magnetic mean direction was obtained by summarizing most of published paleomagnetic data in this area. Inclination shallowing is noticed in the early Cretaceous stratum,which could not be explained by tectonics only if we consider the periphery plates.Some factors,such as quality of paleomagnetic data,sedimentary process,as well as long period non-dipole field and so on are excluded. The compaction is believed to be the most important factor resulting in inclination shallowing.Much more work should be done to verify this hypothesis and this will provide evident for solving the problem in tectonics