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海南岛万宁地区的辉长岩体及穿插其中的辉绿岩脉均为印支期近时基性侵入体.我们对辉长岩和辉绿岩脉进行了磁组构研究.万宁辉长岩体获得61个定向岩芯样品,边杜村辉长岩获得7个定向岩芯样品.横跨7条辉绿岩脉共系统钻取53个定向岩芯样品.岩石磁学分析表明,辉绿岩和辉长岩主要的磁性矿物分别是多畴贫钛磁铁矿和假单畴-多畴贫钛磁铁矿,它们为基性岩中的原生磁性矿物.辉长岩和辉绿岩均具有较低的磁各向异性度(Pj<1.2),它们保留着原生的流动磁组构特征.辉长岩的最大磁化率主轴(K1,磁线理方向)分布相对集中,平均方向为1.9°∠15.7°,绝大多数样品倾角小于30°,显示低倾角正北方向倾伏;7条辉绿岩脉各自的K1主轴集中,且一致性良好,分布在NNW-SSE方向,倾角大致在30°左右.K1分布表明:万宁辉长岩体的侵位方式为以低仰角由北向南侧向侵位,而辉绿岩脉则以中至低仰角从NNW向SSE侧向侵位.它们可能是位于更北部的同源岩浆脉动式侵位的结果,这意味着在万宁北部的印支期花岗岩之下可能隐伏有该期的基性岩体.
The gabbro bodies in Wanning area of Hainan Island and diabase dykes interspersed among them are Indosinian basic intrusions in Indosinian. We studied the magnetostructures of gabbro and diabase dikes. Totally 61 directional core samples were obtained from the long rock mass and 7 directional core samples were obtained from the ducian gabbro.A total of 53 directional core samples were drilled co-system across 7 diabase dikes.The rock magnetism analysis showed that, The main magnetic minerals of diabase and gabbro are multi-domain lean titanomagnetite and pseudo-single domain-multidomain lean titanomagnetite, which are primary magnetic minerals in basic rocks. The rocks have lower magnetic anisotropy (Pj <1.2), which retain the original mobile magnetic structure.The distribution of the maximum susceptibility of the main rocks of the gabbro (K1, magnetocosmic direction) is relatively concentrated, and the average direction And the dip angle of most samples is less than 30 °, which shows that the dip of the low-dip angle is in the northward direction. The K1 spindles of seven diabase dikes are concentrated and well-distributed. They are distributed in the NNW-SSE direction and the dip angle Roughly around 30 ° .The distribution of K1 shows that the emplacement mode of Wanning gabbro body is emplaced from north to south at low elevation angle and diabase vein Elevation angles laterally from NNW to SSE emplacement may be the result of pulsatile emplacement of the same magma located further north, meaning that beneath this Indosinian granite in northern Manning there may be underlying mafic rocks body.