粤西雷州半岛地区1∶5万区域地质调查成果与主要进展

在粤西雷州半岛地区完成的1∶5万区域地质调查,以最新的国际地层表为指南,建立并完善了调查区多重地层划分与对比系统。采用岩性-岩相-火山机构三重填图方法,查明了调查区内火山岩的岩石特征及产出分布特征,详细划分了火山岩相类型及其组合,划分了火山活动旋回,系统总结了各喷发期火山岩的岩石学、地球化学特征,并探讨了火山岩的成因;综合遥感、路线地质调查、物探与钻探等多种方法,基本查明了坡头-海康港隐伏断裂(四会—吴川断裂的南延北支)及火山构造等的展布特征,初步建立了调查区构造格架。开展地质灾害调查,编制了雷州半岛中西部地质灾害分布与易发区图;开展河头镇和唐家镇幅土壤环境专项调查,绘制了土壤质量地球化学等级图,综合评定良好级以上土壤655km^2,圈定富硒土壤510km^2;探索和总结了适用于雷州半岛覆盖区的地质填图方法。

New Progress in 1:50000 Reginal Survey in Leizhou Peninsular Area,Western Guangdong Province

Based on the International Stratigraphy Guide (2015), multiple stratigraphic division and correlation sequence has been improved during 1:50 000 regional geological survey in Leizhou Peninsular area, Western Guangdong Province. Using lithology-lithofacies and volcanic apparatus mapping method, we revealed the distribution, petrological characteristics of the volcanic rocks in this area, and divided volcanic facies, lithofacies associations and volcanic cycles. Through the summarization for the petrological and geochemical characteristics of the volcanic rocks, the petrogenesis was discussed in detail. The volcanic structure and the distributing feature of Potou-Haikanggang buried fault, which is belonging to the southward north branch of the Sihui-Wuchuan fault, were ascertained and the tectonic framework of this area were established by means of remote sensing, geological survey, geophysical exploration and drilling exploration. Meanwhile we carried out the geological disaster investigation and drew up distribution and easy-happening area map of geological disasters in the working area. We also carried out the soil environment survey of Hetouzhen and Tangjiazhen sheet map, and compiled evaluation map of soil environmental quality. Subsequently, we evaluated well graded soil with area of 655 km^2 and selenium-rich soil with area of 510 km^2. Finally, we summarized the mapping method for shallow cover area in Leizhou peninsular.