巴基斯坦胡兹达尔- 拉斯贝拉铅锌成矿带遥感地质特征与找矿模型

巴基斯坦胡兹达尔- 拉斯贝拉铅锌成矿带是特提斯成矿域铅锌成矿带的重要组成部分，该成矿带的矿床类型主要为喷流- 沉积型(SEDEX)和密西西比河谷型(MVT)。目前针对胡兹达尔- 拉斯贝拉铅锌成矿带及典型矿床的研究程度较低，制约了对该成矿带的认识及找矿勘查研究。本研究以胡兹达尔- 拉斯贝拉成矿带为研究区，通过合理选择遥感数据源和图像处理方法，对典型矿床(杜达、贡尕铅锌矿床)及部分矿点的样品光谱特征、影像特征综合分析，结合关键控矿要素研究，建立了胡兹达尔- 拉斯贝拉地区与沉积岩有关铅锌矿遥感找矿标志并开展成矿预测，为该成矿带找矿提供可行性方法。基于本研究建立的找矿标志，利用增强型专题制图仪(Enhanced thematic mapper, ETM)和先进星载热辐射与反射辐射计(Advanced spaceborne thermal emission and reflection radiometer, ASTER)影像圈定主要预测含矿地层分布区30处，结果与已知矿床、矿点吻合较好，圈定的含矿地层分布区主要集中在研究区中部和北部，均位于侏罗纪地层内且矿化带与地层走向一致，矿化主要位于安吉拉组、劳瑞莱组地层内部；根据含矿地层像元光谱，利用资源一号02D高光谱影像提取了中部地区含矿地层的空间分布，提取结果与找矿标志分析结果吻合较好，证实了在该区利用国产高光谱影像开展含铅锌矿地层自动提取与找矿的可行性。

Remote sensing of geological features and mineral prospecting indicators for Pb- Zn deposits in the Khuzdar- Lasbela zone, Pakistan

The Khuzdar- Lasbela Pb- Zn metallogenic belt is part of the Tethyan metallogenic domain, and the Pb- Zn deposits in this belt belong to the sediment- hosted type including two main subtypes: the Mississippi valley- type (MVT) and the sedimentary exhalative (SEDEX) deposits. The Khuzdar- Lasbela Pb- Zn metallogenic belt and its relevant deposits are poorly documented to date, which limits research and mineral prospecting of the metallogenic belt. In this study, the Khuzdar- Lasbela Pb- Zn metallogenic belt was taken as the study area to explore a remote sensing mineral prospecting indicator for sediment- hosted Pb- Zn deposits. Firstly, different remote sensing imageries and image processing methods were selected. Secondly, the ore- controlling factors, reflectance spectral features of the samples, and image characteristics of typical deposits (Duddar and Gunga Pb- Zn deposit) and some mineralized points were synthetically analyzed. Finally, the remote sensing mineral prospecting indicator for the sediment- hosted Pb- Zn deposits was established, which could provide a feasible method for mineral prospecting in the Khuzdar- Lasbela metallogenic belt. Based on the indicator, 30 potential ore- hosting strata targets were delineated by using ETM and ASTER images. The distribution of these targets correlates with the occurrence of nearly all known Pb- Zn deposits and mineralized points in the study area. The potential ore- hosting strata are mainly distributed in the central and north parts and located in the Jurassic strata with the same trending angles. The mineralization targets are mostly hosted by the Jurassic Anjira Formation and the Loralai Formation. Moreover, the ZY- 1- 02D hyperspectral imagery and spectral angle mapper method were used to map the spatial distribution of mineralized strata using the image endmember spectra of a mineralized point as reference spectra. The extracted result from the ZY- 1- 02D image is consistent with the potential ore- hosting strata of the mineral prospecting indicator, which proved the feasibility of automatic detection of mineralized strata and mineral exploration using Chinese space borne hyperspectral imagery in this area.