Mapping patterns of mineral alteration in volcanic terrains using ASTER data and field spectrometry in Southern Peru
Mapping patterns of mineral alteration in volcanic terrains using ASTER data and field spectrometry in Southern Peru
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DOI：
10.1016/j.jsames.2013.09.011
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发表时间：
2013-12
影响因子：
1.8
通讯作者：
M. Brandmeier;S. Erasmi;Christian T. Hansen;A. Höweling;K. Nitzsche;T. Ohlendorf;M. Mamani;G. Wörner
中科院分区：
文献类型：
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作者：
M. Brandmeier;S. Erasmi;Christian T. Hansen;A. Höweling;K. Nitzsche;T. Ohlendorf;M. Mamani;G. Wörner
由于矿床的形成与火山和火山后过程有关，了解火山地区的蚀变类型在经济地质学中具有重要的应用价值，我们使用ASTER（高级星载热发射和反射辐射计）数据和野外光谱法对秘鲁南部中新世至第四纪火山地区进行矿物填图，以更好地描述和了解该地区第三纪火山演化。我们的目标是表征火山地区附近的Puquio（阿亚库乔）的相关领域的强烈蚀变和相关的熔结凝灰岩流出片。特别是，我们光谱和矿物学映射不同类型和强度的蚀变遥感和地面truth data.ASTER比值图像，蚀变指数和假彩色合成的基础上选择地面训练区的样品采集和现场光谱。对蚀变样品进行了地球化学、矿物学和光谱学表征。吸收特征与化学性质（例如铁含量）相关。高光谱数据从现场光谱允许识别重要的蚀变矿物，如高岭石和蒙皂石。蚀变矿物组合从粘土质到粘土质再到沸石型。使用支持向量机分类（SVM）算法的ASTER数据，我们映射不同类型和强度的蚀变，沿着与未蚀变熔结凝灰岩和熔岩流的准确率为80%。我们提出了一个初步模型的解释蚀变设置，讨论了潜在的火山喷发地点的熔结凝灰岩在该地区，并提出了pH值和温度估计的基础上确定的矿物组合的各个类别。
Because formation of ore deposits is linked to volcanic and post-volcanic processes, an understanding of alteration style in volcanic regions has important applications in economic geology.We use ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) data and field spectrometry for mineral mapping in selected Miocene to Quaternary volcanic areas in Southern Peru to better characterize and understand the Tertiary volcanic evolution in this region. Our goal is to characterize volcanic regions near Puquio (Ayacucho) by correlating areas of intense alteration and related ignimbrite outflow sheets. In particular, we spectrally and mineralogically map different types and intensities of alteration based on remote sensing and ground-truth data.ASTER ratio images, alteration indices and false color composites were used to select ground-training areas for sample collection and field spectrometry. Alteration samples were characterized geochemically, mineralogically and spectrally. Absorption features correlate with chemical properties (e.g. iron content). Hyperspectral data from field spectrometry allow identification of important alteration minerals such as kaolinite and smectite. Alteration mineral assemblages range from silicic to argillic to “zeolite-type”. Using a support vector machine classification (SVM) algorithm on ASTER data, we mapped the different types and intensities of alteration, along with unaltered ignimbrite and lava flows with an accuracy of 80%. We propose a preliminary model for the interpretation of alteration settings, discuss the potential eruption sites of the ignimbrites in the region and, propose pH and temperature estimates for the respective classes based on the mineral assemblages identified.