GeoPeP 2011/2012

Here we present results from the geochemistry project GeoPeP 2011/2012 that is part of the Geoscience Master Curriculum at the “Geowissenschaftliches Zentrum Göttingen”. This study deals with hydrothermally altered volcanic rocks in the core of Miocene stratovolcanoes and ignimbrite-related caldera structures in the Central Andes of southern Peru. The selection of field sites was based on prior analysis of multispectral ASTER data.

Carhuarazo: southward directed glacial valley with vegetation

Field work which was carried out between 21st and 26th of september 2011 in the region near Puquio, southern Peru, includes sampling of fine-grained granular scree sediments and measuring its spectral reflectance, utilizing field spectrometry.

During the field work four locations were sampled which are described in detail in the location section.

The samples were analysed using a variety of different methods, some of them element-specific and others mineral-specific.

The results of these measurements are interpreted with respect to different alteration conditions related to different host rocks and hydrothermal temperatures that resulted in (a) low-grade alteration associated with zeolithisized ignimbrites, (b) mild to advanced argillic alteration, (c) silicification and (d) Fe-hydroxide enrichment.

© Christian Hansen, Andres Höweling, Kai Nitzsche, Tammo Ohlendorf 2012