Mapping of hydrothermally altered rocks by the EO-1 Hyperion sensor, Northern Danakil Depression, Eritrea

Ronen Gersman*, Eyal Ben-Dor, Michael Beyth, Dov Avigad, Michael Abraha, Alem Kibreab

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

79 Scopus citations

Abstract

An EO-1 Hyperion scene was used to identify and map hydrothermally altered rocks and a Precambrian metamorphic sequence at and around the Alid volcanic dome, at the northern Danakil Depression, Eritrea. Mapping was coupled with laboratory analyses, including reflectance measurements, X-ray diffraction, and petrographic examination of selected rock samples. Thematic maps were compiled from the dataset, which was carefully pre-processed to evaluate and to correct interferences in the data. Despite the difficulties, lithological mapping using narrow spectral bands proved possible. A spectral signature attributed to ammonium was detected in the laboratory measurements of hydrothermally altered rocks from Alid. This was expressed as spectral absorption clues in the atmospherically corrected cube, at the known hydrothermally altered areas. The existence of ammonium in hydrothermally altered rocks within the Alid dome has been confirmed by previous studies. Spectral information of endmember's mineralogy found in the area (e.g. dolomite) enables a surface mineral map to be produced that stands in good agreement with the known geology along the overpass. These maps are the first hyperspectral overview of the surface mineralogy in this arid terrain and may be used as a base for future studies of remote areas such as the Danakil.

Original languageAmerican English
Pages (from-to)3911-3936
Number of pages26
JournalInternational Journal of Remote Sensing
Volume29
Issue number13
DOIs
StatePublished - 10 Jul 2008

Bibliographical note

Funding Information:
Without the support of Mr H. Goder, Israel ambassador to Eritrea, this project could not have been accomplished. We thank A. Mushkin, S. Pe’eri and Y. Golani for helping with the ASTER and Hyperion images, T. Medhin and staff geologists of the Department of Mines, Asmara, for sharing with us their profound knowledge during the field trip, A. Sandler for the XRD analysis and A. Kultunov for helping with the processing of the Hyperion data. Careful and thoughtful comments by Ed Cloutis and an anonymous reviewer helped to improve this manuscript and are greatly appreciated. This work was funded by the US Agency for International Development, Bureau for Economic Growth, Agriculture and Trade, Project No. C23-001 and Award No. Ta-MOU-03-C23-001.

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