Datensatz

Zusammenfassung

The South African Karoo Basin, which is known for its potentially shale gas bearing formations, was the target of an extensive research programme launched by the Nelson Mandela University, South Africa. The aim of this project was to obtain a fundamental understanding of the geology, petrology and hydrology of the sedimentary layers. In 2014, Magnetotelluric (MT) measurements were conducted in the Eastern Karoo Basin to image the electrical conductivity structure of the shallow subsurface and to develop a three-dimensional (3D) model. Previous studies by Weckmann et al. (2007a, b) and Branch et al. (2007) identified the potentially shale gas bearing Whitehill Formation as an electrically conductive sub-horizontal layer, which covers large parts of the Karoo Basin. The increased interest in future shale gas exploration raised concerns regarding the potential impact on aquifers in this water scarce and fragile environment. Since the electrical conductivity is sensitive to fluids, imaging both, the black shale horizon and the deep aquifer system in this region was the ultimate goal of the MT study. Our field experiment is designed to serve as a baseline study before any activity regarding shale gas exploitation commenced. With high resolution 2D and regional 3D inversion and forward models several aquifers, the Whitehill formation and the possible source region of the Beattie Magnetic Anomaly could be mapped.This data publication (10.5880/GIPP-MT.201423.1) encompasses a detailed report in pdf format with a description of the project, information on the experimental setup, data collection, instrumentation used, recording configuration and data quality. The folder structure and content of the data repository are described in detail in Ritter et al. (2019). Time-series data are provided in EMERALD format (Ritter et al., 2015).