(a) Contours of Chile with location of the PAG clay pan. (b) TEM survey layout in the clay pan. (c) TEM electrical conductivity and seismic p-wave velocity models along profile NS1 (Blanco et al., 2019). (d) Palaeomagnetic results from whole core measurements (grey line), and discrete samples (black crosses) from the PAG core; lithological log and correlation to Geomagnetic Polarity Time Scale (GPTS).

The Rock and Palaeomagnetic Laboratory of the University of Cologne

Project D7 focusses on the application and further development of two different geophysical approaches.

Our objectives are:

(1) the application of geophysical imaging techniques at multiple scales and development of a flexible inversion algorithm for subsurface imaging of Transient Electromagnetic (TEM) data using structural constraints from seismic data, and 

(2) the improvement of age control of sedimentary records using magnetostratigraphy, and the development of the first master record of relative palaeointensity (RPI) for the Atacama, as well as identification of mineral magnetic proxies to unveil details of climatic evolution.

The combined outcome provides key input for the investigation of sites in Chile and Namibia: Subsurface geophysical models are pre-requisite to select optimal coring, excavation and sampling sites and to subsequently link point information from cores to their spatial context. The development of novel interpretation schemes for TEM improves the geophysical imaging for complex scenarios. Magnetic polarity stratigraphy is one of very few methods able to provide age constraints in the hyper arid environmental setting. We will expand the method to new kind of archives and will develop new sampling techniques for very brittle material. The identification of magnetic proxies of extremely dry climatic conditions is another aspect.

Overall, the evidence resulting from the application and further development of geophysical techniques supports the CRC by providing combined information on the depth, structure, age and depositional conditions of sedimentary successions. This will improve the interpretation of the genesis of sedimentary sequences significantly. Besides, the development of palaeomagnetic techniques and novel TEM inversion will amplify geophysical interpretation schemes also beyond the CRC.