After 9 days of intense field work, we successfully finished our geophysical field survey at the key CRC research site - the clay pan PAR north of the Paranal observatories. As part of project A02 (V. Wennrich, M. Melles), an extensive large scale Transient Electromagnetic survey was conducted by the Institute of Geophysics and Meteorology of the UoC (B. Blanco, W. Mörbe, P. Yogeshwar, B. Tezkan). Our colleagues Daniel Diaz and Borja Farah from the University of Chile, Santiago de Chile joined this successful survey. First preliminary TEM results indicate a two channel system with a sedimentary sequence of roughly 150 m above bedrock. The 3D survey setup with ~110 soundings will provide a clear image of the 3D subsurface geometry with respect to the sedimentary infill, bedrock topography and possible deposition regimes down to a depth of 200 - 300 m.

Additional Magnetic measurements covered the complete central part of the clay pan. Two 8 km long NS and EW magnetic transects were measured from volcanic outcrops crossing the basin as well as a fault system blocking the central basin towards the west.

The geophysical results will significantly support the selection of optimal coring positions as well as the core interpretation and understanding of site genesis.

Prior to the geophysical field survey, we were invited by Daniel Diaz for a colloquium on electromagnetic exploration methods. Talks on actual geophysical research projects and state of the art of current developments for shallow to deep exploration were presented (see link below). The colloquium was well attended and followed by inspired and exciting discussions.

https://sfb1211.uni-koeln.de/index.php/news/14-news/latest/91-university-of-chile-first-colloquium-on-electromagnetic-geophysical-exploration-techniques

For the first time, a short course/colloquium on electromagnetic Geophysical exploration techniques is hosted at the University of Chile, Santiago de Chile.

It will take place on Monday the 2^nd of December.

We are very glad to be invited for this special event by our collaborator within the CRC 1211, Dr. Daniel Diaz. Talks on actual geophysical research projects and state of the art of current developments for shallow to deep exploration are presented by researchers from the Institute of Geophysics and Meteorology, University of Cologne (B. Tezkan, P. Yogeshwar, B. Blanco, W. Mörbe).

After the visit at the University of Chile, we will continue a geophysical survey at the CRC key research site in the Atacama desert, Paranal.

more information ...

Between the 18^th and the 24^th of July 2019 a small group of researchers from the CRC-1211 and Sernageomin (Servicio Nacional de Geología y Minería) from Chile conducted the first joint fieldwork in the Atacama Desert. The Chilean group from Sernageomin was formed by Dr. Fernando Sepúlveda, Dr. Paulina Vásquez and Eduardo Martínez (driver), while the CRC-1211 group consisted of Dr. Damián López and Dr. Benedikt Ritter, with the collaboration and support of Alejandro Mancilla from the UCN (Universidad Católica del Norte).

For the first time, samples from the Rio Loa canyon (outcropping bedrock and deposited sediments) were successfully collected from steep slopes and walls with the use of climbing gear. It was a big effort considering the difficult access to the sampling sites and the harsh environmental conditions. The gathered samples will contribute to the understanding of the regional geology concerning timing of deposition of large gravel sequences. They will also contribute to gain hitherto unexplored insights into the paleoclimate and the evolution towards hyperaridity in the core area of the Atacama Desert, covering potentially Eocene/Oligocene to Lower Miocene time scales.

The samples will be processed with new dating techniques at the University of Cologne (partly developed within the 1^st Phase of the CRC-1211) and at the Sernageomin facilities in Santiago de Chile. Combined fieldwork and lab analysis will merge in joint publications in the near future. The exchange of knowledge and on-site discussions about geological processes with the special background of both parties opened up a wide field of opportunities for future research and following projects. Both parties agreed that future collaborative projects in the Atacama Desert should be continued to tackle the complex research questions of this area with regional to over regional impact.

Group picture of the field campaign participants. From left to right: Paulina Vásquez, Fernando Sepúlveda, Damián López, Eduardo Martínez, Alejandro Mancilla and Benedikt Ritter. Hanging Valley at the southern rim of the Rio Loa. Photo: Benedikt Ritter
Extreme sampling at the Rio Loa canyon wall by Damían Lopéz. We used up to 400m of ropes and several kg of climbing gear to sample so far not sampled sediments and bedrock outcropping at the Rio Loa canyon. Photo: Benedikt Ritter		Extreme harsh environment, such as strong winds and difficult terrain compounded the sampling. Salt encrusted sediments and outcropping salt rocks at the rim of the canyon enabled the possibility of damaging ropes and equipement. Photo: Benedikt Ritter
One target for sampling was this paleosol outcropping up to 50-60m below the rim of the Rio Loa. Photo: Damían Lopéz		Drone captured image from the northern rim of the Rio Loa. We used both 4x4 trucks for fixing climbing and safety ropes. In the background, outcropping gravels sequences of the Rio Loa Canyon gravels and Alto Hospicio gravels were the main target of this field campaign. Photo: Benedikt Ritter
Bird’s eye view of the fixing system for climbing and safety rope. Photo: Benedikt Ritter		Outcropping paleosol within gravel sequence. Due to sea-fog, outcropping sediments were strongly cemented, which complicated sampling. Photo: Benedikt Ritter
Morning fog (‘camanchaca’) lying in the Rio Loa canyon. Photo: Benedikt Ritter

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