LIAG
 

Research Drilling Messel Pit (Hesse)

A 433 m deep research drilling in the Messel Pit in 2001 has confirmed a maar structure beyond all doubt. Drilled lapilli tuffs prove the volcanic origin. Based on the petrographic description, core analysis, and geophysical downhole logging data the following profile could be derived:

until 94 m Middle Messel Formation (black shales, variably fine laminated)
until 229 m Lower Messel Formation (alternating deposits of debrites, black shales, clay to fine
sands, breccia, and lapilli tuffit)
until 240 m tuffit
until 373 m lapilli tuff
until 433 m collapse breccia, consisting of amphibolites, granites, granodiorites, and Rotliegend
sediments.

The structure of this maar is excellently imaged by reflection seismic data; the combined interpretation of gravimetric and magnetic surveys enables a 3-dimensional representation of this maar. A drilled basaltic block could be dated to be of 47.8 Ma age by staff of Mainz University. 

In the frame of a project sponsored by the German Research Foundation rock magnetic studies on the lapilli tuffs were carried out. The results demonstrate, that the lower part of the lapilli tuff was deposited by temperatures higher than 300 °C. A classification of the volcanoclasts into a high temperature, geochemical non-differentiated and a low temperature, differentiated eruption phase could be derived. The development of the temperature and the temperature conditions within the volcanoclastic material are mainly controlled by the amount of juvenile components. They are also the source of the observed magnetic anomaly. 

Additional studies since 2004 concentrate on the regional geological situation in the vicinity of the Messel Pit dealing with the question, why 4 of 6 of the known Eocene deposits from the Sprendlingen Horst are found along a straight line east of Darmstadt, which is parallel to the old Variscan strike. Main focus is put on horst structures that were imaged by reflection seismic measurements and are related to anomalies in the earth magnetic field. In 2004 two drillings were performed and geophysical downhole logging was conducted to investigate the source of these anomalies. 

Results of the geophysical pre-site surveys in the Messel Pit. The gravity and magnetic data sets comprise measurements from the University Mainz and the Leibniz Institute for Applied Geophysics, the seismisc surveys were conducted by the Leibniz Institute for Applied Geophysics. The aerial image was taken in August 1999.
 

Project Management

Dr. Gerald Gabriel

Project Team

Dr. Christian Rolf

Duration

01.01.1999 until 31.12.2009

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