Fluid flow-related carbonate build-ups: from lacustrine to (early) marine environments
– The Ries Impact Crater as a Natural Laboratory –
Nördlingen, Germany, 15-19 October 2012
Objectives of the workshop
Towards innovative continental “small mound drilling”
In 2011, the Geological Survey of Bavaria carried out under the scientific direction of Gernot Arp the first scientific drilling of a spring carbonate mound in the Ries Impact Crater, Germany: the Erbisberg Mound drilling project. Preliminary results from the Erbisberg Mound suggest that impact-induced thermal springs were involved in the very early stage of mound formation, at least at this site. The Ries Impact Crater (Nördlingen, Germany) therefore forms the perfect setting to discuss fluid-flow related carbonate build-ups and to exchange views and experience across disciplines and carbonate research fields. The outstanding scientific value of the Ries lacustrine carbonate system and the proximity of a unique Jurassic reef domain moreover meet a second major objective of this combined Workshop and Field Seminar: to add a significant and broadband field training component for young scientists and industrial trainees in carbonate systems.
The Ries carbonate system
The Nördlinger Ries is a circular basin separating the Jurassic limestone plateau’s of the Swabian and Franconian Alb, the latter indeed famous for its vast coral reefs, sponge reefs, microbialites and the lagoonal “lithographic” limestone of Solnhofen, with its legendary fauna. The Ries crater was formed 15 Million years ago by the impact of an asteroid. Apart from its impact nature, the Ries basin offers a great opportunity to study post-impact Miocene lacustrine microbialites and algal build-ups in the light of changing hydrochemical conditions in the crater lake. Prior to the sixties, when the Ries basin was considered to be of volcanic origin, the large calcitic mounds were regarded as hot spring travertines. In the late sixties, these mounds were compared with the Searles Lake tufa pinnacles and thus regarded as “cool” and “built by algae”. Material from soda lake spring mounds from China evidence that the Ries mounds are indeed very similar to the soda lake mounds. Central parts of the mounds and pinnacles are composed of highly porous so-called sickle-cell limestones, with up to cm-sized voids. Marginal mound parts show thrombolites, planar non-skeletal stromatolites and rare green-algal frameworks.
Expected impact of the workshop
The Ries Workshop will discuss in a first session the results of the Erbisberg Mound drilling and frame these in other research efforts on lacustrine Recent spring carbonates in Turkey, the USA, etc. During advanced discussion sessions controversial interpretations will be confronted. The potential of those fluid-flow related carbonate deposits as potential analogues for non-marine carbonates in the South Atlantic subsalt will be discussed during a second session. Moreover, as Industry is recently confronted with such frontier carbonate systems, they are urgently in demand of both interpretation keys and skilled brainpower.
The COCARDE Ries Workshop and Field Seminar offers both a forum for reflecting on such questions and a training platform to expose young scientists and industrial trainees to new exploration concepts. In a third phase, the thematic topics discussed during the previous sessions will be opened to include marine seepage associated carbonate mounds such as encountered on- and offshore in Morocco. The need for drilling will be discussed in a final session. The discussion of methodologies will encompass both data acquisition (drilling and downhole logging of small mounds) and analytical approaches to characterize palaeo-environments (e.g. palaeo-temperature) and to capture the signature of fluid flow – of various, and often varying nature – from mound genesis to diagenesis. This session will be finished by an hands-on writing session where mixed senior and junior scientists will be working in smaller groups to launch potential new drilling and research proposals.
Additionally, this workshop and field seminar will contribute to the long-term objective of the ESF COCARDE-ERN network to evaluate, compile and document (in particular by scientific drilling) in a collective effort “mound reference routes”, which eventually may serve both academic and industrial communities as training routes. The Ries-Franconian Alb region may well qualify for such goal, and adds to the already surveyed Asturias-León route (Oviedo field seminar) and the Moroccan mound heritage route (Morocco field seminar).
Preliminary workshop and field seminar programme
The call for participation of up to 6 young scientists (PhD, postdoc) is now closed.
Below the list of the researchers who obtained the COCARDE grant:
- Natalia Amezcua Torres (Mexico)
- Alexander T. Brasier (The Netherlands)
- Valentin Chesnel (Switzerland)
- Tobias Dauner (Germany)
- Karen Gariboldi (Italy)
- Martin Kugel (Germany)
More details concerning travel schedule, overnight stays, meals, travel cost refund, and scientific reporting are available here.