Carbonate Sedimentology
Sedimentary carbonates are excellent archives of environmental change throughout Earth’s history.
They are widespread deposits that may numerous modes and mechanisms of formation, and are reliable recorders of biogeochemical processes and environmental conditions.
The research group in carbonate sedimentology at the Department of Geology focuses on marine carbonates from the Proterozoic to Present.
A list and description of current projects is shown below:
Project 1: Neoproterozoic carbonate – clastic sequences of Death Valley, USA
The sedimentary record of the Pahrump Group in Death Valley comprises massive, well-exposed successions of carbonate and clastic deposits. The Tonian to Cryogenian strata represent world-class examples of microbial carbonates deposited in the lead up to, and during Earth’s emergence from, Snowball Earth events, thus chronicling one of the most debated and arguably important events in Earth History.
Multiple cycles of small and large-scale carbonate – clastic sequences within the Neoproterozoic Horse Thief Springs Formation are composed of stromatolitic dolostone beds sandwiched between cross-bedded strata featuring ripple marks, trough-cross beds, and chertified ooid horizons.
Project 2: Neoproterozoic carbonate – clastic sequences of Namibia
Neoproterozoic sedimentary successions, such as those from Death Valley, share unusual stratigraphic features such as the occurrence of distinctive glacial deposits related to high-frequency intercalations between carbonate and clastic sequences.
The Otavi Group from the Otavi Fold Belt in Namibia features large-scale well-exposed deposits that record the two largest episodes of glaciation in the Neoproterozoic. Specifically, the pre-glacial successions that led up to the largest glacial episodes in Earth history are still poorly understood.
Project 3: Putative fossilized sulfur oxidizing bacteria from Devonian cold seeps, Morocco
The colorless sulfide-oxidizing bacteria are important agents in the marine sulfur cycle, and may have been so since the Precambrian.
The genera Thiomargerita, Thioploca, and Beggiatoa are all members of the colorless sulfur-oxidizing bacteria, and are among the largest unicellular organisms known on Earth. Today, these bacteria inhabit shallow seafloor sediments where their metabolism couples the carbon, sulfur and nitrogen cycles.
Project 4: Phosphatic stromatolites within black shales from the Devonian – Carboniferous transition, Rheinisches Schiefergebirge, Germany
Phosphatic stromatolites are unusual microbial fossils in the rock record.
These fossil microbiota are known from the Proterozoic to the Phanerozoic, and occur in multitudes of morphologies such as oncoid, cone-like stromatolites, domal stromatolites, and microstromatolites. A yet unknown occurrence of these unique fossils is currently under investigation from black shales deposited during the Devonian – Carboniferous transition in Central Germany.