SC1 Carbonate Diagenesis (Microscopy Course)
1 day, Course leader: Axel Munnecke (Friedrich-Alexander University Erlangen-Nürnberg, Germany)
Every carbonate rock has experienced some sort of diagenetic alteration – otherwise it would not be a solid rock. Whereas most modern carbonate deposits are composed of metastable phases such aragonite and high-Mg-calcite, their fossil counterparts are composed mostly of low-Mg-calcite and/or dolomite. This mineralogical change is one of the results of the diagenetic alteration. Especially shallow-water carbonates are typically lithified very early after their deposition, but might have experienced later diagenetic alteration during burial such as chemical and mechanical compaction, dissolution, recrystallization, or dolomitization. Simply phrased, early diagenesis turns a sediment into a rock, late diagenesis alters the rock. Many of the diagenetic processes can be reconstructed based on careful observation of thin sections, and that is the topic of this course. During the 1-day course, different diagenetic environments will be introduced in several lectures, followed by a microscopic exercise. Thin sections from very different time slices as well as depositional and diagenetic environments will be discussed, and their sequence of diagenetic processes will be reconstructed. A special lecture and exercise deal with the comparatively poorly studied “marine-burial diagenesis”.