Diagenesis of the Pennsylvanian –Lower Permian Copacabana Formation, western Bolivian AltiplanoShow others and affiliations
2020 (English)In: Journal of South American Earth Sciences, ISSN 0895-9811, E-ISSN 1873-0647, Vol. 100, article id 102540Article in journal (Refereed) Published
Abstract [en]
This contribution presents the diagenetic evolution of limestone deposits in the Copacabana Formation that occurs in the northern Altiplano, in the Lake Titicaca area of western Bolivia. The best-exposed stratigraphic succession of the Copacabana Formation occurs in the Yampupata section, and its division into five facies successions is based on petrographic analysis, cathodoluminescence, x-ray fluorescence analysis (chemical composition) and stable isotope data (δ18O and δ13C). The results showed that the carbonate rocks experienced early marine diagenetic processes such as micritization during or after the deposition (eogenesis). The initial burial event (mesogenesis 1), characterized by stabilization of temperature-water carbonates by freshwater, and represented by bladed calcite-cement, equant calcite cement, dissolution, dolomitization, neomorphism, silicification and compaction (physical), occurred in shallow burial conditions. During the second burial episode (mesogenesis 2), in deeper burial environment the processes include: compaction (physical and chemical) and neomorphism. Diagenetic processes have affected reservoir quality in the Copacabana Formation during the mesodiagenesis, and reduced the conditions for development of high-quality conventional hydrocarbon reservoirs. Depleted O and C stable isotope signatures indicate that these carbonate rocks deposits underwent both meteoric and burial diagenesis including moderate water-rock interaction.
Place, publisher, year, edition, pages
Elsevier, 2020. Vol. 100, article id 102540
Keywords [en]
C isotope, O isotope, Titicaca sub-basin, Late paleozoic limestone
National Category
Geology
Research subject
Ore Geology
Identifiers
URN: urn:nbn:se:ltu:diva-78299DOI: 10.1016/j.jsames.2020.102540ISI: 000532794900005Scopus ID: 2-s2.0-85082188082OAI: oai:DiVA.org:ltu-78299DiVA, id: diva2:1421155
Note
Validerad;2020;Nivå 2;2020-04-02 (alebob)
2020-04-022020-04-022025-02-27Bibliographically approved
In thesis