The Torrecilla Reef Complex (Early Kimmeridgian, N Spain): an example of tectonically forced regression

• Autorzy: Benito M. , Mas R.
• Konferencja: International Congress on the Jurassic System (7 ; 06-18.09.2006 ; Kraków, Poland)
• Języki publikacji: EN

Abstrakty

EN

Palaeontological, sedimentological, palaeoecological and/or depositional aspects of most Late Jurassic reefs, specifically coral reefs, have been studied in detail (e.g. see references in Flugel & Flugel-Kahler 1992; Leinfelder et al. 1996; Insalaco et al. 1997; Dupraz & Strasser 2002; among others), but only a few papers deal with their depositional architecture and response to tectonics and/or sea-level change. For example, Leinfelder et al. (1994, 1996) conclude that both eustatic and tectonic changes were important in controlling platform geometry and evolutionary trends in Upper Jurassic reefs. The Early Kimmeridgian Torrecilla Reef Complex in the northern Iberian Basin of Spain consists of a fringing reef composed of eight accretionary units (Alonso et al. 1986-1987;Mas et al. 1997; Benito & Mas 2002, 2006). The first four were deposited along a steep margin. They display down-lapping and off-lapping geometries, and are characterized by poor reef-framework development, large volumes of reworked corals and transported sediment, and limited growth of micro-encrusters.In contrast, deposition of the fifth and younger accretionary units occurred on a shallow platform without a pronounced slope where coral reefs grew in a shallow protected environment (Benito & Mas 2006). The main features of these reefs are: an absence of reef-slope facies, a high proportion of preserved framework elements, relatively low volumes of intrareef sediment, high proportions of terrigenous material, and abundant micro-encrusters and microbialites. These reefs were protected from storm waves by long-shore sand bars, which also protected a very shallow lagoon during the last stage of sedimentation. The Early Kimmeridgian was a period of rising global sea level (Haq et al. 1988; Hallam 2001), a trend apparent across other portions of the Iberian Basin. However, geometry and sedimentary evolution of the Torrecilla Reef Complex is consistent with those of off-lapping reefs that develop during sea-level fall. Thus, we conclude that down-stepping geometries and evolution to progressively shallower environments within the Torrecilla Reef Complex occurred as a result of a tectonically forced regression.

Słowa kluczowe

EN

carbonate platform; coral reef; forced regression; tectonism; Early Kimmeridgian; Iberian Basin

• Wydawca: Państwowy Instytut Geologiczny - Państwowy Instytut Badawczy
• Czasopismo: Volumina Jurassica
• Rocznik: 2006
• Tom: Vol. 4, no. 1
• Strony: 79--80
• Opis fizyczny: Bibliogr. 11 poz.

Twórcy

autor

Benito M.

autor

Mas R.

• Departamento de Estratigrafia, U.E.I. de Correlaciones Estratigraficas, Facultad C.C. Geologicas, Universidad Complutense de Madrid, CSIC, 28040 Madrid, Spain,

Bibliografia

• Alonso A., Mas J. R. and Meléndez N. 1986-1987. Los arrecifes coralinos del Malm en la Sierra de los Cameros (La Rioja, Espana). Acta Geologica Hispanica, 21-22: 296-306.
• Benito M. I. and Mas R. 2002. Evolución sedimentaria y diagenética de los complejos arrecifales kimmeridgienses de la Cuenca de Cameros. La Rioja-Soria. Zubía, 14: 121-142.
• Benito M. I. and Mas R. 2006. Sedimentary evolution of the Torrecilla Reef Complex in response to tectonically forced regression (Early Kimmeridgian, Northern Spain). Sedimentary Geology, 183: 31-49.
• Dupraz C. and Strasser A. 2002. Nutritional modes in coral-microbialite reefs (Jurassic, Oxfordian, Switzerland): Evolution of trophic structure as a response to environmental change. Palaios, 17: 449-471.
• Flügel E. and Flügel-Kahler E. 1992. Phanerozoic reef evolution: basic questions and data base. Facies, 26: 167-278.
• Insalaco E., Hallam A. and Rosen B. 1997. Oxfordian (Upper Jurassic) coral reefs in Western Europe: reef types and conceptual depositional model. Sedimentology, 44: 707-734.
• Hallam A. 2001. A review of the broad pattern of Jurassic sea-level changes and their possible causes in the light of current knowledge. Palaeogeography, Palaeoclimatology, Palaeoecology, 167: 23-37.
• Haq B. U., Hardenbol J. and Vail P. R. 1988. Mesozoic and Cenozoic chronostratigraphy and cycles of sea-level change. In: Wilgus C. K., Hastings B. S., Kendall C. G. St. C., Posamentier H. W., Ross C. A. and van Wagoner J. C. (Eds). Sea-level changes - an integrated approach. SEPM Special Publication, 42: 71-108.
• Leinfelder R. R., Kreutter M., Laternser R., Nose M., Schmid D. U., Schweigert G., Werner W., Keupp H., Brugger H., Herrman R., Rehfeld-Kiefer U., Schroeder J. H., Reinhold C., Koch R., Zeiss A., Schweizer V., Christmann H., Menges G. and Luterbacher H. 1994. The origin of Jurassic reefs: current research developments and results. Facies, 31: 1-56.
• Leinfelder R. R., Werner W., Nose M., Schmid D. U., Krautter M., Laternser R., Takacs M. and Hartman D. 1996. Paleoecology, growth parameters and dynamics of coral, sponge and microbiolite reefs from the Late Jurassic. In: Reitner J., Neuweiler F. and Gunkel F. (Eds). Global and regional controls on biogenic sedimentation. I. Reef evolution. Research Reports. Göttinger Arbeiten zur Geologie und Paläontologie, 2: 227-248.
• Mas J. R., Alonso A. and Benito M. I. 1997. Depositional and diagenetic evolution of late Jurassic coral reefs in Northern Iberian Ranges (North Spain). Boletín Real Sociedad Espanola de Historia Natural (Sección Geología), 92, 1-4: 143-160.