Sedimentation of a lower cretaceous (Aptian) coral mound complex, Zaraya mountains, northern Spain
By: Fernandez-Mendiola, P. A.
Contributor(s): Garcia-Mondejar, J.
Material type: ArticleDescription: 423-434p ; Illustration.Subject(s): Sedimentation - Lower cretaceous coral mound complex - Zaraya mountains - Northern Spain | Depositional environment - Northern Spain | Sedimentary structure - Northern Spain | Biostratigraphy - Northern Spain In: Geological magazine : Vol. 126 Iss. 1-6 Year. 1989Summary: Abstract A Lower Cretaceous mixed carbonate-siliciclastic sequence is well exposed in the Zaraya Mountains in Guipuzcoa Province, northern Spain. The sequence begins with interfingering deltaic platform facies and marine patch-reef carbonates. This unit is dominated by mudstones and sandstone with minor interbeds of shallow-water carbonates (calcareous mudstones and sandstones and grainstone-packstones). A thick mixed carbonate-terrigenous unit overlies the siliciclastics and is composed principally of limestones and marls. Periodic influx of terrigenous sediments over a dominantly carbonate sea-floor gave rise to repeated cycles typical of a mixed shallow-water platform. Demise of the southerly derived deltaic input allowed the development of a mainly carbonate third unit. Large (several metres across) bioherms resulted from high in situ organic productivity (mechanical breakage of bioclasts, algal-induced precipitation, trapping and baffling of lime mudstone). The mounds grew making up a coral carbonate mound complex. This prograded to the south, towards a small backreef basin, and slightly retreated in its forereef margin. A period of tectonic instability is thought to have been responsible for the drowning of the shallow-water complex, which was unable to keep pace with relative sea-level rise.Item type | Current location | Collection | Call number | Status | Date due | Barcode |
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Article | Library and Information Centre Periodical Section | Bound Journal Collection | Not for loan | 002528_89 | ||
Serials/Scientific Journal | Library and Information Centre Periodical Section | Bound Journal Collection | 550 GEO (Browse shelf) | Available | 002528 |
Abstract
A Lower Cretaceous mixed carbonate-siliciclastic sequence is well exposed in the Zaraya Mountains in Guipuzcoa Province, northern Spain. The sequence begins with interfingering deltaic platform facies and marine patch-reef carbonates. This unit is dominated by mudstones and sandstone with minor interbeds of shallow-water carbonates (calcareous mudstones and sandstones and grainstone-packstones). A thick mixed carbonate-terrigenous unit overlies the siliciclastics and is composed principally of limestones and marls. Periodic influx of terrigenous sediments over a dominantly carbonate sea-floor gave rise to repeated cycles typical of a mixed shallow-water platform. Demise of the southerly derived deltaic input allowed the development of a mainly carbonate third unit. Large (several metres across) bioherms resulted from high in situ organic productivity (mechanical breakage of bioclasts, algal-induced precipitation, trapping and baffling of lime mudstone). The mounds grew making up a coral carbonate mound complex. This prograded to the south, towards a small backreef basin, and slightly retreated in its forereef margin. A period of tectonic instability is thought to have been responsible for the drowning of the shallow-water complex, which was unable to keep pace with relative sea-level rise.
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