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Stratigraphic architecture of a Santonian mixed siliciclastic-carbonate succession (Catalonian Pyrenees, Spain)
| Content Provider | Semantic Scholar |
|---|---|
| Author | Sanders, Diethard Pons, Josep María |
| Copyright Year | 2001 |
| Abstract | SummaryAt Collades de Bastus, Catalonian Pyrences, a Santonian mixed siliciclastic-carbonate succession indicates two proximal-distal gradients, and records two styles of stratigraphical development upon relative sea-level change. The succession consists of four small-scale sequences (5.1 to 5.4) within the highstand systems tract of the. “Valicarca-5” depositional sequence of Simo (1993), and is topped by a drowning sequence (small-scale sequence 5.5).The investigated succession (Collades Member) accumulated near the margin of the south-Pyrenean shelf, shortly before development of the south-vergent Boixols thrust system. Deposition of the Collades Member commenced with moderate sea-level rise accompanied by increased siliciclastic input. In the larger, eastern outcrop sector the Collades Member consists of a succession of neritic marls with four intercalated intervals each deposited from a carbonate shelf. Each carbonate interval consists of stacked upward-shoaling cycles interpreted as parasequences. From bottom to top, most parasequences consist of a coral-sponge-rudist bioconstruction, a rudist biostrome, and bioclastic limestones. Depositional sequences 5.1 to 5.4 developed by overstep of shelf carbonates with neritic marls, corresponding to the transgressive systems tract (TST) and to part of the highstand systems tract(HST) The carbonate facies tract of the HST consists of stacked parasequences that become thinner up-section and record a westward component of progradation. Each highstand carbonate interval is overlain by a stack of carbonate parasequences that become thicker up-section and, down depositional dip, by neritic marls. Together, the upward-thickening parasequence stack and the laterally adjacent overlying succession of neritic marls comprise the TST and part of the HST of the successive sequence. The sequence boundary is the level of maximum shoaling within each carbonate shelf interval. The uppermost sequence 5.5 is a drowning sequence (cf. Simo 1993).In the western outcrop sector, the Collades Member consists of hummocky cross-laminated to bioturbated sandy calcarenites, of neritic marls and of relatively thin intervals of coral-sponge-rudist limestones. Sequence development may have started with deposition of sharp-based bedsets of sandy calcarenites that both eastward and up-section become thinner and grade into neritic marls. Together, the succession of sandy calcarenites and neritic marls may comprise the TST and, possibly, part of the HST. In the HST neritic marls and, locally, coral-sponge-rudist bioconstructions accumulated. Deposition of some calcarenite bedsets seems to have started near or closely after maximum progradation of each carbonate shelf in the eastern part of outcrop. The stratigraphic architecture of the Collades Member indicates, for the eastern outcrop sector, an east-west proximal-distal gradient, whereas the western sector records a west-east gradient. The opposite gradients result from outcrop intersection subparallel to oblique to general northward depositional dip, across two distinct shelf depositional systems. |
| Starting Page | 105 |
| Ending Page | 135 |
| Page Count | 31 |
| File Format | PDF HTM / HTML |
| DOI | 10.1007/BF02668170 |
| Alternate Webpage(s) | https://page-one.springer.com/pdf/preview/10.1007/BF02668170 |
| Alternate Webpage(s) | https://doi.org/10.1007/BF02668170 |
| Volume Number | 44 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
