Facies partitioning and sequence stratigraphy of cool-water, mixed carbonate-siliciclastic sediments (Upper Miocene Guadalquivir Domain, southern Spain)

Abstract

During the late Miocene, the Guadalquivir Basin and its satellite basin, the Ronda Basin, were under Atlantic cool-water influence. The aim of our study is to develop a sequence stratigraphic subdivision of the Ronda Basin fill and to provide models for the cool-water carbonates. The Upper Miocene of the Ronda Basin can be divided into three depositional sequences. Sequence 1 is early Tortonian, Sequence 2 late Tortonian to earliest Messinian, and Sequence 3 Messinian in age. The sediments were deposited in a ramp depositional system. Sequence 1 is dominated by conglomerates and marls. In Sequence 2 and Sequence 3, carbonate deposits dominate in the inner ramp whereas siliciclastics preferentially occur in the middle and outer ramp. Bryomol carbonate sediments occur in all sequences whereas rhodalgal carbonates are restricted to Sequence 3. In bays protected from siliciclastic influx, rhodalgal deposits formed under transgressive conditions. A bryomol factory occurs in zones of continuous siliciclastic supply. This distribution results from facies partitioning during the flooding of the Ronda Basin, which has a rugged and irregular relief. Embayments were protected from siliciclastic influx and provided regions with less hydraulic energy.

Messinian paleoenvironmental evolution in the lower Guadalquivir Basin (SW Spain) based on benthic foraminifera

“…There are papers dealing with the biochronology of the late Neogene deposits filling the Guadalquivir Basin (Viguier, 1974;Perconig, 1973;Perconig and Granados, 1973;Sierro, 1985;Aguirre et al, 1995;Sierro et al, 1996) and with the tectonostratigraphic framework (Sierro et al, 1996;Riaza and Martínez del Olmo, 1996). However, the available studies on the Messinian paleoenvironmental evolution of the basin are scarce Gläser and Betzler, 2002). According to these studies a sea-level drop from middle slope to inner shelf related to the MSC took place during the Messinian.…”

Punctuated Neogene tectonics and stratigraphy of the African-Iberian plate-boundary zone: concurrent development of Betic-Rif basins (southern Spain, northern Morocco)

“…The Late Miocene compression of the region is reflected by the wedging-out of the younger basin fill towards an intra-basinal high, the Sierras de Salinas (Gläser & Betzler, 2002). Three unconformity-bounded sequences are distinguished (not shown in Fig.…”

“…of late Tortonian to earliest Messinian age (Sequence 2 of Gläser & Betzler, 2002;Serrano Lozano, 1980). This second sequence is locally truncated by an angular unconformity that was formed in association with uplift of the Sierra de las Salinas (Gläser & Betzler, 2002). It is succeeded by an algal limestone deposit (Las Mesas Fm.)…”

“…and equivalent marine marls and calcarenites. This sequence is assumed to be early/ middle Tortonian in age (Sequence 1 of Gläser & Betzler, 2002;Serrano Lozano, 1980).The upper limit of this sequence is proximally marked by an angular unconformity, which is overlain by a transgressive-regressive series of mostly marine sandstones (El Gastor Fm. ), calcarenites (Setenil Fm.)…”

“…It is succeeded by an algal limestone deposit (Las Mesas Fm.) of Messinian age (Sequence 3 of Gläser & Betzler, 2002;Serrano Lozano, 1980). The Moratalla Basin is located north of the Crevillente Fault and is surrounded by the Subbetic and Western Prebetic.…”