Search results for "sedimentology"

Reconstruction of the paleoenvironmental changes around the Miocene-Pliocene boundary along a W-E transect across the Mediterranean

2006

Abstract In order to reconstruct the environmental changes at the end of the Messinian salinity crisis, a multidisciplinary study has been carried out with a high sampling resolution of the late Messinian–early Zanclean (Zone MPl 1) sediments along a West–East Mediterranean transect. The studied examples comprise sections from southern Spain (Vera/Almanzora), Balearic Basin (ODP Site 975), Tyrrhenian Basin (ODP Site 974), Sicily (Eraclea Minoa), Zakynthos (Kalamaki), Corfu (Aghios Stefanos), Crete (Aghios Vlasis). Previously analyzed sections from the Levantine Basin (Cyprus and ODP Sites 968 and 969) are used for comparison. The sections have been correlated using planktonic foraminiferal …

Sedimentary, stable isotope and micropaleontological records of paleoceanographic change in the Messinian Tripoli Formation (Sicily, Italy)

2002

Abstract The Tripoli Formation (6.96–5.98 Ma) of the Central Sicilian Basin provides a good record of the paleoceanographical changes that affected the Mediterranean during the transition from slightly restricted conditions to the onset of the Messinian Salinity Crisis. The Falconara/Gibliscemi section has been selected for an integrated approach at a high resolution scale using sedimentology, stable isotopes of the carbonates and microfossils. The sedimentary succession includes 46 precession-controlled cycles resulting from the periodical increase in biosiliceous productivity (diatomites) that followed the deposition of marls and pinkish laminites, which appear as sapropel-type deposits i…

Middle Triassic carbonate platforms in eastern Iberia: Evolution of their fauna and palaeogeographic significance in the western Tethys

2015

Abstract This article reports the first integrated study of the Middle Triassic of Iberia, based on the stratigraphy, sedimentology, and fossil fauna of Muschelkalk facies of the Iberian Ranges and the Catalan Coastal Ranges in Spain. On the basis of this study, new palaeogeographic reconstructions of the westernmost Tethys are proposed, and the evolution of the different palaeogeographic domains of Iberia (e.g., Iberian, Mediterranean, and Levantine–Balearic) are described. In these domains, Muschelkalk facies record the development of wide carbonate platforms that were the consequence of the first two broad marine transgressions of the Mesozoic in Iberia, respectively, late Pelsonian–earl…

Provenance and diagenesis of the evaporite-bearing Burns formation, Meridiani Planum, Mars

2005

Abstract Impure reworked evaporitic sandstones, preserved on Meridiani Planum, Mars, are mixtures of roughly equal amounts of altered siliciclastic debris, of basaltic provenance (40 ± 10% by mass), and chemical constituents, dominated by evaporitic minerals (jarosite, Mg-, Ca-sulfates ± chlorides ± Fe-, Na-sulfates), hematite and possibly secondary silica (60 ± 10%). These chemical constituents and their relative abundances are not an equilibrium evaporite assemblage and to a substantial degree have been reworked by aeolian and subaqueous transport. Ultimately they formed by evaporation of acidic waters derived from interaction with olivine-bearing basalts and subsequent diagenetic alterat…

Sedimentology, petrography and geochemistry of a limestone breccia (Pietra di Billiemi) from NW Sicily, Italy: implications for evolution of the Teth…

2009

In this study, the Pietra di Billiemi, a famous dimension stone, is investigated because it records the tectonic evolution of the south Tethys continental margin and preserves a record of major environmental changes occurring near the Triassic/Jurassic boundary. The Pietra di Billiemi is a grey, coarse-grained and clast-supported limestone breccia cropping out in an area of the Palermo Mountains representing a segment of the Apennine–Maghrebian chain in western Sicily. The rock consists of metre-sized to centimetre-sized angular clasts, derived from Upper Triassic sponge boundstones and rudstones, with a differently coloured, silt-grained matrix. Fitted fragments are observed commonly which…

STOP 6: Morphology, internal structure and texture of inland dunes at the Smilškalni site, Middle Gauja Lowland

2014

Controls of mud mound formation: The Early Devonian Kess-Kess carbonates of the Hamar Laghdad, Antiatlas, Morocco

1992

The origin and development of Early Devonian (late Pragian to late Zlichovian; predominantly uppermost Zlichovian as indicated by conodont faunas) mud mounds of the Hamar Laghdad area in the eastern Antiatlas, Morocco, are controlled by extrinsic and intrinsic factors. Extrinsic factors include the existence of a paleohigh (Lochkovian volcaniclastics), unidirectional currents and repeated storm events as well as sea level fluctuations. Intrinsic, biologically induced factors are the preferred growth of organisms on the top and the flanks of the mounds because of more favourable ecological conditions, and a rapid synsedimentary lithification of the steep mound flanks by interskeletal cementa…

Ladinian carbonates of the Cabo Cope Unit (Betic Cordillera, SE Spain): a tethys-maláguide palaeogeographic gateway.

2003

7 pages, 4 figures.

Séries charbonneuses dans des séquences rétrogradantes: cas du bassin houiller paralique westphalien de Jérada (Maroc)

1998

Abstract Several orders of stacked genetic sequences in the Westphalian C of the Jerada Basin are defined from detailed sedimentological data. Eight coal seams were formed in this paralic basin as distal facies passed laterally into proximal facies in retrogradational stages. These stages are related to base level rises that curtailed detrital influx and induced the development of swamps and the preservation of organic matter below anoxic water levels. The base level variations are related to active faulting along the basin margins and to sea level changes in the Palaeo-Tethys.

Multifactorial control of sedimentation patterns in an ocean marginal basin: the Lusitanian Basin (Portugal) during the Kimmeridgian and Tithonian

1987

The Mesozoic Lusitanian Basin developed as a part of the North Atlantic rift system. Tectonic rifting activity was rejuvenated during the Upper Jurassic, leading to intensive differentiation of facies development. Kimmeridgian and Lower Tithonian calcareous and siliciclastic sediments represent basinal and slope, shallow marine, and terrestrial environments. The lithostratigraphic arrangement of facies units is demonstrated. Sediment character, distribution and thicknesses are mainly controlled by synsedimentary faulting, with a partial overprint by uprise of salt diapirs. Eustatic sea level fluctuations, exogenic and biogenic factors resulted in additional control on facies development.