Search results for "Terrigenous sediment"

The Early-Cambrian Boho volcano of the El Graara massif, Morocco: Petrology, geodynamic setting and coeval sedimentation

2006

15 pages; International audience; A major volcanic episode is recorded across the Neoproterozoic-Cambrian transition in the Moroccan Anti-Atlas. Several volcanic cones are still preserved in the El Graara massif, laterally correlatable with volcanic flows dated as Early Cambrian (U/Pb date of 534 ± 10 Ma). Volcanic ashes and flows are interbedded with the uppermost part of the Adoudou dolostones, whereas the best-preserved volcano (the Boho Jbel) is onlapped by the overlying Lie-de-vin strata. Available petro-geochemical data from the Boho volcano suggest an alkaline magmatism probably derived from low-grade melting of a garnet–lherzolite mantle source, followed by fractional crystallizatio…

Community replacement of neritic carbonate organisms during the late Valanginian platform demise: a new record from the Provence Platform.

2012

24 pages; International audience; The Valanginian is marked by amajor platform demise inducing a hiatus in the northern Tethyan neritic carbonate record from the top of the lower Valanginian to the lower Hauterivian. New biostratigraphic and chemostratigraphic data from the Ollioules section (Provence Platform, southern France) are presented here, demonstrating that a large part of the upper Valanginian is preserved in an inner platform environment. The thick, upper Valanginian, aggrading carbonate succession is observed in an aborted rift domain, implying relatively low subsidence. In this context, a relatively long-term sea-level rise was required to sustain a keep-up style of carbonate p…

Smithian shoreline migrations and depositional settings in Timpoweap Canyon (Early Triassic, Utah, USA).

2014

AbstractIn Timpoweap Canyon near Hurricane (Utah, USA), spectacular outcrop conditions of Early Triassic rocks document the geometric relationships between a massive Smithian fenestral-microbial unit and underlying, lateral and overlying sedimentary units. This allows us to reconstruct the evolution of depositional environments and high-frequency relative sea-level fluctuations in the studied area. Depositional environments evolved from a coastal plain with continental deposits to peritidal settings with fenestral-microbial limestones, which are overlain by intertidal to shallow subtidal marine bioclastic limestones. This transgressive trend of a large-scale depositional sequence marks a lo…

Photochemical Mineralization of Terrigenous DOC to Dissolved Inorganic Carbon in Ocean

2018

Carbonate/evaporitic sedimentation during the Messinian salinity crisis in active accretionary wedge basins of the northern Calabria, southern Italy

2020

Abstract This work deals with Messinian deposits belonging to the Neogene infill of the Rossano and Belvedere Basins, respectively developed along the fore-arc and the back-arc areas of the north Calabria accretionary wedge. The main goal is to characterize the carbonate and evaporitic sedimentation during the Messinian Salinity Crisis, in the general framework of the basin architecture and the interplay between eustatic vs tectonic controlled sea-level variations. Fieldwork integrated with seismic lines and well logs interpretations led to the revision of the general stratigraphy of the basins and the proposal of a new sequential stratigraphic model driven by cyclic sea-level variations. E…

Polycyclic aromatic hydrocarbons and trace metal contamination of coastal sediment and biota from Togo

2011

The state of contamination of tropical environments, particularly in Africa, remains a relatively under explored subject. Here, we determined polycyclic aromatic hydrocarbon (PAH) and trace metal concentrations in coastal sediment and biota samples (fish and mussels) from Togo (West Africa). In the sediments, the ∑21 PAH concentrations ranged from4 ng g(-1) to 257 ng g(-1), averaging 92 ng g(-1). Concentration ratios of low molecular weight PAHs (2-3 rings) versus high molecular weight PAHs (≥4 rings) were always lower than 1 (ranging from 0.08 to 0.46) indicating that high molecular weight PAHs were dominant in all sediment samples, and that PAHs originated mainly from anthropogenic combus…

Mineralogical variability of Callovo-Oxfordian clays from the Paris Basin and the Subalpine Basin.

2006

High-resolution clay mineralogical data at the Middle/Upper Jurassic boundary from the French Subalpine Basin, the Jura Mountains and the Paris Basin (ANDRA boreholes) from Callovo-Oxfordian clayey deposits allow spatial and temporal terrigenous flux evolution to be considered over a period of 6 to 7 Myr. Recorded diachronisms of major mineralogical changes and complex clays distribution at the Paris Basin scale result to combined palaeogeographic/eustatic variations and climate input. In the French Subalpine Basin, mineralogical homogeneity confirms the burial diagenesis influence, but other terrigenous supplies must be involved in contrast to the Paris Basin domains. Volcanogenic clays (b…

2016

Rivers carry large amounts of dissolved organic matter (DOM) to the oceans thereby connecting terrestrial and marine element cycles. Photo-degradation in conjunction with microbial turnover is considered a major pathway by which terrigenous DOM is decomposed. To reveal globally relevant patterns behind this process, we performed photo-degradation experiments and year-long bio-assays on DOM from ten of the largest world rivers that collectively account for more than one-third of the fresh water discharge to the global ocean. We furthermore tested the hypothesis that the terrigenous component in deep ocean DOM may be far higher than biomarker studies suggest, because of the selective photoche…

Paleoenvironmental evolution of the Pliocene Villarroya Lake, northern Spain. A multidisciplinary approach

2002

The Pliocene Villarroya basin fill consists of lacustrine and alluvial deposits over 100 m thick. The lacustrine deposits, up to 30 m thick, comprise three sequences. The two lower sequences consist of profundal, laminated deposits formed by mostly terrigenous facies that are overlain by charophytic carbonates and varves. The uppermost, third sequence made up of massive bioturbated mudstones corresponds to a very shallow lacustrine-palustrine environment. Bulk mineralogy comprises carbonates, clay minerals, quartz and feldspars. The carbonates are: exogenic, biogenic calcite and biogenic aragonite. Biogenic calcite constitutes ostracod shells and charophyte stem encrustations, whereas arago…

Permian-Cenozoic deep-water carbonate rocks of the Southern Tethyan Domain. The case of Central Sicily

2016

We present an integrated stratigraphy of the outcropping and buried Permian-Cenozoic deep-water carbonate successions, forming some of the tectonic units mostly buried beneath the Late Neogene sedimentary cover in the fold and thrust belt of Central Sicily. Three main successions, pertaining to the well known Lercara, Imerese and Sicanian domains, have been reconstructed on the basis of a detailed facies analysis, seismostratigraphic interpretation, bio -stratigraphy (mostly based on palynological data) and comparison between outcropping and subsurface deep-water sediments. The main results reveal a continuous sedimentation of the deep-water Southern Tethyan Sicilian succession since the Pe…