Search results for "Depositional environments"
showing 5 items of 5 documents
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…
Lower Cretaceous formations (Berriasian/Valanginian to Albian) from the East of the Paris Basin: lithostratigraphy and depositional environments.
2023
The Paris Basin is a Meso-Cenozoic intracontinental basin characterised during the Early Cretaceous by a continental evolution. However, in its southeastern part, due to transgressions originating from the Tethys, the Lower Cretaceous continental deposits were occasionally interrupted by the deposition of marine sediments. In this area, the sedimentary succession includes above the Lower Tithonian “Calcaires du Barrois”, the transgressive “Sables de Soulaines” Formation on the Late Jurassic emersion surface. This formation showing facies characteristic of a tidal flat is reputed to be Valanginian in age, but there is no dating element and could as well begin in the Late Berriasian. Above,…
Microbial deposits in the aftermath of the end-Permian mass extinction: A diverging case from the Mineral Mountains (Utah, USA)
2015
40 pages; International audience; The Lower Triassic Mineral Mountains area (Utah, USA) preserves diversified Smithian and Spathian reefs and bioaccumulations that contain fenestral-microbialites and various benthic and pelagic organisms. Ecological and environmental changes during the Early Triassic are commonly assumed to be associated with numerous perturbations (productivity changes, acidifica-tion, redox changes, hypercapnia, eustatism and temperature changes) post-dating the Permian–Triassic mass extinction. New data acquired in the Mineral Mountains sediments provide evidence to decipher the relationships between depositional environments and the growth and distribution of microbial …
Depositional environments and iron ooid formation in condensed sections (Callovian Oxfordian, South-eastern part of the Paris basin, France)
2005
Carbonate platforms across Western Europe were superseded at the Middle–Upper Jurassic (Callovian–Oxfordian) boundary either by alternating marl–limestone and widespread marl deposits or by condensed sections containing iron ooids. The characteristics of marine condensed sections in the south-eastern part of the Paris Basin (France) and their distribution pattern are examined here, and a model of iron ooid formation is developed. Iron ooids are found from the shoreface to the offshore zone. They are most abundant in the median-to-distal offshore transition zone, where they originally formed. They also occur commonly, albeit often as reworked grains, in the proximal offshore zone, to which t…
Fault rate controls on carbonate gravity-flow deposits of the Liassic of Central High Atlas (Morocco).
2013
21 pages; International audience; The aim of this work is to describe and to explore linkages between fault activity and gravity-related sedimentary deposits during the early rifting of a carbonate depositional system. The study area, located at the southern edge of Central High Atlas (Morocco), hosts 900 m thick Liassic gravity-related sedimentary deposits, preserved at the hanging wall of one of the possibly inherited, reactivated Hercynian faults (Tizi n'Firest fault). This study documents gravity-flow deposits constrained by a highresolution biostratigraphic framework (ca. 100 ka). These gravity-flow deposits evolve over time. Unstratified conglomerate beds are limited to the Sinemurian…