Search results for "sedimentology"
showing 10 items of 104 documents
Collapse structures in the Permian of the Saar-Nahe area, Southwest Germany
1971
Volcanic breccias near an intrusive rhyolite dome in the Permian Saar-Nahe trough of southwest Germany have been identified as complex pipe-like subsidence-structures occupying the site and immediate neighbourhood of “explosive” volcanoes.
First record of early Aptian Oceanic Anoxic Event 1a from the Paris Basin (France) - Climate signals on a terrigenous shelf
2021
Abstract In 2013, Andra (French National Radioactive Waste Management Agency) drilled boreholes to the south-east of the Paris Basin, to characterise Aptian and Albian clayey formations, including the ‘Argiles a Plicatules’ Formation dated as early Aptian. One of these boreholes intersected this formation with an excellent recovery allowing detailed biostratigraphy (ammonites), sedimentology, clay mineralogy, isotope geochemistry (δ13Corg) and Rock-Eval analyses to be performed. The base of the formation corresponds to transgressive dark-grey silty clays with iron oolites and plant debris indicating a coastal environment evolving up-section to upper offshore environments. Higher in the succ…
New human remains of Archaic Homo sapiens and Lower Palaeolithic industries from Visogliano (Duino Aurisina, Trieste, Italy).
2000
New human remains have been found during recent excavations conducted in the lower section of Visogliano dolina (Trieste, Italy). They are represented by teeth and a fragment of particularly robust mandible that for their morphological and morphometrical characters can be generically attributed to archaic Homo sapiens. The lithic industry is formed by flakes, carinated points, scrapers, choppers and chopping tools and is characteristic of the Italian Pebble Culture. Sediments, pollen and faunal remains indicate that this part of the deposit was formed during interglacial climatic conditions in the early, but not initial phase of Middle Pleistocene (isotopic stadium 13 or 11).
A Palaeoenvironmental Study in Semi-arid Southeastern Spain: the Palynological and Sedimentological Sequence at Perneras Cave (Lorca, Murcia)
1995
Abstract Results are presented of palynological and sedimentological research at the Palaeolithic site of Perneras Cave (coastal Murcia, southeastern Spain). Sedimentological features point to a warm, somewhat humid phase corresponding with the lowermost part of the Mousterian sequence, which was followed by a climatic deterioration which lasted throughout the later Mousterian and Upper Palaeolithic. The palynological study described here barely allows palaeoclimatological inferences to be drawn, but it does highlight interesting paleobotanical data, namely, the presence of Ibero-Maghrebian and Mediterranean elements, which suggest that the site was an important refuge for thermophilous tax…
Rb-Sr geochronology in favour of polymetamorphism in the Pan African Damara belt of Namibia (South West Africa)
1978
New Rb-Sr whole rock age data are reported from two metasedimentary sequences of the Damara Supergroup in the central Pan African Damara belt of Namibia (South West Africa).
Deformation and metamorphism at the base of the Helgeland nappe complex, northwest of Grong (Northern Norway)
1984
Pelites, carbonate-silicate rocks and mafic rocks occurring at the base of the Helgeland nappe complex northwest of Grong (N. Norway) were subjected together with the crystalline basement to medium grade metamorphism and threefold deformation during Caledonian times.
The Nahe Caldera — A resurgent Caldera in the permocarboniferous Saar Nahe basin, SW-Germany
1984
In the Saar Nahe basin, SW-Germany, a large resurgent caldera complex of Lower Permian age was recognized recently, for which the name „Nahe Caldera” is proposed.
Characterisation of sedimentary and petrophysical heterogeneities of a microporous reservoir : the case of Chalk (Upper Cretaceous, Paris Basin, Fran…
2016
Chalk is defined as a microporous reservoir rock. This formation is a prolific hydrocarbon-bearing reservoir in the North Sea and is one of the main aquifers in the Paris Basin. The heterogeneity of chalk in terms of petrophysical properties (both surface and subsurface) is illustrated by porosity ranging from 4 to 52 %, permeability from 0.01 to 100 mD, and P-wave velocity on water-saturated samples from 2.4 to 4.4 km.s-1 (Alam et al., 2011).In the study area (Normandie, France), taken as an outcrop analogue, 114 samples were collected (Cenomanian – Santonian). As in the North Sea fields, these samples show great petrophysical heterogeneity: total porosity () from 6.1 to 46.5 %, very low …
Sedimentological implications of an unusual form of the trace fossil Rhizocorallium from the Lower Muschelkalk (Middle Triassic), S. Poland
2011
Specimens of the trace fossil Rhizocorallium isp. with retrusive limbs occur in 10–20-cm-thick composite beds: the bottom layers contain abundant Planolites and Thalassinoides trace fossils, and the top layers are built of horizontally bedded pelitic limestone and contain less bioturbational structures. The first specimens of Rhizocorallium isp. occur just 2–3 cm above the lower surfaces of the top layers. The horizontal protrusive sections are 1 cm high and 1 cm wide. At some sites, the horizontal tunnels end, and the limbs become first obliquely retrusive (45°) at a distance of 1.5–2.5 cm, and then vertically retrusive at a distance of 4–6 cm, or at once vertically retrusive at a similar …
Areal extent and first U-Pb age of the Pre-Damaran Abbabis complex in the central Damara belt of South West Africa (Namibia)
1978
The Proterozoic Abbabis Complex emerges from beneath the metasediments of the Late Precambrian Damara Supergroup within mantled gneiss domes and anticlinoria over a wide area in the central granite zone of the Pan African Damara belt. U-Pb dating of composite-, size-, and non-magnetic fractions of metamict zircons from two samples of Abbabis granite-gneiss from the farm Abbabis yielded a concordia intercept age of 1925 −280 +330 Ma. It is speculated that the Abbabis basement rocks are continuous under the Damaran metasedimentary cover and may link up with the Franzfontein basement inlier of similar age. This conclusion supports the ensialic character of the northeastern branch of the Damara…