Search results for "Deposits"

Chemical, mineralogical and isotopic observations on hypersaline surficial deposits from Trapani evaporation ponds.

2010

Laminated carbonate deposits in Roman aqueducts: Origin, processes and implications

2013

Carbonate deposits in Roman aqueducts of Patara and Aspendos (southern Turkey) were studied to analyse the nature of their regular layering. Optical microscopy and electron-backscattered diffraction results show an alternation of dense, coarsely crystalline, translucent laminae composed of bundles and fans of elongate calcite crystals with their c-axes parallel to the long axis, and porous, fine-grained laminae with crystals at near-random orientation. The ?18O and ?13C data show a strong cyclicity and anti-correlation, whereby high and low ?18O values correspond to dense columnar and porous fine-grained laminae, respectively. Geochemical analyses show similar cyclic changes in carbonate co…

Environmental and depositional controls on laminated freshwater carbonates: An example from the Roman aqueduct of Patara, Turkey

2013

Carbonate deposits in aqueducts are a new high-resolution data source for environmental changes during the time of the Roman Empire, notably in the fields of palaeoclimate and spring hydrology. In order to distinguish environmental effects from those related to depositional setting, laminated carbonate deposits were compared along the entire length of an ancient aqueduct channel at Patara, Turkey. The carbonate deposits, up to 80mm in thickness, are composed of lamina couplets up to 1mm thick of alternating porous microspar and dense, columnar sparite. The former formed in the dry, warm season and the latter in the wet, cool season. The presence of biofilms seems to play a role in the devel…

New insights from recently migrated CROP multichannel seismic data at the outermost Calabrian arc accretionary wedge (Ionian sea)

2011

This study addresses selected aspects of the stratigraphic-structural setting of the outermost Calabrian Arc accretionary wedge and underlines relationships between structural development and Messinian evaporite stratigraphy through the analysis of re-processed CROP multichannel seismic reflection profiles. A detailed seismostratigraphic analysis, calibrated with P-velocities compiled by previous works, images a general bipartition of the Messinian evaporite deposits: the transparent «lower subunit» appears to have undergone ductile-flow deformation», with the development of salt-cored thrusting structures, and the layered «upper subunit» appears to be characterized by brittle deformation. …

Tectonic evolution of the Sicilian Thrust System (central Mediterranean)

2012

The Sicilian Thrust System (STS) is a south-verging (Africa-verging) fold-and-thrust belt including a Mesozoic-Paleogene sedimentary sequence. This thrust stack owes its origin to the deformation of pre-orogenic strata deposited in different palaeogeographic domains belonging to passive margins of the African plate. The STS was deformed during the Neogene, following the closure of the Tethys Ocean and the continental collision between the Sardo-Corso Block and the North Africa margins. The thrust pile was detached from the underlying basement during the Miocene-Pleistocene. The regional-scale structural setting recognized allows us to reconstruct the tectonic evolution of the STS as follows…

Lacustrine sedimentation in the diapir-controlled Miocene Bicorb Basin, Eastern Spain

1998

The Miocene Bicorb Basin is a small elongated basin developed by normal faulting of a thick Jurassic–Cretaceous carbonate succession and subsequent diapirism of Upper Triassic mudstones and evaporites. The basin fill comprises a sequence over 650 m thick formed by two units. The lower, alluvial unit consists of a complex alternation of conglomerates, sandstones, mudstones, and minor lacustrine limestones. The upper unit comprises marginal alluvial and lacustrine deposits in which seven lacustrine facies associations have been distinguished. The inner lacustrine deposits comprise mudstones and carbonates with minor evaporitic deposits. At the northeast and southwest basin edges, alluvial inp…

Comparative high-resolution chemostratigraphy of the Bonarelli Level from the reference Bottaccione section (Umbria-Marche Apennines) and from an equ…

2006

The Bonarelli Level (BL) from the upper Cenomanian portion of the reference Bottaccione section (central Italy) is characterized by the presence of black shales containing high TOC concentrations (up to 17%) and amounts of CaCO3 near to zero. In the absence of carbonate and, consequently, of relative carbon- and oxygen-isotopic data, the elemental geochemistry revealed to be a very useful tool to obtain information about the palaeoclimatic and palaeoceanographic evolution of the Tethys Ocean during the OAE2. Based on several geochemical proxies (Rb, V, Ni, Cr, Si, Ba), the BL is interpreted as a high-productivity event driven by increasingly warm and humid climatic conditions promoting an a…

Le sanctuaire laténien de Semoine, « Voie Palon » (Aube)

2012

A rescue excavation in 2003 resulted in the discovery of a building on piles, constructed between two sections of ditch, of which the one on the north side has an entrance. The chronological data of the building and two ditches match and demonstrate the existence of cults during La Tène C2. Evidence of the cults is given by a small quantity of deliberately mutilated weapons, as has been found in other La Tène sanctuaries. Dating the creation of the enclosure is problematicaln but it probably derives from La Tène C1. Although sections of the site remained unexcavated, the stratigraphy of the ditches reveals the brevity and limited and unusual nature of the practices. This study links them to…

Nouvelles données sur le genre Bragasellus (Crustacea: Isopoda: Asellidae

1996

From now on, the genus Bragasellus Henry & Magniez, 1968 includes 2 oculated and 17 stygobiotic species. As a natural and monophyletic taxonomic unit, we consider it a good genus. Its original area corresponds to the north-west quarter of the Iberian Peninsula. Secondarily, this area has extended eastward, using mainly the alluvial channels of hydrographic systems (Ríos Douro + Ebro and tributaries), finally reaching the underground waters of several Mediterranean rivers. This active expansion is exclusively due to the migration of two stygobiotic sibling species: B. lagari Henry & Magniez, 1973 towards the high basin of the Río Tajo, then downstream to the basins of the Ríos Jucar and Turi…

The Middle-Late Quaternary littoral deposits of Western Sicily coastal belt (southern Italy): sedimentology and geomorphology

A multidisciplinary study has been carried out on the littoral deposits located along the western Sicily coastal belt, central Mediterranean region, with the aim of unravelling their origin and evolution through analysis of their lithology, texture, sedimentary structures, and geomorphological features. The deposits crop out between the towns of Trapani and Marsala and are distributed from the present-day coastline up to 120 m above sea level, forming four major discrete ridges in the landscape, each of separated by topographic depressions with flat or slightly concave upwards surfaces. The ridges ranging between 5 to 30 m in height, display a NNE-SSW trend almost parallel to the present-da…