Search results for "petrography"

Imaging pore space in tight gas sandstone reservoir: insights from broad ion beam cross-sectioning

2010

Monetization of tight gas reservoirs, which contain significant gas reserves world-wide, represents a challenge for the entire oil and gas industry. The development of new technologies to enhance tight gas reservoir productivity is strongly dependent on an improved understanding of the rock properties and especially the pore framework. Numerous methods are now available to characterize sandstone cores. However, the pore space characterization at pore scale remains difficult due to the fine pore size and delicate sample preparation, and has thus been mostly indirectly inferred until now. Here we propose a new method of ultra high-resolution petrography combining high resolution SEM and argon…

Roman quarries of the Iberian Peninsula: "Anasol" and "Anasol-type".

2007

The Iberian peninsula is rich in marble, both white and coloured, of excellent quality, used in the past (Pliny NH, XXXVI, II) and also at the present time as material for building and decoration. Many types of these marbles are similar to some, better known, Greek, Italian, Egyptian and Asian marbles. During the Roman Empire “ marmor carystium ” was extensively used. Taking into account the great similarity of this marble with the “ anasol ” and “ anasol ”-types mined in Spain and Portugal, this work presents a minero-petrographic, chemical and geochemical characterisation of these lithotypes, aiming at finding parameters to distinguish them from the better-known Greek and Italian “ cipoll…

Querns and mills during Roman times at the northern frontier of the Roman Empire (Belgium, Northern France, Southern Netherlands, Western Germany): U…

2016

International audience; This paper presents the results of a multi-disciplinary provenance study of querns and millstones during the Roman period (1st-4th century CE) in the northern part of the Roman Empire (provinces of Gallia Belgica and Germania Inferior). Comparative petrographical, mineralogical and geochemical analysis allowed an international team of archaeologists and geologists to identify the different raw materials used for the manufacturing of querns and millstones. As a result, (litho-) stratigraphic assignments as well as geological-geographical provenances are suggested or corroborated for the broad spectrum of these natural geo-materials. We give evidence for the exploitati…

Correlation of radioactivity measurements, air kerma rates and geological features of Sicily

2006

Abstract Sicily, the largest Mediterranean island (with an extension of about 25 000 km 2 ), exhibits a very wide variety of lithologies, ranging from sedimentary to metamorphic and volcanic rocks. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) have been applied to air kerma values measured by thermoluminescent dosimetry in several sites and to data of radionuclide concentrations, geochemical and mineralogical features of rocks and soils sampled in 29 sites of Sicily to point out similarities among different lithologies. The study was devoted to find multiple correlations and allow a better classification of Sicilian lithotypes. Samples of rocks and soils have be…

Geochemical and Petrographic Characterization of Marine-Continental Transitional Facies Shale (Qilian Basin, China): Origin of Organic Matter Input, …

2021

This study, for the first time, investigates the source, keroger pattern, evolution degree, sedimentary environment, and evaluates the hydrocarbon generating ability of marine-continental transitional facies shale from the Ebao area of the Qilian Basin in western China. The organic-rich shales of the marine-continental transitional facies were subjected to total organic carbon (TOC), rock pyrolysis, the biomarkers and kerogen microscopy analyses. The kerogen microscopy analyses indicated that the sample from ZK001 well and ZK2002 well had a mass of vitrinite and small number of exinite, so kerogen type was mainly humic. According to vitrinite reflectance, the organic matter was in the stage…

STOP 2-Mesozoic and Cenozoic carbonates of the Imerese basin along the Rocca di Sclafani Bagni outcrop

2011

Carbonate stromatolites from a Messinian hypersaline setting in the Caltanissetta Basin, Sicily: petrographic evidence of microbial activity and rela…

2010

Lower Messinian stromatolites of the Calcare di Base Formation at Sutera in Sicily record periods of low sea-level, strong evaporation and elevated salinity, thought to be associated with the onset of the Messinian Salinity Crisis. Overlying aragonitic limestones were precipitated in normal to slightly evaporative conditions, occasionally influenced by an influx of meteoric water. Evidence of bacterial involvement in carbonate formation is recorded in three dolomite-rich stromatolite beds in the lower portion of the section that contain low domes with irregular crinkly millimetre-scale lamination and small fenestrae. The dominant microfabrics are: (i) peloidal and clotted dolomicrite with c…

INDIGENOUS TABLEWARE PRODUCTION DURING THE ARCHAIC PERIOD IN WESTERN SICILY: NEW RESULTS FROM PETROGRAPHIC ANALYSIS.

2010

Quantitative Analysis of Experimental and Synthetic Microstructures for Sedimentary Rock

1999

A quantitative comparison between the experimental microstructure of a sedimentary rock and three theoretical models for the same rock is presented. The microstructure of the rock sample (Fontainebleau sandstone) was obtained by microtomography. Two of the models are stochastic models based on correlation function reconstruction, and one model is based on sedimentation, compaction and diagenesis combined with input from petrographic analysis. The porosity of all models closely match that of the experimental sample and two models have also the same two point correlation function as the experimental sample. We compute quantitative differences and similarities between the various microstructur…

Micro- to macro-scale internal structures, diagenesis and petrophysical evolution of injectite networks in the Vocontian Basin (France): implications…

2015

27 pages; International audience; This study discusses the characteristics of two Lower Cretaceous injectite networks in the Vocontian Basin (SE France) using combined structural, sedimentary, diagenetic, and petrophysical analyses. Internal structures, at both the macro- and micro-scale, and diagenetic phases characterising these injectite networks have been described. Simultaneously, precementation porosity values were estimated and parameters controlling the geographical distributions of these values were analysed and statistically tested. All of the data were integrated so as to reconstruct the spatial evolution of the porosity from the time of injection to modern times through five maj…