Search results for "Quaternary"

Seismo-stratigraphic model of “La Bandita” area in the Palermo Plain (Sicily, Italy) through HVSR inversion constrained by stratigraphic data

2018

Ambient noise Horizontal-to-Vertical Spectral Ratio (HVSR) technique is commonly used approach to obtain 1D models of the shear-wave velocity in the shallow surface of an investigated area. However, obtained models can have a wide margin of uncertainty if inversions have not been appropriately constrained by detailed stratigraphic information. An application of HVSR inversion constrained by lithostratigraphic data is presented in order to verify the effectiveness of this technique for purposes of geological and geophysical reconstruction of a sedimentary basin in a densely urbanized area. This is often the case of seismic microzonation studies, in which almost all the information derives fr…

Andean Cenozoic volcanic centers reflect basement isotopic domains

1992

Isotopic data for Quaternary volcanic centers from lat 17.5° to 22°S in northern Chile provide evidence for crustal contributions to arc magma genesis in the central Andes and delineate basement domains. Crustal thickness, distance from trench, height of volcanic edifices above the seismically active subduction zone, and sediment supply to the trench are all constant along this segment of the arc. The only significant variable is crustal age (Paleozoic in the south, Proterozoic in the north). Pb isotopic compositions of Quaternary lavas in the northern sector are lower ( 206 Pb/ 204 Pb = 17.89-18.28) and Sr and O isotope ratios are less variable ( 87 Sr/ 86 Sr = 0.7058-0.7077, δ 18 O = +6.5…

Active north-vergent thrusting in the northern Sicily continental margin in the frame of the quaternary evolution of the Sicilian collisional system

2021

Abstract A three-stage evolution has characterized the Sicilian Fold and Thrust Belt (SFTB) during the last 15 My: two main thin-skinned shortening events involving mainly Meso-Cenozoic carbonate units, followed by thick-skinned thrusting involving Plio-Pleistocene deposits in the frontal area as well as the crystalline basement in the inner and deeper sector of the chain. We investigated the northern Sicily continental margin, by using differently-penetrative seismic reflection data and new field surveys, which revealed, both offshore and onshore, north-vergent compressional structures that affected the tectonic edifice during Quaternary time. These structures, correlated with the kinemati…

Des particules charbonneuses, t�moins des variations de l'�rosion chimique d'un bassin versant calcaire durant l'holoc�ne (bassin de chaillexon, doub…

1999

Matter fluxes result from chemical and mechanical weathering that vary as a function of climate, relief, lithology and human activities. The aim of this paper is to characterize chemical weathering variations in the past using coaly particles found in both the geological substratum and the Holocene lacustrine sediments of a calcareous basin (Chaillexon lake, Doubs, France). Results point out that chemical weathering was the predominant erosional process in the watershed, which may be due to the calcareous nature of the bedrock. The significant variability of this process relative to mechanical weathering during the Holocene period can be interpreted as a consequence of the development of th…

INDUSTRY - A PILLAR OF STRENGTH ECONOMIC AND SOCIAL DEVELOPMENT. ROMANIAN SEQUENCES

2012

In the last 300 years, industry was the key driver of economic development and social, political, military, cultural and spiritual, which are inconceivable without the contribution of this important sector of the economy of any country. At least in these 300 years since the first industrial revolution, industrialization took place in every country in the world along with free trade, protectionism alternation - free schimbism contributing to balancing economic and social development. Nothing is more important than industry between the four basic economic sectors (agriculture, industry, trade and transport). Recrudescence services of any kind, but also the unprecedented quaternary sector (lei…

Trivalent cation substitution of pulverulent cobalt—iron molybdates Co1 − xFexMoO4

1998

Abstract Different mixed cobalt—iron molybdates Co1 − xFexMoO4 (0 ≤ x ≤ 1) have been prepared by means of a ceramic process. The oxidation of pulverulent samples leads to ferric molybdate Fe2(MoO4)3, spinelle Co3O4 and cobalt molybdate CoMoO4. After a strong grinding which reduces the grain size (about 0.1 μm) and induces crystallographic defects in the grains, the cobalt—iron molybdates can be partially oxidized into cation-deficient phases. This oxidation corresponds to an isostructural substitution of part of the Fe2+ and Co2+ ions by Fe3+ and Co3+ ions and the creation of cation vacancies. The concomitant presence of trivalent cations and associated cation vacancies in the lattice stabi…

Dimethyl 2-(1-methyl-3-oxo-1,3-dihydroisobenzofuran-1-yl)malonate

2020

In this work we report a facile access to a 3,3-disubstituted isobenzofuranone by tandem addition/cyclization reaction to methyl 2-acetylbenzoate in the presence of dimethyl malonate, under basic conditions.

Calcareous Nannofossil Biostratigraphy and Chronostratigraphy of ODP Hole 964D (eastern Mediterranean Sea)

2008

Quantitative analyses of calcareous nannofossil were carried out on sediments from ODP Hole 964D succession, recovered in the Ionian Sea, Eastern Mediterranean. Results show that the sedimentary sequence, spanning from about 3.5 Ma (Early Pliocene) to the Present, has been investigated through an average sampling resolution of less than 30 kyr. The detailed subdivision into 11 biozones makes it possible to recognize chronostratigraphic the boundaries in the Early Pliocene-Middle Pleistocene interval. Finally, two sedimentary gaps, lasting at least 340 kyr and 120 kyr respectively, have been recognized between the Zanclean and Piacenzian and in the lower part of the Early Pleistocene. SHORT …

STOP 12: Late-glacial and Holocene development of Lake Rāzna as recorded by biostratigraphy

2014

Data from: The origin of the serpentine endemic Minuartia laricifolia subsp. ophiolitica by vicariance and competitive exclusion

2013

Serpentine soils harbour a unique flora that is rich in endemics. We examined the evolution of serpentine endemism in Minuartia laricifolia, which has two ecologically distinct subspecies with disjunct distributions: subsp. laricifolia on siliceous rocks in the western Alps and eastern Pyrenees and subsp. ophiolitica on serpentine in the northern Apennines. We analysed AFLPs and chloroplast sequences from 30 populations to examine their relationships and how their current distributions and ecologies were influenced by Quaternary climatic changes. Minuartia laricifolia was divided into four groups with a BAPS cluster analysis of the AFLP data, one group consisted only of subsp. ophiolitica, …