Search results for "FAC"
showing 10 items of 36366 documents
Conjunctive use of spectral gamma-ray logs and clay mineralogy in defining late Jurassic-early Cretaceous palaeoclimate change (Dorset, U.K.).
2006
Abstract Detrital clay mineralogy is controlled by weathered source rock, climate, transport and deposition that in turn influence the spectral gamma-ray (SGR) response of resultant sediments. Whilst a palaeoclimate signal in clay mineralogy has been established in some ancient successions, the SGR response remains contentious, largely because the data sets have yet to be collected at the same or appropriate vertical scales to allow comparison. In addition, the influence of organic matter on SGR is not always considered. Here, we present clay mineralogical, total organic carbon (TOC) and SGR analyses from the late Jurassic and early Cretaceous of the Wessex Basin, a period of previously doc…
High-resolution geochemical and biotic records of the Tethyan 'Bonarelli Level' (OAE2, latest Cenomanian) from the Calabianca-Guidaloca composite sec…
2004
Abstract High-resolution micropalaeontological and chemostratigraphic records for the upper Cenomanian portion of the Calabianca–Guidaloca composite section (NW Sicily) provide new insight into the palaeoclimatic and palaeoceanographic evolution of the Tethys Ocean. The Bonarelli Level equivalent was identified on the basis of lithology and well constrained by calcareous plankton biostratigraphy and radiolarian assemblages, as well as by the δ 13 C curve showing a marked positive excursion (up to 4.7‰). The Bonarelli Level equivalent deposition is characterized by highly eutrophic conditions as testified by radiolarian proliferation. Black shale samples from the Calabianca–Guidaloca composi…
Early Pliocene continental vertebrate fauna at Puerto de la Cadena (SE Spain) and its bearing on the marine-continental correlation of the Late Neoge…
2017
In this paper, we synthesize sedimentological, magnetostratigraphic and paleontological data from the continental vertebrate site of Puerto de la Cadena (Murcia, SE Spain), in order to clarify its age. The study site is located on the northern edge of the Carrascoy mountain range, in the upper part of the Cigarrón Unit. The end-Messinian discontinuity has been detected at the base of this unit, which indicates it has an early Pliocene age. Abundant remains of small and large vertebrates, including rodents, lagomorphs, primates, carnivorans, perissodactyls, artiodactyls, proboscideans, testudines, squamats, and crocodiles, have been found in this area. Some of these elements are of African o…
Bone diagenesis in arid environments; An intra-skeletal approach
2014
Bone trace element content and isotopic composition are closely related to human nutrition. The investigation of archaeological bone geochemistry can help us to better understand the relationship between past populations and their environment alongside cultural practices as inferred from dietary reconstruction. However, dietary in- formation may be altered post-mortem by diagenetic processes in soil. In this study, bone mineralogy (Ca/P, sec- ondary minerals, organic matter content and bone apatite crystallinity), histology, element content (Mg, Na, F, Sr, Ba, Mn, Fe, La, Ce and U) and stable isotope composition (δ13Candδ18O carbonate) were investigated at the intra- individual scale in ord…
Erratum to “Palaeoecological context for the extinction of the Neanderthals: A small mammal study of Stratigraphic Unit V of the El Salt site, Alcoi,…
2021
El Salt is an important reference site for understanding the extinction of Neanderthal populations in the eastern Iberian Peninsula during MIS 3. In this paper, we describe the small mammal assemblage from Stratigraphic Unit V, the youngest unit with evidence of human presence, based on nearly 1300 specimens. A total of seven rodents (Microtus arvalis, Microtus duodecimcostatus, Microtus cabrerae, Sciurus vulgaris, Arvicola sapidus, Eliomys quercinus and Apodemus sylvaticus), three insectivores (Talpa occidentalis, Crocidura sp., Sorex sp.) and one lagomorph (Oryctolagus cf. cuniculus) were identified. Palaeocological analyses point to drier conditions in this part of the stratigraphic sequ…
Palaeoecological context for the extinction of the Neanderthals: A small mammal study of Stratigraphic Unit V of the El Salt site, Alcoi, eastern Spa…
2019
El Salt is emerging as a reference site for the study of the extinction of Neanderthal populations in the Eastern Iberian Peninsula during MIS 3. The small vertebrate assemblage analysed in this work is framed within this general objective and comes from Stratigraphic Unit V, the most recent unit with human presence. Nearly 1300 small mammal remains have been studied in order to reconstruct the palaeoecological conditions of this debated period. A total of seven rodents (Microtus arvalis, Microtus duodecimcostatus, Microtus cabrerae, Sciurus vulgaris, Arvicola sapidus, Eliomys quercinus and Apodemus sylvaticus), three insectivores (Talpa occidentalis, Crocidura sp., Sorex sp.) and one lagom…
Pre-Hirnantian (latest Ordovician) benthic community assemblages: controls and replacements in a siliciclastic-dominated platform of the eastern Anti…
2007
17 pages; International audience; Lower-middle Ashgill sedimentary strata from the Mediterranean region have recorded a key episode of temperate-to-cold water, carbonate productivity predating the onset of the Hirnantian glaciation. The latitudinal position of the Moroccan margin of North Gondwana during Ashgill should have been adequate for the recorded development of carbonate factories. However, carbonate productivity was neither homogeneous nor laterally persistent, as documented in the eastern Anti-Atlas. Whereas in the Erfoud area, the bryozoan-dominated limestones of the Ashgill Khabt-el-Hajar Formation indicate the intensive activity of carbonate factories, these were dramatically r…
Introducing the Human Factor in Predictive Modelling: a Work in Progress
2012
International audience; In this paper we present the results of a study into integrating socio-cultural factors into predictive modelling. So far, predictive modelling has largely neglected the social and cultural dimensions of past landscapes. To maintain its value for archaeological research, therefore, it needs new methodologies, concepts and theories. For this study, we have departed from the methodology developed in the 1990s during the Archaeomedes Project. In this project, cross-regional comparisons of settlement location factors were made by analyzing the environmental context of Roman settlements in the French Rhône Valley. For the current research, we expanded the set of variables…
The end of the Messinian salinity crisis: Evidences from the Chelif Basin (Algeria).
2007
How did the Messinian Salinity Crisis end is a matter of intense debate between two opposite concepts i.e., the generalised dilution event, the so-called Lago–Mare, followed by the sudden restoration of the marine conditions at the base of the Zanclean, or the early partial or complete marine refill that would have happened earlier during the upper Messinian. The Chelif Basin of Northwestern Algeria, one of the greatest Messinian marginal basins of the Mediterranean, provides an exceptional opportunity to study in detail how this major paleoenvironmental change occurred through continuous sedimentary records of the Miocene–Pliocene boundary. Five sections representative of both the central …
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…