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Moreno D.,French Natural History Museum | Moreno D.,Rovira i Virgili University | Moreno D.,Institute Catala Of Paleoecologia Humana I Evolucio Social | Falgueres C.,French Natural History Museum | And 13 more authors.
Quaternary Geochronology | Year: 2012

The Sierra de Atapuerca (Northern Spain) is characterized by a well-developed karst system where several major archaeological sites have been discovered, attesting an almost continuous hominin occupation of the area during the whole Pleistocene period. Previous geomorphological studies showed a connection between genesis of the karst system and the evolution of the nearby Arlanzón river Valley. However, numerical dating results were missing to refine the chronostratigraphical framework of the Arlanzón valley's fluvial incision. To address this, we applied the Electron Spin Resonance (ESR) dating method to sedimentary optically bleached quartz grains from several fluvial terraces. Nine samples were collected from five of the 14 identified terraces. The ESR age results are stratigraphically coherent and in general agreement with both previous geomorphological observations and available palaeomagnetic data. Consequently, an ESR chronology of the geological evolution of the Arlanzón valley is proposed, which can be then correlated to the sedimentary sequence of the palaeoanthropological site of Atapuerca Gran Dolina. Our results provide important information about the chronology of hominid occupation in this area during Early and Middle Pleistocene. © 2012 Elsevier B.V..


Pares J.M.,Research Center for Human Evolution | Sahnouni M.,Research Center for Human Evolution | Sahnouni M.,Indiana University Bloomington | Sahnouni M.,Center National Of Recherches Prehistoriques | And 5 more authors.
Quaternary Science Reviews | Year: 2014

The question of the earliest hominid settlements in northern Africa has been under debate for a number of years due to the lack of precise chronologies. Here we present new paleomagnetic data that supports an Olduvai Subchron age for the archaeological sites at Ain Hanech and El-Kherba, in northern Algeria. Our study is based on a 22m-thick magnetostratigraphy of the Ain Hanech Formation, which includes contextualized Oldowan and Acheulian lithic tools. Characteristic remanent magnetization directions were obtained from both thermal and alternating field demagnetization procedures of specimens from twenty five sampled horizons. Our results reveal the presence of the Olduvai Subchron in the upper part of the stratigraphic section, constraining the age of these important archaeological sites in northern Africa. © 2014 Elsevier Ltd.


Pares J.M.,Research Center for Human Evolution
Frontiers in Earth Sciences | Year: 2015

The use of the Anisotropy of Magnetic Susceptibility (AMS) has become a rather common practice in Earth Sciences since the pioneer note by Graham (1954). The versatility of the technique, and the rapidness in obtaining and processing AMS data largely improved in the past thirty years, and has generated a wealth of literature, notably on mudrock fabrics. The assessment of the current trends in magnetic fabric studies reveals that AMS has one of its largest potential in sedimentary rocks from structural settings where the ductile component of deformation is cryptic or hindered by the brittle component. Abundant evidence provided by AMS data reveal that deformation extents beyond the deformation or cleavage front in contractional settings, including fold-and-thrust belts and active accretionary prisms, configuring magnetic fabrics as a standard method for fabric quantification in deformed sedimentary rocks. © 2015 Parés.

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