Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Julien Carcaillet is active.

Publication


Featured researches published by Julien Carcaillet.


Proceedings of the National Academy of Sciences of the United States of America | 2008

Cosmogenic nuclide dating of Sahelanthropus tchadensis and Australopithecus bahrelghazali: Mio-Pliocene hominids from Chad

Anne-Elisabeth Lebatard; Didier L. Bourles; Philippe Duringer; Marc Jolivet; Régis Braucher; Julien Carcaillet; Mathieu Schuster; Nicolas Arnaud; Patrick Monié; Fabrice Lihoreau; Andossa Likius; Hassan Taisso Mackaye; Patrick Vignaud; Michel Brunet

Ages were determined at two hominid localities from the Chad Basin in the Djurab Desert (Northern Chad). In the Koro Toro fossiliferous area, KT 12 locality (16°00′N, 18°53′E) was the site of discovery of Australopithecus bahrelghazali (Abel) and in the Toros-Menalla fossiliferous area, TM 266 locality (16°15′N, 17°29′E) was the site of discovery of Sahelanthropus tchadensis (Toumaï). At both localities, the evolutive degree of the associated fossil mammal assemblages allowed a biochronological estimation of the hominid remains: early Pliocene (3–3.5 Ma) at KT 12 and late Miocene (≈7 Ma) at TM 266. Atmospheric 10Be, a cosmogenic nuclide, was used to quasicontinuously date these sedimentary units. The authigenic 10Be/9Be dating of a pelite relic within the sedimentary level containing Abel yields an age of 3.58 ± 0.27 Ma that points to the contemporaneity of Australopithecus bahrelghazali (Abel) with Australopithecus afarensis (Lucy). The 28 10Be/9Be ages obtained within the anthracotheriid unit containing Toumaï bracket, by absolute dating, the age of Sahelanthropus tchadensis to lie between 6.8 and 7.2 Ma. This chronological constraint is an important cornerstone both for establishing the earliest stages of hominid evolution and for new calibrations of the molecular clock.


Earth and Planetary Science Letters | 2004

Geomagnetic moment variation and paleomagnetic excursions since 400 kyr BP : A stacked record from sedimentary sequences of the Portuguese margin

Nicolas Thouveny; Julien Carcaillet; Eva Moreno; Guillaume Leduc; David Nérini

Abstract A paleomagnetic study was performed in clayey-carbonate sedimentary sequences deposited during the last 400 kyr on the Portuguese margin (Northeast Atlantic Ocean). Declination and inclination of the stable remanent magnetization present recurrent deviations from the mean geomagnetic field direction. The normalized intensity documents a series of relative paleointensity (RPI) lows recognized in other reference records. Three directional anomalies occurring during RPI lows chronologically correspond to the Laschamp excursion (42 kyr BP), the Blake event (115–122 kyr BP) and the Icelandic basin excursion (190 kyr BP). A fourth directional anomaly recorded at 290 kyr BP during another RPI low defines the ‘Portuguese margin excursion’. Four non-excursional RPI lows are recorded at the ages of the Jamaica/Pringle Falls, Mamaku, Calabrian Ridge 1, and Levantine excursions. The RPI record is characterized by a periodicity of ∼100 kyr, paleointensity lows often coinciding with the end of interglacial stages. This record sets the basis of the construction of an authigenic 10Be/9Be record from the same sedimentary sequences [Carcaillet et al., this issue].


Earth and Planetary Science Letters | 2004

A high resolution authigenic 10Be/9Be record of geomagnetic moment variations over the last 300 ka from sedimentary cores of the Portuguese margin.

Julien Carcaillet; Didier L. Bourles; Nicolas Thouveny; Maurice Arnold

A high resolution study of authigenic Be isotopes (10Be and 9Be) combined with continuous relative paleointensity records has been performed along the same marine sedimentary sequences from the Portuguese margin (N.E. Atlantic) covering the past 300 ka in order to assess relationships between geomagnetic moment variations and 10Be production rate variations. A carefull examination of the various ways of taking into account environmental disturbing effects on the authigenic 10Be concentration leads to the conclusion that the most reliable proxy of cosmonuclide production rates is presently the authigenic 10Be/9Be ratio. Eight intervals of significant authigenic 10Be/9Be enhancement evidence geomagnetic moment drops related to global paleomagnetic excursions, some being already admitted, others being proposed as new geomagnetic features. Since, contrarily to sedimentary magnetic remanence, the authigenic 10Be/9Be records dipole moment variations without significant acquisition delay, it provides better constraints on their timing. Comparison of 10Be/9Be and benthic δ18O records from the same cores suggests that dipole moment lows preferentially occured during or at the end of interglacial episodes, with a quasi-period of 100 ka.


Earth and Planetary Science Letters | 2010

Application of the authigenic 10Be/9Be dating method to continental sediments: Reconstruction of the Mio-Pleistocene sedimentary sequence in the early hominid fossiliferous areas of the northern Chad Basin

Anne-Elisabeth Lebatard; Didier Bourlès; Régis Braucher; Maurice Arnold; Philippe Duringer; Marc Jolivet; Abderamane Moussa; Pierre Deschamps; Claude Roquin; Julien Carcaillet; Mathieu Schuster; Fabrice Lihoreau; Andossa Likius; Hassan Taisso Mackaye; Patrick Vignaud; Michel Brunet

The concentrations of atmospheric cosmogenic 10Be normalized to the solubilized fraction of its stable isotope 9Be have been measured in the authigenic phase leached from silicated continental sediments deposited since the upper Miocene in the northern Chad Basin. This method is validated by the systematic congruence with the biochronological estimations based on the fossil mammal evolutive degree of faunal assemblages. The fifty-five authigenic 10Be/9Be ages obtained along 12 logs distributed along two West-East cross sections that encompass best representative Mio-Pliocene outcrops including paleontological sites show a systematic stratigraphic decrease when considering all studied sedimentary facies extending from the Pleistocene up to 8 Ma and allow performing geologic correlations otherwise impossible in the studied area. The resulting global sequence evidences and temporally specifies the succession of the main paleoenvironments that have developed in this region since the Miocene. Under the special conditions encountered in the northern Chad Basin, this study demonstrates that the authigenic 10Be/9Be ratio may be used as a dating tool of continental sedimentary deposits from 1 to 8 Ma. The half-life of 10Be theoretically allowing dating up to 14 Ma, it may have fundamental implications on important field research such as paleoclimatology and, through the dating of fossiliferous deposits in paleontology and paleoanthropology.


Tectonics | 2017

Pleistocene slip rates on the Boconó fault along the North Andean Block plate boundary, Venezuela

Lea Pousse-Beltran; Riccardo Vassallo; Franck Audemard; François Jouanne; Julien Carcaillet; Erwan Pathier; Matthieu Volat

The Bocono fault is a strike-slip fault lying between the North Andean Block and the South American plate which has triggered at least five Mw > 7 historical earthquakes in Venezuela. The North Andean Block is moving toward NNE with respect to a stable South American plate. This relative displacement at ~12 mm · yr−1 in Venezuela (within the Maracaibo Block) was measured by geodesy, but until now the distribution and rates of Quaternary deformation have remained partially unclear. We used two alluvial fans offset by the Bocono fault (Yaracuy valley) to quantify slip rates, by combining 10Be cosmogenic dating with measurements of tectonic displacements on high resolution satellite images (Pleiades). Based upon a fan dated at > 79 ka and offset by 1350–1580 m and a second fan dated at 120–273 ka and offset by 1236–1500 m, we obtained two Pleistocene rates of 5.0 - 11.2 and < 20.0 mm · yr−1, consistent with the regional geodesy. This indicates that the Bocono fault in the Yaracuy valley accommodates 40 to 100% of the deformation between the South American plate and the Maracaibo block. As no aseismic deformation was shown by InSAR analysis, we can assume that the fault is locked since the 1812 event. This implies that there is a slip deficit in the Yaracuy valley since the last earthquake ranging from ~ 1 to 4 m, corresponding to a Mw 7 – 7.6 earthquake. This magnitude is comparable to the 1812 earthquake and to other historical events along the Bocono fault.


Quaternary Science Reviews | 2006

Late Pleistocene and Holocene glaciation in the Pyrenees: a critical review and new evidence from 10Be exposure ages, south-central Pyrenees

Raimon Pallàs; Ángel Rodés; Régis Braucher; Julien Carcaillet; María Ortuño; Jaume Bordonau; Didier L. Bourles; Joan Manuel Vilaplana; E. Masana; Pere Santanach


Geochemistry Geophysics Geosystems | 2004

Geomagnetic dipole moment and 10Be production rate intercalibration from authigenic 10Be/9Be for the last 1.3 Ma

Julien Carcaillet; Didier L. Bourles; Nicolas Thouveny


Geomorphology | 2009

Cosmogenic 10Be dating of a sackung and its faulted rock glaciers, in the Alps of Savoy (France)

Jean-Claude Hippolyte; Didier Bourlès; Régis Braucher; Julien Carcaillet; Laetitia Leanni; Maurice Arnold; Georges Aumaître


Geophysical Research Letters | 2003

Geomagnetic moment instability between 0.6 and 1.3 Ma from cosmonuclide evidence

Julien Carcaillet; Nicolas Thouveny; Didier L. Bourles


Earth and Planetary Science Letters | 2006

Authigenic 10Be/9Be signature of the Laschamp excursion: A tool for global synchronisation of paleoclimatic archives

Guillaume Leduc; Nicolas Thouveny; Didier Bourlès; Cecile Blanchet; Julien Carcaillet

Collaboration


Dive into the Julien Carcaillet's collaboration.

Top Co-Authors

Avatar

Didier L. Bourles

Centre national de la recherche scientifique

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Philip Deline

Centre national de la recherche scientifique

View shared research outputs
Top Co-Authors

Avatar

Peter van der Beek

Centre national de la recherche scientifique

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Peter van der Beek

Centre national de la recherche scientifique

View shared research outputs
Top Co-Authors

Avatar

Pradeep Srivastava

Wadia Institute of Himalayan Geology

View shared research outputs
Researchain Logo
Decentralizing Knowledge