+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

Lateritic paleoweathering profiles in French Massif Central; paleomagnetic datings

, : Lateritic paleoweathering profiles in French Massif Central; paleomagnetic datings. Journal of Geophysical Research 115.B10

Geological records of the history of ancient land surfaces are scarce and often fragmented by unconformities. Determining the age of these surfaces has long been the limiting factor in correlating continental paleosurfaces with marine basin deposits. Age determination of the weathering product of continental paleosurfaces as well as weathered material within the crystalline basement, is of prime importance for geodynamic reconstruction in general and more so for assessing differential dynamics between basin and basement areas, erosion rates, etc. In this paper, we examine layers of ferruginous kaolinitic paleoweathering products overlying the basement rocks of the French Massif Central. These layers, which are mainly formed in situ and are azoic (devoid of fossils), have been classically related to the "siderolithic" (Eocene-Oligocene) period because of their geographic ties with Tertiary deposits. The paleomagnetic ages of these paleoweathered surfaces have been obtained by comparing their acquired remanent magnetization, converted into paleomagnetic poles, with the APWP (apparent polar wander path) of the Eurasian plate. Recovered ages indicate late Jurassic to early Cretaceous ages (140-160 Ma with a confidence limit of 10 Ma) which are much older than the previously assumed Tertiary age. The ages obtained in this study considerably alter the present knowledge of the geodynamic evolution of the French Massif Central. Our results suggest a lack of sedimentary cover at the Jurassic-Cretaceous boundary. This implies that at the time of deposition of the siderolithic formations, the basement was cropping out and devoid of any Mesozoic cover. Furthermore, the profiles are not compacted, indicating that they have never been buried beneath a significant sedimentary cover. The obtained ages point to a great stability of French Massif Central throughout the Mesozoic, with very low ablation-erosion, while neighbouring basins (Aquitaine and Paris) were subsiding about 2000 m.


DOI: 10.1029/2010jb007419

Other references

Ljesevic, O.K.covski, T., 1979: Influence of mechanical removal of skin from pork carcasses on hygienic soundness of meat. Tehnologija mesa 20(7-8): 220-222

Smith, M.L.; Bisanz, A.K.; Kempfer, A.J.; Adams, B.; Candelari, T.G.; Blackburn, R.K., 2004: Criteria for determining the appropriate method for an ethics consultation. Hec Forum 16(2): 95-113

Taylor, PS.; Shields, EJ., 1990: Flight thresholds of the armyworm (Lepidoptera: Noctuidae). Flight initiation threshold temperatures for agitated and undisturbed adults of Pseudaletia unipuncta [Mythimna unipuncta] were measured. A predefined sequence of disturbances was applied to individual moths in an empty environmental chamber at va...

Brekke, J.; Mackinney, G., 1950: Aldehydes from rancid corn and avocado oils. Steam distillates of rancid corn and avocado oils, collected in 2,4-dinitrophenylhydrazine soln., yield a complex mixture of dinitrophenylhydrozones (DNPH). These were readily separated by adsorption on anhydrous MgSO4 into derivatives of saturate...

Ferrell, C.L.; Mosen, D.M.; Jaffe, A.C., 2003: Early post-partum well child care and utilization of health care resources Effects in a medicaid managed care population. Pediatric Research 53(4 Part 2): 201A, April

Jansén, C.T., 1986: Lack of NK-cell activity in control and irradiated rat epidermis. Photo-Dermatology 3(3): 196-197

Hamada, H.; Hiramatsu, M.; Edamatsu, R.; Mori, A., 1993: Free radical scavenging action of baicalein. TJ-960 is a Japanese Kampo (traditional herbal) medicine used for the treatment of epilepsy. It's a crude drug, an extract of nine herbs, and consists of many known and unknown components. Among the known components of TJ-960, we found that 5...

Hunt, N.B.; Uys, L.R., 1990: The quality of nursing care of the frail aged in selected institutions in eastern Cape and Natal. An investigation was undertaken to establish standards for the care of the frail aged and to develop an instrument to measure this care. In this process the care in 12 institutions was monitored. In general, the care was found to be of good qualit...

Konstantinos Leontarakis; George V.A.ostolopoulos, 2012: Laboratory study of the Cross-Hole Resistivity Tomography The Model Stacking MOST Technique. Model experiments in the laboratory are used to find the optimal measuring and interpretation parameters that affect the quality of the results for the improved application of resistivity tomography between boreholes or between the surface and a t...

Nuttall, J.R., 1950: The radiation hazards of radiotherapeutic staff. British Journal of Radiology 23(265): 35-40