Skip to Main content Skip to Navigation
Theses

Transect plate-forme-bassin dans les séries carbonatées du Berriasien supérieur et du Valanginien inférieur (domaines jurassien et nord-vocontien) : chronostratigraphie-transferts des sédiments

Abstract : This work synthesizes the knowledge on the sedimentation from the Late Berriasian to the Early Valanginian stratigraphie interval (Lower Cretaceous), on a complete shelf-basin transect from the Jura area (eastern France-western Switzerland) to the vocontian basin (southeastem France). A new chronostratigraphic schema of calpionellids faunas had been defined, thanks to new phylogenetic interpretations. It permits high resolution correlations (precision about 250 000 years) between sections especially from the Upper Berriasian and the Lowermost Valanginian time interval. Benthic foraminifera ranges have been calibrated on calpionellids chronostratigraphic schema in slope sections where both organisms coexist and they are used to complete long range correlations. Thirty sections have been studied on a sedimentologic and biostratigraphic point of view in order to develop a sequence stratigraphy model. The nature and the importance of sediments transfers in each systems tract have been estimated in relation with the sea level variations. This study shows that most of the particles in carbonate deposits can be, against a generally accepted idea, allochtonous as in the siliciclastic deposition. From the Jura shelf to the Vocontian Basin, different correlation taols like biochronology, geometry and sequence stratigraphy lead to recognize a complex carbonate ramp morphology from the Late Berriasian to Early Valanginian. During this period, across the transect, sediments accumulation rate are very different. On the sIope, the sequences which constitute the whole serie, are enriched by new sediment bodies (Lowstand wedges) and in the outer part of ramp and in the basin, the sediment record is uncomplete too. This study permits the constitution of a transect, built with precise correlations between sections. It shows that contemporaneous sediment depositions vary greatly along the transect: - On the shelf, in the inner part (Neuchâtel area), the Berriasian-Valanginian stratas are less than 25 metres thick, sequences Be0, Be1, Be2, Be3, Va0 et Va3 are partially represented, other sequences like Be4, Be5 and Val are eroded, karstified or not deposited (Be6). Few sequences (Be5 ou Va3) are preserved in a very variable way from a section to another on the inner ramp, the importance of reworked materials and irregularities of the surfaces suggest the geometry of incised valleys. - In the mid ramp (shelf "border" and slope), the same stratigraphie interval can be represented by more th an 500 meters of deposits ; the sequences become more and more complete and new sediment bodies appear (lowstand prograding and agrading systems tract). - In the basin, the sedimentation is uncomplete too (Sequence boundary Va0 i.e.) due to the numerous discontinuities (linked or not to gravit y flows). Thanks to high resolution chronostratigraphic resolution, the duration of the stratigraphical gaps associated with key surfaces were estimated by surrounding : on the shelf, they appear to be very long in regard to time-intervals documented by sediments (not deposited or not preserved). The position of the Sequence boundary in regard with the different key surfaces is aiso discussed.
Document type :
Theses
Complete list of metadata

https://tel.archives-ouvertes.fr/tel-00723723
Contributor : Pascale Talour <>
Submitted on : Monday, August 13, 2012 - 11:51:02 AM
Last modification on : Thursday, November 19, 2020 - 3:54:26 PM
Long-term archiving on: : Friday, December 16, 2016 - 6:19:06 AM

Identifiers

  • HAL Id : tel-00723723, version 1

Collections

Citation

Eric Blanc. Transect plate-forme-bassin dans les séries carbonatées du Berriasien supérieur et du Valanginien inférieur (domaines jurassien et nord-vocontien) : chronostratigraphie-transferts des sédiments. Stratigraphie. Université Joseph-Fourier - Grenoble I, 1995. Français. ⟨tel-00723723⟩

Share

Metrics

Record views

893

Files downloads

236