Publication
A. Maillard,
V. Gaullier, B. Vendeville, and F. Odonne, 2003, Influence of differential
compaction above basement steps on salt tectonics in the Ligurian-Provenc¸al
Basin, northwest Mediterranean: Marine and Petroleum Geology, v.
20, p. 13-27 [PDF]
|
Influence
of Differential Compaction Above Basement Steps on Salt Tectonics
in the Ligurian-Provenc¸al Basin, Northwest Mediterranean
|
Agnes
Maillard, Virginie Gaullier, Bruno C. Vendeville, and Francis Odonne
|
Detailed
mapping of the Ligurian-Provenc¸al Basin (northwestern Mediterranean)
indicates that salt diapirs in the deep basin are restricted to an
area whose upslope boundary forms reentrants located above deep crustal
transfer zones associated with the opening of the basin in Oligo-Miocene
times. Because these basement faults were no longer active in Messinian
and post-Messinian times, the geographic correlation between diapirs
and basement faults cannot be attributed to slip along these basement
faults coeval with salt tectonics. Using three physical experiments,
we examine how dormant (i.e. inactive) basement steps can affect the
development of the overlying salt structures during combined gravity-driven
gliding and spreading. Where a basement step trends obliquely with
respect to the direction of the slope and initially offsets the base
salt, grabens and salt ridges form above and downdip from the basement
step, in turn forming a reentrant pointing upslope. Where the basement
step is buried under pre-Messinian compactable sediments, loading
by Messinian and post-Messinian sediments causes differential subsidence
above the step, forcing grabens and salt ridges to form above and
updip of the basement step. There, too, the salt structures are confined
in a triangular, reentrant-shaped area pointing upslope. The combination
of these two mechanisms with passive diapir growth during Plio-Pleistocene
times explains the striking geographic correlation between salt diapirs
and basement structures in the Gulf of Lion.
Agnes Maillard
and Francis Odonne, LMTG, UMR CNRS 5563, Universite´ Paul
Sabatier, 39, Allees Jules Guesde, 31062 Toulouse, France
Virginie Gaullier,
Laboratoire d'e´tude
des Ge´oenvironments marins (LEGEM), Universite´ de
Perpignan, 52, avenue de Villeneuve, 66860 Perpignan, France
|
For
more information, please contact Bruno Vendeville. Telephone 512-471-8334.
E-mail bruno.vendeville@beg.utexas.edu. |
2003
|
|