Halotectonics
and Thrusting Processes in the Spanish Pyrenees
The
primary objective of this research (EAR-8816335) was to understand the
development of both halotectonic and lateral ramp related transverse folding
in the southern Pyrenees. Detailed maps and a three-dimensional grid of
cross sections documented ~50% of regional-scale shortening accommodated
by folds and thrusts emplaced towards S20¾W, oblique to plate convergence
directions. The remainder of the shortening was accommodated by mesoscopic
and macroscopic strain. Two of the transverse folds, Boltaña and
Anisclo anticlines localized the western lateral to oblique ramp of the
Gavarnie thrust sheet. Detailed analysis of growth strata, dated with
magnetostratigraphies, resolved the growth of Mediano anticline, a regional-scale,
transverse halotectonic fold. Development of this 40 km long anticline
spanned ~10 Ma characterized by periods of slow fold growth (2-4¾ of limb
rotation/Ma) driven by sediment progradation which was punctuated at 2-3
Ma intervals by folding rates 3-10 times faster driven by episodic thrust
sheet emplacement. Fault-slip data were used to reconstruct varying tectonic
regimes associated with fold development along the eastern and southern
margins of the Jaca basin. This study shows that fault population analysis
in syntectonic strata provides an opportunity to constrain kinematic evolution
during orogeny.
Funded the doctoral dissertation of J. Holl and baccalaureate thesis of C. Hedlund.
Funded the doctoral dissertation of J. Holl and baccalaureate thesis of C. Hedlund.
Publications Resulting from this Grant:
Anastasio, D.J., and Holl, J.E. 2001.
Transverse fold evolution in the External Sierra, southern Pyrenees,
Spain., Jour. Struct. Geol. , 23, 379-392.
Holl, J. E., and Anastasio, D. J. 1995 Cleavage Development within a Foreland Fold and Thrust Belt, Southern Pyrenees, Spain. Jour. Struct. Geology, v. 17 no. 3, p. 357-369.
Holl, J.E., and Anastasio, D.J. 1995. Kinematics around a large-scale oblique ramp, southern Pyrenees, Spain. Tectonics v. 14. no. 5. p. 1368-1379.
Holl, J.E. 1994. Foreland Deformation Processes, southern Pyrenees, Spain. Unpublished Ph.D. dissertation, Lehigh University, Bethlehem, PA.
Holl, J.E. and Anastasio, D.J. 1993. Paleomagnetically Derived Folding Rates, Southern Pyrenees, Spain. Geology v. 13. no. 3. p. 271-274.
Anastasio, D. J. 1992 Structural Evolution of the External Sierra, Spanish Pyrenees. in The Structural Geology of Fold and Thrust Belts Johns Hopkins University Press, S. Mitra and G.W. (eds.) p. 239-251.
Holl, J. E., and Anastasio, D. J. 1995 Cleavage Development within a Foreland Fold and Thrust Belt, Southern Pyrenees, Spain. Jour. Struct. Geology, v. 17 no. 3, p. 357-369.
Holl, J.E., and Anastasio, D.J. 1995. Kinematics around a large-scale oblique ramp, southern Pyrenees, Spain. Tectonics v. 14. no. 5. p. 1368-1379.
Holl, J.E. 1994. Foreland Deformation Processes, southern Pyrenees, Spain. Unpublished Ph.D. dissertation, Lehigh University, Bethlehem, PA.
Holl, J.E. and Anastasio, D.J. 1993. Paleomagnetically Derived Folding Rates, Southern Pyrenees, Spain. Geology v. 13. no. 3. p. 271-274.
Anastasio, D. J. 1992 Structural Evolution of the External Sierra, Spanish Pyrenees. in The Structural Geology of Fold and Thrust Belts Johns Hopkins University Press, S. Mitra and G.W. (eds.) p. 239-251.