Please use this identifier to cite or link to this item: http://hdl.handle.net/20.500.12136/1341
|Title:||Best of AAPG: episodic deformation rates recovered from growth strata, Pyrenees|
|Authors:||Anastasio, David J.|
Parés, Josep María
|Publisher:||The Geological Society of America (GSA)|
|Citation:||Geological Society of America 130th Annual Meeting, 2018|
|Abstract:||Growth strata are used to recover high-resolution incremental deformation rates in syntectonic strata. The synsedimentary strata preserve the interaction between uplift and sedimentation and require deconvolution of deformational and depositional processes. We used magneto-and biostratigraphy to determine absolute time and to calibrate rock magnetic-based cyclostratigraphy for three regional Paleogene structures near the South Pyrenean mountain front. Incremental folding or fault slip rates were determined for each structure. At Sant Llorenç de Morunys, a fault-propagation fold records uncoupled deformation and depositional rates and folding rates of 0 to 100˚/myr, which resulted from thrusting rates of 115-255m/myr over 3 myr. At Pico del Aguila, the décollement anticline developed for 5.23 myr and records variations in folding rate of 0° to 95°/myrs as a result of episodic thrusting in the fold’s core. Near Sos del Rey Católico, the Peña duplex records the growth of a thrust-related anticline that delineates the southwestern mountain front. Shallowing of the growth strata up-section was related to slip on a mountain front backthrust where deformation and deposition were coupled. Folding rates calculated from the growth strata at the resolution of the polarity chrons (0.42-2.5 myr), varies from 4°/myr to 13°/myr over 10 myr. At each location, our metronome was cyclostratigraphy related to magnetic-mineral concentration variations in the growth strata that were modulated by astronomically forced climate changes. Each fault related-fold recorded episodic deformation at 104 years time scales accompanying depositional rate variations. The marine and continental growth deposits had order of magnitude difference in accumulation rate variability depending on facies and accommodation space development.|
|Appears in Collections:||Congresos, encuentros científicos y estancias de investigación|
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