Diachronous evolution of Late Jurassic-Cretaceous continental rifting in the Northeast Atlantic (west Iberian margin)

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doi: 10.1029/2008TC002337
Author(s): Alves, Tiago M.; Moita, Carlos; Cunha, Tiago; Ullnaess, Magnar; Myklebust, Reidun; Monteiro, Jose H.; Manuppella, G.
Author Affiliation(s): Primary:
Cardiff University, School of Earth, Ocean and Planetary Sciences, Cardiff, United Kingdom
Direccao Geral de Energia e Geologia, Portugal
Oxford University, United Kingdom
TGS-NOPEC Geophysical Company, Norway
Instituto Nacional de Engenharia, Tecnologia e Inovacao, Portugal
Volume Title: Tectonics
Source: Tectonics, 28(4). Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0278-7407 CODEN: TCTNDM
Note: In English. 83 refs.; illus., incl. sects., 1 table, sketch maps
Summary: Regional (2-D) seismic reflection profiles, outcrop, and borehole data are used to characterize the evolution of deep offshore sedimentary basins in southwest Iberia (Alentejo Basin). The interpreted data indicate the bulk of Late Jurassic-earliest Cretaceous subsidence occurred in the present-day continental slope area, as shown by (1) significant thickening of synrift strata basinward from a slope-bounding fault system (SFS), west of which the total thickness of sediment can reach more than 9.0 km, and (2) relatively thin Mesozoic strata east of the SFS, where thickening of synrift units against principal faults is limited. Five principal regressive events and their basal unconformities reflect tectonic uplift and relative emersion in proximal basins, which were located on the rift shoulder to subsiding tilt blocks west of the SFS. These regressive events are correlated with major rift-related events occurring on the deeper margin. Direct comparisons with the Peniche Basin of northwest Iberia reveal that significant portions of the Iberian lower plate margin were uplifted and eroded during the last stages of continental rifting. This process was repeated at different times (and in different areas) as the locus of rifting and continental breakup migrated northward. As a result, two distinct rift axes are recognized in west Iberia, a first axis extending from the Porto Basin to the Alentejo Basin and a second axis located on the outer proximal margin north of 38°30N. In addition, the SFS delimited (1) prograding deposits of Cretaceous-Paleogene age and (2) late Cenozoic deposits draping the modern continental slope. These latter facts demonstrate that on lower plate passive margins, the relative position of the continental slope is established during the final rifting episode(s) preceding continental breakup.
Year of Publication: 2009
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
Key Words: 18 Geophysics, Solid-Earth; 20 Geophysics, Applied; Alentejo Basin; Atlantic Ocean; Basins; Cenozoic; Continental breakup; Continental margin; Continental shelf; Cretaceous; DSDP Site 398; Deep Sea Drilling Project; Europe; Faults; Geophysical methods; Geophysical surveys; IPOD; Iberian Peninsula; Jurassic; Leg 47; Lusitanian Basin; Mesozoic; North Atlantic; Northeast Atlantic; Offshore; Paleogene; Paleogeography; Peniche Basin; Petroleum; Petroleum exploration; Plate tectonics; Porto Basin; Portugal; Reflection methods; Rift zones; Rifting; Sedimentary basins; Seismic methods; Seismic stratigraphy; Southern Europe; Stratigraphic units; Surveys; Tectonics; Tertiary; Uplifts; Upper Jurassic
Coordinates: N380000 N420000 W0063000 W0113000
Record ID: 2010025953
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