Unconformity-bounded seismic reflection sequences define Grenville-age rift system and foreland basins beneath the Phanerozoic in Ohio

Abstract

Interpretation of reprocessed Ohio Consortium for Continental Refl ection Profi ling (COCORP) OH-1 seismic refl ection profi les indicates four structurally complex Precambrian unconformity-bounded stratigraphic sequences that clarify the relative timing of formation of the Fort Wayne Rift and EastContinent Rift System with respect to the Grenville orogeny. Petrographic examination of sparse deep well samples in the region indicates or suggests sedimentary lithologies beneath the Paleozoic sedimentary cover. Other seismic profi les in the region, some with excellent well control, support our proposed model. A generalized model for the latter part of the Grenville orogeny suggests polyphase sedimentation and deformation with multiple episodes of crustal extension and compression. We propose the following events for Ohio and the surrounding region: (1) a major regional unconformity developed on the Eastern Granite-Rhyolite Province and accreted Grenville terranes; (2) western Ohio became the site of extensive fault-bounded rift basins, beginning with the Fort Wayne Rift and extending into west-central Ohio as the East Continent Rift System; (3) westward-advancing thrust sheets followed with deposition of sediments into newly developed basins; (4) continued Grenville thrusting created foreland basins in a westward progression; and (5) a long period of Neoproterozoic to Middle Cambrian erosion removed much of the foreland basin sedimentary sequences prior to Paleozoic deposition. Erosion in the Ohio region did not remove the large volume of rock as in Canada north of Georgian Bay. Other seismic lines in the region suggest that Grenville-age sedimentary basins are preserved beneath the Phanerozoic from Georgian Bay southward. These new fi ndings demonstrate the importance of using fault-and unconformity-bounded seismic sequences to enhance and clarify the relative timing of Proterozoic events in regions where Paleozoic sedimentary cover exists and core samples are sparse or lacking.

The Great Grenvillian Sedimentation Episode: Record of Supercontinent Rodinia's assembly

“…29.5), which reveals that a very high percentage of the basin fill was derived from erosion of the adjacent Grenville Province (Santos et al, 2002). A recent re-interpretation based on reprocessing of the COCORP seismic reflection data and limited well-core data recognized four, unconformity-bounded, Proterozoic sedimentary sequences, which are interpreted to represent episodic sedimentation corresponding to alternating stages of extension and contraction during the Grenvillian orogeny (Baranoski et al, 2009;cf. Rivers, 1997).…”

Detrital zircon geochronology of the Grenville/Llano foreland and basal Sauk Sequence in west Texas, USA

“…In Laurentia, syn-collisional detritus shed off the evolving Grenville deformation front is preserved in a variety of settings, ranging from widely dispersed extensional basins (e.g., Midcontinent Rift, Fort Wayne Rift) to broad, fl uvial aprons hundreds to even thousands of kilometers in width (Cawood et al, 2007;Hadlari et al, 2012;Rainbird et al, 2012, and references therein). In contrast, the preserved lateral extent of foreland basin deposition (as defi ned by Allen and Allen, 2005) is thought to be limited to a small number of localities proximal to the Grenville thrust front (Santos et al, 2002;Cawood et al, 2007;Baranoski et al, 2009;Rainbird et al, 2012). In west Texas (USA), the late Mesoproterozoic Lanoria and Hazel Formations have been interpreted as having formed in extensional basins (Bickford et al, 2000) or as proximal molasse (Soegaard and Callahan, 1994).…”

Zircon U-Pb, Hf and O isotope constraints on growth versus reworking of continental crust in the subsurface Grenville orogen, Ohio, USA

“…Baranoski et al (2009) show an interpretation that the Grenville Province in Ohio is partially allochthonous west of the Grenville front magnetic lineament.…”

“…2) and the lack of higher-grade metamorphic recrystallization (coarsening) of the very fine-grained matrix it is assumed to be affiliated with unmetamorphosed rocks of the Granite Rhyolite Province in the Grenville orogen foreland (cf. Baranoski et al 2009). Zircon grains occur as texturally simple, perfectly euhedral and transparent crystals, with no morphological signs of secondary alteration or growth after igneous crystallization (Fig.…”

“…2B). Baranoski et al (2009) proposed the use of the term Grenville front magnetic lineament due to the absence of published drill-core data from subsurface Ohio and a lack of a direct correlation to its Page 8 of 53…”