Basin architecture and thermal maturation in the strike‐slip Deer Lake Basin, Carboniferous of Newfoundland

Abstract

The Deer Lake Basin is an entirely non‐marine basin associated with the Cabot fault zone. Structural and stratigraphic evidence strongly suggest dextral strike‐slip movements along the fault zone during Tournaisian‐Visean time. Two elongated, end‐on structural blocks (probable positive flower structures) contain fold axes and second‐order faults oriented obliquely to fault traces bounding the blocks, in a manner implying dextral movements. In one part of the basin, the stratigraphic thickness of a long homoclinal section of later basin‐fill sediment (Deer Lake Group) greatly exceeds the suggested depth to basement based on gravity measurements, a situation common to strike‐slip basins. Formations representing basin fill can be arranged into megasequences (from oldest to youngest: Anguille Group, Wetstone Point and Wigwam Brook Formations, Deer Lake Group, Howley Formation) corresponding to lateral growth stages of the basin. Gravity, magnetic, and seismic data show that depths to basement on either side of the end‐on flower structures are comparable, so that the youngest strata in the basin (Howley Formation) are not underlain by earlier basin fill. These geophysical data, therefore, corroborate the geological conclusion of onlapping stratigraphic relations. The geophysical data suggest participation of basement in Carboniferous gravity faulting and show the location of the subsurface extension of the Taylors Brook Fault in the western part of the Deer Lake Basin. Thermal maturation of the Anguille and Deer Lake Groups, as measured by vitrinite reflectance, clay mineral assemblages, illite crystallinity, and Rock‐Eval pyrolysis, indicate a much higher level of maturation for the Anguille than for the Deer Lake Group. Palaeotemperatures for the Anguille and Deer Lake Groups are estimated to be around 200 and 100oC, respectively, suggesting that Anguille Group rocks are overmature whereas Deer Lake Group strata are within the oil‐generating window. Onlapping stratigraphic relations and areally homogeneous time/temperature effects, however, have created a situation in which the Deer Lake Group and Howley Formation have similar maturation levels.

Evaporite tectonics and the late Paleozoic stratigraphic development of the Cumberland basin, Appalachians of Atlantic Canada

“…Despite these arguments, McCutcheon and Robinson (1987) favored a rift model for the Maritimes Basin as a whole, whereas Martel (1987) favored a strike-slip origin for the Sackville basin, the depocenter immediately north of the Cumberland basin. Subsequent authors (e.g., Hyde et al, 1988;MacInnes and White, 2004;Waldron, 2004;Waldron et al, 2007;Murphy et al, 2011) have documented signifi cant strike-slip motion during deposition of various parts of the Maritimes Basin fi ll. Recently, Gibling et al (2008) compared the tectonic development of the Maritimes Basin with that of the eastern Mediterranean, and Hibbard and Waldron (2009) have suggested that subsidence in the Maritimes Basin was related to substantial (~250 km) dextral strike-slip motion throughout the Appalachians, which reactivated a promontory-reentrant system in the early Paleozoic Laurentian continental margin (Thomas, 1977(Thomas, , 1991 Lawrence, Grand Banks, and Cabot Strait (e.g., Durling and Marillier, 1993;Langdon and Hall, 1993;Brown, 1998;Pascucci et al, 1999).…”

Geological setting and resource potential of conventional petroleum plays in Paleozoic basins in eastern Canada

“…Windsor Group equivalent successions of coarse nonmarine clastics, up to 1000 m thick, occur in the western Magdalen Basin (New Brunswick and southern Quebec) where they are assigned to the Percé Group (Jutras and Prichonnet, 2005;Jutras et al 2007; Fig. 17; Hyde et al, 1988;Hamblin et al, 1997;Utting and Giles, 2008). The Windsor Group is gradationally overlain by the Upper Mississippian Mabou Group (and partly equivalent Barachois Group; Fig.…”

“…The polyphase structural history of the Maritimes Basin included extensional, strike-slip, and foreland basin settings associated with the late Paleozoic Alleghenian Orogeny (Hyde et al, 1988;Durling and Marillier 1993a, b;Rehill, 1996;Jutras et al, 2003;Wilson and White, 2006;Park et al, 2008;Gibling et al, 2008;St. Peter and Johnson, 2009;Waldron et al, 2010).…”

Zircon fission‐track ages from Newfoundland—A proxy for high geothermal gradients and exhumation before opening of the Central Atlantic Ocean

“…Fully reset ZFT ages from central Newfoundland thus show that rocks exposed here were reheated to ≥220°C. This is corroborated by estimated palaeotemperatures of ~190 to 230°C based on vitrinite reflectance and illite crystallinity measurements from Tournaisian strata near the Cabot fault (Hyde, Miller, Hiscott, & Wright, ).…”