scholarly journals Geochemistry and regional significance of the early Cretaceous basalt-felsic igneous rock associations on the Grand Banks, eastern Canada

1993 ◽  
Author(s):  
L F Jansa ◽  
G Pe-Piper ◽  
Z Palacz
Keyword(s):  
Early Cretaceous ◽  
Igneous Rock ◽  
Eastern Canada ◽  
Grand Banks

The provenance of Middle Jurassic sandstones in the Scotian Basin: petrographic evidence of passive margin tectonics 1This article is one of a series of papers published in this CJES Special Issue on the theme of Mesozoic–Cenozoic geology of the Scotian Basin. 2Geological Survey of Canada Contribution 20110319.

2012 ◽  
Vol 49 (12) ◽  
pp. 1463-1477 ◽  
Author(s):  
Gang Li ◽  
Georgia Pe-Piper ◽  
David J.W. Piper
Keyword(s):  
Early Cretaceous ◽  
Middle Jurassic ◽  
Mineral Chemistry ◽  
Passive Margin ◽  
Heavy Minerals ◽  
Late Triassic ◽  
Cape Breton Island ◽  
Grand Banks ◽  
Meguma Terrane ◽  
Geomorphological Evolution

The tectonic and geomorphological evolution of the Scotian margin and its hinterland is poorly known between Late Triassic rifting and the Early Cretaceous progradation of major deltas. This study determined sedimentary provenance of Middle Jurassic Mohican Formation sandstones from three wells using heavy minerals and mineral chemistry. Indicator minerals such as xenotime, altered ilmenite, and varietal types of garnet and tourmaline are similar to those in Hauterivian–Barremian sandstones in the western Scotian Basin, which are almost exclusively derived from the Meguma terrane. The wells adjacent to the Canso Ridge have more zircon and less ilmenite, indicating a greater contribution of polycyclic reworking, but with an ultimate source in the Meguma terrane. Zircon and ilmenite were likely derived in part from Carboniferous sandstones in eastern mainland Nova Scotia and Cape Breton Island. Any river drainage from the inboard terranes of the Appalachians either was diverted through the Fundy Basin or entered the easternmost Scotian Basin, where the Mohican Formation is 5.5 km thick, along the linear continuation of the southwest Grand Banks transform. Such sediment did not reach the Canso Ridge, suggesting that the Cobequid–Chedabucto fault zone in Orpheus graben was not a significant physiographic feature. This tectonically controlled paleogeography in the Middle Jurassic is quite different from that during active rifting in the Late Triassic – Early Jurassic. Middle Jurassic quiescence was followed in the Tithonian – Early Cretaceous by renewed tectonic uplift associated with rifting of Grand Banks from Iberia and Labrador from Greenland.

Seismic stratigraphy and structure of the east Canadian continental margin between 41 and 52°N

1985 ◽  
Vol 22 (5) ◽  
pp. 686-703 ◽  
Author(s):  
L. M. Parson ◽  
D. G. Masson ◽  
C. D. Pelton ◽  
A. C. Grant
Keyword(s):  
Early Cretaceous ◽  
Continental Margin ◽  
Magnetic Anomalies ◽  
Seismic Stratigraphy ◽  
Sedimentary Sequence ◽  
The West ◽  
Grand Banks ◽  
Late Precambrian ◽  
Oceanic Basement ◽  
Iberian Margin

The seismic stratigraphy of the eastern Grand Banks continental margin is examined, and a five-fold division of the sedimentary sequence overlying basement is proposed. Oceanic basement of Cretaceous age underlies the eastern part of the study area; to the west, continental basement ranging in age from Late Precambrian to ?Jurassic underlies the Grand Banks. The sediment units, ranging in age from Early Cretaceous to Recent, have been dated by extrapolation of both commercial and DSDP drilling results from the Grand Banks and from the formerly conjugate Iberian margin. Identification of oceanic magnetic anomalies in the Newfoundland Basin agrees with the proposed age of the two oldest, Early Cretaceous units.

Early Cretaceous volcanism in the Scotian Basin 1This article is one of a series of papers published in this CJES Special Issue on the theme of Mesozoic–Cenozoic geology of the Scotian Basin.

2012 ◽  
Vol 49 (12) ◽  
pp. 1523-1539 ◽  
Author(s):  
Sarah J. Bowman ◽  
Georgia Pe-Piper ◽  
David J.W. Piper ◽  
Robert A. Fensome ◽  
Edward L. King
Keyword(s):  
Heat Flow ◽  
Early Cretaceous ◽  
Volcanic Rocks ◽  
Magma Source ◽  
Seismic Profiles ◽  
Scotian Shelf ◽  
Grand Banks ◽  
Hydrocarbon Maturation ◽  
Stratigraphic Position ◽  
Cretaceous Volcanism

Early Cretaceous volcanism is widespread in the eastern Scotian Basin. The stratigraphic position of volcanic rocks within wells was re-evaluated and the volcanological character of the rocks was refined by study of cuttings and well logs. Hauterivian–Barremian volcanic rocks on the SW Grand Banks and Aptian–Albian volcanic rocks in the Orpheus Graben and SE Scotian Shelf resulted from Strombolian type eruptions. More extensive Hawaiian type flows were mapped from seismic profiles near the Mallard and Brant wells on the SW Grand Banks and they appear to have been derived from local basement highs with a positive magnetic anomaly interpreted as volcanic centres. Igneous rocks in the Hesper well on the SE Scotian Shelf are the erosional remnant of basaltic flows that terminated at the paleoshoreline. They correlate with basalt flows both in extensive outcrop on Scatarie Ridge and in several Orpheus Graben wells. The interpretation of the Hesper basalts as an erosional remnant of more extensive basalt flows is consistent with detrital petrographic evidence for substantial uplift of the inboard part of the Scotian Basin in the Hauterivian–Aptian. Widespread volcanic activity indicates a regional and long-lived magma source, which resulted in elevated regional heat flow. Effects of this heat flow are seen in sedimentary rocks of the Sable Subbasin and it had a discernable impact on hydrocarbon maturation.

Application of section-balancing techniques to deep seismic reflection data from offshore eastern Canada: preliminary observations

1990 ◽  
Vol 27 (4) ◽  
pp. 494-500 ◽  
Author(s):  
M. C. Dentith ◽  
J. Hall
Keyword(s):  
Seismic Reflection ◽  
Hanging Wall ◽  
Shear Zones ◽  
Ductile Deformation ◽  
Eastern Canada ◽  
Seismic Reflection Data ◽  
Deep Seismic Reflection ◽  
Grand Banks ◽  
Jeanne D'arc Basin ◽  
Reflection Data

The application of section-balancing techniques to the analysis of deep seismic sections requires account be taken of isostasy and ductile-deformation processes. Structures imaged by deep seismic reflection profiling across the southern Grand Banks, offshore eastern Canada, are analyzed in this way. Correlations of dipping events in the deep crust, interpreted as shear zones, with faults recognized in the shallow part of the section are tested by attempting to restore the sections to their undeformed state by reversing the displacements on the faults. This process tests the geometric compatibility of the interpreted fault and the structures in its hanging wall. Our models suggest that the faults bounding the Whale and Horseshoe basins detach at the Mohorovičić discontinuity. In contrast, the fault bounding the Jeanne d'Arc Basin detaches within the lower crust.

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