scholarly journals Outliers of Lower Cretaceous Chaswood Formation in northern Nova Scotia: results of scientific drilling and studies of sedimentology and sedimentary petrography

2005 ◽  
Author(s):  
G Pe-Piper ◽  
D J W Piper ◽  
T Hundert ◽  
R R Stea
Keyword(s):  
Nova Scotia ◽  
Lower Cretaceous ◽  
Scientific Drilling ◽  
Sedimentary Petrography

Detrital muscovite geochronology and the Cretaceous tectonics of the inner Scotian Shelf, southeastern Canada 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 20120142.

2012 ◽  
Vol 49 (12) ◽  
pp. 1558-1566 ◽  
Author(s):  
Peter H. Reynolds ◽  
Georgia Pe-Piper ◽  
David J.W. Piper
Keyword(s):  
Nova Scotia ◽  
Lower Cretaceous ◽  
Special Issue ◽  
Scotian Shelf ◽  
Single Grain ◽  
Meguma Terrane ◽  
Maritimes Basin ◽  
Uplift And Erosion

Geochronology of detrital muscovite from the Lower Cretaceous of the central Scotian Basin has shown predominant supply of Meguma terrane detritus, including muscovite with Alleghanian (mid-Carboniferous to Permian) ages from the inner Scotian Shelf. In this study, 87 detrital muscovite grains from five wells in the eastern Scotian Basin, representing depositional ages from Tithonian to Early Albian, were dated by single-grain 40Ar/39Ar techniques. Previous work shows that the provenance of this sediment was different from wells in the central Scotian Basin. Compared with the central Scotian Basin, the muscovite age populations from the eastern Scotian Basin have more (20% versus 7%) pre-Devonian ages, derived from inboard terranes of the Appalachians. In both the central and eastern Scotian Basin, most old grains are found in the Tithonian and the Aptian–Albian, with fewer in the Valanginian and almost none in the Kimmeridgian and the Hauterivian–Barremian. These data suggest rapid unroofing of the Meguma terrane in the Kimmeridgian and Hauterivian–Barremian and greater supply of sediment from Newfoundland to the eastern Scotian Basin in the Tithonian and Aptian–Albian. Compared with the central Scotian Basin, which has most ages in the range 340–300 Ma, the muscovite age populations from the eastern Scotian Basin have a higher proportion of 420–340 Ma and in particular 300–260 Ma ages. Such late Alleghanian overprinting of argon ages is very rare on land in Nova Scotia, but in the Maritimes Basin, this was the time of uplift and erosion of strata.

Lower Cretaceous provenance in the northern Austral basin of Patagonia from sedimentary petrography

2015 ◽  
Vol 64 ◽  
pp. 498-510 ◽  
Author(s):  
Vanesa Barberón ◽  
Gonzalo Ronda ◽  
Pablo R. Leal ◽  
Christian Sue ◽  
Matías C. Ghiglione
Keyword(s):  
Lower Cretaceous ◽  
Sedimentary Petrography

Volcanic ash in the Lower Cretaceous Chaswood Formation of Nova Scotia: source and implicationsGeological Survey of Canada Contribution 20100082.

2010 ◽  
Vol 47 (11) ◽  
pp. 1427-1443 ◽  
Author(s):  
Georgia Pe-Piper ◽  
David J.W. Piper
Keyword(s):  
Nova Scotia ◽  
New England ◽  
Lower Cretaceous ◽  
Volcanic Ash ◽  
Bulk Composition ◽  
Volcanic Rocks ◽  
Grand Banks ◽  
Ash Fall ◽  
Volcanic Source ◽  
Cretaceous Volcanism

Lignites and coals, because of their low sedimentation rates of terrigenous detritus, may preserve a record of volcanic ash fall. Lignite from the Lower Cretaceous Chaswood Formation in central Nova Scotia was studied to identify whether any volcanic ash is present and can be correlated to known Early Cretaceous volcanism in southeastern Canada and adjacent New England. The bulk mineralogy and geochemistry of lignite and lignitic mudstones was determined by X-ray diffraction and whole-rock geochemical analysis of ashed samples; selected samples were examined by electron microprobe and scanning electron microscope. Much of the terrigenous component of some lignites consists of detrital sediments. In some lignites, distinctive rare earth element patterns are due to leaching from monazite and concentration in organic matter. Some lignites, however, lack illite and (or) quartz indicative of detrital sources, but show unusual abundance of stable high-field-strength elements such as Nb, Ta, and Hf, suggesting a volcanic source. Wood or charcoal fragments appear mineralized and diagenetic talc is present. Most of any ash component has been altered to kaolinite. Bulk composition of original ash ranges from basaltic to rhyolitic and matches chemically with subalkaline volcanic rocks on the SW Grand Banks and Orpheus graben. Coeval volcanic rocks on the U.S. continental margin and the New England–Quebec igneous province are more alkaline. Altered ash in lignite in the lower member of the Chaswood Formation correlates with Neocomian volcanism on the SW Grand Banks; and in the middle and upper members with Aptian–Albian volcanism in Orpheus graben.

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