scholarly journals The stratigraphy and depositional environment of Upper Ordovician to Lower Devonian rocks in the Antigonish Highlands, Nova Scotia

10.4138/1622 ◽  
1986 ◽  
Vol 23 (2) ◽  
Author(s):  
J. B. Murphy
Keyword(s):  
Nova Scotia ◽  
Lower Devonian ◽  
Depositional Environment ◽  
Upper Ordovician

scholarly journals Upper Ordovician graptolites from the Cape Phillips Formation, Canadian Arctic Islands

1987 ◽  
Vol 35 ◽  
pp. 191-202
Author(s):  
M. J. Melchin
Keyword(s):  
Great Britain ◽  
Shallow Water ◽  
Depositional Environment ◽  
Canadian Arctic ◽  
Late Ordovician ◽  
Outer Shelf ◽  
Upper Ordovician ◽  
The World ◽  
Cape Phillips Formation ◽  
Varying Length

Ashgill age graptolites have been collected from seven sections of the Cape Phillips Formation across most of its outcrop belt. The earliest graptolite zone recognisable is that of Orthograptus fastigatus. It is correla­ted with the Dicellograptus ornatus · Zone of the northern Canadian Cordilllera and the Dicellograptus complexus Subzone of the Dicel/ograptus anceps Zone of Great Britain although no dicellograptids have been found at any of the present sections. The overlying zone is that of Paraorthograptus pacificus, an ea­sily recognisable zone around much of the world. Graptolites of the C/imacograptus extraordinarius and Glyptograptus persculptus zones appear to be en­tirely absent from this formation. This is attributed to the Late Ordovician glaciation which has induced regression and submarine erosion in many areas worldwide. The earliest recognisable Silurian zone varies from section to section due to buried or barren intervals and/or hiatuses of varying length. The Parakidograptus acuminatus Zone has been recognised at only one section. At the others, the Atavograptus atavus, the Lagarograptus acinaces-Coronograptus gregarius, the Monograptus convolutus or the Monograptus spiralis Zone (s.1.) are the earliest recognisable Silurian fau­nas. Relatively low fauna! diversities in the Ashgill and lowest Llandovery portion of the section and the to­tal lack of dicellograptids are interpreted to be due to relatively shallow water, outer shelf or carbonate ramp depositional environment.

Paleoenvironments revealed by rare-earth element systematics in vertebrate bioapatite from the Lower Devonian of Svalbard

2016 ◽  
Vol 53 (8) ◽  
pp. 788-794
Author(s):  
Živilė Žigaitė ◽  
Alexandre Fadel ◽  
Alberto Pérez-Huerta ◽  
Teresa Jeffries ◽  
Daniel Goujet ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Element ◽  
Lower Devonian ◽  
Depositional Environment ◽  
Earth Element ◽  
Long Distance ◽  
Dental Tissues ◽  
Abundance Patterns ◽  
The Eu

In situ rare-earth element (REE) compositions have been measured in early vertebrate microremains from the Lower Devonian basin of Andrée Land (Svalbard), with the aim of obtaining information about their early depositional environment and potential reworking. Vertebrate microremains with different histology were used for the analyses, sourced from two different localities of marginal marine to freshwater sediments from geographically distant parts of the Grey Hœk Formation (Skamdalen and Tavlefjellet members). We selected thelodont and undescribed ?chondrichthyan scales, which allowed us to define potential taxonomic, histological, and taphonomic variables of the REE uptake. Results showed REE concentrations to be relatively uniform within the scales of each taxon, but apparent discrepancies were visible between the studied localities and separate taxa. The compilation of REE abundance patterns as well as REE ratios have revealed that thelodont and ?chondrichthyan originating from the same locality must have had different burial and early diagenetic histories. The shapes of the REE profiles, together with the presence and absence of the Eu and Ce anomalies, equally suggested different depositional and diagenetic environments for these two sympatric taxa resulting from either stratigraphical or long-distance reworking. The REE concentrations appear to have visible differences between separate dental tissues, particularly between enameloid and dentine of thelodonts, emphasizing the importance of in situ measurements in microfossil biomineral geochemistry.

scholarly journals Chrono-, litho- and conodont bio-stratigraphy of the Rauchkofel Boden Section (Upper Ordovician – Lower Devonian), Carnic Alps, Austria

2017 ◽  
Vol 50 (4) ◽  
pp. 445-469 ◽  
Author(s):  
Hans Peter Schönlaub ◽  
Carlo Corradini ◽  
Maria G. Corriga ◽  
Annalisa Ferretti
Keyword(s):  
Lower Devonian ◽  
Upper Ordovician ◽  
Carnic Alps

A sedimentological overview of the coal-bearing Morien Group (Pennsylvanian), Sydney Basin, Nova Scotia, Canada

1987 ◽  
Vol 24 (9) ◽  
pp. 1869-1885 ◽  
Author(s):  
B. R. Rust ◽  
M. R. Gibling ◽  
M. A. Best ◽  
S. J. Dilles ◽  
A. G. Masson
Keyword(s):  
Nova Scotia ◽  
Depositional Environment ◽  
Facies Analysis ◽  
Meandering Rivers ◽  
Meandering Channels ◽  
Basin Fill

The onshore part of the Sydney Basin, Nova Scotia, contains a 2 km fining-upward coal-bearing succession, the Pennsylvanian Morien Group. Facies analysis indicates an upward change in depositional environment from mid- through distal braid-plain to meandering fluvial plain. This change occurred earliest in the southeast part of the basin, where the meandering channels were incised through penecontemporaneous duricrusts. Northeastward drainage was maintained throughout, and the basin fill records gradually decreasing slopes as source relief was worn down and rate of subsidence declined during a period of increasing tectonic quiescence. The uneconomic coals of the lower Morien Group (South Bar and Waddens Cove formations) are thin and inextensive and formed in well-drained swamps of anabranches from the active braided system or between incised meandering channels. The economic coals of the upper Morien (Sydney Mines Formation) are more extensive and formed in broad, humid swamps of large flood basins between the unconfined channels of large meandering rivers.

Origin, sequence stratigraphy and depositional environment of an upper Ordovician (Hirnantian) deglacial black shale, Jordan

2005 ◽  
Vol 220 (3-4) ◽  
pp. 273-289 ◽  
Author(s):  
Howard A. Armstrong ◽  
Brian R. Turner ◽  
Issa M. Makhlouf ◽  
Graham P. Weedon ◽  
Mark Williams ◽  
...  
Keyword(s):  
Sequence Stratigraphy ◽  
Black Shale ◽  
Depositional Environment ◽  
Upper Ordovician

Late Ordovician platform foundering, its paleoceanography and burial, as preserved in separate (eastern Michigan Basin, Ottawa Embayment) basins, southern Ontario

2003 ◽  
Vol 40 (2) ◽  
pp. 135-148 ◽  
Author(s):  
Sajal Sharma ◽  
George R Dix ◽  
J FV Riva
Keyword(s):  
Bottom Water ◽  
Depositional Environment ◽  
Late Ordovician ◽  
Michigan Basin ◽  
Upper Ordovician ◽  
Margin Setting ◽  
Blue Mountain ◽  
Sea Level Variation ◽  
Eastern Ontario ◽  
Sediment Bottom

Comparison of litho-, bio-, and chemostratigraphy in two cores from the northeastern margin of the Michigan Basin (Manitoulin Island) and from within the Ottawa Embayment (eastern Ontario) identifies interbasinal differences of Late Ordovician platform foundering linked to Taconic orogenesis. Graptolite biostratigraphy defines an east-to-west younging (late Edenian to early Maysvillian) of platform burial. A regional unconformity likely caps the platform succession. In both basins, an increased supply of mafic material appears during the final stages of platform collapse, with the accumulation of organic-rich (<8%), petroliferous shales (Collingwood Member — Michigan Basin; Eastview Member — Ottawa Embayment). Both units preserve evidence for deposition coincident with increased dysoxic to possible anoxic bottom-water conditions, but the Collingwood Member accumulated under a relatively stable paleoceanographic environment. Rhythmic interbedding with platform limestone in eastern Ontario, combined with evidence for fluctuating paleoproductivity, suggests the depositional environment of the Eastview Member was more sensitive to higher order controls affiliated with tectonic, oceanographic, and (or) sea level variation. Such interbasinal differences likely reflect a greater rate of subsidence in the Manitoulin region transforming platform sedimentation to a distal ramp facies. In eastern Ontario, a lesser rate of subsidence maintained a shallower water, but open margin, setting. Burial of the Upper Ordovician platform, as preserved in eastern Ontario, occurred during peak dysoxic conditions, with deposition of a hemipelagic facies (Billings Formation) that marks the peak supply of clay-size mafic-derived sediment. Bottom-water ventilation occurred only with appearance of abundant Taconic-derived distal turbidites. An equivalent hemipelagic facies appears to be absent from the Manitoulin region. However, equivalent resedimented deposits are represented by the Blue Mountain Formation.

Early Silurian volcanic rocks at Arisaig, Nova Scotia

1979 ◽  
Vol 16 (8) ◽  
pp. 1635-1640 ◽  
Author(s):  
J. Duncan Keppie ◽  
J. Dostal ◽  
M. Zentilli
Keyword(s):  
Nova Scotia ◽  
Lower Devonian ◽  
Basaltic Magma ◽  
Volcanic Rocks ◽  
Volcanic Belt ◽  
Island Arc ◽  
Temporal Association ◽  
Continental Plate

Petrochemical data for the Early Llandovery subaerial volcanic rocks at Arisaig, Antigonish Highlands, Nova Scotia, show that they are a bimodal suite of altered rhyolites and basalts of tholeiitic affinity with some alkaline tendencies extruded in a nonorogenic extensional environment within a continental plate. These data do not support the island arc origin frequently inferred for these rocks but are consistent with recent petrological data from the Silurian – Lower Devonian Coastal Volcanic Belt in southern Maine, which may be a strike continuation of the Arisaig volcanics. The close spatial and temporal association of basalts and rhyolites is attributed to anatexis of the crust upon contact with the rising basaltic magma.

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