Implications of spore evidence for Late Devonian age of the Piskahegan Group, southwestern New Brunswick

1988 ◽  
Vol 25 (9) ◽  
pp. 1349-1364 ◽  
Author(s):  
D. C. McGregor ◽  
S. R. McCutcheon
Keyword(s):  
New Brunswick ◽  
Eastern Europe ◽  
Volcanic Rocks ◽  
Early Carboniferous ◽  
Surface Expression ◽  
Alluvial Fan ◽  
Late Devonian ◽  
Red Sandstone ◽  
Stratigraphic Position ◽  
Devonian Age

The predominantly volcanic Piskahegan Group has commonly been considered Early Carboniferous, based on its stratigraphic position. However, spores recently discovered in the Carrow Formation, an alluvial fan deposit in the exocaldera facies, indicate that most, if not all, of the group is of Late Devonian (late Famennian) age. The spore assemblage includes several species reported previously from Ireland, Belgium, and eastern Europe, some of them apparently restricted to the southern parts of the Old Red Sandstone Continent in Late Devonian time. Comparison of records of earliest occurrences suggests that the incoming of some species was diachronous. Volcanic rocks of the Piskahegan Group are coeval with post-Acadian, tin–tungsten-bearing granites elsewhere in New Brunswick and are considered the surface expression of plutonism that resulted from Acadian continental collison.

Late Devonian – Early Carboniferous volcanism in western Cape Breton Island, Nova Scotia

1984 ◽  
Vol 21 (7) ◽  
pp. 762-774 ◽  
Author(s):  
Marie-Claude Blanchard ◽  
Rebecca A. Jamieson ◽  
Elizabeth B. More
Keyword(s):  
Tectonic Setting ◽  
Early Carboniferous ◽  
Alluvial Fan ◽  
Late Devonian ◽  
Fluvial Sediments ◽  
Western Cape ◽  
Cape Breton Island ◽  
The North ◽  
Cape Breton ◽  
Geochemical Studies

The Fisset Brook Formation of western Cape Breton Island and its equivalents at MacMillan Mountain and the north Baddeck River are examples of Late Devonian and Early Carboniferous volcanic sequences associated with the formation of post-Acadian successor basins in the northeastern Appalachians. They consist of bimodal basalt–rhyolite suites interbedded with alluvial fan, lacustrine, and rare fluvial sediments. The earliest volcanic products are rhyolites and somewhat evolved basalts associated with coarse sediments, followed by tholeiitic to transitional basalt flows interlayered with lacustrine-type deposits. Geochemical studies on the Fisset Brook Formation indicate extensive remobilization of alkalies, Ca, Rb, and Sr, making these elements inappropriate for determining tectonic setting or magmatic affinity. Use of less mobile elements (Ti, Nb, Y, and Zr) suggests that the basalts are tholeiitic and that the apparent alkalinity of the type section lavas is a result of alteration. We conclude that volcanism in western Cape Breton Island started at MacMillan Mountain and migrated westwards, probably towards the centre of the deepening Magdalen Basin.

Radiometric dating of the Coldbrook Group of southern New Brunswick, Canada

1969 ◽  
Vol 6 (3) ◽  
pp. 393-398 ◽  
Author(s):  
R. F. Cormier
Keyword(s):  
New Brunswick ◽  
Lower Cambrian ◽  
Volcanic Rocks ◽  
The Other ◽  
Radiometric Dating ◽  
Late Devonian ◽  
Initial Ratio ◽  
Initial Value ◽  
Saint John ◽  
Probable Presence

The Coldbrook Group of southern New Brunswick is composed almost entirely of volcanic rocks and has been assigned a Precambrian age on the basis of field relationships. Rocks of the group are overlain by fossiliferous Lower Cambrian beds of the Saint John Group.Rubidium-strontium total-rock analyses of 46 samples of Coldbrook Group volcanic rocks have been carried out. Analysis of the data indicates the probable presence of two different isochron ages. One of these is apparently defined by those rocks in which the ratio 87Rb/86Sr is low, with values less than about 1.0. This isochron yields an age of 750 ± 80 million years, with an initial ratio 87Sr/86Sr of 0.7054 ± 0.0010. The other isochron is defined by rocks in which the value of the ratio 87Rb/86Sr is higher, with values greater than about 1.0. The age calculated from the second isochron is 370 ± 38 million years, with an indicated initial value for the ratio 87Sr/86Sr of 0.7135 ± 0.0010.The 750 million year age is interpreted to represent the time of extrusion of the Coldbrook volcanics. The 370 million year age appears to be secondary and related to metamorphism of the Coldbrook Group. This age is correlated with the Acadian orogeny, which strongly deformed this part of the northern Appalachians in Middle to Late Devonian time.

Pre-Carboniferous history of the Midland Valley of Scotland

1984 ◽  
Vol 75 (2) ◽  
pp. 275-295 ◽  
Author(s):  
B. J. Bluck
Keyword(s):  
Early Carboniferous ◽  
Strike Slip ◽  
Late Devonian ◽  
Reverse Fault ◽  
Red Sandstone ◽  
Northern Margin ◽  
Boundary Fault ◽  
Thrust Faulting ◽  
Marginal Basin ◽  
History Of

ABSTRACTThe pre-Carboniferous Midland Valley of Scotland comprises three tectonic elements: an arc, a proximal fore-arc basin and a marginal basin. These tectonic elements have been juxtaposed by strike-slip and thrust faulting, both of which have effected a 300% reduction in the width of the orogenic belt.Rocks which span Arenig to Late Devonian or Early Carboniferous times and which are found S of the Highland Boundary fault have no clasts of certain Dalradian provenance despite substantial uplift of the Dalradian block at this time. This, combined with other evidence, suggests the Midland Valley to have been remote from this rapidly uplifting terrane. The Dalradian block, eroded down by c. 410 Ma was thrust southeastwards in Late Devonian–Early Carboniferous times. However, this thrust movement was minor, yielding little sediment, but it caused Dalradian rocks to cover the northern margin of the Midland Valley where (1) the source for part of the Old Red Sandstone rocks existed and (2) the faults along which the Midland Valley block was transported to dock against the Dalradian block are thought to be present. The existing Highland Boundary fault is therefore seen as a late Old Red Sandstone reverse fault which covered more significant older structures.

Bechala sommeri Ilger & Brauckmann, 2012 enlightens the Namurian griffenfly diversity (Insecta: Odonatoptera: Bechalidae)

2012 ◽  
Vol 43 (2) ◽  
pp. 161-169 ◽  
Author(s):  
André Nel ◽  
Jan-Michael Ilger ◽  
Carsten Brauckmann ◽  
Jakub Prokop
Keyword(s):  
Ecological Niche ◽  
Type Species ◽  
Early Carboniferous ◽  
Sister Group ◽  
Late Devonian ◽  
Group Relationships ◽  
New Diagnosis ◽  
Devonian Age ◽  
Early Late ◽  
High Diversity

Bechala sommeriIlger & Brauckmann, 2012, the type species of the type genus of the early Late Carboniferous (Namurian) family Bechalidae Ilger & Brauckmann, 2012, is redescribed. It does not belong to the order Megasecoptera as previously proposed. The taxon is clearly attributable to Odonatoptera for the typical venation characters as CuA separating from MP obliquely, a true arculus with concave RP and convex MA emerging from a composite vein R+MA, short ScP, and presence of convex intercalaries IR2 and IR1 between the main branches of RP3/4, RP2 and RP1. We transfer this taxon with the monospecific family Bechalidae to Odonatoptera. A new diagnosis is given for Bechalidae and its type genus Bechala. Furthermore, the presence of an oblique subnodal crossvein very far from the ending of ScP and close to the base of RP2 confirms the hypothesis that the subnodus is a structure originally independent of the nodus with a different function in relation to wing tracheation. The Bechalidae are included in a clade (Meganeuridae–Sinierasipteridae–Bechalidae–Lapeyridae–Nodialata), in contrast to a sister group relationships between the two clades Meganisoptera (=Namurotypidae–Paralogidae–Kargalotypidae–Kohlwaldiidae–Meganeuridae) and Odonatoclada (=Lapeyridae–Nodialata), while the potential relationships between the Campylopteridae and the Lapeyridae and Nodialata are rejected. Bechala represents a ‘damselfly-like’ ecological niche in the Namurian, showing the high diversity of the earliest known Odonatoptera, strongly suggesting an Early Carboniferous, if not Late Devonian age for this pterygote clade.

Tectonic evolution of southwestern Newfoundland as indicated by granitoid petrogenesis

1985 ◽  
Vol 22 (7) ◽  
pp. 1080-1092 ◽  
Author(s):  
Derek H. C. Wilton
Keyword(s):  
Fault Zone ◽  
Point Group ◽  
Volcanic Rocks ◽  
Early Carboniferous ◽  
Late Devonian ◽  
Partial Melt ◽  
Show Evidence ◽  
Partial Melts ◽  
Felsic Volcanic ◽  
Host Rocks

Four granitoid suites are recognized in the region of the Cape Ray Fault Zone of southwestern Newfoundland. The two oldest (Ordovician–Silurian (?)) suites represent partial melts of their enclosing host rocks. The Port aux Basques granite is modelled as a partial melt of the gneissic component of its host, Port aux Basques Complex. The Cape Ray granite forms a dominantly tonalitic terrane derived by partial melting of ophiolitic material. The Red Rocks granite and a megacrystic phase of the Cape Ray granite form coherent lines of geochemical descent from the parental tonalite but show evidence of some continental crust contamination.The Late Devonian Windowglass Hill granite is a subvolcanic equivalent of felsic volcanic rocks in the Windsor Point Group. Both units were derived as partial melts of continental crust.The post-tectonic, Late Devonian to Early Carboniferous Strawberry and Isle aux Morts Brook granites constitute the youngest granitoid suite in the region. These A-type granitoids were derived as partial melts of an underlying depleted granulitic (felsic) crust. The depleted nature of the source may have resulted from previous generation of the Windowglass Hill granite and Windsor Point Group. The only possible protolith for the granulitic source is Precambrian Grenvillian gneiss. The presence of this gneiss beneath the Cape Ray Fault Zone of southwestern Newfoundland implies that the complete series of lithologies is allochthonous.

Geochronology and geochemistry of the Late Devonian–Early Carboniferous volcanic rocks in Aksu River area, western end of the East Kunlun Orogen

2020 ◽  
Vol 55 (4) ◽  
pp. 2881-2901
Author(s):  
Xin Xu ◽  
Changfeng Liu ◽  
Wencan Liu ◽  
Baoying Ye ◽  
Zixian Zhao ◽  
...  
Keyword(s):  
Volcanic Rocks ◽  
Early Carboniferous ◽  
Late Devonian ◽  
East Kunlun

Structural setting and age of the Partridge Island block, southern New Brunswick, Canada: a link to the Cobequid Highlands of northern mainland Nova Scotia

2014 ◽  
Vol 51 (1) ◽  
pp. 1-24 ◽  
Author(s):  
Adrian F. Park ◽  
Robert L. Treat ◽  
Sandra M. Barr ◽  
Chris E. White ◽  
Brent V. Miller ◽  
...  
Keyword(s):  
Nova Scotia ◽  
New Brunswick ◽  
Tectonic Setting ◽  
Sedimentary Rocks ◽  
Alkali Feldspar ◽  
Early Carboniferous ◽  
Late Devonian ◽  
Island Formation ◽  
Lake Formation ◽  
Saint John

The Partridge Island block is a newly identified tectonic element in the Saint John area of southern New Brunswick, located south of and in faulted contact with Proterozoic and Cambrian rocks of the Ganderian Brookville and Avalonian Caledonia terranes. It includes the Lorneville Group and Tiner Point complex. The Lorneville Group consists of interbedded volcanic and sedimentary rocks, subdivided into the Taylors Island Formation west of Saint John Harbour and West Beach Formation east of Saint John Harbour. A sample from thin rhyolite layers interbedded with basaltic flows of the Taylors Island Formation at Sheldon Point yielded a Late Devonian – Early Carboniferous U–Pb (zircon) age of 358.9 +6/–5 Ma. Petrological similarities indicate that all of the basaltic rocks of the Taylors Island and West Beach formations are of similar age and formed in a continental within-plate tectonic setting. West of Saint John Harbour, basaltic and sedimentary rocks of the Taylors Island Formation are increasingly deformed and mylonitic to the south, and in part tectonically interlayered with mylonitic granitoid rocks and minor metasedimentary rocks of the Tiner Point complex. Based on magnetic signatures, the deformed rocks of the Tiner Point complex can be traced through Partridge Island to the eastern side of Saint John Harbour, where together with the West Beach Formation, they occupy a thrust sheet above a redbed sequence of the mid-Carboniferous Balls Lake Formation. The Tiner Point complex includes leucotonalite and aegirine-bearing alkali-feldspar granite with A-type chemical affinity and Early Carboniferous U–Pb (zircon) ages of 353.6 ± 5.7 and 346.4 ± 0.7 Ma, respectively. Based on similarities in age, petrological characteristics, alteration, iron oxide – copper – gold (IOCG)-type mineralization, and deformation style, the Partridge Island block is correlated with Late Devonian – Early Carboniferous volcanic–sedimentary–plutonic rocks of the Cobequid Highlands in northern mainland Nova Scotia. Deformation was likely a result of dextral transpression along the Cobequid–Chedabucto fault zone during juxtaposition of the Meguma terrane.

A possible large-scale sinistral displacement along the Great Glen Fault in Scotland

1974 ◽  
Vol 111 (1) ◽  
pp. 23-30 ◽  
Author(s):  
K. M. Storetvedt
Keyword(s):  
Large Scale ◽  
Late Devonian ◽  
Red Sandstone ◽  
Geological Implications ◽  
Devonian Age

SummaryComparison of Old Red Sandstone palaeomagnetism for NW Scotland and Norway lead to the hypothesis of a 200–300 km sinistral movement along the Great Glen Fault. The displacement is thought to be of late Caledonian (late Devonian) age. The new palaeogeographic reconstruction of Northern Britain (prior to late Caledonian times) seems to have interesting geological implications.

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