Transcurrent motion determined paleomagnetically in the Northern Appalachians and Caledonides and the Acadian Orogeny

1976 ◽  
Vol 13 (9) ◽  
pp. 1236-1243 ◽  
Author(s):  
W. A. Morris
Keyword(s):  
North America ◽  
Middle Devonian ◽  
Lower Devonian ◽  
Upper Devonian ◽  
Paleomagnetic Data ◽  
Taconic Orogeny ◽  
Paleomagnetic Poles ◽  
Acadian Orogeny ◽  
Opening And Closing

After correction for Mesozoic and Tertiary opening of the Atlantic, Ordovician and Silurian – Lower Devonian paleomagnetic poles from Britain are significantly different to contemporaneous results from North America. Upper Devonian poles from the two regions are similar. The discrepancy observed in the Ordovician and Silurian – Lower Devonian data is interpreted as due to major sinistral transcurrent faulting during the Middle Devonian concurrent with the short lived Acadian Orogeny. Rate of motion on this fault (or faults) was approximately 9 ± 4 cm/y. A consequence of this interpretation is that the Caledonide ocean was apparently narrow during the interval Ordovician to Devonian. However, inaccuracies in the paleomagnetic data permit the opening and closing of small ocean basins (≤ 1000 km), which may be related to the more extended Taconic Orogeny.

Gigantocharinus szatmaryi, a new trigonotarbid arachnid from the Late Devonian of North America (Chelicerata, Arachnida, Trigonotarbida)

2000 ◽  
Vol 74 (1) ◽  
pp. 25-31 ◽  
Author(s):  
William A. Shear
Keyword(s):  
North America ◽  
Middle Devonian ◽  
New Genus ◽  
Upper Devonian ◽  
Late Carboniferous ◽  
Late Devonian ◽  
New Genus And Species ◽  
Significant Time ◽  
The Family ◽  
Time Gap

A new trigonotarbid arachnid, Gigantocharinus szatmaryi new genus and species, is described from Upper Devonian (Late Famennian) sediments in Pennsylvania. Devonian trigonotarbids were known before from only a single North American locality and several European ones. The new trigonotarbid occurs in what had previously been a significant time gap between the faunas of the Middle Devonian and the late Carboniferous. Gigantocharinus szatmaryi is assigned with some hesitation to the family Palaeocharinidae.

An enigmatic blastozoan echinoderm fauna from central kentucky

2009 ◽  
Vol 83 (5) ◽  
pp. 739-749 ◽  
Author(s):  
Colin D. Sumrall ◽  
Carlton E. Brett ◽  
Troy A. Dexter ◽  
Alexander Bartholomew
Keyword(s):  
North America ◽  
Northwest Territories ◽  
Middle Devonian ◽  
Fossil Record ◽  
Foreland Basin ◽  
Late Ordovician ◽  
Upper Devonian ◽  
Range Extension ◽  
First Report ◽  
Appalachian Foreland

A series of small road cuts of lower Boyle Formation (Middle Devonian: Givetian) near Waco, Kentucky, has produced numerous specimens of three blastozoan clades, including both “anachronistic” diploporan and rhombiferan “cystoids” and relatively advanced Granatocrinid blastoids. This unusual assemblage occurs within a basal grainstone unit of the Boyle Limestone, apparently recording a local shoal deposit. Diploporans, the most abundant articulated echinoderms, are represented by a new protocrinitid species, Tristomiocystis globosus n. gen. and sp. Glyptocystitoid rhombiferans are represented by isolated thecal plates assignable to Callocystitidae. Three species of blastoids, all previously undescribed, include numerous thecae of the schizoblastid Hydroblastus hendyi n. gen. and sp., the rare nucleocrinid Nucleocrinus bosei n. sp., and an enigmatic troosticrinid radial. The blastoid Nucleocrinus is typical for the age; however, the callocystitid, schizoblastid, and protocrinitid are not. Hydroblastus is the oldest known schizoblastid. Middle and Upper Devonian callocystitids have been previously reported only from Iowa and Michigan USA with unpublished reports from Missouri USA and the Northwest Territories, Canada. This occurrence is thus the first report of a Middle Devonian rhombiferan from the Appalachian foreland basin. Tristomiocystis is the first known protocrinitid in North America and the only protocrinitid younger than Late Ordovician. This occurrence thus represents a range extension of nearly 50 million years for protocrinids. This extraordinary sample of echinoderms in a Middle Devonian limestone from a well-studied area of North America highlights the incompleteness of the known fossil record, at least in fragile organisms such as echinoderms.

Review of the Devonian camerate crinoid Bogotacrinus scheibei Schmidt from Colombia

1987 ◽  
Vol 61 (4) ◽  
pp. 750-757 ◽  
Author(s):  
George C. Mcintosh
Keyword(s):  
North America ◽  
Western Europe ◽  
Lower Devonian ◽  
Appalachian Basin ◽  
Upper Devonian ◽  
Eastern North America ◽  
Late Devonian ◽  
Early Devonian ◽  
Lower Upper

Two recently collected specimens of Bogotacrinus scheibei Schmidt, 1937, from the Devonian (Emsian–Eifelian) Floresta Formation of Colombia reveal that Bogotacrinus is a dicyclic camerate crinoid genus closely related to Pterinocrinus Goldring, 1923 (Lower–Upper Devonian of eastern North America and western Europe), and Ampurocrinus McIntosh, 1981 (Lower Devonian of Bolivia). The new diplobathrid camerate crinoid family Pterinocrinidae, characterized by species with low conical dicyclic cups and rami composed of compound, bipinnulate brachials, is herein proposed to accommodate these three genera. This family originated in western Europe and migrated into the Malvinokaffric and southern Eastern Americas Realms during the Early Devonian and into the northeastern Appalachian Basin by the Late Devonian.

Spilitic Rocks in South-east Devonshire

1960 ◽  
Vol 97 (3) ◽  
pp. 192-207 ◽  
Author(s):  
Gerard V. Middleton
Keyword(s):  
Middle Devonian ◽  
Lower Devonian ◽  
Upper Devonian ◽  
Final Phase ◽  
Upper Carboniferous ◽  
Pillow Lavas

AbstractVolcanism began in South-east Devonshire with the extrusion of keratophyric tuffs in the Lower Devonian. The majority of extra ves in the Middle and Upper Devonian are basic spilites but there are intermediate varieties. Volcanism in the Middle Devonian was local and in the Ashprington area appears to have been continuous throughout the epoch. At the beginning of the Upper Devonian keratophyric crystal and vitric tuffs were extruded in the Dartington area. Later in the Upper Devonian the Chipley pillow lavas were extruded: it is shown that these lavas were widespread and may probably be correlated with similar lavas at Pentire Head in North Cornwall. The final phase of volcanism is represented by the intrusion of swarms of sill-like bodies of spilitic dolerites in Upper Carboniferous times. Intrusive and extrusive rocks are distinguished, mapped, and classified petrographically

The Devonian System in China

1981 ◽  
Vol 118 (2) ◽  
pp. 113-138 ◽  
Author(s):  
Yang Shih-Pu ◽  
P'an Kiang ◽  
Hou Hung-Fei
Keyword(s):  
South China ◽  
Middle Devonian ◽  
Lower Devonian ◽  
North China ◽  
Eastern China ◽  
Regional Metamorphism ◽  
Upper Devonian ◽  
West China ◽  
Plant Fossils ◽  
Lithostratigraphic Units

SummaryThe Devonian System of China occurs in the Tianshan–Hingan* Geosyncline of North China, the Yangtze Paraplatform of South China and in the geosynclinal areas of West China. Devonian formations are entirely absent from the Sino-Korean Paraplatform and the Tarim Platform, but along the border of the Tarim Basin and the slopes of Qilianshan (Chilienshan) are continental sequences rich in vertebrate and plant fossils. On the basis of differences in biostratigraphic characteristics the Devonian is divisible into 8 regions: 1. Junggar–Hingan (Dzungar–Khingan), 2. South Tianshan (South Tienshan), 3. Qilianshan (Chilienshan), 4. Longmenshan (Lungmenshan), 5. South China, 6. South-eastern China, 7. West Sichuan–North Xizang (West Szechuan-North Tibet), 8. Himalaya–West Yunnan.Using both lithology and fossil content, five principal facies (types) may be further differentiated: 1. Hingan type (eugeosynclinal facies), 2. Baoxin type (miogeosynclinal facies), 3. Xiangzhou type (platform near-shore facies), 4. Nandan type (platformal off-shore facies), 5. Cuifengshan (Chuifeng shan) type (continental facies).The Devonian of South China occurs in various facies, but has a well-defined principal stratotype. It has been divided by Chinese geologists into eight stages, two in the Upper Devonian, two in the Middle Devonian and four in the Lower Devonian.The Devonian sequences of the geosynclinal regions of West China are characterized by facies which contain graptolites and tentaculites, and have largely been affected by regional metamorphism. The Devonian biota of the Junggar–Hingan Region is essentially an endemic one, but it is associated with a few European and North American elements. Marine pyroclastics are the principal rocks. General stratigraphical columns of those regions are given with a correlation with other parts of China. The continental Devonian of China is unique especially in the light of its vertebrate content. Red sandstones are widespread in the Lower Devonian, and intercalated with argillaceous limestone and mudstone. This sequence is rich in endemic East Asiatic faunal elements including agnatha (Galeaspida, Polybranchiaspida), Antiarchi, etc. Middle and Upper Devonian lithostratigraphic units consist principally of light coloured quartzose sandstone formations in Southeastern China, with some red beds in South and North China, while their fauna and flora are cosmopolitan in character. Their exact geological ages vary, however, as clearly shown in the South China region, especially towards the top of the Upper Devonian (with Asterolepis) and in the early Middle Devonian (with Bothriolepis).

Xenacanthid shark teeth in Middle Devonian limestones of the Rhenish Schiefergebirge, West Germany

1986 ◽  
Vol 60 (5) ◽  
pp. 1134-1135 ◽  
Author(s):  
Rüdiger Stritzke
Keyword(s):  
North America ◽  
Middle Devonian ◽  
Upper Devonian ◽  
West Germany ◽  
Shark Teeth

During investigations in the Rhenish Schiefergebirge, West Germany, concerning the Devonian biostratigraphy of forereef limestones in the Brilon area (Figure 1) several diplodont teeth of fossil sharks were discovered by chance. Remains of xenacanthid teeth from marine Givetian beds are rare. They have been described by Hotton (1952) of probable Givetian/Frasnian age from North America, by Gross (1973) from Middle Devonian Hunsrück Shales, and by Young (1982) from Middle/Upper Devonian strata of Australia and Antarctica.

Contribution a l'etude du Couvinien dans le bassin de Fort-de-Polignac (Sahara)

1961 ◽  
Vol S7-III (5) ◽  
pp. 449-456 ◽  
Author(s):  
Jean Chaumeau ◽  
Philippe Legrand ◽  
Alzine Renaud
Keyword(s):  
Middle Devonian ◽  
Lower Devonian ◽  
Upper Devonian ◽  
Lower Upper ◽  
Shaly Sandstone ◽  
Lateral Variations

Abstract The contact of lower Devonian sandstone and shaly sandstone with middle Devonian shaly limestone is exposed at several points in the vicinity of Fort-de-Polignac in the Sahara. The lower Devonian beds show large lateral variations. Instead of the Givetian (upper middle Devonian) transgressing the lower Devonian, as previously supposed, the transgression began in the center of the basin in the Couvinian or Eifelian, i.e., lower middle Devonian, spread progressively eastward and westward, and did not reach the Oued Samene area until upper Couvinian. The submergence of the lower part of Tihemboka, west of In Akaouet, did not occur until Frasnian (lower upper Devonian).

Systematics of some Lower and Middle Devonian spiriferid brachiopods from Gaspé with a revision of the superfamily Delthyridoidea

1999 ◽  
Vol 73 (6) ◽  
pp. 1056-1077 ◽  
Author(s):  
Martin Bizzarro ◽  
Pierre J. Lespérance
Keyword(s):  
Phylogenetic Analysis ◽  
New Species ◽  
North America ◽  
Middle Devonian ◽  
Lower Devonian ◽  
New Genus ◽  
Stepping Stone ◽  
Taxonomic Treatment ◽  
First Occurrence

The component subfamilies of the Delthyridoidea are critically reviewed and subjected to phylogenetic analysis. This shows the presence of two clades, assigned to the Delthyrididae and Acrospiriferidae, within the superfamily. The subfamilial categories are redefined mainly on the basis of the characters used in the phylogenetic analysis. The spiriferid, mainly delthyridide, Gaspé fauna is formally revised and redescribed. This new taxonomic treatment leads to more precise biostratigraphy and to the recognition of a new subfamily, the Gaspespiriferinae, based on the new genus Gaspespirifer. Five new species are described: Howellella (Howellella) forillonensis, Brachyspirifer (Brachyspirifer) briseboisi, Paraspirifer desbiensi, Brevispirifer florentinus, and B. quebecensis, The occurrence of Brevispirifer species with Middle Devonian chonetaceans confirms the presence of marine Eifelian strata in the Matapédia Valley. Paraspirifer desbiensi n. sp. and two species left in open nomenclature, Vandercammenina sp. and Mucrospirifer sp., have considerable biostratigraphic and biogeographic significance in the Lower Devonian. The first occurrence in the Eastern Americas Realm of the typically Rhenish genera Brachyspirifer, Paraspirifer, and Vandercammenina are in Gaspé. This reinforces the hypothesis that Gaspé served as a stepping stone for Rhenish species invading North America in Pragian and Emsian times, as previously suggested by bivalve biogeography.

IV.—The Devonian Rocks of Cornwall

1904 ◽  
Vol 1 (12) ◽  
pp. 587-591
Author(s):  
W. A. E. Ussher
Keyword(s):  
Middle Devonian ◽  
Lower Devonian ◽  
Upper Devonian ◽  
The South ◽  
Ample Evidence ◽  
The North

Sedgwick and Murchison, the Rev. D. Williams, and Dr. Holl, taking the Plymouth limestones as a middle division, placed them below the rocks to the south and above those to the north. The prevalent southerly dips of schistosity were regarded as ample evidence of a downward succession proceeding northward.The Staddon grits and other Lower Devonian rocks were thus placed above the Middle Devonian, and the slates in which I have at various times since 1892 found Upper Devonian fossils (between Menbeniot and St. Budeaux) were relegated to a position below the Middle Devonian.

Stratigraphie du Paleozoique de la zone axiale pyreneenne a l'E de l'Ariege

1958 ◽  
Vol S6-VIII (8) ◽  
pp. 853-867 ◽  
Author(s):  
Pierre Cavet
Keyword(s):  
Middle Devonian ◽  
Lower Devonian ◽  
Upper Devonian ◽  
Axial Zone ◽  
Middle Ordovician ◽  
Bottom Upward

Abstract The Paleozoic section in the axial zone of the Pyrenees east of the Ariege, France, consists, from the bottom upward, of the Canaveilles series of interbedded graphitic schists, limestones, and metavolcanics (attributed to the Cambrian), the more homogeneous Jujols schists (lower and middle Ordovician), dated Ashgillian and Gotlandian (Silurian) schists and fossiliferous limestones, grading upward into undifferentiated lower Devonian beds, gray massive middle Devonian limestones, diversified upper Devonian formations, and a zone of transgressive Dinantian (Carboniferous) beds which forms the transition to shaly Visean so-called Culm deposits.

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