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 Middle and Upper Devonian callocystitids have been previously reported only from Iowa and Michigan USA with unpublished reports from Missouri USA and the Northwest Territories, Canada.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.

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.

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.

First report of protoceratopsians (Neoceratopsia) from the Late Cretaceous Judith River Group, Alberta, Canada

1998 ◽  
Vol 35 (7) ◽  
pp. 820-826 ◽  
Author(s):  
Michael J Ryan ◽  
Philip J Currie
Keyword(s):  
North America ◽  
Late Cretaceous ◽  
Fossil Record ◽  
Coastal Environments ◽  
First Report ◽  
Skeletal Material ◽  
First Occurrence ◽  
Dinosaur Park Formation ◽  
Milk River Formation

Protoceratopsians are best known in North America from associated skeletal material of Montanoceratops from the early Maastrichtian of Montana and Campanian of Alberta and Leptoceratops from the late Maastrichtian of Alberta and Wyoming. We report here the first occurrence of protoceratopsian elements from the middle Campanian (Dinosaur Park Formation) of Alberta. The specimens consist of a fragmentary right dentary and an almost complete left dentary which can be referred to Leptoceratops sp. Recent examination of Albertan microvertebrate material has identified cf. protoceratopsians teeth from the latest Santonian (Milk River Formation), extending the record of Albertan protoceratopsians back almost 20 million years. The rarity of these small ornithischians in the fossil record of Alberta may have been due to ecological exclusion from the wet, coastal environments that were preferred by the larger, more abundant ceratopsids.

Are modern chemosynthesis-based communities a ‘glimpse of antiquity’? The changing fate of bivalves and brachiopods at ancient methane seeps as recorded in the Middle Palaeozoic of Morocco

2020 ◽  
Author(s):  
Michał Jakubowicz ◽  
Krzysztof Hryniewicz
Keyword(s):  
Middle Devonian ◽  
Fossil Record ◽  
Hydrothermal Vents ◽  
Upper Devonian ◽  
Early Evolution ◽  
Methane Seeps ◽  
The Past ◽  
Early Mesozoic ◽  
Morphological Adaptations ◽  
Chemosynthetic Ecosystems

<p>Despite much scientific effort aimed over the past three decades to better constrain the fossil record of chemosynthesis-based communities, our understanding of their early evolution remains fragmentary. Until recently, a dominant perception was that, unlike the Cenozoic, bivalve-dominated chemosynthetic ecosystems, the Paleozoic to mid-Mesozoic methane seeps and hydrothermal vents were dominated by brachiopods. Similarly, the pattern of brachiopod vs. bivalve predominance at seeps and vents over the Phanerozoic was believed to have crudely followed that observed in normal-marine benthic shelly assemblages. Recent discoveries from the Middle Palaeozoic of Morocco have questioned this simple perception, documenting the presence of late Silurian and Middle Devonian seeps dominated by mass accumulations of large, semi-infaunal, modiomorphid bivalves (Hryniewicz et al., 2017; Jakubowicz et al., 2017). While representing a lineage unrelated to modern seep-obligate bivalve taxa, the mid-Palaeozoic seep bivalves developed a set of morphological adaptations strikingly similar to those of their modern ecological counterparts, and formed analogous, densely-packed, nearly monospecific assemblages, both suggesting their chemosymbiotic lifestyle. The new documentation of Palaeozoic establishment of the bivalve-dominated seep communities provides a fresh look at the concept of modern chemosynthetic ecosystems as a 'glimpse of antiquity', showing that although it is largely not true taxonomically, it clearly is in terms of recurring morphological themes. At the same time, this refined Palaeozoic record makes the factors responsible for the apparent scarcity of seep-related bivalves during the upper Devonian to early Mesozoic, a period of the remarkable success of brachiopod-dominated seep assemblages, ever more enigmatic.</p>

Origin of the Odd-twins anomaly: magnetic effect of a unique stratigraphic marker in the Appalachian foreland basin, Gulf of St. Lawrence

2002 ◽  
Vol 39 (11) ◽  
pp. 1675-1687 ◽  
Author(s):  
John WF Waldron ◽  
Jerry DeWolfe ◽  
Robert Courtney ◽  
Doris Fox
Keyword(s):  
Point Group ◽  
Foreland Basin ◽  
Late Ordovician ◽  
Magnetic Survey ◽  
Seismic Profiles ◽  
Mineral Concentration ◽  
Appalachian Orogen ◽  
Land Survey ◽  
Laurentian Margin ◽  
Appalachian Foreland

The "Odd-twins magnetic anomaly" is a pair of linear asymmetric positive anomalies located in the Gulf of St. Lawrence, over the post-Taconian, pre-Acadian foreland basin fill related to the development of the Appalachians. A marine magnetic survey allowed the anomaly to be traced close to the coast of Newfoundland, and an on-land survey identified both peaks within the area of outcrop of the Late Ordovician Long Point Group. Sandstones of high susceptibility sampled from sparse outcrops close to the locations of the anomaly peaks contain up to 0.58% magnetite. Models involving dipping sheets of sandstone having similar and slightly higher susceptibility can explain both the onshore and offshore anomaly. The magnetite is of detrital origin and represents a paleoplacer heavy mineral concentration formed in a marginal marine environment. The anomaly provides a unique tie point between the known onshore stratigraphy and the succession in the foreland basin, known only from industry seismic profiles. This tie point indicates that nearly half of the recorded subsidence of the post-Taconian foreland basin took place in the Late Ordovician, suggesting that a major event within the Appalachian orogen loaded the Laurentian margin at this time. A subsequent hiatus, representing the Early Silurian, may record thermal uplift associated with the Salinian orogeny. Renewed Late Silurian to Devonian loading and sedimentation resulted from the Acadian orogeny.

Upper Devonian Echinoderm Debris Beds with Graded Texture, District of Mackenzie, Northwest Territories

1973 ◽  
Vol 10 (4) ◽  
pp. 519-528 ◽  
Author(s):  
W. S. MacKenzie
Keyword(s):  
Northwest Territories ◽  
Black Shale ◽  
Middle Devonian ◽  
Skeletal Remains ◽  
Upper Devonian ◽  
The South ◽  
South Side ◽  
Local Origin ◽  
Mackenzie River

A sequence of Upper Devonian echinoderm debris beds with graded texture, interbedded with shale, overlies the Middle Devonian Ramparts Formation in the subsurface at McDermott Canada GCO South Maida Creek G-56 well on the south side of Mackenzie River near Carcajou Ridge.The interval of echinoderm debris can be divided into thick 2- to 7-ft (0.6- to 2.1-m) beds of graded skeletal remains lacking shale, and thinner intervals from 1 to 2 ft (0.3 to 0.6 m) thick of graded skeletal remains with interbedded black shale. The echinoderm beds, not present in the subsurface at nearby wells, are probably of local origin. Similar beds of echinoderm debris with graded texture, also of probable local origin, crop out at Powell Creek in the Mackenzie Mountain foothills.

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