Paleoecologic and paleogeographic factors in the distribution of lower Middle Devonian conodonts from north-central Ohio

1984 ◽  
pp. 113-126 ◽  
Author(s):  
Dale R. Sparling
Keyword(s):  
Middle Devonian ◽  
North Central

Conodonts from the Middle Devonian Plum Brook Shale of north-central Ohio

1995 ◽  
Vol 69 (6) ◽  
pp. 1123-1139 ◽  
Author(s):  
Dale R. Sparling
Keyword(s):  
New Species ◽  
Adaptive Radiation ◽  
Middle Devonian ◽  
Considerable Part ◽  
Type Region ◽  
North Central ◽  
Index Species ◽  
Conodont Fauna ◽  
Three New Species

The Plum Brook Shale of north-central Ohio lies disconformably between the Eifelian (lower Middle Devonian) Delaware Limestone and the middle Givetian (upper Middle Devonian) Prout Dolomite. Its diverse conodont fauna indicates that it represents a transgression into the area in earliest Givetian time accompanied by the products of a notable adaptive radiation within two lineages ofIcriodus.One of these (I. expansusGroup) includesI. expansus, I. arkonensisandI. brevis, and complete intergradation of forms suggests that the group at this level involves conspecific ecotypes. A more extensive radiation involved descendants ofI. regularicrescens(I. regularicrescensGroup), including three new species,I. eriensis, I. janeaeandI. ohioensis.Other representatives of this lineage occur here as well as in strata of comparable age in the type region of the Givet Limestone as described by Bultynck (1987). A third lineage is represented byI. excavatusin both areas, but evidence of radiation within this branch is limited to the Givet Limestone. Remarkable diversity also occurs among forms considered herein to involvePolygnathus pseudofoliatusand its descendants. The existence of intermediate forms and shared characteristics between and among the various species, including some that first appeared well before the end of the Eifelian, implies that they may be conspecific ecotypic variants at this level. New morphotypes within this group are treated informally. The greatest overall diversity occurs just above the basal Plum Brook, in strata interpreted to reflect inner-sublittoral conditions. The entire Plum Brook belongs to the upperensensisZone. A considerable part of the type Givetian placed in the LowervarcusSubzone by Bultynck (1987) lies below the lowest occurrence of its index species (P. timorensis); it contains some of the species found in the Plum Brook, and much of this section may also belong to theensensisZone.

Conodonts from the Prout Dolomite of north-central Ohio and Givetian (upper Middle Devonian) correlation problems

1999 ◽  
Vol 73 (5) ◽  
pp. 892-907 ◽  
Author(s):  
Dale R. Sparling
Keyword(s):  
New York ◽  
New Species ◽  
North America ◽  
Middle Devonian ◽  
Taxonomic Status ◽  
Middle Part ◽  
North Central ◽  
Continuous Sedimentation ◽  
Stratotype Section ◽  
A New Species

The Prout Dolomite of north-central Ohio lies disconformably above the lowest Givetian (upper Middle Devonian) Plum Brook Shale and below the lowest Famennian (upper Upper Devonian) Ohio Shale. A sample from its base yielded over 4,000 diverse conodont specimens. Included isPolygnathus ansatusZiegler and Klapper, 1976, the index species for the MiddlevarcusSubzone, which is not reported from strata of this age in Ontario and Indiana, a fact that long caused their miscorrelation with the LowervarcusSubzone. Also present isP. rhenanusKlapper, Philip, and Jackson, 1970, considered to be also indicative of the MiddlevarcusSubzone in North America, andP. ovatinodosusZiegler and Klapper, 1976. Lowest occurrences of the latter are in the middle part of this subzone; its presence indicates correlation with the lower Tully Limestone of New York, the basal unit of the Taghanic Series. The Prout and equivalent strata in the region therefore represent a long unrecognized continuous time-rock unit created by Johnson's (1970) Taghanic onlap. The collection includes a new species ofAncyrolepis, A. huntleyi; a new species ofPolygnathusis left in open nomenclature, as are nine specimens assigned toTortodusbut of otherwise uncertain taxonomic status.Givetian conodont correlation between North America and the Global Stratotype Section and Point established by the Subcommission on Devonian Stratigraphy (SDS) in Morocco is extremely problematical because of relatively erratic distribution (probably owing to limited ecologic adaptability) ofP. ansatusandP. hemiansatusBultynck, considered herein to be an early morphotype ofP. ansatus.The base of the Givetian Stage has been defined by the SDS as coinciding with the lowest occurrence ofP. hemiansatus.The only possible evidence for the SDS'shemiansatusZone in North America involves reported occurrence of that morphotype in the uppermost Arkona Shale of Ontario, a position above the top of the Plum Brook Shale, which has been considered to be of Givetian age for decades. Also it appears that the interval between the Eifelian (lower Middle Devonian)kockelianusZone and thehemiansatusZone at the SDS's global-stratotype section in Morocco is of questionable age and probably too thin to represent continuous sedimentation. Adoption of a widely recognized faunal break at the base of strata deposited during the If T-R cycle of North America and Europe as the base of the Givetian could provide a sound alternative.

The Catamaran Fault, North-Central New Brunswick

1972 ◽  
Vol 9 (10) ◽  
pp. 1278-1286 ◽  
Author(s):  
F. D. Anderson
Keyword(s):  
New Brunswick ◽  
Compressive Stress ◽  
Middle Devonian ◽  
Fracture Analysis ◽  
Strike Slip ◽  
Maritime Provinces ◽  
North Central ◽  
The Core ◽  
Principal Compressive Stress ◽  
Metamorphic Core

The Catamaran Fault cuts pre-Carboniferous rocks of the Miramichi Geanticline in north-central New Brunswick. It has been examined for about 60 miles (100 km) across the intrusive and metamorphic core of the geanticline and into the Siluro-Devonian flank rocks. The fault strikes easterly in the core and northeasterly in the flanks.Where displacement could be determined movement on the fault is mainly right lateral strike-slip. There is no evidence for major dip-slip. Fracture analysis indicates that faulting was in response to a northwest-southeast trending principal compressive stress similar to that deduced for other faults in the Maritime Provinces. Latest movement along the fault was post-Middle Devonian (i.e. post-dates the emplacement of the Acadian granite) and pre-Pennsylvanian.The Catamaran Fault may extend eastward along a fault possibly underlying Miramichi Bay and continuing under the Gulf of St. Lawrence, and westward along a southwesterly trending fault in western New Brunswick. As such the Catamaran Fault may exceed 250 miles (400 km) in length.

Stromatoporoids from the Famennian (Devonian) Wabamun Formation, Normandville oilfield, north–central Alberta, Canada

1988 ◽  
Vol 62 (03) ◽  
pp. 411-419 ◽  
Author(s):  
Colin W. Stearn
Keyword(s):  
Patch Reef ◽  
Abundant Species ◽  
The Other ◽  
North Central ◽  
Biotic Crisis

Stromatoporoids are the principal framebuilding organisms in the patch reef that is part of the reservoir of the Normandville field. The reef is 10 m thick and 1.5 km2in area and demonstrates that stromatoporoids retained their ability to build reefal edifices into Famennian time despite the biotic crisis at the close of Frasnian time. The fauna is dominated by labechiids but includes three non-labechiid species. The most abundant species isStylostroma sinense(Dong) butLabechia palliseriStearn is also common. Both these species are highly variable and are described in terms of multiple phases that occur in a single skeleton. The other species described areClathrostromacf.C. jukkenseYavorsky,Gerronostromasp. (a columnar species), andStromatoporasp. The fauna belongs in Famennian/Strunian assemblage 2 as defined by Stearn et al. (1988).

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