Lower Cambrian cavity-dwelling endolithic (boring) sponges

1981 ◽  
Vol 18 (5) ◽  
pp. 972-980 ◽  
Author(s):  
David R. Kobluk
Keyword(s):  
Lower Cambrian ◽  
Middle Ordovician ◽  
Early Ordovician ◽  
Patch Reefs ◽  
Sponge Body ◽  
Boring Sponges

In the Lower Cambrian Forteau Formation (middle Bonnia–Olenellus zone) of southern Labrador, cavities in archaeocyath patch reefs contain preserved coelobiontic endolithic sponges. Scallops and carbonate chips produced by sponge boring, spicules, and preserved endolithic sponge body fossils all point to the presence of endolithic sponges in Lower Cambrian reef cavities.The oldest previously described endolithic sponges are Early Ordovician in age and the oldest previously known reef interior bioerosion is Middle Ordovician in age. The presence of endolithic sponges in reef cavities of the Forteau Formation therefore extends both the record of endolithic sponges and of reef interior bioerosion from the Ordovician to the upper Lower Cambrian.

Autochthonous and allochthonous rocks in the Pistolet Bay area in northernmost Newfoundland

1968 ◽  
Vol 5 (3) ◽  
pp. 501-513 ◽  
Author(s):  
M. F. Tuke
Keyword(s):  
Lower Cambrian ◽  
Volcanic Rocks ◽  
The Other ◽  
North Central ◽  
Middle Ordovician ◽  
Early Ordovician ◽  
Bay Area

Rocks outcropping in the northernmost part of the island of Newfoundland belong to two sequences, which are partly contemporaneous and very different in lithology. One sequence consists of Lower Cambrian sandstones and Lower and Middle Ordovician carbonates and shales. The other sequence consists of graywackes, volcanic rocks, and ultrabasic intrusions, which are, in part, early Ordovician. This latter sequence is interpreted as allochthonous because it is underlain by major low-angle faults and because of its strong facies contrast with the first sequence. The allochthonous rocks occur in three separate klippen.The trend of slickensides, attitude of folds, and deflection of beds at fault surfaces all indicate that movement along the low-angle faults that underlie the klippen was to the northwest. The klippen probably originated from an area 60 km to the southeast, which is on strike with similar rocks in north-central Newfoundland.It is suggested that the klippen moved by gravity sliding in late Middle Ordovician time.

Lower Cambrian pediculate lingulids from Yunnan, China

1993 ◽  
Vol 67 (5) ◽  
pp. 788-798 ◽  
Author(s):  
Jin Yugan ◽  
Hou Xianguang ◽  
Wang Huayu
Keyword(s):  
New York ◽  
British Columbia ◽  
Lower Cambrian ◽  
Structure And Function ◽  
The Other ◽  
Burgess Shale ◽  
Middle Cambrian ◽  
Middle Ordovician ◽  
Early Ordovician ◽  
And Function

The vermiform pedicle is one of the most distinctive organs of modern lingulids, but it is rarely preserved. Only two fossil specimens of lingulids with pedicle casts have been reported, one from the Ordovician and the other from the Devonian. No record of fossil pedicles of Lingulella and Lingulepis, the dominant Cambrian and Early Ordovician lingulids, is known. Fossil lingulids from the Lower Cambrian of Chengjiang County, Yunnan, suggest that the structure and function of the pedicle of the lingulids has not changed significantly from its first appearance. A comparison of fossil pedicle of lingulids from the Lower Cambrian, Chengjiang County (China), the Burgess Shale, Middle Cambrian, British Columbia (Canada), the Trenton Formation, Middle Ordovician, New York (U.S.A.), and the Devonian, Devonshire (England, U.K.) shows that the delthyrial area to which the pedicle muscles are attached was reduced in length through time until these muscles were completely embraced by the two valves.Two species, Lingulella chengjiangensis n. sp. and Lingulepis malongensis Rong, are described.

scholarly journals Cambrian and Ordovician geology of Warming Land and southern Wulff Land, central North Greenland

1980 ◽  
Vol 101 ◽  
pp. 55-60
Author(s):  
J.S Peel
Keyword(s):  
Lower Cambrian ◽  
The West ◽  
Middle Ordovician ◽  
Early Ordovician ◽  
Late Cambrian ◽  
Clastic Sediments ◽  
Middle And Late Cambrian ◽  
North Greenland

Fossiliferous Lower Cambrian clastic sediments in Warming Land and southern Wulff Land, central North Greenland, are overlain by about 600 m of mainly carbonates which have yielded Middle and Late Cambrian trilobites. About 560 m of succeeding carbonates and subsidiary clastics are tentatively correlated with sequences in Washington Land, to the west, which range in age from Early Ordovician to early Middle Ordovician. The Ordovician sequence is completed by limestones of the Morris Bugt Group, also originally defined from Washington Land.

Upper Ordovician (Richmondian) cavity-dwelling (coelobiontic) organisms from southern Ontario

1980 ◽  
Vol 17 (12) ◽  
pp. 1616-1627 ◽  
Author(s):  
David R. Kobluk
Keyword(s):  
Lower Cambrian ◽  
Upper Ordovician ◽  
Southern Ontario ◽  
First Report ◽  
Middle Ordovician ◽  
Patch Reefs ◽  
Modern Reef

Upper Ordovician (Richmondian) patch reefs in exposures of the Meaford Formation (Streetsville Member) in Mullett Creek, Mississauga, Ontario contain a preserved coelobiontic (cavity-dwelling) biota. This is the first report of Upper Ordovician reef coelobionts.The cavity biota is dominated by algae that grew attached to the roof and walls of cavities. The fauna and flora consist of: (1) algae (including Girvanella, mammillary and laminated algae, micrite pendants, and a Renalcis-like alga); (2) calcareous vermiform tubes; (3) endolithic metazoa (Trypanites); (4) bryozoans; and (5) hemispherical worm tubes. In addition, thin micrite sheets, of possible organic origin, also line the roofs of some cavities.An infauna of burrowing worms, and coelobiontic sponges, which are common in Lower Cambrian and Middle Ordovician reef cavities, is absent from these Upper Ordovician cavities. In comparison, therefore, with older and also modern reef cavity biotas this Upper Ordovician coelobiontic biota is unusual.

New echinoderms from the Early Ordovician of west Texas

1994 ◽  
Vol 68 (2) ◽  
pp. 324-338 ◽  
Author(s):  
James Sprinkle ◽  
Gregory P. Wahlman
Keyword(s):  
North America ◽  
El Paso ◽  
Middle Ordovician ◽  
Early Ordovician ◽  
West Texas ◽  
Lower Ordovician ◽  
Single Well ◽  
Thecal Plate ◽  
Stem Segments

Four specimens of blastozoan and crinozoan echinoderms are described from the Lower Ordovician El Paso Group in the southern Franklin Mountains just north of El Paso, west Texas.Cuniculocystis flowerin. gen. and sp., based on two partial specimens, appears to be a typical rhombiferan in most of its morphologic features except that it lacks pectinirhombs and instead has covered epispires (otherwise known only from Middle Ordovician eocrinoids) opening on most of the thecal plate sutures. The covered epispires inCuniculocystisindicate that some early rhombiferans had alternate respiratory structures and had not yet standardized on pectinirhombs, a feature previously used as diagnostic for the class Rhombifera.Bockia?elpasoensisn. sp. is a new eocrinoid based on one poorly preserved specimen that has a small ellipsoidal theca and unbranched brachioles attached to a flat-topped spoutlike summit. It is the earliest known questionable representative of this genus and the only one that has been described from North America.Elpasocrinus radiatusn. gen. and sp. is an early cladid inadunate crinoid based on a single well-preserved calyx. It fits into a lineage of early cladids leading to the dendrocrinids and toCarabocrinus.Several additional separate plates, stem segments, and a holdfast of these and other echinoderms are also described.

scholarly journals The Wandel Valley Formation (Early - Middle Ordovician) of North Greenland and its correlatives

1988 ◽  
Vol 137 ◽  
pp. 61-92
Author(s):  
J.S Peel ◽  
M.P Smith
Keyword(s):  
Canadian Arctic ◽  
East Greenland ◽  
Middle Ordovician ◽  
Early Ordovician ◽  
Lowermost Part ◽  
North Greenland

Members are formally described within the Wandel Valley Formation (Early - Middle Ordovician) of the Ryder Gletscher Group in central and eastem North Greenland. In Peary Land the names Pyramideplateau Member (the combined lower and middle informal members of previous usage) and Vestervig Elv Member (the upper member) are proposed. In Kronprins Christian Land, the Alexandrine Bjerge Member (new) overlies the previously named Danmarks Fjord and Amdrup Members. Conodont studies, supported by the macrofauna, indicate that the Pyramideplateau, Danmarks Fjord and Amdrup Members are of late Canadian (Early Ordovician) age. The Canadian-Whiterockian boundary lies within the lowermost part of the Vestervig Elv and Alexandrine Bjerge Members. The top of the former is of earliest Late Whiterockian age while the Alexandrine Bjerge Member only extends into the late Middle Whiterockian. The members of the Wandel Valley Formation are correlated with coeval successions in western North Greenland, East Greenland, the Canadian Arctic Islands and Svalbard.

Middle Ordovician (Chazy Group) cavity-dwelling boring sponges

1981 ◽  
Vol 18 (6) ◽  
pp. 1101-1108 ◽  
Author(s):  
David R. Kobluk
Keyword(s):  
Cavity Wall ◽  
Hard Substrate ◽  
Middle Ordovician ◽  
Siliceous Spicules ◽  
Boring Sponges

Microcavities in lower Middle Ordovician bryozoan mounds from the Laval Formation (Chazy Group) near Montreal, Quebec contain evidence that endolithic (boring) sponges were present. Ramose borings with scalloped walls and swellings resembling endolithic sponge galleries, faceted carbonate grains similar to modern sponge chips, and siliceous spicules both in situ on the cavity wall or roof and in the sediment, all point to the activities of endolithic sponges in the hard substrate of the wall and roof.Coelobiontic (cavity-dwelling) endolithic sponges therefore infested cavities in skeletal mounds and reefs in the Middle Ordovician and appear to have exploited the cavity habitat very soon after the appearance of metazoan skeletal reefs in the Ordovician.

South America’s earliest (Ordovician, Floian) crinoids

2015 ◽  
Vol 89 (4) ◽  
pp. 622-630 ◽  
Author(s):  
Thomas E. Guensburg ◽  
Beatriz G. Waisfeld
Keyword(s):  
Late Ordovician ◽  
Middle Ordovician ◽  
Early Ordovician ◽  
Northwest Argentina ◽  
Anal Sac

AbstractTwo new Early Ordovician crinoids have been discovered in Gondwanan rocks of northwest Argentina.Ramseyocrinus argentinusn. sp., among the most complete for the genus, aids in reconstructing key morphology.Ramseyocrinusis unorthodox with just four radials forming the entire cup, these articulating to five arms above and a tetrameric stem below. Evidence is presented radials comprise A, B, D, and E ray elements (C absent) with B and D radials adjoining to form a compound facet for the C arm. Thus the cup entirely lacks posterior plating; an elongate anal sac projects from the CD tegmen region alongside the C arm. Cup synapomorphies closely linkRamseyocrinusand the Middle OrdovicianTetragonocrinus; inclusion of this clade within disparids is tenuous.Quechuacrinus ticsan. gen. and sp., increases the paleogeographic range of reteocrinid camerates, previously documented only from Laurentia. This taxon expresses synapomorphies characterizing the Late OrdovicianReteocrinus, demonstrating the antiquity of this morphotype.

scholarly journals Biostratigraphic reconnaissance in the Lower Palaeozoic of western North Greenland

1984 ◽  
Vol 121 ◽  
pp. 19-51
Author(s):  
P.R Dawes ◽  
J.S Peel
Keyword(s):  
Fault Zone ◽  
Deep Water ◽  
Lower Cambrian ◽  
The South ◽  
The West ◽  
Middle Ordovician ◽  
Water Trough ◽  
Lower Palaeozoic ◽  
North Greenland ◽  
Land Region

Sections and fossil collections resulting from activities under Operation Grant Land 1965-66 in the Hall Land - Wulff Land region of western North Greenland are briefly discussed. Strongly tectonised Lower Cambrian to Silurian strata are present in the northern part of the area in association with the Wulff Land anticline and the Nyeboe Land fault zone. To the south, platform and deep-water trough sequences are generally little disturbed and strata range in age from Middle Ordovician to Late Silurian (Pridoli). Most stratigraphic units can be accommodated in stratigraphic schemes established in Washington Land, to the west, or Peary Land, to the east.

scholarly journals Cambrian–Silurian stratigraphy of Børglum Elv, Peary Land, eastern North Greenland

1977 ◽  
Vol 82 ◽  
pp. 1-48
Author(s):  
R.L Christie ◽  
J.S Peel
Keyword(s):  
Black Shale ◽  
Lower Cambrian ◽  
Late Ordovician ◽  
Dolomitic Limestone ◽  
Carbonate Mounds ◽  
Middle Ordovician ◽  
Clastic Rocks ◽  
Shale Formation ◽  
Lower Palaeozoic ◽  
North Greenland

A sequence of Lower Palaeozoic carbonate and clastic rocks is described from Børglum Elv, Peary Land, eastem North Greenland, and briefly compared to Lower Palaeozoic sections elsewhere in Greenland and in Spitsbergen. Lower Cambrian clastic rocks of the Buen Formation are followed by dolomite of the Lower Cambrian Brønlund Fjord Formation (125 m). Succeeding dolomite and dolomitic limestone of the Wandel Valley Formation (320 m) of Early to Middle Ordovician age are overlain by limestone of the Børglum River Formation (430 m) of Middle to Late Ordovician age. Un-narned Early Silurian dolomite and limestone formations (150 m and 320 m respectively) are followed by an un.narned Middle Silurian black shale formation (c. 100 m) and at least 800 m of a late Middle Silurian and younger un-named flysch formation. Carbonate mounds, originating in the highest beds of the un-named Silurian limestone formation, occupy stratigraphic levels through the overlying black shale formation and into the flysch formation.

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