Sphenothallus-like fossils from the Martinsburg Formation (Upper Ordovician), Tennessee, USA

2011 ◽  
Vol 85 (2) ◽  
pp. 353-359 ◽  
Author(s):  
Maya Li Wei-Haas ◽  
Bosiljka Glumac ◽  
H. Allen Curran
Keyword(s):  
Marine Invertebrate ◽  
Limited Evidence ◽  
Upper Ordovician ◽  
Shallow Marine ◽  
Storm Waves ◽  
Waves And Currents

Tubular fossils, up to 2 mm in diameter and 60 mm in length, occur rarely in the upper Martinsburg Formation (Upper Ordovician), northeastern Tennessee Appalachians, U.S.A. The fossils are unbranched, straight or slightly bent, occasionally twisted and wrinkled, and not significantly tapered. Orientation of the fossils within shallow-marine tempestites suggests that they represent remains of organisms that were broken, transported, and deposited by storm waves and currents. The fossils are morphologically similar to many of the previously identified species belonging to the genus Sphenothallus, a relatively rare tube-dwelling Paleozoic marine invertebrate. Owing to the limited evidence for distal widening of the tubes, lack of holdfasts, and carbonaceous rather than phosphatic composition, the affinity of these fossils remains uncertain, and we refer to them as Sphenothallus-like.

scholarly journals An unusual sponge – microbe – synsedimentary cement framework in a Late Ordovician reef, Southampton Island (Nunavut, Canada)

2016 ◽  
Vol 53 (8) ◽  
pp. 815-822 ◽  
Author(s):  
Ariane Castagner ◽  
André Desrochers ◽  
Denis Lavoie
Keyword(s):  
Spatial Relationship ◽  
Late Ordovician ◽  
Calcareous Algae ◽  
Upper Ordovician ◽  
Shallow Marine ◽  
Early Ordovician ◽  
Subaerial Exposure ◽  
Close Spatial Relationship ◽  
Diverse Community ◽  
Calcite Cement

A large, resistant buildup at the top of the Upper Ordovician (Hirnantian?) Red Head Rapids Formation on Southampton Island (Nunavut, Arctic Canada) is dominated by massive boundstone and cementstone facies. These massive facies have more in common with the sponge–microbial reefs that dominated worldwide in the Early Ordovician, including the following primary components: early calcified sponge material, microbial elements, and synsedimentary cement. A close spatial relationship between sponge and microbial framework elements suggests that a poorly preserved decaying sponge framework provided substrates for the attachment and development of microbes and that the microbes played essential roles as reef consolidators. Centimetre-scale colonial metazoans are present and locally intergrown with the sponge and microbial components. Other mound-dwelling invertebrates or calcareous algae are rare. Although altered now to calcite, cement fabrics suggest that aragonite was ubiquitous as seafloor precipitate. Prior to its subaerial exposure in the latest Ordovician, the Red Head Rapids Formation buildup developed on the margin of a shallow-marine evaporative epicratonic basin where a diverse community of reef-building metazoans was unable to flourish.

Occurrence and regional geological setting of Paleozoic rocks on the Grand Banks of Newfoundland

1986 ◽  
Vol 23 (4) ◽  
pp. 504-526 ◽  
Author(s):  
Lewis H. King ◽  
Gordon B. J. Fader ◽  
W. A. M. Jenkins ◽  
Edward L. King
Keyword(s):  
Oil And Gas ◽  
Black Shales ◽  
Source Rocks ◽  
Upper Ordovician ◽  
Acoustic Basement ◽  
Lower Paleozoic ◽  
Shallow Marine ◽  
Grand Banks ◽  
Younger Age ◽  
Seismic Reflection Profiles

Analyses of seismic reflection profiles supported by lithological and palynological studies of core samples from submarine outcrops indicate that the lower Paleozoic succession of the Avalon Terrane, southeast Newfoundland, is continuous offshore. The succession crops out over an area greater than 30 000 km2 and is approximately 8 km thick. The sequence is dominantly siltstone and is of Late Cambrian to ?Devonian or younger age. It is relatively unmetamorphosed, underlain by Hadrynian acoustic basement, and overlain along its eastern and southern margins by a Mesozoic–Cenozoic succession that is economically important from an oil and gas perspective.Lithofacies studies indicate that in Early Ordovician time restricted shallow-marine conditions probably prevailed over a vast area of the Avalon Terrane. Upper Ordovician and Silurian siltstones show evidence of deposition under more-dynamic and well-oxygenated conditions and probably represent a normal shallow-marine environment. Redbeds of possible Devonian or younger age are interpreted to be of continental origin. Black shales of Ordovician age are potential source rocks for the generation of hydrocarbons.

Storm-dominated shallow marine deposits: the Fernie–Kootenay (Jurassic) transition, southern Rocky Mountains

1979 ◽  
Vol 16 (9) ◽  
pp. 1673-1690 ◽  
Author(s):  
Anthony P. Hamblin ◽  
Roger G. Walker
Keyword(s):  
Rocky Mountains ◽  
Tidal Current ◽  
Density Current ◽  
Sedimentary Structure ◽  
Fair Weather ◽  
Shallow Marine ◽  
Southern Rocky Mountains ◽  
Marine Deposits ◽  
Storm Waves ◽  
Lowermost Part

The transition from the Passage Beds of the Fernie into the lowermost part of the Kootenay Formation is exposed in 11 sections in the Crowsnest Pass to Banff area. Six distinct facies can be defined. Facies A (thin bedded turbidites) and facies B (thicker bedded turbidites) both have sole marks indicating north-northwestward flow. Facies C is the most important and consists of interbedded sandstones and shales, with sole marks indicating north-northwestward flow, and "hummocky cross stratification" as the characteristic internal sedimentary structure. It is interpreted to be formed by storm waves in depths below fair-weather wave base. Facies D contains low angle intersecting sets of parallel lamination (beach) and facies E is characterized by trough cross bedding (fluvial). Facies F consists of lenticular sandstones and shales, with coals. The facies occur in the sequence listed and indicate a northward prograding beach complex. Following intense storms, water driven toward the beach surges back seaward, entraining sand and developing into a density current. If deposition from the density current takes place in depths stirred by the storm waves, hummocky cross stratification is formed. In slightly deeper, quieter water the density current deposits a classical turbidite. Thus, the eastward-prograding Kootenay "delta" of previous interpretations now appears to be a northward-prograding beach complex fed by rivers, but with sand transported alongshore by waves. There is no evidence of tidal current activity, and shallow marine deposition is dominated by storms.

scholarly journals Early complex tiering pattern: Upper Ordovician, Barrandian area, the Czech Republic

2021 ◽  
Vol 77 (1) ◽  
pp. 17-35
Author(s):  
Pavel Bokr ◽  
Radek Mikuláš ◽  
Petr Budil ◽  
Petr Kraft
Keyword(s):  
Czech Republic ◽  
Trace Fossils ◽  
Preferred Orientation ◽  
Upper Ordovician ◽  
The Czech Republic ◽  
Shallow Marine ◽  
Fine Grained ◽  
Bedding Planes ◽  
Barrandian Area

Upper Ordovician shallow marine fine-grained sandstones and siltstones exposed in the Loděnice – vinice locality yielded a distinct and well-preserved tiering pattern of trace fossils. The two uppermost tiers are composed mainly of Bifungites and Nereites. Deeper in the sediment, tiers dominated by Thalassinoides, Zoophycos and Teichichnus occur. Most of the succession is completely bioturbated; however, several storm layers enabled study of a well-preserved frozen tiering pattern. Large portions of the bedding planes (ichnologic snapshots) showed a considerable patchiness of intensive surface bioturbation and a preferred orientation of Bifungites. The identified tiering pattern is one of the earliest examples of a well-documented complex tiering of burrows documented in detail.

Homeomorphy in the Asteroidea (Echinodermata); a new Late Cretaceous genus and species from Colorado

2002 ◽  
Vol 76 (6) ◽  
pp. 1007-1013 ◽  
Author(s):  
Daniel B. Blake ◽  
Barry S. Kues
Keyword(s):  
Upper Cretaceous ◽  
New Genus ◽  
New Genus And Species ◽  
Limited Evidence ◽  
Morphological Response ◽  
Shallow Marine ◽  
Body Form ◽  
Selective Pressures ◽  
Modern Species ◽  
The Family

Codellaster keepersae new genus and species, from the Upper Cretaceous Codell Sandstone Member of the Carlile Shale of Colorado (U.S.A.), is assigned to the asteroid (Echinodermata) family Goniasteridae. Although clearly a goniasterid, the flattened body form and details of morphology of C. keepersae are remarkably similar to corresponding features of the modern astropectinid Astropecten regalis and also of the luidiid Luidia (Platasterias) latiradiata. The discovery facies of C. keepersae includes low-angle crossbeds and asymmetrical ripple marks that are suggestive of a very shallow marine environment. Both the modern species occur in shallow, turbulent settings, and homeomorphy beween ancient and modern asteroids suggests similar selective pressures and evolutionary responses. Limited evidence suggests goniasterids might have been more common in shallower waters during the Cretaceous than they are today, and absence of modern Codellaster-like goniasterids indicates that the family abandoned these habitats, although the fundamental morphological response to such settings remained viable for asteroid organization.

Cardium Formation (U. Cretaceous) at Seebe, Alberta—storm-transported sandstones and conglomerates in shallow marine depositional environments below fair-weather wave base

1981 ◽  
Vol 18 (4) ◽  
pp. 795-809 ◽  
Author(s):  
Marsha E. Wright ◽  
Roger G. Walker
Keyword(s):  
Depositional Environments ◽  
Density Currents ◽  
Fair Weather ◽  
Sand Waves ◽  
Shallow Marine ◽  
Medium Scale ◽  
Total Absence ◽  
Long Period ◽  
Storm Waves ◽  
Cardium Formation

As a result of detailed mapping at Seebe, Alberta, we have defined five coarsening-upward sequences in the Turanian Cardium Formation. The sequences begin with bioturbated mudstones and coarsen into sandstones, commonly with conglomeratic veneers on top. In sequence 2, the conglomerate is up to 20 cm thick, and has been molded into sand waves a few centimetres high and with wavelengths of about 1 m.The sandstones are dominated by hummocky cross-stratification (HCS), a broad, low-angle undulating stratification now believed to be formed below fair-weather wave base by long-period storm waves. Sandstones with HCS occur in the upper parts of sequences 1, 2, 3, and 5, suggesting that all of these sequences terminate in water deeper than fair-weather wave base (10–15 m). The trace fossil assemblage of abundant Zoophycos and long, horizontal Rhizocorallium suggests similar depths. Foraminifera in sequences 3 and 4 show a high diveristy of agglutinated species, also suggesting deposition below fair-weather wave base.In view of the physical and biological evidence for deposition in a few tens of metres of water, and the total absence of medium-scale cross-bedding, we suggest that the entire Cardium Formation at Seebe was deposited below fair-weather wave base. The sandstones were emplaced by storm-generated density currents, the same storm both generating the flow and imprinting HCS on the deposit. Finally, we suggest that the conglomerates were also moved rapidly out to sea by density currents, there being no evidence for the traditional beach or transgressive lag interpretation of these rocks.

scholarly journals Taphonomic Implications of a Crinoid from Echinoderm-Poor Lithofacies in the Upper Ordovician (Katian: Cincinnatian) of Northern Kentucky

2020 ◽  
Vol 120 (2) ◽  
pp. 14
Author(s):  
James R. Thomka ◽  
Thomas J. Malgieri ◽  
Kailyn M. Popovich-Martin ◽  
Carlton E. Brett
Keyword(s):  
Skeletal Remains ◽  
Upper Ordovician ◽  
Shallow Marine ◽  
Column Material ◽  
Attachment Structures ◽  
Lake Formation ◽  
A Minor ◽  
Paleoenvironmental Analysis ◽  
Carbonate Deposits

Crinoids (Phylum Echinodermata) represent major components of fossil assemblages in the type Cincinnatian (Upper Ordovician: Katian) of the greater Cincinnati Arch region. However, certain shallow marine lithofacies are characterized by a nonexistent to depauperate crinoid fauna, being instead dominated by trilobites, bryozoans, mollusks, and in some layers solenoporid algae? and stromatoporoids. One such setting is represented by the Grant Lake Formation, equivalent to the upper Corryville and Mount Auburn members of the McMillan Formation of Ohio, as exposed south of Flemingsburg, Fleming County, northern Kentucky. Described herein is an articulated crinoid crown (Anomalocrinus?) from this otherwise crinoid-poor interval. This occurrence may reflect either (1) a brief interval where conditions were more amenable to occupation by crinoids, possibly corresponding to a minor flooding surface, or (2) transportation of skeletal remains from nearby, deeper offshore areas that contained crinoids in greater abundance. The second interpretation seems more likely given the absence of in situ attachment structures and rarity of disarticulated column material at the study site. This study illustrates the value of echinoderm remains in paleoenvironmental analysis, the significance of crinoidal material in taphonomic interpretation of Paleozoic argillaceous carbonate deposits, and the sensitivity of crinoid fossils as indicators of allochthony or autochthony.

Forces on the Cognac Platform in Combined Storm Waves and Currents

1989 ◽  
Author(s):  
G.Z. Forristall ◽  
C.A. Gutierrez ◽  
E.G. Ward ◽  
P.W. Marshall
Keyword(s):  
Storm Waves ◽  
Waves And Currents

Lagrangian sediment motion in a crescentic nearshore bar under storm-induced waves and currents

1982 ◽  
Vol 19 (3) ◽  
pp. 424-433 ◽  
Author(s):  
Brian Greenwood ◽  
Peter B. Hale
Keyword(s):  
Steady State ◽  
Oscillatory Flow ◽  
Tracer Experiment ◽  
Recurrence Interval ◽  
Sediment Flux ◽  
Frequent Occurrence ◽  
Rip Current ◽  
Fluorescent Tracer ◽  
Storm Waves ◽  
Waves And Currents

A fluorescent tracer experiment, in conjunction with morphological and sedimentological data, demonstrates the Lagrangian sediment flux induced by storm waves and currents in a permanently submerged, outer crescentic nearshore bar system. The steady state bar form (height = 2.6 m, wavelength = 390 m) is maintained in the presence of landward sediment advection under asymmetric oscillatory flow during storm buildup and decay and seaward advection under rip-cell flows at the peak of the storm. The seaward displacement of the bar crest in the areas of the convex seaward crescent reflects transport associated with the rip current, which, though variable in its location through time, is never located over the landward projecting horns. The storm studied had a recurrence interval of approximately 1 month and reworked upwards of 16% of the bar sediments. The sediment flux indentified is therefore associated with an event of frequent occurrence and is most likely the control on both bar form and dynamics of the bar system.

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