Early Silurian carbonate platforms in the Appalachian orogenic belt: the Sayabec – La Vieille formations of the Gaspé–Matapédia basin, Quebec

1992 ◽  
Vol 29 (4) ◽  
pp. 704-719 ◽  
Author(s):  
Denis Lavoie ◽  
Pierre-André Bourque ◽  
Yvon Héroux
Keyword(s):  
Microbial Communities ◽  
Sea Level ◽  
Carbonate Platforms ◽  
Northern Margin ◽  
Lime Mud ◽  
Rugose Coral ◽  
Mud Flat ◽  
First Occurrence ◽  
Appalachian Orogen ◽  
Siliciclastic Sediments

The coeval Early Silurian (late Llandoverian to late Wenlockian) Sayabec and La Vieille formations represent the first occurrence of shallow-water platformal limestones and reefs in the Paleozoic sequence of the Gaspé Belt of the northern Appalachians. Both units display very similar fades, representing laterally well-zoned, south-dipping carbonate platforms with four parallel depositional belts. These, from nearshore to offshore, are (i) a peritidal mud flat dominated by microbial communities (laminites, stromatolites, thrombolites, oncolites); (ii) a low knob reef rim built by skeletal metazoans (corals, bryozoans, stromatoporoids), skeletal calcareous algae, and microbial communities; (iii) a well-sorted lime sand belt; and (iv) a deeper water nodular lime mud belt supporting a tabulate and rugose coral, stromatoporoid, skeletal algae, and large-shelled brachiopod biota. The two platforms developed at the margin of the Quebec Reentrant and St. Lawrence Promontory in the Gaspé Belt of the northern Appalachian Orogen. It is not clear whether they were parts of a single continuous platform stretching along the northern margin of the Gaspé Belt or two separate platforms occupying distinct tectonic blocks. The development of the Sayabec and La Vieille platforms corresponds to the peak of the first shallowing phase in the Gaspé Belt after the Taconian orogeny. The platforms, with their reefs, grew during a period of sea-level stability from the earliest to late Wenlockian. The reefs were killed by an influx of deeper water siliciclastic sediments during a late Wenlockian transgression.

Revision of Tenticospirifer Tien, 1938, and similar spiriferid brachiopod genera from the Late Devonian (Frasnian) of Eurasia, North America, and Australia

2000 ◽  
Vol 74 (3) ◽  
pp. 444-463 ◽  
Author(s):  
Xueping Ma ◽  
Jed Day
Keyword(s):  
North America ◽  
Sea Level ◽  
South China ◽  
North American ◽  
Type Species ◽  
Western Europe ◽  
Late Devonian ◽  
Carbonate Platforms ◽  
The North ◽  
New Family

The cyrtospiriferid brachiopod genus Tenticospirifer Tien, 1938, is revised based on restudy of the type species from the Frasnian (Late Devonian) of the Russian Platform. As revised the genus includes cyrtospiriferid species with pyramidal ventral valves, catacline ventral interareas, a narrow delthyrium, few sinal plications, and lack a median dorsal septum and pseudodeltidium. All species retained in the genus are of Givetian and Frasnian age. All Famennian age species described from South China and North America are rejected from the genus. It appears that Tenticospirifer evolved during the early Givetian in western Europe and remained endemic to that region during the remainder of the Givetian. Successive migrations of Tenticospirifer from eastern Laurussia to North America, then to South China and possibly Australia, coincided with middle and late Frasnian eustatic sea level rises, respectively. The North American species Spirifera cyrtinaformis Hall and Whitfield, 1872, and related species identified as Tenticospirifer by North American workers, are reassigned to Conispirifer Lyashenko, 1985. Its immigration to and widespread dispersal in carbonate platforms of western Laurussia, northern Gondwana and tropical island arcs (?) coincided with a major late Frasnian eustatic sea level rise. The new family Conispiriferidae is proposed with Conispirifer Lyashenko, 1985, selected as the type genus. The new family also includes the new genus Pyramidaspirifer with Platyrachella alta Fenton and Fenton, 1924, proposed as the type species. The affinity of the new family remains uncertain pending restudy of key genera currently included in the Superfamily Cyrtospiriferoidea. Available data from the Devonian brachiopod literature indicate that species of Pyramidaspirifer are restricted to late Frasnian deposits of central and western North America.

Correlation of calcareous nannofossil zones to the local first occurrence of Pachydiscus neubergicus (von Hauer, 1858) (Ammonoidea) in European Upper Cretaceous sections

2003 ◽  
Vol 82 (3) ◽  
pp. 283-288 ◽  
Author(s):  
M. Wagreich ◽  
T. Küchler ◽  
H. Summesberger
Keyword(s):  
Upper Cretaceous ◽  
Type Locality ◽  
Calcareous Nannofossil ◽  
Northern Spain ◽  
Northern Margin ◽  
First Occurrence ◽  
Stratotype Section ◽  
Sw France

AbstractThe first occurrence (FO) of the ammonite Pachydiscus neubergicus (von Hauer, 1858) has been correlated to calcareous nannofossil zonations in several European sections along the northern margin of the Tethyan palaeobiogeographic realm. Both the proposed stratotype section of Tercis (SW France) and complete, ammonite-bearing sections in northern Spain document the FO of P. neubergicus within standard nannofossil zone CC23a (UC16), below the LO of Broinsonia parca constricta. Other sections such as the type locality Neuberg (Austria), Nagoriani (the Ukraine) and Bjala (Bulgaria) indicate considerable diachroneity of local FOs and show P. neubergicus to range up to nannofossil zone CC25b/c (UC20; Late Maastrichtian).

scholarly journals Role of microorganisms in the production of lime mud and implications for interpretation of ancient micrite deposits

1992 ◽  
Vol 6 ◽  
pp. 248-248
Author(s):  
L.L. Robbins ◽  
K. Yates
Keyword(s):  
Calcium Carbonate ◽  
Green Algae ◽  
Close Association ◽  
Carbonate Platforms ◽  
Blue Green Algae ◽  
Marine Deposits ◽  
Lime Mud ◽  
Transmission Electron ◽  
Geologic Record

Geologists have long been plagued by the lack of evidence for the origin of ancient micrite deposits: any paleontological evidence is typically obscured or lacking altogether. The role of modern marine picoplankton gives insight into the origin of one mode of lime mud formation and may aid in the interpretation of ancient marine deposits.Whitings, patches of floating lime mud in supersaturated seawater on carbonate platforms, obtained from the Bahama Bank were analyzed utilizing biochemical techniques and Transmission Electron Microscopy. All Whitings indicated a close association between picoplankton cellular material and calcium carbonate crystals. Culture experiments indicated the presence of at least ten different picoplankton species in Whitings water. Two major genera found were the blue-green algae, Synechococcus and Synechocystis. Field and laboratory experimental data indicated that these cells and cellular organics play a major role in Whitings formation. The cells may undergo epicellular precipitation of calcium carbonate induced by photosynthesis. Environmental conditions necessary for this process have been delineated through field data and laboratory experiments.While picoplankton organics are rarely preserved over geologic time, the product of their life habit, namely lime mud, is preserved as micrite. Thick occurrences of micrite deposited in marine environments are widespread throughout the geologic record, ranging in age from Precambrian to Recent. Although rare, fossilized blue-green algae have been observed in Archean rocks and may be the only evidence that implicates these organisms in lime mud formation. The Whitings phenomenon serves as an excellent example in which a specific type of organism may be a prolific contributor to the rock record, and yet leaves no direct paleontological evidence of its involvement.

Sea-level variation and the zonation of microbialites in Hamelin Pool, Shark Bay, Western Australia

2012 ◽  
Vol 63 (11) ◽  
pp. 994 ◽  
Author(s):  
Robert V. Burne ◽  
Ken Johnson
Keyword(s):  
Microbial Communities ◽  
Sea Level ◽  
Seasonal Cycle ◽  
Microbial Mats ◽  
Level Variation ◽  
Short Term ◽  
Shark Bay ◽  
Astronomical Tide ◽  
Sea Level Variation ◽  
Modern Methods

The application of modern methods of time-series analysis to a record of sea-level variation at Flint Cliff, Hamelin Pool, between October 1983 and April 1985, shows that astronomical tides account for only one of the following five key components of the record: a seasonal oceanic cycle; a short-term irregular cycle; the complex astronomical tidal system in the Pool; isolated major events; and less marked variations probably reflecting wind stress, still able to defeat the astronomical tide in the short-term. We have compared the inundation record with precisely surveyed elevation ranges of various microbial communities. The dominance of a seasonal cycle is the fundamental determinant of variation in the duration of immersion and exposure determining the littoral zonation of microbial mats in Hamelin Pool. The astronomical tide is not the major cause of this variation. The microbial communities fall into three zones. In Zone 3, the microbialite-forming colloform mat is virtually never exposed. In Zone 2, smooth, reticulate and mamillate mats colonise the lower littoral environment. Here, many of the exposed microbialites have been stranded by the falling sea level, and are colonised by intermittently submerged microbial communities that modify the stranded lithified microbialites. Zone 1 is inundated only under exceptional circumstances and microbial communities are ephemeral.

scholarly journals Review and palaeoecological analysis of the late Tremadocian – early Floian (Early Ordovician) cephalopod fauna of the Montagne Noire, France

Fossil Record ◽  
2011 ◽  
Vol 14 (1) ◽  
pp. 5-34 ◽  
Author(s):  
B. Kröger ◽  
D. H. Evans
Keyword(s):  
New Taxa ◽  
Open Water ◽  
Carbonate Platforms ◽  
Early Ordovician ◽  
West Gondwana ◽  
Depositional Settings ◽  
Sea Bottom ◽  
Montagne Noire ◽  
East And West ◽  
Siliciclastic Sediments

The Early Ordovician successions of the southern Montagne Noire consist of a thick sequence of predominantly siliciclastic sediments of which the late Tremadocian St. Chinian Formation and the earliest Floian La Maurerie Formation contain a comparatively rich and abundant cephalopod association. The cephalopods of the St. Chinian and La Maurerie Formation are interpreted as generally authochthonous, representing a fauna which originally lived in the open water above the sediments or related to the sea bottom. The cephalopod associations of the St. Chinian and La Maurerie formations are similar to other contemporaneous assemblages known from higher palaeolatitudes and associated with deeper depositional settings. They are composed almost exclusively of longiconic orthocones, in this case predominantly of eothinoceratids and baltocerids. The occurrences of <i>Annbactrocera</i>, and <i>Bactroceras</i> in the St. Chinian Formation are at present the earliest unambiguous reports of the Orthocerida. The available data suggest an initial expansion of orthoceroid cephalopod faunas from open water habitats of high paleo-latitudes, and a subsequent expansion on the carbonate platforms during the Floian. The presence of the eothinoceratid <i>Saloceras</i> in abundance demonstrates the Gondwanan affinity of the assemblage whilst adding further support for the presence of a "<i>Saloceras realm</i>" that may have extended along the margins of East and West Gondwana at least into intermediate latitudes. The following new taxa are proposed: <i>Annbactroceras</i> n. gen., <i>Annbactroceras felinense</i> n. sp., <i>Cyclostomiceras thorali</i> n. sp., <i>Felinoceras</i> n. gen., <i>Felinoceras constrictum</i> n. sp., <i>Lobendoceras undulatum</i> n. sp., Rioceratidae n. fam., <i>Saloceras murvielense</i> n. sp., <i>Thoraloceras</i> n. gen., <i>Thoraloceras bactroceroides</i> n. sp. <br><br> doi:<a href="http://dx.doi.org/10.1002/mmng.201000013" target="_blank">10.1002/mmng.201000013</a>

Late Cretaceous stratigraphy in the Mudurnu–Göynük Basin (Turkey) and inferences on sea-level change in the Late Campanian to Early Maastrichtian

2019 ◽  
Vol 498 (1) ◽  
pp. 129-146 ◽  
Author(s):  
Erik Wolfgring ◽  
Michael Wagreich ◽  
Ismail O. Yilmaz ◽  
Liu Shasha ◽  
Katharina Boehm
Keyword(s):  
Sea Level ◽  
Upper Cretaceous ◽  
Planktonic Foraminifera ◽  
Sea Level Change ◽  
Sedimentation Rates ◽  
Calcareous Nannofossil ◽  
Level Change ◽  
Composite Section ◽  
First Occurrence ◽  
Regional Sea Level

AbstractUpper Cretaceous strata at Göynük, northwestern Anatolia, Turkey, provide a geological record of the Campanian–Maastrichtian from the Sakarya Terrane along the active Neotethys margin. Shales and shaly marls with siliciclastic and volcaniclastic intercalations indicate a pelagic palaeoenvironment rich in planktonic and benthonic foraminifera and calcareous nannofossil assemblages. A composite record from the Campanian to the Maastrichtian records nannofossil standard zones UC15c (CC21) to UC20a (CC26) as well as the Globotrunanella havanensis planktonic foraminifera Zone to the Racemiguembelina fructicosa planktonic foraminifera Zone. The complete ‘mid’-Campanian to early Maastrichtian composite section can be correlated to other western Tethyan sections. The Campanian–Maastrichtian boundary is positioned between the first occurrence of the planktonic foraminifera Gansserina gansseri and the last occurrence of the nannofossil Uniplanarius trifidus. Clastic input and higher sedimentation rates constrain regional sea-level lowstands around the late Campanian calcarata Zone and the Campanian–Maastrichtian boundary, corresponding to the Campanian–Maastrichtian boundary event.

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