A study of the ostracode fauna from the Silurian of Norway has been undertaken. All of the taxa recoverd and described are from the Llandovery and Wenlock Series; one species from the topmost part of the Ordovician of the Oslo region is also figured. Research has concentrated particularly upon the Palaeocopa Henningsmoen, 1954, but also includes the Leperditicopida Scott, 1961. The 'non-palaeocopes', because of particular problems related to preservation and taxonomy, are not treated as extensively. Primary revision has been made wherever possible. Such work has been augmented by studies of extensive new collections made from throughout the Oslo region, particularly from the Ringerike, Oslo-Asker and Holmestrand districts. This study has concentrated firstly on the taxonomy of the fauna. There are chapters on the Leperditicopa, Palaeocopa and 'non-palaeocopes'. Other chapters deal with the palaeoecology, biostratigraphy and correlation and affinities of the fauna. A full faunal and associated locality list, together with information on regional stratigraphy, is also presented. The fauna is 26 genera (2 new), 43 named species (14 new) and 15 other forms are described under open nomenclature. The Silurian ostracode fauna of Norway is mostly endemic (at specific level) but does have affinities with Gotland, Siberia and Britain. Ostracode potential for correlation between various districts of the Oslo region is best realised in the Steinsfjorden Formation. Standard micropalaeontological techniques have been used throughout, with most material being prepared by 'Vibrotool', and photographed on the Scanning Electron Microscope.

No description available.

This study establishes the stratigraphic framework and conodont biostratigraphy of Lower Paleozoic strata of the Northern Canadian Cordilleran Miogeocline, which document a non-passive tectonic evolution of the rifted margin of Laurentia. Only a few reconnaissance stratigraphic studies have been conducted previously in the study area. Nine key sections span an east-west transect from the Macdonald Platform to the Kechika Trough (platform-miogeocline-basin) and 3 key sections comprise a transect across the parautochthonous Cassiar Terrane. Over 12 000 m of strata from the Kechika and Skoki formations and Road River Group in northeastern British Columbia were measured and described, from which a total of 405 conodont samples (4-5 kg each) were taken. A total of 39 526 conodonts have been used to refine the Upper Cambrian to Lower Silurian conodont biostratigraphy across the transect. The stratigraphy is revised to divide the Kechika Formation (late Cambrian to early Arenig in age) into 5 formal members: Lloyd George, Quentin, Grey Peak. Haworth and Mount Sheffield members. The Skoki Formation (early to late Arenig in age) comprises 3 new formal members defined as: Sikanni Chief. Keily and Redfern members. The Road River Group is divided into 3 new formations: Ospika (early Arenig to Llanvim in age), Pesika (Lower Silurian in age) and Kwadacha (formerly the Silurian Siltstone). The Ospika Formation is further subdivided into 5 formal members: Cloudmaker, Finlay Limestone, Chesterfield, Finbow Shale and Ware. Conodonts of Late Cambrian to Early Silurian age are described taxonomically from the Kechika, Skoki, Ospika and Pesika formations across the transect. A total of 39 526 identifiable conodonts recovered from 142 productive samples indicate high species diversity and abundance in shallow water facies and less diversity and abundance with in deeper water facies. Elements are moderately to well preserved, typically with a colour alteration index (CAl) of 3-5. A total of 197 species, representing 73 genera are identified and illustrated among which 6 new genera and 39 new species are described. Fifteen of the 39 new species had too little material and were described in open nomenclature. The new genera are Graciloconus, Kallidontus, Planusodus and 3 new genera (A, B, C) treated in open nomenclature. The new species are Acodus kechikaensis n. sp., A. quentinensis n. sp., A. warenesis n. sp., Cordylodus delicatus n. sp., Colaptoconus greypeakensis n. sp., ?Diaphorodus n. sp., Drepanoistodus minutus n. sp., Graciloconus concinnus n. gen. n. sp., Kallidontus serratus n. gen. n. sp., K. nodosus n. gen. n. sp., K. princeps n. gen. n. sp., Laurentoscandodus sinuosus n. sp., Macerodus cristatus n. sp., M lunatus n. sp., Microzarkodina n. sp., Oepikodus n. sp., Oistodus n. sp., Paroistodus n. sp., Planusodus gradus n. gen. n. sp., ?Prioniodus n. sp., Protoprioniodus n. sp., Rossodus kwadachaensis n. sp., R. muskwaensis n. sp., R. sheffieldensis n. sp.. R. subtilis n. sp., Scolopodus amplus n. sp., Striatodontus strigatus n. sp., Triangulodus akiensis n. sp., Tricostatus infundibulum n. sp., T. terilinguis n. sp., 3 unnamed new genera and 3 new species and 5 new species of Drepanoistodus (A, B. C, D, E). The conodont zonation for Upper Cambrian to Lower Silurian strata is refined, using Sections 4, 5, 13 and Grey Peak as reference sections. It allows close dating of stratigraphic boundaries. The oldest zones in the Kechika are cosmopolitan and include the Eoconodontus Zone (upper Cambrian), Cordylodus proavus and Cordylodus lindstromi zones (uppermost Cambrian) and lapetognathus Zone (base of Tremadoc). Ten higher zones are recognized and redefined for shallow water platform facies containing faunas of the Midcontinent Realm. Four of these are new (Polycostatus falsioneotensis, Rossodus tenuis, Scolopodus subrex and Acodus emanualensis zones) and 10 new subzones are established. Those for the Kechika Formation include, in ascending order, the Polycostatus falsioneotensis Zone (lower Tremadoc). Rossodus tenuis Zone (lower Tremadoc); Rossodus manitouensis Zone with R. muskwaenesis and R. sheffieldensis subzones (middle Tremadoc), Low diversity interval (upper Tremadoc), Scolopodus subrex Zone with Graciloconus concinnus and Colaptoconus bolites subzones (lower Arenig) and Acodus kechikaensis Zone with Kallidontus serratus. Diaphorodus russoi and Kallidontus nodosus subzones (lower Arenig). Those for the Skoki Formation include the Oepikodus communis Zone with Tropodus sweeti, Bergstroemognathus extensus and Juanognathus variabilis subzones (middle Arenig). The O. communis Zone spans the Kechika-Skoki boundary and the uppermost Kechika lies within the lowermost part of the O. communis zone underlying the T. sweeti Subzone. The Skoki Formation also contains the Jumudontus gananda Zone (middle Arenig) and Tripodus laevis Zone (upper Arenig). The Phragmodus undatus Zone (Upper Ordovician) lies within the Road River Group in the Cassiar Terrane. Thirteen deep water zones are recognized for basinal facies containing faunas of predominantly the North Atlantic Realm. Five new zones are established (Drepanoistodus nowlani, Acodus deltatus, Paracordylodus gracilis, Paroistodus horridus and Dzikodus tableheadensis zones) and one new subzone within the P. gracilis Zone is proposed. Those within the Kechika Formation include Cordylodus angulatus Zone (lower Tremadoc), Paltodus deltifer Zone (middle Tremadoc), Drepanoistodus nowlani Zone (middle Tremadoc), Acodus deltatus Zone, (middle Tremadoc), Paroistodus proteus Zone (upper Tremadoc), Paracordylodus gracilis Zone with Oelandodus elongatus Subzone (upper Tremadoc) and Prioniodus elegans Zone (base of Arenig). Those within the Skoki and Ospika formations include Oepikodus evae Zone (Skoki Formation, middle Arenig), Paroistodus originalis Zone (Skoki and Ospika formations, upper Arenig), Paroistodus horridus and Dzikodus tableheadensis zones (both within the Ospika Formation, lower Llanvim). The Amorphognathus tvaerensis Zone lies within the Road River of the Cassiar Terrane (Upper Ordovician). The Distomodus staurognathoides Zone lies within the Pesika Formation (middle Llandovery). The conodont faunas therefore provide detailed temporal constraints for the stratigraphic framework. Some evolutionary remarks are made for selected species involved in radiations, especially in the Tremadoc and Arenig, that are useful in further refining the standard Midcontinent Realm zonation. The Midcontinent Realm conodont faunas are used for regional correlations within North America and those of the Atlantic Realm provide calibration on an interregional scale, for example, with Baltica. / Graduate

The Silurian rocks in Delaware County, Indiana, include, in ascending order, the Salamonie Dolomite, Limberlost Dolomite, Waldron Formation, and Louisville Limestone, and Mississinewa Shale Member of the Wabash Formation, all of the Niagaran Series (middle Silurian).The oldest exposed Silurian rocks are the Salamonie and the overlying Limberlost Formation (lower Niagaran) are exposed in Irving and Eaton quarries. The Salamonie is 25 feet of apparently reefflank rocks within the Salamonie, with primary dips to 20 degrees, are exposed in Eaton Quarry. The Limberlost, averages six feet and is generally brown, vuggy, dolostone.The Waldron and Louisville formations (middle Niagaran), are exposed in Hoyt, Irving, and Eaton quarries. The Waldron averages six feet and is interbedded grey shale and argillaceous dolostone, and is fossiliferous. It is conformably overlain by about 60 feet of Louisville Formation, predominately argillaceous dolostone with nodular chert and fossils.At Buchanan Quarry, 10 feet of grey dolomitic siltstone and shale of the Mississinewa Member, Wabash Formation, comprise the youngest Silurian strata exposed.Correlation of distinct units within the Louisville between Hoyt, Irving, and Eaton quarries shows considerable lateral continuity and general thinning toward the north.

The storm-dominated paleotropical carbonate succession exposed on Anticosti Island in Eastern Canada represents one of the most complete, thickest, and well-preserved successions in the world spanning the O/S Boundary. This study develops a new high resolution integrated lithostratigraphic, cyclostratigraphic, and chemostratigraphic framework for the upper Hirnantian to lower Telychian (Upper Ordovician to lower Silurian) succession on Anticosti, by examining ~450 m of strata from a recent stratigraphic drill core (Martin La Mer), supplemented by ~120 m of outcrop, all from the south-central part of the island. Four facies assemblages and three time-specific facies were identified in this succession and can be organized into three orders of superimposed transgressive-regressive cycles. New high resolution isotopic curves were produced by sampling well-preserved bulk micrite at a resolution of 0.5-1.0 m per sample; in total 443 samples were taken from core and 168 from outcrop, corresponding to the Ellis Bay, Becscie, Merrimack, Gun River, Menier, Jupiter and Chicotte formations. Four distinct positive carbon isotope excursions are recognized in the study interval; the upper Hirnantian (+5‰), Lower Aeronian (+2‰), Upper Aeronian (+6‰), and Valgu (+3.5‰) excursions. These δ13C excursions accompany lithology, and sea level changes and are likely driven by transitions between humid and arid climate states coupled with ocean changes. Multi-ordered δ18O trends are recognized to occur in association with δ13C trends; long-term and intermediate scale δ18O fluctuations are likely controlled by glacio-eustasy and Silurian climate fluctuations, while high-frequency fluctuations may record an astronomical forcing signal.

Anticosti Island, located in Eastern Canada, displays one of the most complete, best exposed, and most fossiliferous carbonate successions spanning the Ordovician-Silurian (O/S) Boundary in the World. This study develops a new high-resolution framework for the post End-Ordovician extinction strata (~ 260 m thick) exposed in coastal outcrops and recovered from a continuous drill core (La Loutre #1), both located in the western part of the island. In total, eight facies, all associated with a storm-dominated carbonate system, were recognized and organized into a multi-order depositional cycles. A new high resolution isotopic curve with more than 300 data points from well-preserved bulk micrite samples covers the late Hirnantian to Early Aeronian time interval and corresponds to the upper Ellis Bay, Becscie, Merrimack and lower Gun River formations. Two distinct positive carbon isotope excursions are present in the late Hirnantian part of the Ellis Bay Formation (+5‰) and in the lower Aeronian part of the Gun River Formation (+2‰). These positive isotopic carbon excursions provide a distinctive chemostratigraphic signature for regional and global correlations with other O/S sections. Like the Quaternary δ18O marine signal, our δ18O record is largely coupled with multi-order cyclic facies changes. This study demonstrates the importance of glacio-eustasy following the End-Ordovician glacial maxima as one of the primary factors controlling the stratigraphic architecture of paleotropical neritic carbonates during the Early Silurian.

A study of 12 cores and 2 wells with cuttings through the Silurian (444 to 416 m..y.) succession of the Wabash Platform, Indiana was done to establish the high resolution sequence stratigraphy of a sediment-starved low-latitude epeiric sea platform during the transition from Ordovician icehouse to Devonian greenhouse. The Wabash Platform (approximately 200,000 square km area) is bounded to the north by the Michigan Basin, to the east by the Appalachian Basin, and passed to the southwest into the Vincennes Basin, which was open to the ocean. Facies developed include: crinoidal grainstone-packstone sheets (updip shoals), buildup facies (stromatactis wackestone - lime mudstone, below storm wave-base settings; stromatoporoid skeletal wackestone - floatstone, storm wave-base to fair-weather wave-base; and crinoidal rudstone to packstone; flank facies); non-cherty, skeletal packstone, wackestone, mudstone (sub-fair-weather- to storm wave-base); and cherty, skeletal wackestone - mudstone and variably argillaceous carbonate mudstone (below storm wave-base). Eight thin sequences (1.3 to 4 m.y. duration) occur and range from 2 m to 10 m, with the upper two sequences up to 20 m downdip; most of the sequences can be correlated to global cycles. Except for the lower three disconformity-bounded sequences, most sequences are relatively conformable and lack well defined sequence boundaries or subaerial exposure surfaces. The most easily mapped surfaces are the transgressive surfaces, given that the correlative conformities are cryptic. Lowstand system tracts probably include downdip grainy facies and the deep ramp seaward of updip late highstand deposits. Transgressive systems tracts are upward deepening, upward fining carbonate units, some of which become more argillaceous and silty upward. This contrasts with the usual association of clastic-prone units with lowstand to early transgressive systems tracts. Highstand systems tracts are subtly upward coarsening from carbonate mudstone to skeletal wackestone/packstone and rarely skeletal grainstone. During deposition of the uppermost two sequences, mudmound barrier banks grew upward into shallow water buildups to form a discontinuous raised rim (40 m relief) to the ramp. Even though subsidence rates were very low (<1 cm/k.y.), the low sedimentation rates (0.3 cm/k.y. to 0.8 cm/k.y.) generally prevented the seafloor from building to sea level except for the basal three sequences in which Early Silurian third order glacio-eustacy generated disconformable boundaries. Thus the ramp remained subtidal through most of the relatively ice-free greenhouse later Silurian except over the buildups which locally shallowed to sea level. Parasequence development in high accommodation settings elsewhere in North America are compatible with the transition from moderate ice-sheets to an ice free world. However, this is poorly expressed on the Wabash Platform due to the dominantly deeper subtidal setting. The Silurian provides a window into climate change from a global cool period to global hothouse, which may have implications for understanding future climate change. / Master of Science

No description available.

<p> Field observation at seven outcrops and subsequent polished section studies reveal that lead and zinc mineralization in the Hamilton vicinity occurred after the lithification of the host carbonates. The availability of open structures and the presence of potential reducing agents are the main controlling factors of sulphide deposition, The absence of an igneous source demands an origin of the metals from the sedimentary country rocks. Analysis of 14 shales and 12 dolomites by atomic absorption for Cu, Pb, and Zn indicates that the argillaceous rocks are potential source of the heavy metals. Furthermore, a simple leaching experiment has demonstrated that concentrated brine (sodium chloride solution) can preferentially leach lead and zinc from the shales. A mode of origin involving preferential.leaching can then adequately explain the scarcity of copper minerals in the Mississippi Valley-Type ore, It is suggested that better controlled leaching experiments at various temperatures should be done in conjunction with more extensive field work to check the plausibility of such a theory. </p> / Thesis / Bachelor of Science (BSc)

No description available.