Resedimented volcaniclastics in the Carmanville area, northeastern Newfoundland—depositional remnants of Early Palaeozoic oceanic islands

1981 ◽  
Vol 18 (1) ◽  
pp. 55-70
Author(s):  
R. K. Pickerill ◽  
G. E. Pajari Jr. ◽  
K. L. Currie
Keyword(s):  
Depositional Environment ◽  
Water Environment ◽  
Oceanic Islands ◽  
Volcanic Material ◽  
Ophiolitic Mélange ◽  
Tectonic Transport ◽  
Submarine Slides ◽  
Volcaniclastic Rocks ◽  
Volcanic Islands ◽  
Early Palaeozoic

The olistostromal Carmanville ophiolitic mélange of northeastern Newfoundland contains two extensive mafic volcanic and volcaniclastic rafts (4 km × 1 km, 11 km × 7 km), which were previously interpreted as an assemblage of lavas and pyroclastics. These rafts are ? Upper Cambrian – Arenigian in age and, prior to tectonic transport and subsequent resedimentation and incorporation into the submarine slides (olistostromes) of the Carmanville ophiolitic mélange, were originally deposited on the slopes of a volcanic edifice (volcanic islands). The primary sedimentation history and depositional environment of the volcanic and volcaniclastic rocks are examined in detail. Four volcaniclastic facies are now recognized (facies 1–4), each differentiated on the basis of megascopic descriptive and genetic criteria. The essential characteristics of each facies are described in detail. These facies essentially represent shallow-water mafic volcanic material resedimented into a deeper water submarine slope or fan valley system by mass-emplacement depositional mechanisms, which included debris, turbidity, and possibly fluidized sediment flows. Normal contour-following bottom currents could possibly have been responsible for depositing or at least reworking some of the volcaniclastic siltstones of facies 3. Facies 1–4 were introduced into a deeper water environment itself characterized by the formation of massive and pillowed lavas and their hyaloclastic equivalents (facies 5) envisaged as the end product of deposition from submarine seamounts and guyots.

scholarly journals "Mineralogical & Petrographic Microfacies Study of the Zahraa formation (Pliocene– Pleistocene) in Sawa Lake Surrounding area- IRAQ "

2017 ◽  
Vol 4 (1) ◽  
pp. 11-20
Author(s):  
Saleh A. Lazam
Keyword(s):  
Organic Matter ◽  
Fresh Water ◽  
Depositional Environment ◽  
Water Environment ◽  
Lake Area ◽  
Surrounding Area ◽  
Thin Sections ◽  
Project Area ◽  
Mineralogical Study ◽  
Fresh Water Environment

"Mineralogical, Petorographic Microfacies study has been done on (16) samples of Zahraa formation (Pliocene – Pleistocene) of outcrop in Surrounded Sawa Lake area. The mineralogical study showed that Calcite is the main mineral within the rock formation, whereas the upper rocks of Zahraa Formation consist silty or sandy claystone is dominant in the middle and the upper portion, in addition to quartz, clay minerals, iron oxide and organic matter as insoluble residues. From thin sections study, Three main microfacies have been identified which are: Charophyte shelly bioclastic wackestone, Charophyte shelly bioclastic dolowackestone and Algal wackestone. Based on microfacies study and its fossils content, it has been possible to determine the depositional environment of Zahraa Formation which deposits in the area of the presence of Charaphytes, indicates fresh water environment. From the depositioal situation and the large extension in the project area, the type of fresh water environment is ephemeral freshen water lakes."

scholarly journals Petrogenesis and depositional environment of paleozoic Sedili and Pengerang Volcaniclastics in East Johor Basin, Peninsular Malaysia

2019 ◽  
Vol 76 ◽  
pp. 04009
Author(s):  
Sugeng Sapto Surjono ◽  
Mohd. Shafeea Leman ◽  
Che Aziz Ali ◽  
Kamal Roslan Mohamed ◽  
Fathan Hanifi Mada M
Keyword(s):  
Depositional Environment ◽  
Active Continental Margin ◽  
Volcanic Rocks ◽  
Peninsular Malaysia ◽  
Calc Alkaline ◽  
Great Abundance ◽  
Volcaniclastic Rocks ◽  
Geochemical Analyses ◽  
Depositional Setting ◽  
Magma Series

Volcaniclastic rocks in East Johor Basin are found in a relatively great abundance comprising Sedili and Pengerang Formations excluding the metamorphics, siliciclastics, and granites. Since the volcaniclastic rocks are found in a different formation, this study aims to find out the characteristics of each rock. Geology, petrography, and geochemical analyses were elaborated to reveal the petrogenesis and depositional environment in the studied area on the basis of fieldwork data and 24 samples collected from outcrops. The Sedili and Pengerang Formations are dominated by acidic rocks of rhyolite, rhyodacite, ignimbrite, and lava classifiied into calc-alkaline magma series which indicates a subduction-related product. Moreover, those acidic rocks are grouped into active continental margin. Eventhough volcanic rocks in Sedili and Pengerang Formations exhibit similar characteristics, they are different in several major contents. Therefore, it is inferred that both Sedili and Pengerang Formations were deposited in different phase. Coincidentally, depositional environment of both formations is also distinct. Sedili Formation were deposited in the subaerial to shallow marine, meanwhile, Pengerang Formation is interpreted to be deposited in deeper depositional setting.

Charles Darwin in the Cape Verde and Galápagos archipelagos: The role of serendipity in development of theories on the ups and downs of oceanic islands

2015 ◽  
Vol 34 (2) ◽  
pp. 220-242 ◽  
Author(s):  
Markes E. Johnson ◽  
B. Gudveig Baarli
Keyword(s):  
Charles Darwin ◽  
Galapagos Islands ◽  
Oceanic Islands ◽  
Cape Verde ◽  
Galápagos Islands ◽  
Cape Verde Islands ◽  
Upward Growth ◽  
Volcanic Islands ◽  
The Look ◽  
St Helena

The 1831–1836 voyage of H.M.S. Beagle under Captain Robert FitzRoy launched Charles Darwin's entry into the world of geology with two pioneering publications on oceanic islands to his credit. Best known is Darwin's 1842 contribution on the theory of atoll development from the subsidence of volcanic islands and coeval upward growth of coral reefs. This work can be linked, in part, to the ten days during which the Beagle visited the Keeling (Cocos) Islands. The subsequent and lesser known of Darwin's parallel contributions is his 1844 summary on all the volcanic islands visited during the expedition, including Santiago (Cape Verde Islands), Terceira (Azores), St. Paul's Rocks, Fernando Noronha, Ascension, St. Helena, the Galápagos Islands, Tahiti, and Mauritius. Ostensibly, the centerpiece of the 1844 volume is Darwin's extensive coverage of Ascension based on the five days spent there in 1836. However, Darwin had many more days at his disposal in the Galápagos and ‘St. Jago’ (Santiago), where the Beagle stopped in the Cape Verde Islands at the outset and again near the end of the voyage. The volcanic islands where Darwin spent the most time were in the Galápagos (thirty-five days) and the Cape Verdes (twenty-nine days). In particular, those island groups make an interesting comparison with respect to the development of Darwin's ideas on tectonic uplift based on basalt flows with inter-bedded limestone formations. Chance played a huge role in what Darwin saw and did not see during his island travels. The initial visit to the Cape Verde islands was instrumental in shaping Darwin's earliest vision of a book on volcanic islands, but his time there was entirely fortuitous due to a forced change in FitzRoy's plan for a stay in the Canary Islands. Although Darwin was on the look out for limestone formations in the Galápagos islands comparable to those on Santiago in the Cape Verdes, he missed finding them due only to the vagaries of FitzRoy's charting schedule in the Galápagos. This overview looks at limestone distribution in the Cape Verde and Galápagos archipelagos as now understood and speculates on how a wider knowledge of both regions may have influenced Darwin's thinking on global patterns of island uplift and subsidence.

The metamorphic history of the concealed Caledonides of eastern England and their foreland

1993 ◽  
Vol 130 (5) ◽  
pp. 613-620 ◽  
Author(s):  
R. J. Merriman ◽  
T. C. Pharaoh ◽  
N. H. Woodcock ◽  
P. Daly
Keyword(s):  
Lower Devonian ◽  
Regional Metamorphism ◽  
White Mica ◽  
Fold Belt ◽  
Illite Crystallinity ◽  
Metamorphic History ◽  
Diagenetic Alteration ◽  
History Of ◽  
Volcaniclastic Rocks ◽  
Early Palaeozoic

AbstractWhite mica (illite) crystallinity data, derived mostly from borehole samples, have been used to generate a contoured metamorphic map of the concealed Caledonide fold belt of eastern England and the foreland formed by the Midlands Microcraton. The northern subcrop of the fold belt is characterized by epizonal phyllites and quartzites of possible Cambrian age, whereas anchizonal grades characterize Silurian to Lower Devonian strata of the Anglian Basin in the southern subcrop of the fold belt. Regional metamorphism in the Anglian Basin resulted from deep burial and Acadian deformation beneath a possible overburden of 7 km, assuming a metamorphic field gradient of 36 °C km-1. Late Proterozoic volcaniclastic rocks forming the basement of the microcraton show anchizonal to epizonal grades that probably developed during late Avalonian metamorphism. Cambrian to Tremadoc strata, showing late diagenetic alteration, rest on the basement with varying degrees of metamorphic discordance. During early Palaeozoic times, much of the microcraton was a region of slow subsidence with overburden thicknesses of 3.3–5.5 km. However, concealed Tremadoc strata in the northeast of the microcraton reach anchizonal grades and may have been buried to depths of 7 km beneath an overburden of uncertain age.

A revised correlation of Silurian rocks in the Girvan district, SW Scotland

2002 ◽  
Vol 93 (4) ◽  
pp. 383-392 ◽  
Author(s):  
James D. Floyd ◽  
Mark Williams
Keyword(s):  
Depositional Environment ◽  
Late Ordovician ◽  
Important Research ◽  
British Geological Survey ◽  
Marine Fauna ◽  
Comprehensive Review ◽  
Iapetus Ocean ◽  
Northern Side ◽  
Lower Palaeozoic ◽  
Early Palaeozoic

ABSTRACTIn late Ordovician and early Silurian times, the Girvan district lay in a shelf marinesetting on the margin of Laurentia, on the northern side of the Iapetus Ocean. The Lower Palaeozoic rocks of the Girvan district, and their shelly and graptolitic fossil fauna, were systematically described by Lapworth in 1882 and have formed an important research resource ever since. They provide valuable evidence for the depositional environment and geological setting of Girvan during the early Palaeozoic, in both regional and wider contexts, and demonstrate the long-recognised close affinity with contemporaneous Laurentian faunas. However, by late Ordovician and into Silurian times, the earlier Iapetus oceanic barrier to faunal migration had largely gone and there is good correlation between contemporaneous marine fauna throughout the British Isles and Scandinavia. Despite much recent research in the area, including resurvey work by the British Geological Survey, no comprehensive review of Silurian lithostratigraphy at Girvan has been published since the revision by Cocks and Toghill in 1973. The present review of the Silurian rocks addresses this need and complements the recently published (Fortey et al. 2000) revision of the underlying Ordovician rocks, thus bringing the entire Girvan Lower Palaeozoic succession up to modern standards of nomenclature.

Evidence from ocean islands suggesting movement in the Earth

1965 ◽  
Vol 258 (1088) ◽  
pp. 145-167 ◽  
Keyword(s):  
Upper Jurassic ◽  
Oceanic Islands ◽  
Chemical Characteristics ◽  
Ocean Ridges ◽  
East Pacific ◽  
The Earth ◽  
The Pacific ◽  
Mid Ocean Ridge ◽  
Volcanic Islands ◽  
Ocean Ridge

Oceanic islands increase in age from the mid-ocean ridges towards continents and the andesite line reaching a maximum known age of Upper Jurassic. The Seychelles appear to be a continental fragment. Several pairs of lateral aseismic ridges extend from islands on the mid-ocean ridge to adjacent continents. Their continental junctions mark points on opposite coasts which would also fit if the continents were reassembled according to the criteria used by Wegener. As Holmes has shown each pair of ridges tends to have distinctive chemical characteristics. One possible explanation is that convection currents in the mantle rising along the mid-ocean ridges and sinking beneath trenches have carried the crust apart across the Atlantic, India and East Pacific Oceans. The lateral ridges may be approximately streamlines. Although Darwin showed that most volcanic islands sink, a few have been uplifted. Most of these lie a few hundred kilometres in front of deep trenches, suggesting that they may be on the crest of a standing wave in front of the trenches and that the crust is rigid. Of eleven straight chains of young islands in the Pacific ten get older away from the East Pacific Ridge. They could also be streamlines, fed by lava rising from deep within convection cells with stagnant cores. The regularity of ridges suggests non-turbulent flow.

Evaluation of geological age and environmental factors in changing aspects of the terrestrial vertebrate fauna during the Carboniferous

1993 ◽  
Vol 84 (3-4) ◽  
pp. 427-431 ◽  
Author(s):  
Robert L. Carroll
Keyword(s):  
Nova Scotia ◽  
Environmental Factors ◽  
Shallow Water ◽  
Geographical Distribution ◽  
Deep Water ◽  
Depositional Environment ◽  
Water Environment ◽  
Terrestrial Vertebrate ◽  
Geological Age ◽  
Shallow Water Environment

ABSTRACTOf all the localities that have yielded a diversity of Carboniferous tetrapods, the fossil assemblage at East Kirkton most closely resembles that of the Joggins locality in Nova Scotia. Both assemblages are dominated by dendrerpetontid temnospondyls and a smaller number of small anthracosaurs, which are thought to have been primarily terrestrial in habits. Both localities lack adelogyrinids and lysorophids, and such presumably deep water genera as Crassigyrinusand large embolomeres. The East Kirkton Limestone differs in the presence of aïstopods and a possible nectridean, which are associated with a shallow-water environment in other localities. The absence of amniotes and microsaurs may be explained by the later evolution of these groups, their limited geographical distribution, or the lack of any aspects of the depositional environment that would preferentially select primarily terrestrial animals.

scholarly journals Upper cretaceous magmatic suites of the Timok magmatic complex

2010 ◽  
pp. 13-22 ◽  
Author(s):  
Miodrag Banjesevic
Keyword(s):  
Depositional Environment ◽  
Upper Cretaceous ◽  
Volcanic Front ◽  
Magmatic Complex ◽  
Volcanic Material ◽  
Volcanic Processes ◽  
Different Types ◽  
Volcanic Facies ◽  
Volcanic Cycle ◽  
Upper Campanian

The Upper Cretaceous Timok Magmatic Complex (TMC) developed on a continental crust composed of different types of Proterozoic to Lower Cretaceous rocks. The TMC consists of the magmatic suites: Timok andesite (AT) - Turonian-Santonian, Metovnica epiclastite (EM) - Coniacian-Campanian, Osnic basaltic andesite (AO) and Jezevica andesite (AJ) - Santonian-Campanian, Valja Strz plutonite (PVS) - Campanian and Boljevac latite (LB). The sedimentary processes and volcanic activity of the TMC lasted nearly continuously throughout nearly the whole Late Cretaceous. The sedimentation lasted from the Albian to the Maastrichtian and the magmatism lasted for 10 million years, from the Upper Turonian to the Upper Campanian. The volcanic front migrated from East to West. The volcanic processes were characterized by the domination of extrusive volcanic facies, a great amount of volcanic material, a change in the depositional environment during the volcanic cycle, sharp facial transitions and a huge deposition of syn- and post-eruptive resedimented volcaniclastics.

scholarly journals Chert blocks in the ophiolitic mélange of Zlatibor Mt. (SW Serbia): Age and geodynamic implications

2016 ◽  
pp. 13-21 ◽  
Author(s):  
Natasa Gerzina ◽  
Nevenka Djeric
Keyword(s):  
Continental Margin ◽  
Depositional Environment ◽  
The West ◽  
Ophiolitic Mélange ◽  
Oceanic Sediments ◽  
Younger Age ◽  
Tectonic Window ◽  
Internal Dinarides

Cherts are quite frequently occurring rocks in the Internal Dinarides, an extremely complex area composed of several tectonostratigraphic units in which oceanic sediments, ophiolites and partly metamorphosed parts of the distal continental margin of Adria are preserved. Therefore, these cherts differ in age and the original depositional environment in which they were formed. Results of investigations carried out in the chert blocks found in the melange in the vicinity of Jasenovo village on SE slopes of Zlatibor Mt. are presented here. Radiolarian cherts from the studied localities represent blocks in melange of the East-Bosnian-Durmitor Unit, exposed in a large tectonic window below the Triassic carbonates of Drina-Ivanjica Unit. Biostratigraphic data revealed Callovian-early Kimmeridgian ages of the studied chert blocks, thus implying a Kimmeridgian or younger age of obduction of the West Vardar ophiolites.

scholarly journals Vendian stratigraphy and sedimentology of the East Greenland Caledonides

1985 ◽  
Vol 125 ◽  
pp. 88-94
Author(s):  
M.J Hambrey ◽  
A.C.M Moncrieff
Keyword(s):  
North Atlantic ◽  
Depositional Environment ◽  
Arctic Region ◽  
Harvard University ◽  
University Of Iowa ◽  
East Greenland ◽  
The North ◽  
Iapetus Ocean ◽  
Field Season ◽  
Early Palaeozoic

The present two-year programme 1984-1985 on the Vendian Tillite Group in central East Greenland follows comprehensive investigations on similar sequences in eastern Svalbard. The project aims to establish through Vendian time the disposition of land masses and oceans in relation to the East Greenland depositional environment, and to erect detailed stratigraphic correlations with other parts of the North Atlantic - Arctic region. This is important for understanding the tectonic evolution of the region prior to the opening of the Iapetus Ocean. The work is a collaborative venture involving N. Abrahamsen (University of Aarhus, palaeomagnetism), G. Bylund (University of Lund, palaeomagnetism), A. H. Knoll (Harvard University, biostratigraphy), A. M. Spencer (Statoil, sedimentology), K. Swett (University of Iowa, sedimentology of bounding rock units) and G. Vidal (University of Lund, biostratigraphy). The authors were accompanied in the 1984 field season by Bylund and Vidal who undertook extensive sampling of the Late Proterozoic to Early Palaeozoic sequence.

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