PALAEOZOIC FLOOD BASALTS IN NORTHERN NEWFOUNDLAND AND LABRADOR

1965 ◽  
Vol 2 (3) ◽  
pp. 183-187 ◽  
Author(s):  
Paul M. Clifford
Keyword(s):  
Newfoundland And Labrador ◽  
Lower Cambrian ◽  
Flood Basalt ◽  
Flood Basalts ◽  
Clastic Rocks ◽  
Younger Age ◽  
Age Limit

Columnar basalt of the Cloud Hills in northern Newfoundland, previously regarded as of Keeweenawan age, now is thought to be post-Lower Cambrian, since it lies on coarse clastic rocks correlated with known Lower Cambrian strata nearby. A younger age limit is given by a whole rock K-A date of 334 m.y. Perhaps these and similar basalts in southern Labrador represent a flood basalt province, once much more continuous than now.

Flood Basalts and Mass Extinctions

2019 ◽  
Vol 47 (1) ◽  
pp. 275-303 ◽  
Author(s):  
Matthew E. Clapham ◽  
Paul R. Renne
Keyword(s):  
Environmental Changes ◽  
Flood Basalt ◽  
Respiratory Physiology ◽  
Mass Extinctions ◽  
Flood Basalts ◽  
Volatile Release ◽  
Ocean Carbon ◽  
Biological Extinction ◽  
Extinction Events ◽  
Environmental Disruption

Flood basalts were Earth's largest volcanic episodes that, along with related intrusions, were often emplaced rapidly and coincided with environmental disruption: oceanic anoxic events, hyperthermals, and mass extinction events. Volatile emissions, both from magmatic degassing and vaporized from surrounding rock, triggered short-term cooling and longer-term warming, ocean acidification, and deoxygenation. The magnitude of biological extinction varied considerably, from small events affecting only select groups to the largest extinction of the Phanerozoic, with less-active organisms and those with less-developed respiratory physiology faring especially poorly. The disparate environmental and biological outcomes of different flood basalt events may at first order be explained by variations in the rate of volatile release modulated by longer trends in ocean carbon cycle buffering and the composition of marine ecosystems. Assessing volatile release, environmental change, and biological extinction at finer temporal resolution should be a top priority to refine ancient hyperthermals as analogs for anthropogenic climate change. ▪ Flood basalts, the largest volcanic events in Earth history, triggered dramatic environmental changes on land and in the oceans. ▪ Rapid volcanic carbon emissions led to ocean warming, acidification, and deoxygenation that often caused widespread animal extinctions. ▪ Animal physiology played a key role in survival during flood basalt extinctions, with reef builders such as corals being especially vulnerable. ▪ The rate and duration of volcanic carbon emission controlled the type of environmental disruption and the severity of biological extinction.

scholarly journals Intrusion Induced Global Warming Preceding Continental Flood Basalt Volcanism

2021 ◽  
Author(s):  
Xiaochuan Tian ◽  
W Buck
Keyword(s):  
Global Warming ◽  
Flood Basalt ◽  
Causal Link ◽  
Mass Extinctions ◽  
Flood Basalts ◽  
Continental Flood Basalt ◽  
Major Phase ◽  
Continental Flood Basalts ◽  
Temporal Correlations ◽  
Crustal Density

Abstract Temporal correlations between continental flood basalt eruptions and mass extinctions are well known 1. Massive carbon degassing from volcanism of Large Igneous Provinces can cause catastrophic global climatic and biotic perturbations 1–3. However, recent more accurate dating of the Deccan Traps 4 and Columbia River Basalts 5 challenges this causal link by showing that global warming preceded the major phase of flood basalts eruptions by several hundred thousand years. Here, we argue that major eruptions of continental flood basalts may require densification of the crust by intrusion of larger volumes of magma than are extruded. Simple models show that magma crystallization and release of CO2 from such intrusions could produce global warming before the main phase of flood basalt eruptions on the observed timescale. Being consistent with many geological, geophysical, geochemical and paleoclimate data, our model suggests that the evolving crustal density has a first order control on timing of the major phase of continental flood basalt volcanism while the preceding intrusion induced underground degassing of CO2 plays a significant role in controlling the Earth's climate and habitability.

scholarly journals The North Greenland fold belt in eastern Nansen Land

1985 ◽  
Vol 126 ◽  
pp. 69-78
Author(s):  
J.D Friderichsen ◽  
H.-J Bengaard
Keyword(s):  
Lower Cambrian ◽  
Upper Cretaceous ◽  
Field Work ◽  
Strike Slip ◽  
Fold Belt ◽  
Clastic Rocks ◽  
The North ◽  
Major Strike ◽  
East West ◽  
Strike Slip Movement

Field work in 1984 shows that Nansen Land consists of clastic rocks of the carbonaceous Paradisfjeld Group and terrigeneous rocks of the Polkorridoren Group; both are lower Cambrian in age and deposited in a slope and fan environment. Two major Ellesmerian (Devonian to Carboniferous) phases of deformation gave rise to east-west trending folds and schistosities. Three phases of Eurekan (upper Cretaceous to Tertiary) deformation, associated with dyke intrusion, are recognised. The second of these may be related to transpression on the Harder Fjord fault zone, though no major strike-slip movement seems to have taken place.

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.

scholarly journals Longevity of the Permian Emeishan mantle plume (SW China): 1 Ma, 8 Ma or 18 Ma?

2008 ◽  
Vol 145 (3) ◽  
pp. 373-388 ◽  
Author(s):  
J. GREGORY SHELLNUTT ◽  
MEI-FU ZHOU ◽  
DAN-PING YAN ◽  
YANBIN WANG
Keyword(s):  
Trace Element ◽  
Flood Basalt ◽  
Large Igneous Province ◽  
Flood Basalts ◽  
Geological Evidence ◽  
Ocean Island Basalts ◽  
Igneous Province ◽  
Emeishan Mantle Plume ◽  
Decompressional Melting ◽  
Shrimp Zircon

AbstractAfter the formation of the ~ 260 Ma Emeishan large igneous province, there were two volumetrically minor magmatic pulses at ~ 252 Ma and ~ 242 Ma, respectively. Alkaline mafic dykes intruding both 260 Ma and 252 Ma felsic plutons in the Panxi region, southwestern China, have compositions similar to the Emeishan flood basalts. One dyke is dated using the SHRIMP zircon U–Pb technique at 242 ± 2 Ma, ~ 18 Ma younger than the start of Emeishan magmatism. The dykes have enriched light rare earth element patterns (La/YbN = 4.4–18.8) and trace element patterns similar to the Emeishan flood basalts and average ocean-island basalts. Some trace element ratios of the dykes (Zr/Nb = 3.8–8.2, La/Nb = 0.4–1.7, Ba/La = 7.5–25.6) are somewhat similar to EM1 source material, however, there are differences. Their εNd values (εNd = +2.6 and +2.7) andISr (ISr = 0.704542 and 0.704554) ratios are indicative of a mantle source. Thus Emeishan magmatism may have lasted for almost 20 Ma after the initial eruption. However, geological evidence precludes the possibility that the post-260 Ma magmatic events were directly related to Emeishan magmatism, which began at and ended shortly after 260 Ma. The 252 Ma plutons and 242 Ma dykes represent volumetrically minor melting of the fossil Emeishan plume-head beneath the Yangtze crust. The 252 Ma magmatic event was likely caused by post-flood basalt extension of the Yangtze crust, whereas the 242 Ma event was caused by decompressional melting associated with the collision between the South China and North China blocks during the Middle Triassic.

Were Karoo flood basalts derived from a LLSVP-related plume source?

2020 ◽  
Author(s):  
Arto Luttinen ◽  
Jussi Heinonen ◽  
Sanni Turunen ◽  
Richard Carlson ◽  
Mary Horan
Keyword(s):  
Oceanic Crust ◽  
Mantle Plume ◽  
Flood Basalt ◽  
Planetary Science ◽  
Large Igneous Province ◽  
Primitive Mantle ◽  
Geochemical Data ◽  
Flood Basalts ◽  
Depleted Mantle ◽  
Mantle Reservoir

<p>Examination of the least-contaminated rocks of the Jurassic Karoo flood basalt province indicates considerable compositional variability in the mantle source. New and previously published Sr, Nd, and Pb isotopic data are suggestive of two main categories of mantle reservoirs: one coincides with the field of depleted mantle (DM) -affinity oceanic crust and the other has low initial eNd (+3.3 to 0.3) and high <sup>87</sup>Sr/<sup>86</sup>Sr (0.7039 to 0.7057) and Δ8/4 (92 to 138) typical of enriched mantle 1 (EM1) -affinity oceanic crust. Previous studies have proposed the DM type reservoir included domains affected by subduction-related fluids and recycled oceanic components (e.g. Heinonen et al., 2014). The EM1 type reservoir probably also contained subducted crustal components, but the geochemical data are suggestive of an additional primitive mantle (PM) type component (Turunen et al., 2019).</p><p>Importantly, the two reservoirs can be geochemically linked to a recently identified bilateral compositional asymmetry in the volumious Karoo flood basalts (Luttinen, 2018): The DM type  reservoir is the most likely source of Nb-depleted flood basalts in the southeastern Karoo subprovince (Lebombo rifted margin and Antarctica), whereas the EM1-PM type reservoir has been identified as the principal source of the Nb-undepleted flood basalts in the northwestern subprovince (Karoo-Kalahari-Zambezi basins). The boundary between the flood basalt subprovinces and the occurrences of the DM-affinity and EM1-PM-affinity rocks overlie the Jurassic location of the margin of the Jurassic sub-African LLSVP. Magmas derived from the EM1-PM type reservoir were largely emplaced above the deep mantle anomaly, whereas those derived from the DM type reservoir were emplaced outside the footprint of the LLSVP.</p><p>Based on isotopic similarity, the EM1-PM type reservoir of the Karoo province may record the same overall LLSVP material as the Gough component in the zoned Tristan da Cunha plume (e.g. Hoernle et al., 2015). Furthermore, it is possible that the DM type reservoir of the Karoo province, which has been interpreted to represent depleted upper mantle heated by mantle plume, could also represent a plume component and that the bilateral Karoo flood basalt province as a whole could thus register melting of a large zoned plume source associated with the margin of the sub-African LLSVP.</p><p>References</p><p>Heinonen, J.S., Carlson, R.W., Riley, T.R., Luttinen, A.V., Horan, M.F. (2014). Subduction-modified oceanic crust mixed with a depleted mantle reservoir in the sources of the Karoo continental flood basalt province. Earth and Planetary Science Letters 394, 229–241. http://dx.doi.org/10.1016/j.epsl.2014.03.012</p><p>Hoernl, K., Ronde, J., Hauff, F., Garbe-Schönberg, D., Homrighausen, S., Werner, W., Morgan, J.P. (2015).  How and when plume zonation appeared during the 132 Myr evolution of the Tristan Hotspot. Nature Communications 6:7799. doi: 10.1038/ncomms8799</p><p>Luttinen, A.V. (2018). Bilateral geochemical asymmetry in the Karoo large igneous province. Scientific Reports 8:5223. doi:10.1038/s41598-018-23661-3</p><p>Turunen, S.T., Luttinen, A.V., Heinonen, J.S., Jamal, D.L. (2019). Luenha picrites, Central Mozambique – Messengers from a mantle plume source of Karoo continental flood basalts? Lithos 346–347. https://doi.org/10.1016/j.lithos.2019.105152</p>

Principal characteristics of the Upper Silesian Block and Małopolska Block border zone (southern Poland)

1997 ◽  
Vol 134 (5) ◽  
pp. 669-677 ◽  
Author(s):  
ZBIGNIEW BUŁA ◽  
MONIKA JACHOWICZ ◽  
JERZY ŻABA
Keyword(s):  
Lower Cambrian ◽  
Border Zone ◽  
Lateral Part ◽  
Tectonic Zone ◽  
Principal Characteristics ◽  
East European ◽  
Lower Silurian ◽  
Clastic Rocks ◽  
Lower Palaeozoic ◽  
Małopolska Block

The Upper Silesian and Małopolska blocks are situated near the southwestern boundary of the East European Platform within the Trans-European Suture Zone. The Lower Palaeozoic lithologies of the blocks reveal different stratigraphic and diastrophic development. In the Upper Silesian Block, unmetamorphosed and gently folded Lower Cambrian to Ordovician sedimentary rocks rest on a Cadomian basement. The Lower Cambrian is represented by an older (sub-Holmia) Borzęta Formation and a younger (Holmia) Goczałkowice Formation. The thickness of the Cambrian lithologies increases from the southwest towards the lateral part of the block. In the Małopolska Block Palaeozoic and Precambrian lithologies are represented by regionally metamorphosed and intensely folded Lower Cambrian–Vendian clastic rocks which are unconformably overlain by Ordovician–Lower Silurian carbonates and Upper Silurian clastic rocks. The crystalline basement of the Małopolska Block has yet to be recognized. The Lower Palaeozoic sediments of both blocks are overlain by Devonian and Carboniferous rocks. The blocks are in direct contact along a narrow tectonic zone, a part of the largely concealed Hamburg–Kraków fault zone, in which tectonic evolution has taken place spasmodically with strike-slip movements predominating.

The Kraemer Island macrodyke, East Greenland: solidification of a flood basalt conduit

2002 ◽  
Vol 139 (2) ◽  
pp. 171-190 ◽  
Author(s):  
PETER MOMME ◽  
J. RICHARD WILSON
Keyword(s):  
Partition Coefficients ◽  
Parental Magma ◽  
Flood Basalt ◽  
Wall Rock ◽  
Dyke Swarm ◽  
Flood Basalts ◽  
Skaergaard Intrusion ◽  
Continuous Feeding ◽  
Late Stages ◽  
Light Rare Earth Elements

The Kraemer Island macrodyke that is exclusively exposed on Kraemer Island about 7 km west of the Skaergaard Intrusion belongs to a regional dyke swarm termed the ‘Skaergaard-like dykes’ (or FG-1 dykes). Weakly modally layered olivine gabbros dominate the exposed parts of the intrusion that has a width of 650 m to 1000 m. Plagioclase (core An68±2) and Ca-rich pyroxene (core Mg no. 79±1) grains are normally zoned, whereas olivine grains (Fo50–65) are homogeneous. Calculated mineral–magma equilibria, based on experimentally determined Mg–Fe magma–olivine and magma–clinopyroxene partition coefficients, suggest that the observed olivine and clinopyroxene compositions in the gabbros cannot have formed from a common parental magma. The unzoned nature of olivine grains and their iron-rich com-positions relative to clinopyroxene suggest post-cumulus Mg–Fe exchange between olivine and interstitial melt. A gabbroic pegmatite is developed in the centre of the intrusion along its entire exposed 5 km strike length. Here, mineral zonation is limited and compositions are similar to rims of cumulus minerals in the enveloping olivine gabbros. The pegmatite could therefore represent interstitial melt mobilized from gabbroic cumulates that later accumulated and crystallized at its present stratigraphic location. Cumulus olivines in the gabbros are close to equilibrium with Ca-rich pyroxene in the pegmatite. This is interpreted as reflecting interstitial melt mobility during the late stages of solidification of the macrodyke. Chilled margins are well preserved at the intrusion margins and are rich in Fe (14–15.3% FeOTOT), Ti (3–3.3% TiO2) and light rare-earth elements ([La/Sm]N = 1.2–1.3), similar to magmas well represented in the overlying sequence of contemporaneous High-Ti Series flood basalts. It is therefore likely that extensive wall-rock melting adjacent to the macrodyke reflects continuous feeding of the overlying flood basalts through the Kraemer Island macrodyke.

First regular archaeocyaths from the northern Appalachians, Forteau Formation, western Newfoundland

1980 ◽  
Vol 17 (12) ◽  
pp. 1609-1615 ◽  
Author(s):  
Noel P. James ◽  
Françoise Debrenne
Keyword(s):  
North America ◽  
Newfoundland And Labrador ◽  
Lower Cambrian ◽  
Southern Appalachians ◽  
The West

Archaeocyaths of the class Regulares have been discovered in the Devils Cove Member of the Forteau Formation in eastern and southern parts of western Newfoundland. The three species recovered are the first Regulares reported from the northern Appalachians, all archaeocyaths from the bioherms and biostromes to the west and north in Newfoundland and Labrador are Irregulares. This sparse, but well-preserved fauna is similar to the poorly-preserved fauna from the central and southern Appalachians, as well as the abundant and diverse Regulares fauna from the Cordillera, but unlike contemporaneous asiatic and australoantarctic faunas, lending support to the view that late Lower Cambrian archaeocyaths in North America were endemic.

scholarly journals Understanding the offshore flood basalt sequence using onshore volcanic facies analogues: an example from the Faroe–Shetland basin

2009 ◽  
Vol 146 (3) ◽  
pp. 353-367 ◽  
Author(s):  
DOUGAL A. JERRAM ◽  
RICHARD T. SINGLE ◽  
RICHARD W. HOBBS ◽  
CATHERINE E. NELSON
Keyword(s):  
Volcanic Rocks ◽  
Flood Basalt ◽  
Reflection Seismology ◽  
Flood Basalts ◽  
Geological Interpretation ◽  
Seismic Modelling ◽  
The North ◽  
Volcanic Facies ◽  
Volcanic Succession ◽  
Simple Flows

AbstractFlood basalts in associated volcanic rifted margins, such as the North Atlantic Igneous Province, have a significant component of lavas which are preserved in the present day in an offshore setting. A close inspection of the internal facies architecture of flood basalts onshore provides a framework to interpret the offshore sequences imaged by remote techniques such as reflection seismology. A geological interpretation of the offshore lava sequences in the Faroe–Shetland Basin, using constraints from onshore analogues such as the Faroe Islands, allows for the identification of a series of lava sequences which have characteristic properties so that they can be grouped. These are tabular simple flows, compound-braided flows, and sub-aqueously deposited hyaloclastite facies. The succession of volcanic rocks calculated in this study has a maximum thickness in excess of 6800 m. Down to the top of the sub-volcanic sediments, the offshore volcanic succession has a thickness of about 2700 m where it can be clearly identified across much of the area, with a further 2700 m or more of volcanic rock estimated from the combined gravity and seismic modelling to the north and west of the region. A large palaeo-waterbody is identified on the basis of a hyaloclastite front/apron consisting of a series of clinoforms prograding towards the eastern part of the basin. This body was > 500 m deep, must have been present at the onset of volcanism into this region, and parts of the water body would have been present during the continued stages of volcanism as indicated by the distribution of the hyaloclastite apron.

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