Flood Basalts and Magmatic Ni, Cu, and PGE Sulphide Mineralization: Comparative Geochemistry of the Noril'sk (Siberian Traps) and West Greenland Sequences

2013 ◽  
pp. 357-380 ◽  
Author(s):  
Peter C. Lightfoot ◽  
Chris J. Hawkesworth
Keyword(s):  
Flood Basalts ◽  
Sulphide Mineralization ◽  
West Greenland ◽  
Siberian Traps

Field evidence for coal combustion links the 252 My-old Siberian Traps with global carbon disruption

2021 ◽  
Author(s):  
Linda Elkins-Tanton ◽  
Steven Grasby ◽  
Benjamin Black ◽  
Roman Veselovskiy ◽  
Omid Ardakani ◽  
...  
Keyword(s):  
Organic Matter ◽  
Carbon Isotope ◽  
Flood Basalts ◽  
Siberian Traps ◽  
Field Evidence ◽  
Carbon Isotope Excursion ◽  
Show Evidence ◽  
Volcaniclastic Rocks ◽  
Atmospheric Changes ◽  
Global Carbon

<p>The Permo-Triassic Extinction was the most severe in Earth history. The Siberian Traps eruptions are strongly implicated in the global atmospheric changes that likely drove the extinction. A sharp negative carbon isotope excursion coincides within geochronological uncertainty with the oldest dated rocks from the Norilsk section of the Siberian flood basalts. The source of this light carbon has been debated for decades.</p><p>We focused on the voluminous volcaniclastic rocks of the Siberian Traps, relatively unstudied as potential carriers of carbon-bearing gases. Over six field seasons we collected rocks from across the Siberian platform and show the first direct evidence that the earliest eruptions particularly in the southern part of the province burned large volumes of a combination of vegetation and coal. Samples from the Maymecha-Kotuy region, from the Nizhnyaya Tunguska, Podkamennaya Tunguska, and Angara Rivers all show evidence of high-temperature organic matter carbonization and combustion.</p><p>Field evidence indicates a process in which ascending magmas entrain xenoliths of coal and carbonaceous sediments that are carbonized in the subsurface and also combusted either through reduction of magmas or when exposed to the atmosphere. We demonstrate that the volume and composition of organic matter interactions with magmas may explain the global carbon isotope signal, and have significantly driven the extinction.</p>

scholarly journals Field evidence for coal combustion links the 252 Ma Siberian Traps with global carbon disruption

Geology ◽  
2020 ◽  
Vol 48 (10) ◽  
pp. 986-991 ◽  
Author(s):  
L.T. Elkins-Tanton ◽  
S.E. Grasby ◽  
B.A. Black ◽  
R.V. Veselovskiy ◽  
O.H. Ardakani ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
Coal Combustion ◽  
Direct Evidence ◽  
Flood Basalts ◽  
Siberian Traps ◽  
Field Evidence ◽  
Carbon Isotope Excursion ◽  
Volcaniclastic Rocks ◽  
Atmospheric Changes ◽  
Global Carbon

Abstract The Permian-Triassic extinction was the most severe in Earth history. The Siberian Traps eruptions are strongly implicated in the global atmospheric changes that likely drove the extinction. A sharp negative carbon isotope excursion coincides within geochronological uncertainty with the oldest dated rocks from the Norilsk section of the Siberian flood basalts. We focused on the voluminous volcaniclastic rocks of the Siberian Traps, relatively unstudied as potential carriers of carbon-bearing gases. Over six field seasons we collected rocks from across the Siberian platform, and we show here the first direct evidence that the earliest eruptions in the southern part of the province burned large volumes of a combination of vegetation and coal. We demonstrate that the volume and composition of organic matter interacting with magmas may explain the global carbon isotope signal and may have significantly driven the extinction.

Rapid Eruption of the Siberian Traps Flood Basalts at the Permo-Triassic Boundary

Science ◽  
1991 ◽  
Vol 253 (5016) ◽  
pp. 176-179 ◽  
Author(s):  
P. R. RENNE ◽  
A. R. BASU
Keyword(s):  
Flood Basalts ◽  
Triassic Boundary ◽  
Siberian Traps

scholarly journals Palaeodirectional and palaeointensity results of Paleocene and Eocene basalts from West Greenland

1999 ◽  
Vol 46 ◽  
pp. 69-78
Author(s):  
Janna Riisager ◽  
Mireille Perrin
Keyword(s):  
High Temperature ◽  
Remanent Magnetization ◽  
Dipole Moments ◽  
Early Eocene ◽  
Flood Basalts ◽  
West Greenland ◽  
Three Samples ◽  
Geomagnetic Polarity ◽  
Geomagnetic Polarity Time Scale ◽  
High Median

Twelve sites (57 drill cores) from two lava series and one dike were sampled for a palaeomagnetic study of the late Paleocene and early Eocene West Greenland flood basalts. Most of the rocks exhibited well-defined one component remanent magnetization with high unblocking temperatures (mostly above 500°C) and high median destructive fields (30–40 mT). All the rocks are reversely magnetized and, when combined with 40Ar/39Ar ages (Storey et al. 1998), a direct correlation with the geomagnetic polarity time scale can be made. Rock magnetic experiments indicate varying degree of both high temperature (deuteric) and low temperature (hydrothermal) oxidation of primary titanomagnetite. Twenty-three samples with high Curie point (~570°C) were chosen for Thellier palaeointensity experiments. Eleven of them, coming from three different cooling units, yielded reliable palaeointensity estimates. The results are reasonably coherent within sites, and the site-mean virtual dipole moments (VDM) are 1.8, 9.0 and 15.4×1022Am2 . The lowest VDM most probably corresponds to the ~94 ka long C24n.1r subchron, while the two other VDM’s close to present-day and higher than present-day values correspond to chrons C26r and C24r respectively.

scholarly journals Early Tertiary flood basalts from Hareøen and western Nûgssuaq, West Greenland

1976 ◽  
Vol 120 ◽  
pp. 1-36
Author(s):  
N Hald
Keyword(s):  
Thin Layers ◽  
Igneous Rocks ◽  
Chemical Analyses ◽  
Flood Basalts ◽  
The West ◽  
West Greenland ◽  
Basaltic Rocks ◽  
Magmatic Rocks ◽  
Incompatible Elements ◽  
Early Tertiary

In central West Greenland flood basalts were erupted in the Early Tertiary. On Hareøen and western Nûgssuaq the upper part of the volcanic sequence predominates reaching a thickness of more than 3 km. In these two areas tholeiitic, olivine porphyritic basalts and picritic basalts are followed by tholeiitic basalts with plagioclase as the dominant phenocryst. The content of incompatible elements in the plagioclase porphyritic basalts is low in the early stages, as is the case in most of the older olivine porphyritic lavas in the province; however, after a pause in the volcanic activity, the concentration of these elements is increased by a factor of 3-6. A few thin layers of peralkaline, rhyolitic tuffs are found in the upper part of the plagioclase porphyritic sequence. The tholeiitic lavas are intruded by dykes. Most of these are petrographically the equivalent of the extrusive rocks, but dykes of transitional olivine basalts are presumed to represent a younger magmatic episode from which no lavas are known. The youngest igneous rocks in the area – and perhaps the youngest lavas in all of the West Greenland basalt province – are olivine porphyritic, alumina enriched transitional basalts deposited unconformably on the tholeiitic sequence on Hareøen. Forty-three new chemical analyses of the magmatic rocks are presented as well as micro-probe data on phenocryst and groundmass phases. The diversity of basaltic rocks cannot be explained by low pressure crystal fractionation alone, and it is suggested that the chemical evolution of the lavas and dyke rocks reflect chemical variations in batches of olivine rich magmas injected into the crust from the mantle.

scholarly journals Lithostratigraphy of the early Tertiary volcanic rocks of central West Greenland

1975 ◽  
Vol 69 ◽  
pp. 17-24
Author(s):  
N Hald ◽  
A.K Pedersen
Keyword(s):  
Marine Sediments ◽  
Volcanic Rocks ◽  
Igneous Rocks ◽  
Metamorphic Rocks ◽  
Flood Basalts ◽  
West Greenland ◽  
Early Tertiary ◽  
Volcanic Sequence ◽  
Geological Map

A sequence of flood basalts, in places more than 8-10 km thick, was erupted during the Early Tertiary in the central part of West Greenland between latitudes 69° and 73°N. The volcanic rocks rest on Precambrian metamorphic rocks and non-marine and marine sediments from the Cretaceous and Paleocene. The lower part of the volcanic sequence is dominated by tholeiitic olivinerich basalts and picrite basalts, whereas the upper part is characterized by tholeiitic basalts with plagioclase as the dominant phenocryst mineral; transitional and alkaline lavas and tuffs are found, especially in the upper part of the sequence. The geology of the Tertiary igneous rocks has been summarized by Munck & Noe-Nygaard (1957), Rosenkrantz & Pulvertaft (1969) and Clarke & Pedersen (in press). However, until now no formal lithostratigraphy has been established. A geological map at scale 1:100 000 covering the greater part of Nugssuaq (sheet Agatdal-70 V. 1 Nord) has been published by GGU.

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