Complexity in elucidating crustal thermal regime in geodynamically affected areas: A case study from the Deccan large igneous province (western India)

2017 ◽  
Vol 90 (3) ◽  
pp. 289-300 ◽  
Author(s):  
O. P. Pandey ◽  
Nimisha Vedanti ◽  
Ravi P. Srivastava
Keyword(s):  
Thermal Regime ◽  
Large Igneous Province ◽  
Western India ◽  
Igneous Province

scholarly journals Volumetric extrusive rates of silicic supereruptions from the Afro-Arabian large igneous province

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jennifer E. Thines ◽  
Ingrid A. Ukstins ◽  
Corey Wall ◽  
Mark Schmitz
Keyword(s):  
Environmental Change ◽  
Global Environmental Change ◽  
Volcanic Eruptions ◽  
Large Igneous Province ◽  
Silicic Volcanism ◽  
Global Environmental ◽  
Igneous Province ◽  
Geomagnetic Polarity

AbstractThe main phase of silicic volcanism from the Afro-Arabian large igneous province preserves some of the largest volcanic eruptions on Earth, with six units totaling >8,600 km3 dense rock equivalent (DRE). The large volumes of rapidly emplaced individual eruptions present a case study for examining the tempo of voluminous silicic magma generation and emplacement. Here were report high-precision 206Pb/238U zircon ages and show that the largest sequentially dated eruptions occurred within 48 ± 34 kyr (29.755 ± 0.023 Ma to 29.707 ± 0.025 Ma), yielding the highest known long-term volumetric extrusive rate of silicic volcanism on Earth. While these are the largest known sequential silicic supereruptions, they did not cause major global environmental change. We also provide a robust tie-point for calibration of the geomagnetic polarity timescale by integrating 40Ar/39Ar data with our 206Pb/238U ages to yield new constraints on the duration of the C11n.1r Subchron.

Evaluating petrophysical properties of volcano-sedimentary sequences: A case study in the Paraná-Etendeka Large Igneous Province

2019 ◽  
Vol 102 ◽  
pp. 638-656 ◽  
Author(s):  
Lucas M. Rossetti ◽  
David Healy ◽  
Malcolm J. Hole ◽  
John M. Millett ◽  
Evandro F. de Lima ◽  
...  
Keyword(s):  
Large Igneous Province ◽  
Petrophysical Properties ◽  
Sedimentary Sequences ◽  
Igneous Province

Magma flux of silicic supereruptions from the Afro-Arabian large igneous province

2021 ◽  
Author(s):  
Jennifer Thines ◽  
Ingrid Ukstins ◽  
Corey Wall ◽  
Mark Schmitz
Keyword(s):  
High Precision ◽  
Volcanic Eruptions ◽  
Large Igneous Province ◽  
Silicic Volcanism ◽  
Zircon Dating ◽  
Igneous Province ◽  
Magma Flux ◽  
Silicic Magmas ◽  
Geomagnetic Polarity

Abstract The Main Silicics phase of the Afro-Arabian large igneous province preserves some of the largest volcanic eruptions on Earth, with six units totaling >8,600 km3 dense rock equivalent (DRE). The large volumes of rapidly emplaced individual eruptions present a case study for examining the tempo of generation and emplacement of voluminous silicic magmas. We use high-precision 206Pb/238U zircon dating to differentiate individual eruption ages and show that the largest sequentially dated eruptions occurred within a timeframe of 48 ± 34 kyr (29.755 ± 0.023 Ma to 29.707 ± 0.025 Ma), yielding a maximum magma flux of 3.09 x 10-1 km3/yr for 4,339 km3 DRE and making this sequence the highest known flux of silicic volcanism on Earth. The Main Silicics phase of volcanism occurred within a timeframe of 130 ± 150 kyr (29.80 ± 0.80 Ma to 29.67 ± 0.13 Ma), yielding a maximum magma flux of 3.05 x 10-2 km3/yr. We also provide a robust tie-point for calibration of the geomagnetic polarity timescale by integrating recalculated 40Ar/39Ar data with our high-precision 206Pb/238U ages to yield new constraints on the duration of the C11n.1r Subchron.

Lithostratigraphy of the Palaeoproterozoic Hekpoort Formation (Pretoria Group, Transvaal Supergroup), South Africa

2020 ◽  
Vol 123 (4) ◽  
pp. 655-668
Author(s):  
N. Lenhardt ◽  
W. Altermann ◽  
F. Humbert ◽  
M. de Kock
Keyword(s):  
South Africa ◽  
Bushveld Complex ◽  
Sedimentary Rocks ◽  
Type Locality ◽  
Large Igneous Province ◽  
Braided River ◽  
River Systems ◽  
The West ◽  
Igneous Province ◽  
Transvaal Supergroup

Abstract The Palaeoproterozoic Hekpoort Formation of the Pretoria Group is a lava-dominated unit that has a basin-wide extent throughout the Transvaal sub-basin of South Africa. Additional correlative units may be present in the Kanye sub-basin of Botswana. The key characteristic of the formation is its general geochemical uniformity. Volcaniclastic and other sedimentary rocks are relatively rare throughout the succession but may be dominant in some locations. Hekpoort Formation outcrops are sporadic throughout the basin and mostly occur in the form of gentle hills and valleys, mainly encircling Archaean domes and the Palaeoproterozoic Bushveld Complex (BC). The unit is exposed in the western Pretoria Group basin, sitting unconformably either on the Timeball Hill Formation or Boshoek Formation, which is lenticular there, and on top of the Boshoek Formation in the east of the basin. The unit is unconformably overlain by the Dwaalheuwel Formation. The type-locality for the Hekpoort Formation is the Hekpoort farm (504 IQ Hekpoort), ca. 60 km to the west-southwest of Pretoria. However, no stratotype has ever been proposed. A lectostratotype, i.e., the Mooikloof area in Pretoria East, that can be enhanced by two reference stratotypes are proposed herein. The Hekpoort Formation was deposited in a cratonic subaerial setting, forming a large igneous province (LIP) in which short-termed localised ponds and small braided river systems existed. It therefore forms one of the major Palaeoproterozoic magmatic events on the Kaapvaal Craton.

Ultramafic-alkaline-carbonatite complexes as a result of two-stage melting of mantle plume: evidence from the mid-paleoproterozoic Tiksheozero intrusion, Northern Karelia, Russia

2019 ◽  
Vol 486 (4) ◽  
pp. 460-465
Author(s):  
E. V. Sharkov ◽  
A. V. Chistyakov ◽  
M. M. Bogina ◽  
O. A. Bogatikov ◽  
V. V. Shchiptsov ◽  
...  
Keyword(s):  
Fractional Crystallization ◽  
Mantle Plume ◽  
Large Igneous Province ◽  
Intrusive Complex ◽  
Incongruent Melting ◽  
Isotopic Data ◽  
Two Stage ◽  
Similar Composition ◽  
Igneous Province ◽  
Alkaline Magmas

Tiksheozero ultramafic-alkaline-carbonatite intrusive complex, like numerous carbonatite-bearing complexes of similar composition, is a part of large igneous province, related to the ascent of thermochemical mantle plume. Our geochemical and isotopic data evidence that ultramafites and alkaline rocks are joined by fractional crystallization, whereas carbonatitic magmas has independent origin. We suggest that origin of parental magmas of the Tiksheozero complex, as well as other ultramafic-alkaline-carbonatite complexes, was provided by two-stage melting of the mantle-plume head: 1) adiabatic melting of its inner part, which produced moderately-alkaline picrites, which fractional crystallization led to appearance of alkaline magmas, and 2) incongruent melting of the upper cooled margin of the plume head under the influence of CO2-rich fluids  that arrived from underlying zone of adiabatic melting gave rise to carbonatite magmas.

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