40Ar/39Ar dating of the Rajahmundry Traps, Eastern India and their relationship to the Deccan Traps

Knight, Kim B.; Renne, Paul R.; Halkett, A.; White, Nicky

doi:10.1016/s0012-821x(02)01154-8

Cited by 85 publications

(142 citation statements)

References 37 publications

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“…(following the terminology of Knight et al, 2003, where a plateau comprises five or more successive heating steps not showing a resolvable slope, representing >50% of the total released 39 Ar, and concordant within 2-σ errors) at 19.15± 0.18 Ma (Zaruma; Fig. 10a) and 10.6±0.3 Ma (Chaucha; Fig.…”

Section: Resultsmentioning

confidence: 88%

Metallogenic features of Miocene porphyry Cu and porphyry-related mineral deposits in Ecuador revealed by Re-Os, 40Ar/39Ar, and U-Pb geochronology

et al. 2011

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Mineralization and alteration events at ten Miocene porphyry Cu and porphyry-related epithermal mineral deposits in southern, central, and northern Ecuador were dated by means of molybdenite Re-Os, biotite and alunite 40 Ar/ 39 Ar, and titanite U-Pb geochronology. Most of these hydrothermal events show a spatio-temporal correlation with porphyry intrusion emplacement as constrained by zircon U-Pb ages. The total age range for these events spans the 23.5-6.1 Ma period, without displaying systematic along-or across-arc age distribution trends. While epithermal deposits tend to be spatially associated with volcanic rocks of a similar age, porphyry Cu deposits in Ecuador are frequently spatially associated with deeper-seated basement units and batholith-scale precursor intrusive systems assembled over ≥5 m.y. time periods. In most cases, formation of the porphyry Cu deposits is related to the -011-0378-z youngest magmatic (-hydrothermal) event in a given area, postdating batholith construction at a regional scale. The majority of Miocene deposits occurs in southern Ecuador where areally extensive, post-mineralization (late Miocene to recent) volcanic sequences with the potential to conceal mineralization at depth are lacking. Only few Miocene deposits occur in northern-central Ecuador, where they mainly crop out in the Western Cordillera, west of the productive present-day volcanic arc. The surface distribution of post-mineralization arc volcanism reflects along-arc variations in subducting slab geometry. Porphyry Cu and epithermal deposits in Ecuador define a Miocene metallogenic belt broadly continuous with its coeval counterpart in northern-central Peru. Although both belt segments were formed in an overall similar tectonomagmatic and metallogenic setting, their respective metal endowments differ significantly.Miner Deposita (2012) 47:383-410 DOI 10.1007/s00126

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Section: Resultsmentioning

confidence: 88%

Metallogenic features of Miocene porphyry Cu and porphyry-related mineral deposits in Ecuador revealed by Re-Os, 40Ar/39Ar, and U-Pb geochronology

et al. 2011

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“…66 Ma, but possibly over a time range as large as 69-64 Ma. Within these ages, if we discount results of Venkatesan et al (1993) for the Poladpur and Ambenali Formations, which appear to be biased by 39 Ar recoil artifacts, in favor of the more reliable ages from Knight et al (2003) and Hooper et al (2010), the Wai Subgroup ages are consistent with eruption at or just following CretaceousPaleogene boundary time. The Lonavala Subgroup formations have not been dated yet, and the Kalsubai Formations are only poorly constrained, but presumably were erupted before Cretaceous-Paleogene time.…”

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confidence: 75%

“…Ar plateau ages for lavas in the Western Ghats that are assigned to specifi c formations, published since the year 1990, along with 2σ error bars (Venkatesan et al, 1993;Hofmann et al, 2000;Knight et al, 2003;Pande et al, 2004;Hooper et al, 2010). All ages have been recalculated per the calibration of Renne et al (2011).…”

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confidence: 99%

Triggering of the largest Deccan eruptions by the Chicxulub impact

Richards

Álvarez

Self

et al. 2015

Geological Society of America Bulletin

176

151

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“…Rao and Lakshmi [144] confirmed that most of a 338-m-long core from a borehole near the southeastern boundary of the traps had reversed magnetization and was likely coeval with the C29r age of the bulk of the Mahabaleshwar sections. Even farther from the main sections of the western Ghats, lavas of the Rajahmundry Traps on the eastern coast of India, chemically identical to the Poladpur and Ambenali formations, have recently [96] been dated by 40 Ar/ 39 Ar as being indistinguish-able from these formations. Thus, the original extent of Deccan magmatism is even significantly larger than commonly believed.…”

Section: The Deccan Trapsmentioning

confidence: 99%

On the ages of flood basalt events

Courtillot

Renne

2003

Comptes Rendus. Géoscience

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We review available data constraining the extent, volume, age and duration of all major Phanerozoic continental flood basalts (CFB or traps) and oceanic plateaus (OP), together forming the group of large igneous provinces (LIP), going from the smallest Columbia flood basalts at ∼16 Ma to the as yet ill-known remnants of a possible trap at ∼360 Ma in eastern Siberia. The 16 traps (CFB and OP) reviewed form a rather unimodal distribution with an initial modal volume of the order of 2.5 Mkm 3 . Most provinces agree with a rather simple first order model in which volcanism may have lasted of the order of 10 Ma, often resulting in continental break-up, but where most of the volume was erupted in about 1 Ma or sometimes less. This makes CFBs/OPs (LIPs) major geodynamic events, with fluxes exceeding the total output of present day hot spots and even possibly exceeding over short times the entire crustal production of mid-ocean ridges. The proposed correlation between trap ages and the ages of several geological events, including mass extinctions and oceanic anoxia, is found to have improved steadily as more data have become available, to the point that the list of trap ages may coincide with many major divisions in the geological time scale. The four largest mass extinctions in the last 260 Ma coincide to the best resolution available with four traps, making a causal connection between the two through some form of catastrophic climatic perturbations the most likely hypothesis. The time sequence of LIPs appears to have been random and there is no robust evidence for long time trends in the corresponding crustal production rate over the last 260 Ma.  2003 Académie des sciences/Éditions scientifiques et médicales Elsevier SAS. All rights reserved. RésuméNous passons en revue l'ensemble des données qui permettent de contraindre l'étendue, le volume, l'âge et la durée de toutes les grandes provinces magmatiques basaltiques (en anglais LIP) d'âge Phanérozoïque, qu'il s'agisse des trapps ou plateaux basaltiques continentaux (en anglais CFB) ou des plateaux océaniques (OP), allant de la plus récente et plus petite (le plateau de Columbia âgé de ∼16 Ma) à l'une des plus anciennes, encore mal connue, située dans l'Est de la Sibérie et sans doute âgée de ∼360 Ma. Les 16 provinces passées en revue forment une distribution assez unimodale, avec des volumes initiaux de lave de l'ordre de 2,5 Mkm 3 . La plupart des provinces sont compatibles, au premier ordre, avec un modèle simple selon lequel le volcanisme a pu durer une dizaine de millions d'années et a en général conduit à une déchirure des continents et à l'ouverture d'un nouveau bassin océanique, mais où l'essentiel du volume des laves a été émis en environ 1 million d'années, parfois moins. Ceci fait des trapps (des LIP en général) des événements géodynamiques majeurs, avec des flux de matière ayant dépassé la production totale actuelle des points chauds et même, peut-être, pendant de brefs intervalles, la totalité de la production de croûte V.E. Courtillot, P.R. Renn...

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40Ar/39Ar dating of the Rajahmundry Traps, Eastern India and their relationship to the Deccan Traps

Cited by 85 publications

References 37 publications

Metallogenic features of Miocene porphyry Cu and porphyry-related mineral deposits in Ecuador revealed by Re-Os, 40Ar/39Ar, and U-Pb geochronology

Metallogenic features of Miocene porphyry Cu and porphyry-related mineral deposits in Ecuador revealed by Re-Os, 40Ar/39Ar, and U-Pb geochronology

Triggering of the largest Deccan eruptions by the Chicxulub impact

On the ages of flood basalt events

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