A short interval of Jurassic continental flood basalt volcanism in Antarctica as demonstrated by 40Ar39Ar geochronology

Heimann, A.; Fleming, Thomas H.; Elliot, David H.; Foland, K. A.

doi:10.1016/0012-821x(94)90029-9

Cited by 130 publications

(70 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The sinusoidal age and correlated K/Ca spectra are striking and frequently reported in argon geochronological studies (e.g., Jessberger et al, 1974;Sebai et al, 1991;Heimann et al, 1994;De Min et al, 2003;Rosset et al, 2007) and thought to reflect discordance due to: i) post magmatic sericitic alteration of plagioclase (Sebai et al, 1991;Dalrymple et al, 1995), ii) complex 39 Ar and 37 Ar redistribution between 20 cryptoperthite lamellae and host (Rosset et al, 2007), iii) potassium-rich mesostasis associated with plagioclase (Jessberger et al, 1974;Heimann et al, 1994), or iv) the presence of graphic intergrowth between quartz and alkali feldspar (Foland et al, 1993;Heimann et al, 1994). Feldspars in sample T98-41 (and other dyke samples included in this study) display no sign of sericite alteration and surface scanning SEM imaging on HF etched sample surfaces (thin section) revealed no complex exsolution features.…”

Section: Argon Release Spectra and Implications For The Timing Of Thesupporting

confidence: 54%

“…These areas were also strongly affected by HF leaching. The presence of graphic intergrowths of quartz and alkali feldspar could provide a source of discordance due to radiationinduced 39 Ar recoil redistribution in the sample with high and low apparent ages at low and high temperatures steps, respectively (Heimann et al, 1994, Jourdan et al, 2007. The plagioclase grain size (>125 m) used in our experiments is too large for recoil to be significant and there is no evidence of smaller sub-domains in the plagioclase that could act as fine grained recoil sites.…”

Section: Argon Release Spectra and Implications For The Timing Of Thementioning

confidence: 78%

“…The patterns of disturbance are reminiscent of argon loss and recoil, and indicate a heterogeneous distribution of Ar isotopes (e.g., Heimann et al, 1994;Note: Walderhaug et al (2005) reported similar disturbed argon release pattern in their experiments; their Figure 11). The total fusion ages for these two experiments are 239.2 ± 0.6 Ma and 238.2 ± 0.7 Ma, respectively, and are interpreted to provide minimum ages of crystallisation.…”

Section: Taimyr Intrusive Sample (Weather Station Flats)mentioning

confidence: 91%

See 2 more Smart Citations

Petrogenesis and timing of mafic magmatism, South Taimyr, Arctic Siberia: A northerly continuation of the Siberian Traps?

Reichow

Saunders

Scott

et al. 2016

Lithos

View full text Add to dashboard Cite

The Siberian large igneous province (LIP) forms the world's most extensive continental exposure of basalt and has several sub-provinces surrounding it, which may be genetically related. The Taimyr peninsula of north Siberia is one of these sub-provinces and is frequently assumed to be the northerly continuation of the basalts exposed at Noril'sk, the best-studied area of the Siberian LIP. However, the correlation is uncertain. The major and trace element data for both groups are consistent with a process of fractional crystallisation coupled with small degrees of assimilation of incompatibleelement-enriched lower crust involving different contaminants. Trace element model calculations indicate a process of magma formation at large degrees of partial melting and at pressures of less than 3 GPa, probably within the garnet-spinel transition zone or the spinel stability field of the asthenospheric mantle. We obtained an argon plateau age of ~252 (252.7 ± 1.5) Ma and a ~239 Ma total fusion age from a Taimyr lava and intrusive sample, respectively, confirming that volcanism is only partly contemporaneous with the activity of the Siberian LIP. Although this is in agreement with previous interpretations, we argue that the age difference between both events is only ~13 myrs and probably less (~5 myrs) although further investigation of the relationship is required. Our data allow correlation with distinct Noril'sk members and most importantly to the ore-bearing (Ni-Cu) intrusions implying that whole rock chemistry could have value as a prospecting tool in Taimyr.

show abstract

Section: Argon Release Spectra and Implications For The Timing Of Thesupporting

confidence: 54%

Section: Argon Release Spectra and Implications For The Timing Of Thementioning

confidence: 78%

Section: Taimyr Intrusive Sample (Weather Station Flats)mentioning

confidence: 91%

See 1 more Smart Citation

Petrogenesis and timing of mafic magmatism, South Taimyr, Arctic Siberia: A northerly continuation of the Siberian Traps?

Reichow

Saunders

Scott

et al. 2016

Lithos

View full text Add to dashboard Cite

show abstract

“…The sills have been dated as Jurassic (183.6 ± 1.0 by U-Pb on zircon and baddeleyite; Encarnación et al 1996), confirming Ar-Ar results (Fleming et al 1997). Lavas forming the Kirkpatrick Basalts are the eruptive equivalent of the Ferrar sills, with which they are contemporaneous, as dated by Ar-Ar (Heimann et al 1994). The Kirkpatrick Basalts are locally over 700 m thick and associated with phreatomagmatic deposits that indicate local eruptions (Hanson & Elliot 1996).…”

Section: Victoria Landmentioning

confidence: 64%

“…It has long been an enigma among basaltic LIPs. It was emplaced at about 183 Ma (Early Jurassic), during the emplacement of the adjacent Karoo LIP (Heimann et al 1994;Encarnación et al 1996;Duncan et al 1997;Fleming et al 1997;Minor & Mukasa 1997;Riley & Knight 2001). It forms an elongate outcrop that is over 3 500 km long by only some 160 km wide ( Fig.…”

mentioning

confidence: 99%

On the long-distance transport of Ferrar magmas

Leat

2008

View full text Add to dashboard Cite

Abstract:The distribution and geochemical relationships of the Early Jurassic Ferrar large igneous province (LIP) are examined and it is concluded that they support the lateral flow model for the emplacement of the province, with a source along the strongly magmatic Early Jurassic Antarctica-Africa rifted margin. Published data and new analyses from the Pensacola Range are used to show that the dominant magma type in the Ferrar, the Mount Fazio chemical type (MFCT) occurs in the Theron Mountains, Shackleton Range, Whichaway Nunataks, Pensacola Mountains (all Antarctica), and South Africa, as well as well-known outcrops in Victoria Land, Antarctica, southeast Australia and New Zealand. Chemical compositions are shown to be somewhat varied, but similar enough for them to be considered as representing closely related magmas. Examination of geochemical trends with distance from the interpreted magma source indicates that Mg# and MgO abundances decline with distance travelled, and it is argued that this is consistent with the lateral flow model. The Scarab Peak chemical type (SPCT) occurs as sills in the Theron Mountains and Whichaway Nunataks, and as lavas in Victoria Land, is geochemically very homogeneous. Despite this, Mg#, MgO, Ti/Y and Ti/Zr all fall with distance from the interpreted source, consistent with fractional crystallisation occurring during the lateral flow of the magmas. Flow took place in dykes or (more likely) sills. No feeder dyke swarm has been identified. The distances flowed, at least 4 100 km for MFCT and 3 700 km for SPCT are the longest interpreted lateral magma flows on Earth.End of abstract

show abstract

Eruptive history of the Karoo lava flows and their impact on early Jurassic environmental change

et al. 2017

View full text Add to dashboard Cite

This paper reports new paleomagnetic and geochronologic data from a ~1500 m thick composite section belonging to the Drakensberg group, the thickest remnant of the Karoo lavas in Northern Lesotho. Flow‐by‐flow analysis of paleomagnetic directions reveals 21 magnetic directional groups, corresponding to single eruptive events, and 16 individual lava flows. The new age determinations of lava flows range from 180.1 ± 1.4 to 182.8 ± 2.6 Ma. These data, combined with previous results, allow us to propose that the main part of the Drakensberg group and the Karoo intrusive complex dated around 181–183 Ma may have been erupted over a period as short as 250 kyr and may have coincided with the two main phases of extinction in the Early Toarcian. This scenario agrees well with the discontinuous rhythm of environmental and biotic perturbations in the Late Pliensbachian‐Toarcian interval.

show abstract

A short interval of Jurassic continental flood basalt volcanism in Antarctica as demonstrated by 40Ar39Ar geochronology

Cited by 130 publications

References 31 publications

Petrogenesis and timing of mafic magmatism, South Taimyr, Arctic Siberia: A northerly continuation of the Siberian Traps?

Petrogenesis and timing of mafic magmatism, South Taimyr, Arctic Siberia: A northerly continuation of the Siberian Traps?

On the long-distance transport of Ferrar magmas

Eruptive history of the Karoo lava flows and their impact on early Jurassic environmental change

Contact Info

Product

Resources

About