Alder Creek sanidine (ACs-2): A Quaternary 40Ar/39Ar dating standard tied to the Cobb Mountain geomagnetic event

Nomade, Sébastien; Renne, Paul R.; Vogel, N.; Deino, Alan L.; Sharp, Warren D.; Becker, T.; Jaouni, Abdur-Rahim; Mundil, Roland

doi:10.1016/j.chemgeo.2005.01.005

Cited by 165 publications

(99 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Each Ar isotope measurement consisted of 20 cycles of peak switching of the argon isotopes. Neu- (Nomade et al 2005) and the total decay constant of Steiger and Jäger (1977). The precision and accuracy of the mass discrimination correction was monitored by daily measurements of air argon (see full experimental description in Nomade et al 2010).…”

Section: Methodsmentioning

confidence: 99%

Petrology of the Late Cretaceous peralkaline rhyolites (pantellerite and comendite) from Lake Chad, Central Africa

Mbowou¹,

Lagmet²,

Nomade³

et al. 2012

J. Geosci.

Self Cite

View full text Add to dashboard Cite

Late Cretaceous peralkaline rhyolites (69.4 ± 0.4 Ma -2σ analytical, 1.9 Ma full external uncertainty, 40 Ar/ 39Ar sanidine single crystal laser dating) from Lake Chad are the oldest lavas of the "Cameroon Hot Line". These lavas (pantellerite and comendite), consisting of quartz ± alkali feldspar ± fluoro-arfvedsonite ± augite-hedenbergite ± aegirine ± fayalite (Fa 97-99 ) and ilmenite, are characterized by a progressive increase in the total REE contents and the magnitude of the negative Eu anomaly owing to the alkali feldspar-dominated fractionation. Two groups of peralkaline rhyolites have been distinguished according to mineralogical and geochemical data. Both, group-1 (La N /Yb N : 8.4-9.0; Zr/Nb: ~ 8) and group-2 (La N /Yb N : 10.7-12.6; Zr/Nb: ~ 6) are genetically related. The peralkaline rhyolites from Lake Chad could not be solely the product of fractional crystallization from a basaltic parental magma. The influx of F-rich fluids could have greatly modified the composition of rhyolitic magmas as attested by the presence of fluoro-arfvedsonite.

show abstract

Section: Methodsmentioning

confidence: 99%

Petrology of the Late Cretaceous peralkaline rhyolites (pantellerite and comendite) from Lake Chad, Central Africa

Mbowou¹,

Lagmet²,

Nomade³

et al. 2012

J. Geosci.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Inverse isochrons include the maximum number of consecutive steps with a probability of fit ≥ 0.05. Complete descriptions of the analytical procedure are given in and (NOMADE et al, 2005). Detailed 40 Ar/ 39 Ar results are shown in Appendix 1 and summarized in Table 2.…”

Section: 2bmentioning

confidence: 99%

“…Samples were irradiated in aluminum discs along with the Alder Creek sanidine standard, for which an age of 1.193 Ma is adopted (NOMADE et al, 2005). 40 Ar/ 39 Ar analyses were performed at the Berkeley Geochronology Center using a CO 2 laser.…”

Section: 2bmentioning

confidence: 99%

Combined U–Th/He and 40Ar/39Ar geochronology of post-shield lavas from the Mauna Kea and Kohala volcanoes, Hawaii

Aciego¹,

Jourdan²,

DePaolo³

et al. 2010

Geochimica et Cosmochimica Acta

Self Cite

View full text Add to dashboard Cite

“…Two irradiations were used. The VCD-series materials, along with 37 Alder Creek feldspars (1,193 ± 1 ka; Nomade et al 2005), used to monitor the neutron fluence, were irradiated at the Oregon State University TRIGA reactor in the Cd-lined CLICIT facility for 30 min within a series of stacked aluminum disks, permitting precise monitoring of both vertical (J = *1.341 9 10 -4 to *1.350 9 10 -4 ) and lateral (negligible) flux gradients. The PRCO-series materials, along with 54 Alder Creek feldspar crystals, were irradiated in a similar fashion in a single aluminum disk [J = *1.41 (±0.01) 9 10 -4 ].…”

Section: Methodsmentioning

confidence: 99%

“…Total fusion and stepheating feldspar and glass analyses were performed. Glasses and three to eight grain feldspar aliquots were analyzed by laser step-heating following procedures described previously (Nomade et al 2005; and references therein). Age spectra derived from laser step-heating of samples from previously dated domes show that excess 40 Ar contamination likely biased some K-Ar results.…”

Section: Methodsmentioning

confidence: 99%

Accessory mineral U–Th–Pb ages and 40Ar/39Ar eruption chronology, and their bearing on rhyolitic magma evolution in the Pleistocene Coso volcanic field, California

Simon

Renne

Schmitt

et al. 2009

Contrib Mineral Petrol

View full text Add to dashboard Cite

We determined Ar/Ar eruption ages of eight extrusions from the Pleistocene Coso volcanic field, a longlived series of small volume rhyolitic domes in eastern California. Combined with ion-microprobe dating of crystal ages of zircon and allanite from these lavas and from granophyre geothermal well cuttings, we were able to track the range of magma-production rates over the past 650 ka at Coso. In B230 ka rhyolites we find no evidence of protracted magma residence or recycled zircon (or allanite) from Pleistocene predecessors. A significant subset of zircon in the *85 ka rhyolites yielded ages between *100 and 200 Ma, requiring that generation of at least some rhyolites involves material from Mesozoic basement. Similar zircon xenocrysts are found in an *200 ka granophyre. The new age constraints imply that magma evolution at Coso can occur rapidly as demonstrated by significant changes in rhyolite composition over short time intervals (B10's to 100's ka). In conjunction with radioisotopic age constraints from other young silicic volcanic fields, dating of Coso rhyolites highlights the fact that at least some (and often the more voluminous) rhyolites are produced relatively rapidly, but that many small-volume rhyolites likely represent separation from long-lived mushy magma bodies.

show abstract

Alder Creek sanidine (ACs-2): A Quaternary 40Ar/39Ar dating standard tied to the Cobb Mountain geomagnetic event

Cited by 165 publications

References 32 publications

Petrology of the Late Cretaceous peralkaline rhyolites (pantellerite and comendite) from Lake Chad, Central Africa

Petrology of the Late Cretaceous peralkaline rhyolites (pantellerite and comendite) from Lake Chad, Central Africa

Combined U–Th/He and 40Ar/39Ar geochronology of post-shield lavas from the Mauna Kea and Kohala volcanoes, Hawaii

Accessory mineral U–Th–Pb ages and 40Ar/39Ar eruption chronology, and their bearing on rhyolitic magma evolution in the Pleistocene Coso volcanic field, California

Contact Info

Product

Resources

About