A proposal by the IUGS Subcommission on the Systematics of Igneous Rocks for a chemical classification of volcanic rocks based on the total alkali silica (TAS) diagram

Maitre, R. W. Le

doi:10.1080/08120098408729295

Cited by 209 publications

(70 citation statements)

References 9 publications

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“…Although our field NRM data are inconclusive in determining the genesis of the deposit at the type locality, we argue in favour of an origin from a small-volume pumice flow based on the field characteristics of the deposits preserved at this locality. The abundance of lowdensity pumice of high-silica composition, the large quantity of loose fine ash in the matrix of the deposit, and low abundance of juvenile andesite lithic clasts is Bas et al 1986 andLe Maitre 1984) showing a whole-pumice and whole-rock compositions of Pourahu Member (crosses) and Okupata Member (squares) and glass compositions of Pourahu Member at Mangaturuturu (triangles); b glass compositions of Okupata Member unit Ok 1 (triangles; outlined), Okupata Member unit Ok 3 (squares) and a more distal coarse ash (crosses) sampled from Hydro Access Rd. 10 section and correlated to Okupata Member.…”

Section: Results Of Laboratory Analysis Of Remanencementioning

confidence: 99%

The Taurewa Eruptive Episode: evidence for climactic eruptions at Ruapehu volcano, New Zealand

Donoghue

Palmer

McClelland

et al. 1999

Bulletin of Volcanology

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The ca. 10,500 years B.P. eruptions at Ruapehu volcano deposited 0.2-0.3 km 3 of tephra on the flanks of Ruapehu and the surrounding ring plain and generated the only known pyroclastic flows from this volcano in the late Quaternary. Evidence of the eruptions is recorded in the stratigraphy of the volcanic ring plain and cone, where pyroclastic flow deposits and several lithologically similar tephra deposits are identified. These deposits are grouped into the newly defined Taurewa Formation and two members, Okupata Member (tephra-fall deposits) and Pourahu Member (pyroclastic flow deposits). These eruptions identify a brief (~ca. 2000-year) but explosive period of volcanism at Ruapehu, which we define as the Taurewa Eruptive Episode. This Episode represents the largest event within Ruapehu's ca. 22,500-year eruptive history and also marks its culmination in activity ca. 10,000 years B.P. Following this episode, Ruapehu volcano entered a ca. 8000-year period of relative quiescence. We propose that the episode began with the eruption of smallvolume pyroclastic flows triggered by a magma-mingling event. Flows from this event travelled down valleys east and west of Ruapehu onto the upper volcanic ring plain, where their distal remnants are preserved. The genesis of these deposits is inferred from the remanent magnetisation of pumice and lithic clasts. We envisage contemporaneous eruption and emplacement of distal pumice-rich tephras and proximal welded tuff deposits. The potential for generation of pyroclastic flows during plinian eruptions at Ruapehu has not been previously considered in hazard assessments at this volcano. Recognition of these events in the volcanological record is thus an important new factor in future risk assessments and mitigation of volcanic risk at Tongariro Volcanic Centre.

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Section: Results Of Laboratory Analysis Of Remanencementioning

confidence: 99%

The Taurewa Eruptive Episode: evidence for climactic eruptions at Ruapehu volcano, New Zealand

Donoghue

Palmer

McClelland

et al. 1999

Bulletin of Volcanology

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“…Using the compositional classification scheme of Le Maitre (1984), >90% of the tephras fall within the rhyolite field (Fig. 7).…”

Section: Glass Shard Chemistrymentioning

confidence: 99%

Deep‐ocean record of major late Cenozoic rhyolitic eruptions from New Zealand

Carter

Alloway

Shane

et al. 2004

New Zealand Journal of Geology and Geophysics

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A 12 m.y. record of large rhyolitic eruptions from the Coromandel (CVZ) and Taupo (TVZ) Volcanic Zones of New Zealand is contained in cores retrieved by Leg 181 of the Ocean Drilling Program. Site 1124, located 670 km from the TVZ, has a maximum of 134 macroscopic tephra layers with a total thickness of 13.18 m. These units, along with between 7 and 63 tephras from 3 other sites, were dated by a combination of magnetostratigraphy, biostratigraphy, isothermal plateau fission track determinations, and geochemical correlation with onshore tephra deposits. Additional time control for the last 3 m.y. came from an orbitally tuned, benthic, oxygen isotope profile for Site 1123.Results extend the incomplete terrestrial record of volcanism by placing the first major rhyolitic eruption in the CVZ at c. 12 Ma, c. 1.6-1 m.y. earlier than previously known. Tephras became thicker and more frequent from the late Miocene into the Quaternary-a trend that probably reflected (1) more frequent and intense volcanism and (2) reduced distances between sources and depositional sites on the evolving Australian/Pacific plate system. The passage from CVZ to Quaternary TVZ occurred without a major hiatus in activity, suggesting the transition was gradational. The ensuing TVZ volcanism was more continuous than known previously from the onshore geology. Ash dispersal was primarily eastward, highlighting the dominance of westerly winds since the middle Miocene. Nevertheless, variations in dispersal patterns suggest periodic changes in wind direction/speed and/or ejection of ash beyond the Roaring Forties.

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“…The terminology used for volcanic and plutonic rocks throughout this report is that recommended by the IUGS (International U^ion of Geological Sciences) in reports by Le Maitre (1984) and Streckeisen (1975). Thus, the igneous rock names used differ slightly from those used by Lipman (1976a), Steven and Lipman (1976), and Lipman and others (1973); as well as from the names used by numerous other authors.…”

Section: Introductionmentioning

confidence: 83%

Geologic, alteration, and vein maps of the Redcloud Peak (Lake City caldera) and Handies Peak Wilderness Study Areas, Hinsdale County, Colorado

Hon¹

1987

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A proposal by the IUGS Subcommission on the Systematics of Igneous Rocks for a chemical classification of volcanic rocks based on the total alkali silica (TAS) diagram

Cited by 209 publications

References 9 publications

The Taurewa Eruptive Episode: evidence for climactic eruptions at Ruapehu volcano, New Zealand

The Taurewa Eruptive Episode: evidence for climactic eruptions at Ruapehu volcano, New Zealand

Deep‐ocean record of major late Cenozoic rhyolitic eruptions from New Zealand

Geologic, alteration, and vein maps of the Redcloud Peak (Lake City caldera) and Handies Peak Wilderness Study Areas, Hinsdale County, Colorado

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