scholarly journals Stratigraphy and Chronology of Widespread Tephra Layers during the Past 430 ky in the Kinki District and the Yatsugatake Mountains: Major Element Composition of the Glass Shards Using EDS Analysis

2004 ◽  
Vol 43 (1) ◽  
pp. 15-35 ◽  
Author(s):  
Yoshitaka Nagahashi ◽  
Shusaku Yoshikawa ◽  
Chihiro Miyakawa ◽  
Takashi Uchiyama ◽  
Yoshio Inouchi
Keyword(s):  
Major Element ◽  
Element Composition ◽  
Major Element Composition ◽  
The Past ◽  
Eds Analysis ◽  
Tephra Layers ◽  
Glass Shards

scholarly journals AMS 14C Dates and Major Element Composition of Glass Shards of Late Pleistocene Tephras on Tanegashima Island, Southern Japan

Radiocarbon ◽  
2012 ◽  
Vol 54 (3-4) ◽  
pp. 351-358 ◽  
Author(s):  
Mitsuru Okuno ◽  
Masayuki Torii ◽  
Hideto Naruo ◽  
Yoko Saito-Kokubu ◽  
Tetsuo Kobayashi
Keyword(s):  
Late Pleistocene ◽  
Major Element ◽  
Volcanic Glass ◽  
Archaeological Site ◽  
Major Element Composition ◽  
Ams Radiocarbon Dating ◽  
Southern Japan ◽  
Tephra Layers ◽  
C 32 ◽  
Glass Shards

Four late Pleistocene tephra layers—Tane I (Tn1), II (Tn2), III (Tn3), and IV (Tn4) in ascending order—are intercalated between widespread tephras, Kikai-Tozurahara (K-Tz: 95 ka) and Aira-Tn (AT: 30 cal kBP), on Tanegashima Island, in southern Japan. Paleolithic ruins such as the Yokomine C and Tatikiri archaeological sites were excavated from the loam layer between the Tn4 and Tn3 tephras. To refine the chronological framework on the island, we conducted accelerator mass spectrometry (AMS) radiocarbon dating for 2 paleosol and 6 charcoal samples related with the late Pleistocene tephras and the Yokomine C archaeological site. The obtained 14C dates are consistent with the stratigraphy in calendar years, 33 cal kBP for Tn4, 40 cal kBP for Tn3, and >50 cal kBP for Tn2 and Tn1. The charcoal dates from Yokomine C, 32–38 cal kBP, not only constrain the age of Tn4 and Tn3 ashes, but also serve as a possible date for the site. We also measured the major element compositions of volcanic glass shards with EDS-EPMA to characterize these tephras. Although we could not find a possible correlative for Tn3 and Tn4 ashes using major element oxides of the glass shards, i.e. 75–76 wt% in SiO2, the glass chemistry obtained in this study will be valuable in correlating these tephras with their source volcanoes in the near future.

scholarly journals Identification of Some Global Volcanic Horizons by Major Element Analysis of Fine Ash in Antarctic Ice

1990 ◽  
Vol 14 ◽  
pp. 216-220 ◽  
Author(s):  
Julie M. Palais ◽  
Severine Kirchner ◽  
Robert J. Delmas
Keyword(s):  
Electrical Conductivity ◽  
Volcanic Ash ◽  
Major Element ◽  
Ice Sheets ◽  
Volcanic Eruptions ◽  
South American ◽  
Element Analysis ◽  
Major Element Composition ◽  
Tephra Layers ◽  
Glass Shards

Acid fallout from volcanic eruptions is well documented in the Greenland and Antarctic ice sheets (Hammer and others, 1980; Hammer, 1984; Legrand and Delmas, 1987). However, to date, no volcanic ash (tephra) layers have been positively identified in association with any of the high electrical conductivity layers that mark the volcanic acid deposition. In this paper we report the results of a study of the chemical composition of insoluble microparticles filtered from five intervals of a core from the South Pole. These five intervals were identified by Kirchner (1988) as being due to volcanic fallout, on the basis of electrical conductivity and sulfuric acid measurements.The major element composition of tiny (<5µm) glass shards found in these layers was determined and compared with analyses of volcanic ash from known eruptions or from volcanic sources suspected of having produced the fallout. Glass shards from volcanic eruptions of both local (Antarctic and sub-Antarctic) and of global (Indonesian/South American) importance have been identified in this study.

scholarly journals Identification of Some Global Volcanic Horizons by Major Element Analysis of Fine Ash in Antarctic Ice

1990 ◽  
Vol 14 ◽  
pp. 216-220 ◽  
Author(s):  
Julie M. Palais ◽  
Severine Kirchner ◽  
Robert J. Delmas
Keyword(s):  
Electrical Conductivity ◽  
Volcanic Ash ◽  
Major Element ◽  
Ice Sheets ◽  
Volcanic Eruptions ◽  
South American ◽  
Element Analysis ◽  
Major Element Composition ◽  
Tephra Layers ◽  
Glass Shards

Acid fallout from volcanic eruptions is well documented in the Greenland and Antarctic ice sheets (Hammer and others, 1980; Hammer, 1984; Legrand and Delmas, 1987). However, to date, no volcanic ash (tephra) layers have been positively identified in association with any of the high electrical conductivity layers that mark the volcanic acid deposition. In this paper we report the results of a study of the chemical composition of insoluble microparticles filtered from five intervals of a core from the South Pole. These five intervals were identified by Kirchner (1988) as being due to volcanic fallout, on the basis of electrical conductivity and sulfuric acid measurements.The major element composition of tiny (<5µm) glass shards found in these layers was determined and compared with analyses of volcanic ash from known eruptions or from volcanic sources suspected of having produced the fallout. Glass shards from volcanic eruptions of both local (Antarctic and sub-Antarctic) and of global (Indonesian/South American) importance have been identified in this study.

Provenance of basaltic tephra from Vatnajökull subglacial volcanoes, Iceland, as determined by major- and trace-element analyses

The Holocene ◽  
2011 ◽  
Vol 21 (7) ◽  
pp. 1037-1048 ◽  
Author(s):  
Bergrún Arna Óladóttir ◽  
Olgeir Sigmarsson ◽  
Gudrún Larsen ◽  
Jean-Luc Devidal
Keyword(s):  
Trace Element ◽  
Inductively Coupled Plasma ◽  
Major Element ◽  
Element Composition ◽  
Major Element Composition ◽  
Volcanic System ◽  
The Holocene ◽  
Inductively Coupled ◽  
Ice Cap ◽  
The North

The Holocene eruption history of subglacial volcanoes in Iceland is largely recorded by their tephra deposits. The numerous basaltic tephra offer the possibility to make the tephrochronology in the North Atlantic area more detailed and, therefore, more useful as a tool not only in volcanology but also in environmental and archaeological studies. The source of a tephra is established by mapping its distribution or inferred via compositional fingerprinting, mainly based on major-element analyses. In order to improve the provenance determinations for basaltic tephra produced at Grímsvötn, Bárdarbunga and Kverkfjöll volcanic systems in Iceland, 921 samples from soil profiles around the Vatnajökull ice-cap were analysed for major-element concentrations by electron probe microanalysis. These samples are shown to represent 747 primary tephra units. The tephra erupted within each of these volcanic system has similar chemical characteristics. The major-element results fall into three distinctive compositional groups, all of which show regular decrease of MgO with increasing K2O concentrations. The new analyses presented here considerably improve the compositional distinction between products of the three volcanic systems. Nevertheless, slight overlap of the compositional groups for each system still remains. In situ trace-element analyses by laser-ablation-inductively-coupled-plasma-mass-spectrometry were applied for better provenance identification for those tephra having similar major-element composition. Three trace-element ratios, Rb/Y, La/Yb and Sr/Th, proved particularly useful. Significantly higher La/Yb distinguishes the Grímsvötn basalts from those of Bárdarbunga and Rb/Y values differentiate the basalts of Grímsvötn and Kverkfjöll. Additionally, the products of Bárdarbunga, Grímsvötn and Kverkfjöll form distinct compositional fields on a Sr/Th versus Th plot. Taken together, the combined use of major- and trace-element analyses in delineating the provenance of basaltic tephra having similar major-element composition significantly improves the Holocene tephra record as well as the potential for correlations with tephra from outside Iceland.

scholarly journals Miocene and Pliocene Silicic Coromandel Volcanic Zone Tephras from ODP Site 1124-C: Petrogenetic Applications and Temporal Evolution

2021 ◽  
Author(s):  
◽  
Matthew Thomas Stevens
Keyword(s):  
Trace Element ◽  
Mantle Wedge ◽  
Major Element ◽  
Volcanic Glass ◽  
Fractional Crystallisation ◽  
Volcanic Zone ◽  
Arc Magmas ◽  
Glass Shard ◽  
Tephra Layers ◽  
Glass Shards

<p>The Coromandel Volcanic Zone (CVZ) was the longest-lived area of volcanism in New Zealand hosting the commencement of large explosive rhyolitic and ignimbrite forming eruptions. The NW trending Coromandel Peninsula is the subaerial remnant of the Miocene-Pliocene CVZ, which is regarded as a tectonic precursor to the Taupo Volcanic Zone (TVZ), currently the most dynamic and voluminous rhyolitic volcanic centre on Earth. This study presents new single glass shard major and trace element geochemical analyses for 72 high-silica volcanic tephra layers recovered from well-dated deep-sea sediments of the SW Pacific Ocean by the Ocean Drilling Program (ODP) Leg 181. ODP Site 1124, ~720 km south and east from the CVZ, penetrated sediments of the Rekohu Drift yielding an unprecedented record of major explosive volcanic eruptions owing to the favourable location and preservation characteristics at this site. This record extends onshore eruptive sequences of CVZ explosive volcanism that are obscured by poor exposure, alteration, and erosion and burial by younger volcanic deposits. Tephra layers recovered from Site 1124 are well-dated through a combination of biostratigraphic and palaeomagnetic methods allowing the temporal geochemical evolution of the CVZ to be reconstructed in relation to changes in the petrogenesis of CVZ arc magmas from ~ 10 to 2 Ma. This thesis establishes major and trace element geochemical "fingerprints" for all Site 1124-C tephras using well-established (wavelength dispersive electron probe microanalysis) and new (laser ablation inductively coupled plasma mass spectrometry) in situ single glass shard microanalytical techniques. Trace element analysis of Site 1124-C glass shards (as small as 20 um) demonstrate that trace element signatures offer a more specific, unequivocal characterisation for distinguishing (and potentially correlating) between tephras with nearly identical major element compositions. The Site 1124-C core contains 72 unaltered Miocene-Pliocene volcanic glass-shard-bearing laminae > 1 cm thick that correspond to 83 or 84 geochemical eruptive units. Revised eruptive frequencies based on the number of geochemical eruptive units identified represent at least one eruption every 99 kyr for the late Miocene and one per 74 kyr for the Pliocene. The frequency of tephra deposition throughout the history of the CVZ has not been constant, rather reflecting pulses of major explosive eruptions resulting in closely clustered groups of tephra separated by periods of reduced activity, relative volcanic quiescence or non-tephra deposition. As more regular activity became prevalent in the Pliocene, it was accompanied by more silicic magma compositions. Rhyolitic volcanic glass shards are characterised by predominantly calc-alkaline and minor high-K enriched major element compositions. Major element compositional variability of the tephras deposited between 10 Ma and 2 Ma reveals magma batches with pre-eruptive compositional gradients implying a broad control by fractional crystallisation. Trace element characterisation of glass shards reveals the role of magmatic processes that are not readily apparent in the relatively homogeneous major element compositions. Multi-element diagrams show prominent negative Sr and Ti anomalies against primitive mantle likely caused by various degrees of plagioclase and titanomagnetite fractional crystallisation in shallow magma chambers. Relative Nb depletion, characteristic of arc volcanism, is moderate in CVZ tephras. HFSEs (e.g. Nb, Zr, Ti) and HREEs (e.g. Yb, Lu) remain immobile during slab fluid flux suggesting they are derived from the mantle wedge. LILE (e.g. Rb, Cs, Ba, Sr) and LREE (e.g. La, Ce) enrichments are consistent with slab fluid contribution. B/La and Li/Y ratios can be used as a proxy for the flux of subducting material to the mantle wedge, they suggest there is a strong influence from this component in the generation of CVZ arc magmas, potentially inducing melting. CVZ tephra show long-term coherent variability in trace element geochemistry. Post ~ 4 Ma tephras display a more consistent, less variable, chemical fingerprint that persists up to and across the CVZ/TVZ transition at ~ 2 Ma. Initiation of TVZ volcanism may have occurred earlier than is presently considered, or CVZ to TVZ volcanism may have occurred without significant changes in magma generation processes.</p>

scholarly journals Linking Cellulose Fiber Sediment Methyl Mercury Levels to Organic Matter Decay and Major Element Composition

AMBIO ◽  
2014 ◽  
Vol 43 (7) ◽  
pp. 878-890 ◽  
Author(s):  
Olof Regnell ◽  
Mark Elert ◽  
Lars Olof Höglund ◽  
Anna Helena Falk ◽  
Anders Svensson
Keyword(s):  
Organic Matter ◽  
Methyl Mercury ◽  
Major Element ◽  
Cellulose Fiber ◽  
Element Composition ◽  
Major Element Composition

The geochemistry of hydrothermal and pelagic sediments from the Galapagos Hydrothermal Mounds Field, D.S.D.P. Leg 70

1983 ◽  
Vol 47 (344) ◽  
pp. 291-300 ◽  
Author(s):  
S. A. Moorby ◽  
D.S. Cronan
Keyword(s):  
Major Element ◽  
Hydrothermal Solution ◽  
Element Composition ◽  
Pelagic Sediment ◽  
Solution Composition ◽  
Major Element Composition ◽  
Sediment Samples ◽  
Mn Oxide ◽  
Formation Conditions ◽  
Metal Ratios

AbstractOver 200 sediment samples taken from ten holes drilled in the Galapagos Hydrothermal Mounds Field during D.S.D.P. Leg 70 have been analysed for twenty-one elements. The three main sediment lithologies recognized are siliceous carbonate ooze, Mn-oxide crust, and an Fe-rich silicate (nontronite), the latter two being of hydrothermal origin. The major element composition of the hydrothermal deposits is similar in each mound hole, suggesting that formation conditions and hydrothermal solution composition have been constant both geographically and with time. The large variations which occur in the concentration of some trace elements in the Mn-oxide crusts and in transition metal ratios in the nontronite compared with the pelagic ooze suggests a hydrothermal supply to the mounds of Li, Mo, Pb, and Ba in addition to Mn, Fe, and silica.The data are compatible with suggestions that the nontronite formed at depth in the pelagic sediment blanket by replacement of biogenic ooze, whilst the Mn crusts formed at or near the sediment-water interface. Pelagic sediments in the mounds which have not been replaced are similar in composition to pelagic sediments from non-mounds holes.

A Kaolin-smectite interstratification sequence from a red and black complex

Clay Minerals ◽  
1991 ◽  
Vol 26 (3) ◽  
pp. 343-358 ◽  
Author(s):  
C. Bühmann ◽  
P. L. C. Grubb
Keyword(s):  
Major Element ◽  
Element Composition ◽  
Chemical Analyses ◽  
Sand Content ◽  
Major Element Composition ◽  
Genetic Link ◽  
Sequential Development ◽  
Mineral Compositions

AbstractThe sequential development of kaolin by progressive alteration of smectite, involving kaolin-smectite interstratifications as a genetic link is described from a red and black complex. Mineral compositions were studied using XRD, DTA and XRF techniques. The basalt-derived soils are situated along a 600 m transect and grade in colour from dark grey (10 YR 3/1) to red (5 YR 3/3). The kaolin proportions in the interstratification increase almost linearly with increasing reddening up to ∼80%. Whole-soil chemical analyses exhibit no significant variations in the major element composition, but dithionite extractable Fe increases along the transect from 1% to 4·16%. Hematite and goethite are the only secondary iron phases. Topographic differences are slight but sub-surface bedrock contours plus appreciable variations in sand content between red and black soils could be genetically significant.

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