Rare Earth, Major, and Trace Element Geochemistry of Surface and Geothermal Waters from the Taupo Volcanic Zone, North Island New Zealand

2005 ◽  
pp. 67-88 ◽  
Author(s):  
Robyn E. Hannigan
Keyword(s):  
Rare Earth ◽  
New Zealand ◽  
Trace Element ◽  
Taupo Volcanic Zone ◽  
Trace Element Geochemistry ◽  
Volcanic Zone ◽  
Element Geochemistry ◽  
Geothermal Waters

Genesis of Recent Mafic Magmatism in the Taupo Volcanic Zone, New Zealand: Insights into the Birth and Death of Very Large Volume Rhyolitic Systems?

2020 ◽  
Vol 61 (2) ◽  
Author(s):  
Georg F Zellmer ◽  
Jun-Ichi Kimura ◽  
Claudine H Stirling ◽  
Gert Lube ◽  
Phil A Shane ◽  
...  
Keyword(s):  
New Zealand ◽  
Trace Element ◽  
Large Volume ◽  
Mantle Source ◽  
Source Parameters ◽  
Taupo Volcanic Zone ◽  
Volcanic Zone ◽  
Mafic Magmatism ◽  
Mafic Magmas ◽  
Rhyolitic Volcanism

Abstract Mafic magmatism of the rifting Taupo Volcanic Zone (TVZ) of the North Island, New Zealand, is volumetrically minor, but is thought to tap the material that provides the heat source for voluminous rhyolite production through partial melting of the crust, which ultimately results in very large volume explosive eruptions. We have studied the major and trace element chemistry of 14 mafic samples from across the entire TVZ, and the U isotopic composition of whole-rocks, groundmasses and separates of mafic mineral phases from a selection of nine samples (with the remaining five too sparsely phyric for mineral separation). Some minerals yield significant 234U enrichments despite groundmass and whole-rock close to 238U–234U secular equilibrium, pointing to uptake of variably hydrothermally altered antecrystic minerals prior to the eruption of originally sparsely phyric to aphyric mafic magmas. However, incompatible trace element patterns indicate that there are three chemically distinct groups of samples, and that samples may be used to derive primary melt compositions. We employ the latest version of the Arc Basalt Simulator (ABS5) to forward model these compositions, deriving mantle source parameters including mantle fertility, slab liquid flux, mantle volatile content, degree of melting, and P–T conditions of melt segregation. We show that mafic rocks erupted in areas of old, now inactive calderas constitute low-degree, deep melts, whereas those in areas of active caldera-volcanism are high-degree partial melts segregated from a less depleted source at an intermediate depth. Finally, high-Mg basaltic andesites erupted in the SW and NE of the TVZ point to a fertile, shallow mantle source. Our data are consistent with a petrogenetic model in which mantle melting is dominated by decompression, rather than fluid fluxing, and progresses from shallow to deeper levels with time. Melt volumes initially increase to a tipping point, at which large-scale crustal melting and caldera volcanism become prominent, and then decrease owing to progressive depletion of the mantle wedge by melting, resulting in the dearth of heat provided and eventual cessation of very large volume rhyolitic volcanism. ABS5 modelling therefore supports the notion of a direct link between the chemistry of recently erupted mafic magmas and the long-term activity and evolution of rhyolitic volcanism in the TVZ.

scholarly journals Geothermal waters from the Taupo Volcanic Zone, New Zealand: Li, B and Sr isotopes characterization

2012 ◽  
Vol 27 (3) ◽  
pp. 677-688 ◽  
Author(s):  
Romain Millot ◽  
Aimee Hegan ◽  
Philippe Négrel
Keyword(s):  
New Zealand ◽  
Taupo Volcanic Zone ◽  
Sr Isotopes ◽  
Volcanic Zone ◽  
Geothermal Waters

Rare earth and trace element geochemistry of a fragment of jurassic seafloor, Point Sal, California

1977 ◽  
Vol 41 (10) ◽  
pp. 1419-1430 ◽  
Author(s):  
Martin Menzies ◽  
Douglas Blanchard ◽  
Joyce Brannon ◽  
Randy Korotev
Keyword(s):  
Rare Earth ◽  
Trace Element ◽  
Trace Element Geochemistry ◽  
Element Geochemistry

scholarly journals Tectonic Exhumation of the Central Alps Recorded by Detrital Zircon in the Molasse Basin, Switzerland

2020 ◽  
Author(s):  
Owen A. Anfinson ◽  
Daniel F. Stockli ◽  
Joseph C. Miller ◽  
Andreas Möller ◽  
Fritz Schlunegger
Keyword(s):  
Rare Earth ◽  
Trace Element ◽  
Detrital Zircon ◽  
Late Eocene ◽  
Tectonic Activity ◽  
Trace Element Geochemistry ◽  
Molasse Basin ◽  
Age Group ◽  
Central Alps ◽  
Element Geochemistry

Abstract. Eocene to Miocene sedimentary strata of the Northern Alpine Molasse Basin in Switzerland are well studied, yet they lack robust geochronologic and geochemical analysis of detrital zircon for provenance tracing purposes. Here, we present detrital zircon U-Pb ages coupled with rare earth and trace element geochemistry (petrochronology) to provide insights into the sedimentary provenance and to elucidate the tectonic activity of the central Alpine Orogen from the late Eocene to mid Miocene. Between 35–22.5 ± 1 Ma, the detrital zircon U-Pb age signatures were dominated by age groups of 300–370 Ma, 370–490 Ma, and 490–710 Ma, with minor Proterozoic age contributions. In contrast, from 21.5 ± 1 Ma to ~ 13.5 Ma (youngest preserved sediments), the detrital zircon U-Pb age signatures were dominated by a 252–300 Ma age group, with a secondary abundance of the 370–490 Ma age group, and only minor contributions of the 490–710 Ma age group. The Eo-Oligocene provenance signatures are consistent with interpretations that initial basin deposition primarily recorded exhumation and erosion of the Austroalpine orogenic cover and minor contributions from underlying Penninic units, containing reworked detritus from Variscan, Caledonian, and Cadomian orogenic cycles. The dominant 252–300 age group from the younger Miocene deposits is associated with the exhumation of Variscan-aged crystalline rocks of upper-Penninic basement units. Noticeable is the lack of Alpine-aged detrital zircon in all samples with the exception of one late Eocene sample, which reflects Alpine volcanism associated with incipient continent-continent collision. In addition, the rare earth and trace element data from the detrital zircon, coupled with zircon morphology and U/Th ratios, point to primarily igneous and rare metamorphic sources of zircon. The observed change in detrital input from Austroalpine to Penninic provenance in the Molasse Basin at ~ 22 Ma appears to be correlated with the onset of synorogenic extension of the Central Alps. Synorogenic extension accommodated by slip along the Simplon fault zone promoted updoming and exhumation the Penninic crystalline core of the Alpine Orogen. The lack of Alpine detrital zircon U-Pb ages in all Oligo-Miocene strata also shows that the Molasse Basin drainage network was not accessing the prominent Alpine age intrusions and metamorphic complexes located in the southern portion of the Central Alps.

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