Zircon megacrysts from basalts of the Venetian Volcanic Province (NE Italy): U–Pb ages, oxygen isotopes and REE data

Visonà, Dario; Caironi, Valeria; Carraro, Anna; Dallai, Luigi; Fioretti, A. M.

doi:10.1016/j.lithos.2006.06.007

Cited by 40 publications

(27 citation statements)

References 27 publications

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“…The first area is represented by the volcanic districts of the Adige valley (near Arco and Rovereto) of middle Paleocene to middle Eocene age; by the Lessini Mts., to the West of the Castelvero tectonic lineament, of Paleocene to middle Eocene age (Visonà et al 2007a); by the area between the Castelvero and Schio-Vicenza lineaments, of middle Paleocene to upper Oligocene age; and by the Marosticano area of middle-upper Oligocene to Miocene age. The magmatic products of these areas are prevailingly basic to ultrabasic volcanic rocks which belong to an alkaline (mela-nephelinites, nephelinites, basanites, alkali basalts, hawaiites, trachybasalts) and to moderately sub-alkaline series (transitional basalts, basaltic andesites).…”

Section: Veneto Volcanic Provincementioning

confidence: 98%

Permo–Paleogene magmatism in the eastern Alps

Bellieni

Fioretti

Marzoli

et al. 2010

Rend. Fis. Acc. Lincei

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The present-day configuration of the lithosphere in the eastern Alps and more broadly in the northern Adriatic zone, records a multistage geologic evolution that was active since Precambrian times. Major evolutionary events (e.g., ocean opening, collision, subduction, etc.) were marked by the emplacement of large quantities of magmatic products. In this paper we present an overview of the field, petrographic, and geochemical characteristics of the main plutonic and volcanic bodies outcropping in the northern Adriatic zone and spanning from Permian to Cainozoic. Geochemical and petrologic study of these igneous occurrences greatly helped unraveling the geologic history of this area.

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Section: Veneto Volcanic Provincementioning

confidence: 98%

Permo–Paleogene magmatism in the eastern Alps

Bellieni

Fioretti

Marzoli

et al. 2010

Rend. Fis. Acc. Lincei

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“…Zircon xenocrysts from the RVP typify zircons that crystallize from a juvenile, Zr-saturated, REE+Y-enriched alkaline magma or melt with low HfO 2 (<0.9 wt %), Y 2 O 3 (<0.2 wt %), U, Th, ΣREE (<600 ppm), Eu/Eu* N ≈ 1, and steep, and HREE-enriched REE profiles [4,5,94]. RVP zircon xenocrysts exhibit the depletion of ΣREE+Y, U, and Th with increasing Yb/Sm N from core to rim at almost a constant Hf content.…”

Section: Classification and Comparisons Of Rvp Zircon Xenocrystsmentioning

confidence: 99%

“…RVP zircon xenocrysts exhibit the depletion of ΣREE+Y, U, and Th with increasing Yb/Sm N from core to rim at almost a constant Hf content. Such zoning favors zircon growth as a single growth stage in an alkaline environment rather than growth involving fractional crystallization [22,94,95]. In depolymerized alkaline melts, the partition coefficients for Hf and Zr between zircon and melt are approximately equal over a wide T range and melt compositions [22].…”

Section: Classification and Comparisons Of Rvp Zircon Xenocrystsmentioning

confidence: 99%

“…The lack of a negative Eu anomaly in these zircons also suggests crystallization in a system where plagioclase did not crystallize or at pressures above the plagioclase stability zone (~0.80 GPa in fertile mantle lherzolite [96]), which lends further support to a sodium-potassium-rich melt. Increasing Yb/Sm N from core to rim may indicate the depletion of the melt in LREE as a result of a co-crystallizing phase (i.e., apatite) or selective absorption of HREE during the crystallization period [94]. RVP zircon xenocrysts found as isolated crystals within the host alkali basalt, contain corroded REE-rich apatite, and REE carbonates as rare inclusions in larger crystals.…”

Section: Classification and Comparisons Of Rvp Zircon Xenocrystsmentioning

confidence: 99%

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Zircon Xenocrysts from Cenozoic Alkaline Basalts of the Ratanakiri Volcanic Province (Cambodia), Southeast Asia—Trace Element Geochemistry, O-Hf Isotopic Composition, U-Pb and (U-Th)/He Geochronology—Revelations into the Underlying Lithospheric Mantle

et al. 2018

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Zircon xenocrysts from alkali basalts in Ratanakiri Province, Cambodia represent a unique low-Hf zircon within a 12,000 km long Indo-Pacific megacryst zone. Colorless, yellow, brown, and red crystals ({100}, {101}, subordinate {211}, {1103}), with hopper growth and corrosion features range up to 20 cm in size. Zircon chemistry indicates juvenile, Zr-saturated, mantle-derived alkaline melt (Hf 0.6-0.7 wt %, Y <0.2 wt %, U + Th + REE (Rare-Earth Elements) < 600 ppm, Zr/Hf 66-92, Eu/Eu* N~1 , positive Ce/Ce* N , HREE (Heavy REE) enrichment). Incompatible element depletion with increasing Yb/Sm N from core to rim at~constant Hf suggests single stage growth. Ti-in-zircon temperatures (~570-740 • C) are lower than predicted by crystal morphology (800-900 • C) and decrease from core to rim (∆T = 10-50 • C). The δ 18 O values (4.88 to 5.01 Abstract: Zircon xenocrysts from alkali basalts in Ratanakiri Province, Cambodia represent a unique low-Hf zircon within a 12,000 km long Indo-Pacific megacryst zone. Colorless, yellow, brown, and red crystals ({100}, {101}, subordinate {211}, {1103}), with hopper growth and corrosion features range up to 20 cm in size. Zircon chemistry indicates juvenile, Zr-saturated, mantlederived alkaline melt (Hf 0.6-0.7 wt %, Y <0.2 wt %, U + Th + REE (Rare-Earth Elements) < 600 ppm, Zr/Hf 66-92, Eu/Eu*N ~1, positive Ce/Ce*N, HREE (Heavy REE) enrichment). Incompatible element depletion with increasing Yb/SmN from core to rim at ~ constant Hf suggests single stage growth. Ti-in-zircon temperatures (~570-740 C) are lower than predicted by crystal morphology (800-900 C) and decrease from core to rim (T = 10-50 C). The  18 O values (4.88 to 5.01‰ VSMOW (Vienna Standard Mean Ocean Water)) are relatively low for xenocrysts from the zircon Indo-Pacific zone (ZIP). The 176 Hf/ 177 Hf values (+ εHf 4.5-10.2) give TDepleted Mantle model source ages of 260-462 Ma and TCrustal ages of 391-754 Ma. The source magmas reflect variably depleted lithospheric mantle with little supracrustal input. Zircon U-Pb (0.88-1.56 Ma) and (U-Th)/He (0.86-1.02 Ma) ages are older than host basalt ages (~0.7 Ma), which suggests limited residence before transport. Zircon genesis suggests Zr-saturated, Al-undersaturated, carbonatitic-influenced, low-degree partial melting (<1%) of peridotitic mantle at ~60 km beneath the Indochina terrane.

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“…A final example is taken from the study of Visonà et al (2007) in their investigation of zircon megacrysts from mafic alkaline lavas of the Venetian Volcanic Province in NE Italy. Zircons from this lava sequence show the strong positive slope to the chondritenormalized pattern of the typical profile described above for the Boggy Plain zircons.…”

Section: Review Of Zircon Chemistry From a Range Of Magmatic Suitesmentioning

confidence: 99%

Stonehenge rhyolitic bluestone sources and the application of zircon chemistry as a new tool for provenancing rhyolitic lithics

Bevins

Pearce

Ixer

2011

Journal of Archaeological Science

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Zircon megacrysts from basalts of the Venetian Volcanic Province (NE Italy): U–Pb ages, oxygen isotopes and REE data

Cited by 40 publications

References 27 publications

Permo–Paleogene magmatism in the eastern Alps

Permo–Paleogene magmatism in the eastern Alps

Zircon Xenocrysts from Cenozoic Alkaline Basalts of the Ratanakiri Volcanic Province (Cambodia), Southeast Asia—Trace Element Geochemistry, O-Hf Isotopic Composition, U-Pb and (U-Th)/He Geochronology—Revelations into the Underlying Lithospheric Mantle

Stonehenge rhyolitic bluestone sources and the application of zircon chemistry as a new tool for provenancing rhyolitic lithics

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