scholarly journals Magmatic Signature in Submarine Hydrothermal Fluids Vented Offshore Ventotene and Zannone Islands (Pontine Archipelago, Central Italy)

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Francesco Italiano ◽  
Davide Romano ◽  
Cinzia Caruso ◽  
Manfredi Longo ◽  
Andrea Corbo ◽  
...  
Keyword(s):  
Thermal Energy ◽  
Volcanic Activity ◽  
Hydrothermal System ◽  
Isotope Composition ◽  
Central Italy ◽  
Carbon Isotope Composition ◽  
Hydrothermal Fluids ◽  
Middle Pleistocene ◽  
Tyrrhenian Sea ◽  
Variable Extent

Geochemical investigations carried out on submarine hydrothermal fluids vented offshore the Pontine Islands (Tyrrhenian Sea) revealed the existence of gas vents to the W of Zannone Island and SW of Ventotene Island. The geochemical features of the CO2-rich gas samples show a clear mantle-derived signature with3He/4He of 3.72-3.75 Ra and 1.33 Ra at Zannone and Ventotene, respectively. Gas geochemistry denotes how CO2-rich gases undergo fractionation processes due to CO2dissolution to a variable extent favoring enrichment in the less soluble gas species, i.e., CH4, N2, and He. The carbon isotope composition of CO2, expressed asδ13C vs. V-PDB, ranges from -0.71 and -6.16‰ at Zannone to 1.93‰ at Ventotene. Preliminary geothermometric and geobarometric estimations indicate equilibrium temperatures in the range of 150-200°C at Zannone and >200°C at Ventotene besides H2O pressures in the range of 5 bar and 20 bar at Zannone and Ventotene, respectively. Although the latest volcanic activity at the Pontine Archipelago is dated Middle Pleistocene, the combination of the new geochemical information along with geothermometric estimations indicates that cooling magmas are likely releasing enough thermal energy to form an efficient hydrothermal system.

scholarly journals Pleistocene volcaniclastic units from North-Eastern Sicily (Italy): new evidence for calc-alkaline explosive volcanism in the Southern Tyrrhenian Sea

2016 ◽  
Vol 67 (4) ◽  
pp. 371-389 ◽  
Author(s):  
Marcella Di Bella ◽  
Francesco Italiano ◽  
Giuseppe Sabatino ◽  
Alessandro Tripodo ◽  
Angela Baldanza ◽  
...  
Keyword(s):  
Volcanic Activity ◽  
Sea Water ◽  
Explosive Volcanism ◽  
Middle Pleistocene ◽  
Tyrrhenian Sea ◽  
Calc Alkaline ◽  
Interaction Field ◽  
Field Investigations ◽  
New Information ◽  
Southern Tyrrhenian Sea

Abstract A well-preserved volcaniclastic sequence crops out in Pleistocene marine sediments along the Tyrrhenian coastline of the Calabrian-Peloritani arc (Sicily, Italy), testifying the occurrence of Lower-Middle Pleistocene volcanic activity in Southern Tyrrhenian Sea. The presence of dominant highly vesicular and minor blocky glassy particles indicates that the volcanic clasts were originated by explosive events related to the ascent and violent emission of volatile-rich magmas accompanied by and/or alternated with hydromagmatic fragmentation due to magma-sea water interaction. Field investigations and sedimentological features of the studied volcaniclastic units suggest a deposition from sediment-water density flows. The chemical classification of the pumice clasts indicates prevalent rhyolitic and dacitic compositions with calc-alkaline to high-K calc-alkaline affinity. The geochemical features of immobile trace elements together with the presence of orthopyroxene are indicative of a provenance from an arc-type environment. The age (from 980-910 to 589 ka), the chemical composition and the evidence of subaerial explosive volcanic activity constrain the origin nature and temporal evolution of the arc-type volcanism in the Southern Tyrrhenian domain. Finally, the new information here provided contribute to a better understanding of the temporal geodynamic evolution of this sector of the Mediterranean domain.

scholarly journals Geochemical constraints on the origin of enigmatic cemented chalks, Norfolk, UK

2008 ◽  
Vol 146 (2) ◽  
pp. 291-299 ◽  
Author(s):  
G. WOOLHOUSE ◽  
J. E. ANDREWS ◽  
A. MARCA-BELL ◽  
P. F. DENNIS
Keyword(s):  
Calcium Carbonate ◽  
Stable Isotope ◽  
Isotope Composition ◽  
Carbon Isotope Composition ◽  
Biologically Active ◽  
Middle Pleistocene ◽  
Isotope Data ◽  
Glacial Tills ◽  
Geochemical Constraints ◽  
Stable Isotope Data

AbstractVery hard cemented chalk stacks and crusts found locally in the upper part of the Cretaceous Chalk of north Norfolk, UK, are related to solution features. The solution features, mainly pipes and caves, formed after deposition of the overlying Middle Pleistocene Wroxham Crag, probably by routing of sub-glacial, or glacial, melt-waters derived from late Pleistocene glaciers. New geochemical (particularly stable isotope) data shows that cementation of the chalks, although related spatially to the solution features, was not caused by glacier-derived waters. The carbon isotope composition of the chalk cements is typically around −9.5‰, indicative of biologically active soils. Moreover, the oxygen isotope compositions of the cements, around −5‰, are incompatible with water δ18O values much below −9 to −10‰ (which probably precludes isotopically negative glacier-derived water), as resulting palaeo-temperatures are below zero. Taken together, the isotope data suggest chalk cementation occurred under interglacial conditions similar to the present. Dissolved calcium carbonate for cementation came from dissolution of reworked chalk in overlying MIS 12 glacial tills.

An Exceptionally Thick Middle Pleistocene Tephra Layer from Epirus, Greece

1998 ◽  
Vol 49 (3) ◽  
pp. 280-286 ◽  
Author(s):  
David M. Pyle ◽  
Tjeerd H. van Andel ◽  
Panayiotis Paschos ◽  
Paul van den Bogaard
Keyword(s):  
Volcanic Activity ◽  
Volcanic Ash ◽  
Central Italy ◽  
Volcanic Eruptions ◽  
Middle Pleistocene ◽  
Tephra Layer ◽  
The Past ◽  
Ash Deposit ◽  
Ash Fallout ◽  
Northwestern Greece

A newly recognized 2-m-thick trachytic volcanic ash deposit from northwestern Greece is dated at 374,000 ± 7000 yr and correlated with the Middle Pleistocene volcanic activity of central Italy. The deposit represents ash fallout from one of the largest volcanic eruptions in Europe of the past 400,000 yr and should provide an important stratigraphic marker within the poorly dated Middle Pleistocene deposits of Italy and Greece.

scholarly journals Rolling Ironstones from Earth and Mars: Terrestrial Hydrothermal Ooids as a Potential Analogue of Martian Spherules

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 460
Author(s):  
Marcella Di Bella ◽  
Franco Pirajno ◽  
Giuseppe Sabatino ◽  
Simona Quartieri ◽  
Roberto Barbieri ◽  
...  
Keyword(s):  
High Resolution ◽  
Volcanic Activity ◽  
Hydrothermal System ◽  
Mineralogical Composition ◽  
Hydrothermal Activity ◽  
Hydrothermal Fluids ◽  
Cause Of Formation ◽  
The Earth ◽  
High Resolution Images ◽  
Iron Ooids

High-resolution images of Mars from National Aeronautics and Space Administration (NASA) rovers revealed mm-size loose haematite spherulitic deposits (nicknamed “blueberries”) similar to terrestrial iron-ooids, for which both abiotic and biotic genetic hypotheses have been proposed. Understanding the formation mechanism of these haematite spherules can thus improve our knowledge on the possible geologic evolution and links to life development on Mars. Here, we show that shape, size, fabric and mineralogical composition of the Martian spherules share similarities with corresponding iron spherules currently forming on the Earth over an active submarine hydrothermal system located off Panarea Island (Aeolian Islands, Mediterranean Sea). Hydrothermal fluids associated with volcanic activity enable these terrestrial spheroidal grains to form and grow. The recent exceptional discovery of a still working iron-ooid source on the Earth provides indications that past hydrothermal activity on the Red Planet is a possible scenario to be considered as the cause of formation of these enigmatic iron grains.

scholarly journals Coeval primary and diagenetic carbonates in lacustrine sediments challenge palaeoclimate interpretations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jeremy McCormack ◽  
Ola Kwiecien
Keyword(s):  
Isotope Composition ◽  
Lacustrine Sediments ◽  
Carbon Isotope Composition ◽  
Large Variability ◽  
Oxygen And Carbon Isotope ◽  
Temperature And Precipitation ◽  
Lacustrine Carbonates ◽  
Geochemical Analyses ◽  
Mixed Nature ◽  
Water Carbonate

AbstractLakes are sensitive to climate change and their sediments play a pivotal role as environmental recorders. The oxygen and carbon isotope composition (δ18O and δ13C) of carbonates from alkaline lakes is featured in numerous studies attempting a quantitative reconstruction of rainfall, temperature and precipitation-evaporation changes. An often-overlooked challenge consists in the mineralogically mixed nature of carbonates themselves. We document a large variability of carbonate components and their respective distinct δ18O and δ13C values from sediments of Lake Van (Turkey) covering the last 150 kyr. The carbonate inventory consists of primary (1) inorganic calcite and aragonite precipitating in the surface-water, (2) biogenic calcite ostracod valves; and post-depositional phases: (3) dolomite forming in the sediment, and previously overlooked, (4) aragonite encrustations formed rapidly around decaying organic matter. We find a systematic relation between the lithology and the dominant deep-water carbonate phase formed recurrently under specific hydrological conditions. The presence of the different carbonates is never mutually exclusive, and the isotopic composition of each phase forms a distinctive cluster characteristic for the depth and timing of their formation. Our findings stretch the envelope of mechanisms forming lacustrine carbonates and highlight the urge to identify and separate carbonate components prior to geochemical analyses.

The influence of hydrodynamics on the carbon isotope composition of inorganically precipitated calcite

2021 ◽  
Vol 565 ◽  
pp. 116932
Author(s):  
Hao Yan ◽  
Wolfgang Dreybrodt ◽  
Huiming Bao ◽  
Yongbo Peng ◽  
Yu Wei ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
Isotope Composition ◽  
Carbon Isotope Composition

scholarly journals Analysis of Hydrothermal Systems Beneath Tayukeng through Long-Term Geochemical Signals of Hydrothermal Fluids in Tatun Volcano Group, Taiwan

2021 ◽  
Vol 18 (14) ◽  
pp. 7411
Author(s):  
Hsin-Fu Yeh ◽  
Hung-Hsiang Hsu
Keyword(s):  
Surface Temperature ◽  
Hydrothermal System ◽  
Hydrothermal Fluid ◽  
Thermal Water ◽  
Hydrothermal Systems ◽  
Hydrothermal Fluids ◽  
Geochemical Variations ◽  
Northern Taiwan

The Tatun Volcano Group (TVG) is located in northern Taiwan and consists of many springs and fumaroles. The Tayukeng (TYK) area is the most active fumarole site in the TVG. In this study, we analyzed the long-term geochemical variations of hydrothermal fluids and proposed a mechanism responsible for the variation in TYK. There are two different aquifers beneath the TYK area: a shallow SO42−-rich aquifer and a deeper aquifer rich in Cl−. TYK thermal water was mainly supplied by the shallow SO42−-rich aquifer; therefore, the thermal water showed high SO42− concentrations. After 2015, the inflow of deep thermal water increased, causing the Cl− concentrations of the TYK to increase. Notably, the inferred reservoir temperatures based on quartz geothermometry increased; however, the surface temperature of the spring decreased. We inferred that the enthalpy was lost during transportation to the surface. Therefore, the surface temperature of the spring does not increase with an increased inflow of deep hydrothermal fluid. The results can serve as a reference for understanding the complex evolution of the magma-hydrothermal system in the TVG.

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