Outgassing of Mantle Volatiles in Compressional Tectonic Regime Away From Volcanism: The Role of Continental Delamination

Caracausi, A.

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Abstract

In this study we discuss the occurrence of mantle-derived heat and volatiles (i.e., helium and CO 2 ) feeding hydrothermal systems in a seismically active margin between two convergent plates (African and European) without any signals of volcanism. The helium (He) isotopes clearly indicate a mantle-derived component in the outgassing volatiles. The estimated mantle-derived He fluxes are up to two to three orders of magnitude greater than those in a stable continental area. Such high He fluxes cannot be provided by a long-lasting diffusion, thereby implying a more efficient transport (i.e., advective transport through faults). He data coupled to heat-He relationship suggest the occurrence of active degassing of magmatic intrusions in this area of continental collisional. Geophysical data indicate the presence of a hot mantle wedge below the outgassing of mantle volatiles and a system of faults cutting the continental crust down to the hot mantle wedge. Here we discuss the hot mantle wedge and possible associated magmatic intrusions as the source of the mantle-derived volatiles outgassing in the region. We also assessed the output of mantle-derived CO 2 from the investigated hydrothermal basins. The possible occurrence of magma at depth as well as the geometry of the thick-skinned deformed wedge unambiguously indicates delamination processes that are related to continental subduction. Hence, we show that delamination processes can really produce magma at depth without evidences of volcanism at the surface. Finally, we have also provided the fault systems that work as a network of pathways and actively sustain the advective transfer of the mantle fluids toward the surface.
Lingua originaleEnglish
pagine (da-a)2007-2020
Numero di pagine14
RivistaGeochemistry, Geophysics, Geosystems
Volume20
Stato di pubblicazionePublished - 2019

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@article{1bba105fe46640b9be352233be80d695,
title = "Outgassing of Mantle Volatiles in Compressional Tectonic Regime Away From Volcanism: The Role of Continental Delamination",
abstract = "In this study we discuss the occurrence of mantle-derived heat and volatiles (i.e., helium and CO 2 ) feeding hydrothermal systems in a seismically active margin between two convergent plates (African and European) without any signals of volcanism. The helium (He) isotopes clearly indicate a mantle-derived component in the outgassing volatiles. The estimated mantle-derived He fluxes are up to two to three orders of magnitude greater than those in a stable continental area. Such high He fluxes cannot be provided by a long-lasting diffusion, thereby implying a more efficient transport (i.e., advective transport through faults). He data coupled to heat-He relationship suggest the occurrence of active degassing of magmatic intrusions in this area of continental collisional. Geophysical data indicate the presence of a hot mantle wedge below the outgassing of mantle volatiles and a system of faults cutting the continental crust down to the hot mantle wedge. Here we discuss the hot mantle wedge and possible associated magmatic intrusions as the source of the mantle-derived volatiles outgassing in the region. We also assessed the output of mantle-derived CO 2 from the investigated hydrothermal basins. The possible occurrence of magma at depth as well as the geometry of the thick-skinned deformed wedge unambiguously indicates delamination processes that are related to continental subduction. Hence, we show that delamination processes can really produce magma at depth without evidences of volcanism at the surface. Finally, we have also provided the fault systems that work as a network of pathways and actively sustain the advective transfer of the mantle fluids toward the surface.",
keywords = "delamination; helium; mantle volatiles; mantle wedge; output CO 2; Geophysics; Geochemistry and Petrology",
author = "{Caracausi, A.} and Attilio Sulli",
year = "2019",
language = "English",
volume = "20",
pages = "2007--2020",
journal = "Geochemistry, Geophysics, Geosystems",
issn = "1525-2027",
publisher = "American Geophysical Union",

}

TY - JOUR

T1 - Outgassing of Mantle Volatiles in Compressional Tectonic Regime Away From Volcanism: The Role of Continental Delamination

AU - Caracausi, A.

AU - Sulli, Attilio

PY - 2019

Y1 - 2019

N2 - In this study we discuss the occurrence of mantle-derived heat and volatiles (i.e., helium and CO 2 ) feeding hydrothermal systems in a seismically active margin between two convergent plates (African and European) without any signals of volcanism. The helium (He) isotopes clearly indicate a mantle-derived component in the outgassing volatiles. The estimated mantle-derived He fluxes are up to two to three orders of magnitude greater than those in a stable continental area. Such high He fluxes cannot be provided by a long-lasting diffusion, thereby implying a more efficient transport (i.e., advective transport through faults). He data coupled to heat-He relationship suggest the occurrence of active degassing of magmatic intrusions in this area of continental collisional. Geophysical data indicate the presence of a hot mantle wedge below the outgassing of mantle volatiles and a system of faults cutting the continental crust down to the hot mantle wedge. Here we discuss the hot mantle wedge and possible associated magmatic intrusions as the source of the mantle-derived volatiles outgassing in the region. We also assessed the output of mantle-derived CO 2 from the investigated hydrothermal basins. The possible occurrence of magma at depth as well as the geometry of the thick-skinned deformed wedge unambiguously indicates delamination processes that are related to continental subduction. Hence, we show that delamination processes can really produce magma at depth without evidences of volcanism at the surface. Finally, we have also provided the fault systems that work as a network of pathways and actively sustain the advective transfer of the mantle fluids toward the surface.

AB - In this study we discuss the occurrence of mantle-derived heat and volatiles (i.e., helium and CO 2 ) feeding hydrothermal systems in a seismically active margin between two convergent plates (African and European) without any signals of volcanism. The helium (He) isotopes clearly indicate a mantle-derived component in the outgassing volatiles. The estimated mantle-derived He fluxes are up to two to three orders of magnitude greater than those in a stable continental area. Such high He fluxes cannot be provided by a long-lasting diffusion, thereby implying a more efficient transport (i.e., advective transport through faults). He data coupled to heat-He relationship suggest the occurrence of active degassing of magmatic intrusions in this area of continental collisional. Geophysical data indicate the presence of a hot mantle wedge below the outgassing of mantle volatiles and a system of faults cutting the continental crust down to the hot mantle wedge. Here we discuss the hot mantle wedge and possible associated magmatic intrusions as the source of the mantle-derived volatiles outgassing in the region. We also assessed the output of mantle-derived CO 2 from the investigated hydrothermal basins. The possible occurrence of magma at depth as well as the geometry of the thick-skinned deformed wedge unambiguously indicates delamination processes that are related to continental subduction. Hence, we show that delamination processes can really produce magma at depth without evidences of volcanism at the surface. Finally, we have also provided the fault systems that work as a network of pathways and actively sustain the advective transfer of the mantle fluids toward the surface.

KW - delamination; helium; mantle volatiles; mantle wedge; output CO 2; Geophysics; Geochemistry and Petrology

UR - http://hdl.handle.net/10447/359264

UR - http://agupubs.onlinelibrary.wiley.com/agu/journal/10.1002/(ISSN)1525-2027/

M3 - Article

VL - 20

SP - 2007

EP - 2020

JO - Geochemistry, Geophysics, Geosystems

JF - Geochemistry, Geophysics, Geosystems

SN - 1525-2027

ER -