The Role of Boron-Chloride and Noble Gas Isotope Ratios in TVZ Geothermal Systems

ABSTRACT:The Lu-Hf and Re-Os isotope systems have been applied sparsely to elucidate the origin of granites, intracrustal processes and the evolution of the continental crust. The presence or absence of garnet as a residual phase during partial melting will strongly influence Lu/Hf partitioning, making the Lu–Hf isotope system exceptionally sensitive to evaluating the role of garnet during intracrustal differentiation processes. Mid-Proterozoic (1·1–1·5Ga ) ‘anorogenic’ granites from the western U.S.A. appear to have anomalously high εHf values, relative to their εNd values, compared with Precambrian orogenic granites from several continents. The Hf-Nd isotope variations for Precambrian orogenic granites are well explained by melting processes that are ultimately tied to garnet-bearing sources in the mantle or crust. Residual, garnet-bearing lower and middle crust will evolve to anomalously high εHf values over time and may be the most likely source for later ‘anorogenic’ magmas. When crustal and mantle rocks are viewed together in terms of Hf and Nd isotope compositions, a remarkable mass balance is apparent for at least the outer silicate earth where Precambrian orogenic continental crust is the balance to the high-εHf depleted mantle, and enriched lithospheric mantle is the balance to the low-εHf depleted mantle.Although the continental crust has been envisioned to have exceptionally high Re/Os ratios and very radiogenic Os isotope compositions, new data obtained on magnetite mineral separates suggest that some parts of the Precambrian continental crust are relatively Os-rich and non-radiogenic. It remains unclear how continental crust may obtain non-radiogenic Os isotope ratios, and these results have important implications for Re-Os isotope evolution models. In contrast, Phanerozoic batholiths and volcanic arcs that are built on young mafic lower crust may have exceptionally radiogenic Os isotope ratios. These results highlight the unique ability of Os isotopes to identify young mafic crustal components in orogenic magmas that are essentially undetectable using other isotope systems such as O, Sr, Nd and Pb.

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Tracing the Origins of the Ice Giants through Noble Gas Isotopic Composition

10.5194/egusphere-egu21-7798 ◽

2021 ◽

Author(s):

Kathleen Mandt ◽

Olivier Mousis ◽

Jonathan Lunine ◽

Bernard Marty ◽

Thomas Smith ◽

...

Keyword(s):

Solar System ◽

Isotopic Composition ◽

Heavy Element ◽

Noble Gas ◽

Giant Planet ◽

Isotope Ratios ◽

Building Blocks ◽

Giant Planets ◽

Element Abundances ◽

Current State

The current composition of giant planet atmospheres provides information on how such planets formed, and on the origin of the solid building blocks that contributed to their formation. Noble gas abundances and their isotope ratios are among the most valuable pieces of evidence for tracing the origin of the materials from which the giant planets formed. In this review we first outline the current state of knowledge for heavy element abundances in the giant planets and explain what is currently understood about the reservoirs of icy building blocks that could have contributed to the formation of the Ice Giants. We then outline how noble gas isotope ratios have provided details on the original sources of noble gases in various materials throughout the solar system. We follow this with a discussion on how noble gases are trapped in ice and rock that later became the building blocks for the giant planets and how the heavy element abundances could have been locally enriched in the protosolar nebula. We then provide a review of the current state of knowledge of noble gas abundances and isotope ratios in various solar system reservoirs, and discuss measurements needed to understand the origin of the ice giants. Finally, we outline how formation and interior evolution will influence the noble gas abundances and isotope ratios observed in the ice giants today. Measurements that a future atmospheric probe will need to make include (1) the 3He/4He isotope ratio to help constrain the protosolar D/H and 3He/4He; (2) the 20Ne/22Ne and 21Ne/22Ne to separate primordial noble gas reservoirs similar to the approach used in studying meteorites; (3) the Kr/Ar and Xe/Ar to determine if the building blocks were Jupiter-like or similar to 67P/C-G and Chondrites; (4) the krypton isotope ratios for the first giant planet observations of these isotopes; and (5) the xenon isotopes for comparison with the wide range of values represented by solar system reservoirs.Mandt, K. E., Mousis, O., Lunine, J., Marty, B., Smith, T., Luspay-Kuti, A., & Aguichine, A. (2020). Tracing the origins of the ice giants through noble gas isotopic composition. Space Science Reviews, 216(5), 1-37.

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8. Noble Gas Isotope Geochemistry of Mid-Ocean Ridge and Ocean Island Basalts: Characterization of Mantle Source Reservoirs

Noble Gases ◽

10.1515/9781501509056-010 ◽

2002 ◽

pp. 247-318 ◽

Cited By ~ 74

Author(s):

David W. Graham

Keyword(s):

Mantle Source ◽

Isotope Geochemistry ◽

Noble Gas ◽

Ocean Island ◽

Ocean Island Basalts ◽

Mid Ocean Ridge ◽

Noble Gas Isotope ◽

Ocean Ridge

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Leading Interaction Components in the Structure and Reactivity of Noble Gases Compounds

Molecules ◽

10.3390/molecules25102367 ◽

2020 ◽

Vol 25 (10) ◽

pp. 2367

Author(s):

Francesca Nunzi ◽

Giacomo Pannacci ◽

Francesco Tarantelli ◽

Leonardo Belpassi ◽

David Cappelletti ◽

...

Keyword(s):

Chemical Bond ◽

Theoretical Approach ◽

Noble Gases ◽

Halogen Bond ◽

Noble Gas ◽

Anomalous Behavior ◽

Type Interaction ◽

Long Life ◽

Weak Chemical

The nature, strength, range and role of the bonds in adducts of noble gas atoms with both neutral and ionic partners have been investigated by exploiting a fine-tuned integrated phenomenological–theoretical approach. The identification of the leading interaction components in the noble gases adducts and their modeling allows the encompassing of the transitions from pure noncovalent to covalent bound aggregates and to rationalize the anomalous behavior (deviations from noncovalent type interaction) pointed out in peculiar cases. Selected adducts affected by a weak chemical bond, as those promoting the formation of the intermolecular halogen bond, are also properly rationalized. The behavior of noble gas atoms excited in their long-life metastable states, showing a strongly enhanced reactivity, has been also enclosed in the present investigation.

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Noble Gases in Terrestrial Planets: Evidence for Cometary Impacts?

International Astronomical Union Colloquium ◽

10.1017/s0252921100109789 ◽

1989 ◽

Vol 116 (1) ◽

pp. 429-437

Author(s):

Tobias Owen ◽

Akiva Bar-Nun ◽

Idit Kleinfeld

Keyword(s):

Low Temperatures ◽

Noble Gases ◽

Noble Gas ◽

Terrestrial Planets ◽

Laboratory Studies ◽

The Impact ◽

Gas Patterns ◽

Atmosphere Of Venus

AbstractThe possible role of comets in bringing volatiles to the inner planets is investigated by means of laboratory studies of the ability of ice to trap gases at low temperatures. The pattern of the heavy noble gases formed in the atmosphere of Venus can be explained by the impact of a planetesimal composed of ices formed in the range of 20 to 30 K. The noble gas patterns on Mars and Earth are less explicable by cometary bombardment alone.

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