Lithium systematics in the Krafla volcanic system: comparison between surface rhyolites and felsic cuttings from the Iceland deep drilling project-1 (IDDP-1)

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00025798%3A_____%2F24%3A10169208" target="_blank" >RIV/00025798:_____/24:10169208 - isvavai.cz</a>

Result on the web

<a href="https://doi.org/10.1007/s00410-024-02119-y" target="_blank" >https://doi.org/10.1007/s00410-024-02119-y</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1007/s00410-024-02119-y" target="_blank" >10.1007/s00410-024-02119-y</a>

Result language

angličtina

Original language name

Lithium systematics in the Krafla volcanic system: comparison between surface rhyolites and felsic cuttings from the Iceland deep drilling project-1 (IDDP-1)

Original language description

The unexpected discovery of felsic magma by the Iceland Deep Drilling Project-1 (IDDP-1) in the Krafla volcanic system (KVS) presents a unique opportunity to investigate pre-eruptive lithium (Li) dynamics and establish a more direct connection between magma reservoirs and volcanic deposits. Our study provides new insights into Li abundances and isotope compositions in bulk-rock, minerals, and groundmass glass from rhyolitic lavas at KVS, encompassing various stages of groundmass crystallisation. Additionally, we examined felsic cuttings retrieved from the IDDP-1 well, comprising crystal-poor obsidian and crystal-bearing to -rich &apos;felsite&apos; particles. Groundmass glasses from surface lavas show limited variability in K/Na, indicating limited secondary hydration of the glasses and that their Li contents seem to not be affected by this post-eruptive process. Lithium inventories in groundmass glasses and minerals within lavas exhibit variations consistent with the cooling history of the deposit, resembling patterns seen in Snake River Plain ignimbrites. Lithium contents of glassy rhyolitic lavas, whether bulk-rock (avg. 27.2 +/- 3.1 mu g/g) or groundmass glass (average 28.4 +/- 4.7 mu g/g), and their bulk isotopic compositions (avg. delta 7Li =+ 4.4 +/- 0.2 parts per thousand) overlap with those observed in IDDP-1 obsidian cuts (avg. 24.9 mu g/g Li in bulk, 28.6 +/- 1.5 mu g/g in groundmass glass, and delta 7Li = 4.5 +/- 0.2 parts per thousand). Glassy lavas lacking spherulites may potentially preserve pristine magmatic Li element and isotope compositions, while areas with extensive groundmass crystallisation reveal Li enrichments in phenocrysts. Plagioclases in slowly cooled parts of the deposit record a two-fold increase in Li contents compared to plagioclase found in glassy counterparts, along with evidence of open-system degassing marked by heavier bulk Li isotope compositions and lower bulk Li contents of the crystallised lava portions (avg. delta 7Li = +7.2 +/- 0.1 parts per thousand and 7 +/- 0.8 mu g/g Li) relative to bulk glassy lithologies (avg. delta 7Li = +4.1 +/- 0.1 parts per thousand and 28 +/- 2 mu g/g Li). Partition coefficients derived from IDDP-1 cuts successfully predict Li inventories in vitrophyres of rhyolites on the surface of the KVS. Lithium isotope compositions of the crystal-rich IDDP-1 cuts are significantly heavier (avg. delta 7Li = +7.2 +/- 0.2 parts per thousand) than lavas and IDDP-1 obsidian cuts, casting doubt on the notion that the IDDP-1 rhyolitic magma could result from the melting of felsite lenses in the KVS. Lithium contents in groundmass glasses within IDDP-1 crystal-rich cuts show higher Li contents (avg. 55.1-60.7 mu g/g), correlating with the higher crystal content and an increase in other incompatible elements (avg. 250 mu g/g Rb) relative to obsidian cuttings (avg. 75 mu g/g Rb).

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10505 - Geology

Project

<a href="/en/project/GA23-07625S" target="_blank" >GA23-07625S: Pre-Variscan oceanic basins of the Bohemian Massif - Integrating petrology, geochronology and non-traditional stable isotope systems</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2024

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Contributions to Mineralogy and Petrology

ISSN

0010-7999

e-ISSN

1432-0967

Volume of the periodical

179

Issue of the periodical within the volume

4

Country of publishing house

DE - GERMANY

Number of pages

21

Pages from-to

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UT code for WoS article

001197459300002

EID of the result in the Scopus database

2-s2.0-85189624165