Magnetization related to late-Variscan extensional collapse in the Lugo Dome (NW Iberian Massif): a metamorphic petrology approach

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00025798%3A_____%2F24%3A10169103" target="_blank" >RIV/00025798:_____/24:10169103 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1016/j.lithos.2024.107745" target="_blank" >https://doi.org/10.1016/j.lithos.2024.107745</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.lithos.2024.107745" target="_blank" >10.1016/j.lithos.2024.107745</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Magnetization related to late-Variscan extensional collapse in the Lugo Dome (NW Iberian Massif): a metamorphic petrology approach

Popis výsledku v původním jazyce

The Eastern Galicia Magnetic Anomaly (EGMA) is one of the most distinctive and best studied magnetic anomalies in Iberia. It is located in NW Spain and overlaps the Variscan gneissic domes of Lugo and Sanabria. The Lugo Dome, in the north of the EGMA, deforms a large thrust sheet, the Mondoñedo Nappe, allowing the outcropping of its relative autochthon in the Xistral Tectonic Window, where extensional detachments resulting from late-Variscan tectonics crop out. A younger major detachment, the Viveiro Fault, developed on the western limb of the dome. Detailed ground-based magnetic mapping and geological charts show a clear spatial relationship between magnetic maxima and the extensional structures. Magnetic and paleomagnetic studies carried out on samples from this region indicate that rocks in the detachments commonly bear magnetite and hematite carrying induced but also remanent magnetizations and a very well-defined anisotropy of the magnetic susceptibility with directions matching those of the late-Variscan extensional fabrics. Three pairs of metasedimentary samples in equivalent structural positions display variously developed medium-pressure Barrovian parageneses attributed to the early compressional phases of the Variscan orogeny, and low-pressure Buchan-type parageneses associated with the late Variscan extension. Our phase diagram-based petrological study suggests that the non-magnetic samples preserve the Barrovian conditions of 560-640 oC, 5-8.7 kbar. The lithologically and structurally equivalent samples, originally non-magnetic, developed magnetite/hematite-bearing mineral assemblages during decompression and cooling to 500-620 oC, 1.5-6 kbar. This recrystallization was probably assisted by metasomatic oxidizing fluids. The induced component of magnetization is essentially carried by magnetite, while hematite seems the main carrier of remanence. These results support the existing cartographic, geophysical and paleomagnetic findings indicating that the magnetization in the Lugo Dome is related to late-Variscan extension.

Název v anglickém jazyce

Magnetization related to late-Variscan extensional collapse in the Lugo Dome (NW Iberian Massif): a metamorphic petrology approach

Popis výsledku anglicky

The Eastern Galicia Magnetic Anomaly (EGMA) is one of the most distinctive and best studied magnetic anomalies in Iberia. It is located in NW Spain and overlaps the Variscan gneissic domes of Lugo and Sanabria. The Lugo Dome, in the north of the EGMA, deforms a large thrust sheet, the Mondoñedo Nappe, allowing the outcropping of its relative autochthon in the Xistral Tectonic Window, where extensional detachments resulting from late-Variscan tectonics crop out. A younger major detachment, the Viveiro Fault, developed on the western limb of the dome. Detailed ground-based magnetic mapping and geological charts show a clear spatial relationship between magnetic maxima and the extensional structures. Magnetic and paleomagnetic studies carried out on samples from this region indicate that rocks in the detachments commonly bear magnetite and hematite carrying induced but also remanent magnetizations and a very well-defined anisotropy of the magnetic susceptibility with directions matching those of the late-Variscan extensional fabrics. Three pairs of metasedimentary samples in equivalent structural positions display variously developed medium-pressure Barrovian parageneses attributed to the early compressional phases of the Variscan orogeny, and low-pressure Buchan-type parageneses associated with the late Variscan extension. Our phase diagram-based petrological study suggests that the non-magnetic samples preserve the Barrovian conditions of 560-640 oC, 5-8.7 kbar. The lithologically and structurally equivalent samples, originally non-magnetic, developed magnetite/hematite-bearing mineral assemblages during decompression and cooling to 500-620 oC, 1.5-6 kbar. This recrystallization was probably assisted by metasomatic oxidizing fluids. The induced component of magnetization is essentially carried by magnetite, while hematite seems the main carrier of remanence. These results support the existing cartographic, geophysical and paleomagnetic findings indicating that the magnetization in the Lugo Dome is related to late-Variscan extension.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10505 - Geology

Projekt

—

Návaznosti

V - Vyzkumna aktivita podporovana z jinych verejnych zdroju

Rok uplatnění

2024

Kód důvěrnosti údajů

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

Název periodika

Lithos

ISSN

0024-4937

e-ISSN

—

Svazek periodika

484-485

Číslo periodika v rámci svazku

107745

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

22

Strana od-do

—

Kód UT WoS článku

001296379800001

EID výsledku v databázi Scopus

2-s2.0-85200967731