Polyphase Deformation During Prolonged High-Temperature, Low-Pressure Metamorphism: An Example From the Namibfontein-Vergenoeg Migmatite Domes, Central Zone, Damara Belt, Namibia

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00025798%3A_____%2F25%3A10169571" target="_blank" >RIV/00025798:_____/25:10169571 - isvavai.cz</a>

Result on the web

<a href="https://doi.org/10.1111/jmg.12818" target="_blank" >https://doi.org/10.1111/jmg.12818</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1111/jmg.12818" target="_blank" >10.1111/jmg.12818</a>

Result language

angličtina

Original language name

Polyphase Deformation During Prolonged High-Temperature, Low-Pressure Metamorphism: An Example From the Namibfontein-Vergenoeg Migmatite Domes, Central Zone, Damara Belt, Namibia

Original language description

The Pan-African Damara Belt in Namibia is considered a polydeformed and polymetamorphic terrain, with a long history of magmatism (similar to 100 m.y.). However, the timing, duration and tectonic significance of high-temperature, low-pressure metamorphic phases in relation to deformation in the Central Zone remain unclear. A combined pressure-temperature-time deformation (P-T-t-d) approach applied to rocks of the Namibfontein-Vergenoeg domes, two contiguous migmatitic domes in the southern Central Zone of the Damara Belt, suggests that these rocks underwent multiple deformation phases at suprasolidus HTLP conditions, over a prolonged period of time. Monazite petrochronology of structurally controlled leucogranite and leucosome reveals that early E-W shortening (D1) linked to the Kaoko Belt formation operated from &lt; 558 to similar to 535 Ma. At similar to 535-532 Ma, a tectonic switch from E-W to NNW-SSE shortening and progressive D2 and D3 occurred, linked to the formation of the Damara Belt. Lastly, enigmatic localised NE-SW shortening (D4), parallel to the main structural trend of the Damara Belt, was active from similar to 523 to similar to 494 Ma. Monazite U-Pb geochronology records at least similar to 50 m.y. (similar to 540 to similar to 494 Ma) of monazite crystallisation and recrystallisation at suprasolidus conditions. Petrography and pseudosection modelling of Damara Supergroup metapelite indicate that all deformation occurred at similar, anatectic, HTLP conditions of 740 degrees C-780 degrees C and similar to 5 kbar. This tectono-metamorphic evolution is recorded in a shallow dP/dT PT path where the three regional shortening events (D1, D2-D3 and D4) operated in a thermally driven system with little change in pressure. These results suggest that deformation is compatible with a model of distributed strain at the scale of the orogen and a lack of pronounced crustal thickening. Long-lasting, high-temperature suprasolidus conditions raise questions regarding possible heat sources for sustained HTLP metamorphism in the Central Zone. Furthermore, these data call into question the importance of crustal thickening and subsequent exhumation of the Central Zone.

Czech name

—

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

—

OECD FORD branch

10505 - Geology

Project

<a href="/en/project/GA23-07821S" target="_blank" >GA23-07821S: Pervasive melt migration in continental crust: a micro-scale process with large-scale implications</a><br>

Continuities

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

Publication year

2025

Confidentiality

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

Name of the periodical

Journal of Metamorphic Geology

ISSN

0263-4929

e-ISSN

1525-1314

Volume of the periodical

43

Issue of the periodical within the volume

6

Country of publishing house

US - UNITED STATES

Number of pages

35

Pages from-to

555-589

UT code for WoS article

001468310300001

EID of the result in the Scopus database

2-s2.0-105003242597