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Curie Temperatures and Emplacement Conditions of Pyroclastic Deposits From Popocatépetl Volcano, Mexico

Dudzisz, K. 1; Kontny, A. 1; Alva-Valdivia, L. M.
1 Institut für Angewandte Geowissenschaften (AGW), Karlsruher Institut für Technologie (KIT)

Abstract:

Most pyroclastic deposits of Popocatépetl volcano were emplaced at high temperatures and have similar mafic to more evolved compositions, suggesting a long-lived, interconnected magma environment. We performed a magnetic and microscopic study on different eruptive sequences <14 ky in age and found that temperature and field dependence of magnetic susceptibility are suited to separate eruption phases. We observed homogeneous titanomagnetite with Curie temperatures (T$_{C}$) of 50–200°C and 200–400°C, together with different amounts of oxy-exsolved titanomagnetite with T$_{C}$ ∼ 570°C. Some block-and-ash flow deposits show remarkably irreversible T$_{C}$ in heating and cooling branches with a positive ΔT$_{C}$ (T$_{C}$ $_{heating}$ –T$_{C}$ $_{cooling}$) of up to 130°C in the center. The central part of this sequence is characterized by decreasing magnetic susceptibility and low field dependence of magnetic susceptibility (<10%), which is atypical for ulvöspinel-rich titanomagnetite. The nonreversibility of heating and cooling runs measured with rates of around 10 K/min is probably related to vacancy-enhanced nanoscale chemical clustering, which seems to occur preferentially during rapid quenching, possibly combined with subtle maghemitization. ... mehr


Verlagsausgabe §
DOI: 10.5445/IR/1000151267
Veröffentlicht am 20.10.2022
Originalveröffentlichung
DOI: 10.1029/2022GC010340
Scopus
Zitationen: 4
Web of Science
Zitationen: 4
Dimensions
Zitationen: 3
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Angewandte Geowissenschaften (AGW)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 08.2022
Sprache Englisch
Identifikator ISSN: 1525-2027
KITopen-ID: 1000151267
Erschienen in Geochemistry, Geophysics, Geosystems
Verlag John Wiley and Sons
Band 23
Heft 8
Seiten Nr. e2022GC010340
Bemerkung zur Veröffentlichung Gefördert durch den KIT-Publikationsfonds
Vorab online veröffentlicht am 29.08.2022
Nachgewiesen in Web of Science
Scopus
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