J 2019

Titanite composition and SHRIMP U-Pb dating as indicators of post-magmatic tectono-thermal activity: Variscan I-type tonalites to granodiorites, the Western Carpathians

UHER, P., I. BROSKA, E. KRZEMINSKA, M. ONDREJKA, T. MIKUS et. al.

Základní údaje

Originální název

Titanite composition and SHRIMP U-Pb dating as indicators of post-magmatic tectono-thermal activity: Variscan I-type tonalites to granodiorites, the Western Carpathians

Autoři

UHER, P. (garant), I. BROSKA, E. KRZEMINSKA, M. ONDREJKA, T. MIKUS a Tomáš VACULOVIČ (203 Česká republika, domácí)

Vydání

Geologica Carpathica, BRATISLAVA, SLOVAK ACAD SCIENCES GEOLOGICAL INST, 2019, 1335-0552

Další údaje

Jazyk

angličtina

Typ výsledku

Článek v odborném periodiku

Obor

10505 Geology

Stát vydavatele

Slovensko

Utajení

není předmětem státního či obchodního tajemství

Odkazy

Impakt faktor

Impact factor: 1.535

Kód RIV

RIV/00216224:14310/19:00113427

Organizační jednotka

Přírodovědecká fakulta

UT WoS

000504072500001

Klíčová slova anglicky

titanite; I-type granites; Zr-in-titanite thennometry; LA-ICP-MS analyses; SHRIMP U-Pb dating; Western Carpathians

Štítky

Příznaky

Mezinárodní význam, Recenzováno
Změněno: 31. 3. 2020 21:05, Mgr. Marie Šípková, DiS.

Anotace

V originále

Titanite belongs to the common accessory minerals in Variscan (similar to 360-350 Ma) metaluminous to slightly peraluminous tonalites to granodiorites of I-type affinity in the Tatric and Veporic Units, the Western Carpathians, Slovakia. It forms brown tabular prismatic-dipyramidal crystals (similar to 0.5 to 10 mm in size) in association with quartz., plagioclase, and biotite. Titanite crystals commonly shows oscillatory, sector and convolute irregular zonal textures, reflecting mainly variations in Ca and Ti versus Al (1-2 wt. % Al2O3, 0.04-0.08 Al apfu), Fe (0.6-1.6 wt. % Fe2O3, 0.02-0.04 Fe apfu), REE (La to Lu+ Y: 54.8 wt. % REE2O3, <= 0.06 REE apfu), and Nb (up to 0.5 wt. % Nb2O5, <= 0.01 Nb apfu). Fluorine content is up to 0.5 wt.% (0.06 F apfu). The compositional variations indicate the following principal substitutions in titanite: REE3++ Fe3+= Ca-2+Ti4+, 2REE(3+)+ Fe2+ = 2Ca(2+) Ti4+, and (Al,Fe)(3+)+ (OH, F)(-) = Ti4++O2-. The U-Pb SHRIMP dating of titanite reveal their Variscan ages in an interval of 351.0 +/- 6.5 to 337.9 +/- 6.1 Ma (Tournaisian to Visean); titanite U-Pb ages are thus similar to 5 to 19 Ma younger than the primary magmatic zircon of the host rocks. The Zr-in-titanite thermometry indicates a relatively high temperature range of titanite precipitation (similar to 650-750 degrees C), calculated for assumed pressures of 0.2 to 0.4 GPa and a(TiO2)=0.6-1.0. Consequently, the textural, geochronological and compositional data indicate relatively high-temperature, most probably early post-magmatic (subsolidus) precipitation of titanite. Such titanite origin could be connected with a subsequent Variscan tectono-thermal event (similar to 340 +/- 10 Ma), probably related with younger small granite intrusions and/or increased fluid activity. Moreover, some titanite crystals show partial alteration and formation of secondary titanite (depleted in Fe and REE)+allanite-(Ce) veinlets (Sihla tonalite. Veporic Unit), which probably reflects younger Alpine (Cretaceous) tectono-thermal overprint of the Variscan basement of the Western Carpathians.