TY - JOUR
T1 - Protracted Thermal Evolution of a Migmatitic Terrane as Revealed by Multiple Geochronometers From the Retro-Arc of the Early Paleozoic Famatinian Orogen in NW Argentina
AU - Farias, Pablo
AU - Weinberg, Roberto F.
AU - Sola, Alfonso
AU - Finch, Melanie
N1 - Funding Information:
We thank Tato Becchio and Nestor Suzaño for discussions and a great time in the field. We thank Massimo Raveggi and Vitor Barrote for technical support. We would also like to thank the very careful and helpful reviews by Kathryn Cutts, Oscar Laurent, Friedrich Lucassen and an anonymous reviewer, and the handling of associate editor Djordje Grujic. A. Sola thanks the Agencia Nacional de Promoción Científica y Tecnológica for the Grant PICT-2018-02889 (FONCyT). This research was supported by the Australian Research Council Grant DP110102543 to R.F.W. Open access publishing facilitated by Monash University, as part of the Wiley - Monash University agreement via the Council of Australian University Librarians.
Funding Information:
We thank Tato Becchio and Nestor Suzaño for discussions and a great time in the field. We thank Massimo Raveggi and Vitor Barrote for technical support. We would also like to thank the very careful and helpful reviews by Kathryn Cutts, Oscar Laurent, Friedrich Lucassen and an anonymous reviewer, and the handling of associate editor Djordje Grujic. A. Sola thanks the Agencia Nacional de Promoción Científica y Tecnológica for the Grant PICT‐2018‐02889 (FONCyT). This research was supported by the Australian Research Council Grant DP110102543 to R.F.W. Open access publishing facilitated by Monash University, as part of the Wiley ‐ Monash University agreement via the Council of Australian University Librarians.
Publisher Copyright:
© 2023. The Authors.
PY - 2023/3
Y1 - 2023/3
N2 - U-Pb dates of zircon, monazite, and titanite combined with trace element composition, allows characterization of the thermal evolution of the migmatitic Agua del Sapo complex. This complex comprises Al-rich and Ca-rich metasedimentary rocks with a detrital zircon maximum depositional age of 550 Ma. The rocks record two consecutive early Paleozoic orogenies. During subduction associated with the 550–510 Ma Pampean orogeny, the complex was in the fore-arc region and was intruded by 550–520 Ma granites indicative of anomalous heating possibly related to ridge subduction. During the subsequent 500–440 Ma Famatinian orogeny, the arc migrated trenchwards and the region became part of a retro-arc that underwent melting at upper-amphibolite facies. This event was recorded differently by each of the accessory phases. Detrital zircon cores were overgrown by rare Famatinian rims that range from 500 to 420 Ma, while monazite records only Famatinian dates with a growth peak at ∼457 Ma that extends to 410 Ma, possibly due to coupled dissolution-precipitation. Published titanite dates define a 120 Myr thermal history, starting at ∼500 Ma with temperatures of ∼750°C ± 25°C, ending at 380 Ma and ∼700°C ± 25°C. Cooling was accompanied by a decrease in titanite light rare earth element contents in response to increased abundance of allanite/epidote. Thus, the complementary time-compositional record of the accessory phases reveals continued high heat flow, associated with deformation, to 380 Ma. This prolonged event blurs the boundary between the Famatinian and the subsequent Achalian/Chanic orogenies and extends the Silurian Rinconada tectonic phase of the Famatinian orogeny to the east into the Eastern Sierras Pampeanas.
AB - U-Pb dates of zircon, monazite, and titanite combined with trace element composition, allows characterization of the thermal evolution of the migmatitic Agua del Sapo complex. This complex comprises Al-rich and Ca-rich metasedimentary rocks with a detrital zircon maximum depositional age of 550 Ma. The rocks record two consecutive early Paleozoic orogenies. During subduction associated with the 550–510 Ma Pampean orogeny, the complex was in the fore-arc region and was intruded by 550–520 Ma granites indicative of anomalous heating possibly related to ridge subduction. During the subsequent 500–440 Ma Famatinian orogeny, the arc migrated trenchwards and the region became part of a retro-arc that underwent melting at upper-amphibolite facies. This event was recorded differently by each of the accessory phases. Detrital zircon cores were overgrown by rare Famatinian rims that range from 500 to 420 Ma, while monazite records only Famatinian dates with a growth peak at ∼457 Ma that extends to 410 Ma, possibly due to coupled dissolution-precipitation. Published titanite dates define a 120 Myr thermal history, starting at ∼500 Ma with temperatures of ∼750°C ± 25°C, ending at 380 Ma and ∼700°C ± 25°C. Cooling was accompanied by a decrease in titanite light rare earth element contents in response to increased abundance of allanite/epidote. Thus, the complementary time-compositional record of the accessory phases reveals continued high heat flow, associated with deformation, to 380 Ma. This prolonged event blurs the boundary between the Famatinian and the subsequent Achalian/Chanic orogenies and extends the Silurian Rinconada tectonic phase of the Famatinian orogeny to the east into the Eastern Sierras Pampeanas.
KW - geochronology
KW - hot orogen
KW - monazite
KW - petrochronology
KW - titanite
KW - zircon
UR - http://www.scopus.com/inward/record.url?scp=85162111897&partnerID=8YFLogxK
U2 - 10.1029/2021TC007027
DO - 10.1029/2021TC007027
M3 - Article
AN - SCOPUS:85162111897
SN - 0278-7407
VL - 42
JO - Tectonics
JF - Tectonics
IS - 3
M1 - e2021TC007027
ER -