Correction to: Ion microprobe dating of fissure monazite in the Western Alps: insights from the Argentera Massif and the Piemontais and Briançonnais Zones

Following publication of the original article (Ricchi et al. 2020), multiple typesetting errors were identified in the article. The updated sections/sentences are given below and the changes have been highlighted in bold typeface

Age and Crystallization Duration of Alpine Fissure Monazite-(Ce) and Correlation with Tectonically-Driven Hydrothermal Dissolution-(Re)Precipitation Events

This study investigates deformation along the retrograde path of the Alps through in-situ Th-Pb dating of hydrothermal (or fissure) monazite-(Ce). Fissure monazite-(Ce) crystals are found in alpine-type fissures and crystallizes at relatively low temperatures (∼200 - 400 ̊C). The Th-Pb isotopic system of fissure monazite-(Ce) can only be disturbed by dissolution-(re)precipitation events due to chemical disequilibrium with the hydrothermal fluids, commonly induced by tectonic activity. Fissure monazite-(Ce) ages (i) corroborate existing chronological data, (ii) were completed with structural information in order to constrain tectonic movements associated with monazite-(Ce) crystallization, (iii) were used to attribute fluid inclusion data to different episodes of fissure formation. The combined data show that across the Alps monazite-(Ce) crystallization occurred episodically over 85 Ma. The oldest ages of ∼90 Ma were found in the Eastern Alps whereas younger ages, down to ∼5 Ma, were recorded towards the Central and Western Alps

Constraining deformation phases in the Aar Massif and the Gotthard Nappe (Switzerland) using Th Pb crystallization ages of fissure monazite-(Ce)

Fissure monazite-(Ce) (hereafter called monazite) commonly crystallizes during deformation at low metamorphic grade and offers the possibility to date protracted deformation over several millions of years and to identify distinct deformation phases. We performed Th-Pb geochronology at the microscale on 10 samples of fissure monazite from two Alpine crystalline massifs (Aar Massif and Gotthard Nappe). Ion microprobe ages show that the earliest stage of crystallization recorded by fissure monazite domain ages occurred around 15.9 Ma in the Gotthard Nappe and about 1 My later in the Aar Massif, with the latest crystallization event recorded at 6 Ma. Protracted monazite crystallization in fissures indicates that deformation datable with fissure monazite lasted about 10 Ma. Comparison of Th-Pb crystallization ages of fissure monazite to existing thermochronological data shows that early monazite crystallization coincide with zircon fission track ages, whereas the youngest monazite crystallization overlaps with apatite fission track ages. Monazite also grows contemporaneous with muscovite/illite crystallization (K-Ar ages) in fault gouges. As monazite can grow during dissolution/precipitation cycles induced by tectonic activity, their chronology allows to further constrain in the Aar Massif the final Handegg phase at 12–11.5 Ma, and the coeval activity of the Pfaffenchopf (11.5–9 Ma), and the Oberaar and Rhone-Simplon phases (11.5 and 6 Ma). In the Gotthard Nappe, monazite crystallization constrains a major portion of the Chièra backfolding phase at 14–13 Ma, and confirms that the south-western termination of the nappe was affected by the Rhone-Simplon phase

Cenozoic deformation in the Tauern Window (Eastern Alps) constrained by in situ Th-Pb dating of fissure monazite

Thorium–lead (Th-Pb) crystallization ages of hydrothermal monazites from the western, central and eastern Tauern Window provide new insights into Cenozoic tectonic evolution of the Tauern metamorphic dome. Growth domain crystallization ages range from 21.7 ± 0.4 to 10.0 ± 0.2 Ma. Three major periods of monazite growth are recorded between ∼ 22–20 (peak at 21 Ma), 19–15 (major peak at 17 Ma) and 14–10 Ma (major peak around 12 Ma), respectively, interpreted to be related to prevailing N–S shortening, in association with E–W extension, beginning strike-slip movements and reactivation of strike-slip faulting. Fissure monazite ages largely overlap with zircon and apatite fission track data. Besides tracking the thermal evolution of the Tauern dome, monazite dates reflect episodic tectonic movement along major shear zones that took place during the formation of the dome. Geochronological and structural data from the Pfitschtal area in the western Tauern Window show the existence of two cleft generations separated in time by 4 Ma and related to strike-slip to oblique-slip faulting. Moreover, these two phases overprint earlier phases of fissure formation