U-Pb Garnet, Sphene, Monazite, and Rutile Ages: Implications for the Duration of High-Grade Metamorphism and Cooling Histories, Adirondack Mts., New York

Mezger, Klaus; Rawnsley, C. M.; Bohlen, Steven R.; Hanson, Gilbert N.

doi:10.1086/629503

Cited by 329 publications

(203 citation statements)

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“…1.03 Ga and hornblende 40 Ar/ 39 Ar ages to ca. 0.98 Ga to the southeast of the Carthage-Colton shear zone (Mezger et al 1991(Mezger et al , 1992Streepey et al 2001;Heumann et al 2006).…”

Section: Geology Of the Adirondack Mountainsmentioning

confidence: 99%

“…1.164 Ga Diana Syenite Complex (McLelland et al 2010a, Baird andShrady 2011). Overthrusting of the ALT placed it into the domain of the Adirondack orogenic lid accounting for its preservation of Shawinigan titanite ages (Mezger et al 1991;McLelland et al 1996McLelland et al , 2010a, as well as hornblende 40 Ar/…”

Section: Regional Aspects Of Thementioning

confidence: 99%

“…Recently, Bonamici et al (2011) used δ 18 O zoning profiles in titanite to compute cooling rates in the CCZ, and their results showed that cooling took place at 6-60 times previous estimates with the best fit being a cooling rate of 30-50°C/m.y., a rate vastly in excess of earlier estimates of 2°C/m.y. (Mezger et al 1991;Streepey et al 2001). It is inferred that the differences result from time-averaging of several rapid pulses of down-faulting and cooling followed by longer intervals of quiescence.…”

mentioning

confidence: 99%

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Tectonic Evolution of the Adirondack Mountains and Grenville Orogen Inliers within the USA

McLelland

Selleck

Bickford³

2013

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Recent investigations in geochronology and tectonics provide important new insights into the evolution of the Grenville Orogen in North America. Here, we summarize results of this research in the USA and focus upon ca. 1.4–0.98 Ga occurrences extending from the Adirondack Mountains to the southern Appalachians and Texas. Recent geochronology (mainly by U/Pb SHRIMP) establishes that these widely separated regions experienced similar tectonomagmatic events, i.e., the Elzevirian (ca. 1.25–1.22 Ga), Shawinigan (ca. 1.2–1.14 Ga), and Grenvillian (ca. 1.09–0.98 Ga) orogenies and associated plate interactions. Notwithstanding these commonalities, Nd model ages and Pb isotopic mapping has revealed important differences that are best explained by the existence of contrasting compositions of deep crustal reservoirs beneath the Adirondacks and the southern Appalachians. The isotopic compositions for the Adirondacks lie on the same Pb–Pb array as those for the Grenville Province, the Granite-Rhyolite Province and the Grenvillian inliers of Texas suggesting that they all developed on Laurentian crust. On the other hand, data from the southern Appalachians are similar to those of the Sunsas Terrane in Brazil and suggest that Amazonian crust with these Pb–Pb characteristics was thrust onto eastern Laurentia during its Grenvillian collision with Amazonia and subsequently transferred to the latter during the late Neoproterozoic breakup of the supercontinent, Rodinia, and the formation of the Iapetus Ocean. The ca. 1.3–1.0 Ga Grenville Orogen is also exposed in the Llano Uplift of Texas and in small inliers in west Texas and northeast Mexico. The Llano Uplift contains evidence for a major collision with a southern continent at ca. 1.15–1.12 Ga (Kalahari Craton?), magmatic arcs, and back-arc and foreland basins, all of which are reviewed. The Grenvillian Orogeny is considered to be the culminating tectonic event that terminated approximately 500 m.y. of continental margin growth along southeastern Laurentia by accretion, continental margin arc magmatism, and metamorphism. Accordingly, we briefly review the tectonic and magmatic histories of these Paleoproterozoic and Mesoproterozoic pre-Grenvillian orogens, i.e., Penokean, Yavapai, and Mazatzal as well as the Granite-Rhyolite Province and discuss their ~5000 km transcontinental span.SOMMAIREDes recherches récentes en géochronologie et en tectonique révèlent d’importants faits nouveaux sur l’évolution de l’orogénie de Grenville en Amérique du Nord. Nous présentons ici un sommaire des résultats de cet effort de recherche aux USA en mettant l’accent sur les indices datés entre env. 1,4 et 0,98 Ga, à partir des monts Adirondack jusqu’au sud des Appalaches et au Texas. Des données géochronologiques récentes (par microsonde SHRIMP principalement) indiquent que les roches de ces régions très éloignées les unes des autres ont subies l’effet d’épisodes tectonomagmatiques similaires, par exemple, aux orogenèses de l’Elzévirien (env. 1.25–1.22 Ga), de Shawinigan (env. 1.2–1.14 Ga), et du Grenvillien (env. 1.09–0.98 Ga), ainsi que des interactions des plaques associées. Malgré ces points communs, la chronologie Nd et la cartographie isotopique Pb a révélé des différences importantes qui s’expliquent plus aisément par des compositions contrastées des réservoirs profonds de croûte sous les Adirondacks et le sud des Appalaches. Les compositions isotopiques des Adirondacks sont de la même gamme Pb-Pb que ceux de la Province de Grenville, de la Province Granite-rhyolite et des boutonnières grenvilliennes du Texas, suggérant qu'ils se sont tous développées sur la croûte des Laurentides. Par ailleurs, les données des Appalaches du sud sont semblables à celles du terrane de Sunsas au Brésil, ce qui incite à penser que la croûte amazonienne, avec de telles caractéristiques Pb-Pb, a été poussée sur la portion est de Laurentia lors de sa collision grenvillienne avec l’Amazonie puis laissée à cette dernière au cours de la rupture du supercontinent Rodinia vers la fin du Néoprotérozoïque, avec la formation de l'océan Iapetus. L’orogène de Grenville (1,3 à 1,0 Ga env.) est également exposé dans le soulèvement de Llano au Texas et dans de petites boutonnières dans l'ouest du Texas et le nord du Mexique. Le soulèvement de Llano montre des indices d'une collision majeure avec un continent au sud, entre env. 1,15 et 1,12 Ga (craton de Kalahari?), des zones d’arcs magmatiques, d'arrière-arc et de bassin d'avant-pays, chacun étant présenté ci-dessous. L'orogenèse de Grenville est considéré comme l'événement tectonique culminant qui marqué la fin d’une période d’environ 500 ma d’accroissement de la marge continentale le long de la bordure sud-est de la Laurentie, par accrétion, magmatisme d’arc de marge continentale, et métamorphisme. C’est pourquoi, nous passons brièvement en revue l'histoire tectonique et magmatique de ces orogènes pré-grenvilliennes paléoprotérozoïques et mésoprotérozoïques, pénokéenne, de Yavapai, et de Mazatzal ainsi que la Province de Granite-rhyolite, et discutons de son étendue sur env. 5 000 km.

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“…1.03 Ga and hornblende 40 Ar/ 39 Ar ages to ca. 0.98 Ga to the southeast of the Carthage-Colton shear zone (Mezger et al 1991(Mezger et al , 1992Streepey et al 2001;Heumann et al 2006).…”

Section: Geology Of the Adirondack Mountainsmentioning

confidence: 99%

Section: Regional Aspects Of Thementioning

confidence: 99%

mentioning

confidence: 99%

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Tectonic Evolution of the Adirondack Mountains and Grenville Orogen Inliers within the USA

McLelland

Selleck

Bickford³

2013

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“…1300 Ma (McLelland et al, 1996), marking the beginnings of Rodinia assembly. The protracted assembly event ultimately resulted in continentcontinent collision and the uplift of a global chain of mountain belts (Dalziel, 1991;Hoffman, 1991), which reached peak thermal metamorphism asynchronously over the interval 1160-1050 Ma (Mezger et al, 1991(Mezger et al, , 1993McLelland et al, 1996;Cosca et al, 1998), and unroofing occurred nearly concurrently with peak thermal events (Cosca et al, 1991(Cosca et al, , 1992(Cosca et al, , 1998. Unroofing continued until 850-800 Ma at a uniformly low rate (Cosca et al, 1991;Mezger et al, 1991;Cosca et al, 1992;McLelland et al, 1996;Cosca et al, 1998).…”

Section: Implications For Global E6entsmentioning

confidence: 99%

Global events across the Mesoproterozoic–Neoproterozoic boundary: C and Sr isotopic evidence from Siberia

Bartley¹,

Семихатов²,

Kaufman³

et al. 2001

Precambrian Research

170

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“…Studies of thermal histories of ancient metamorphic terrains using thermochronologic techniques frequently yield large ranges of apparent ages, sometimes spanning hundreds of millions of years (Onstott and Peacock 1987;Mezger et al 1991;Hodges and Bowring 1995). Such ranges are often interpreted in terms of a protracted cooling history, assuming reasonable closure temperatures for mineral-isotopic systems (e.g., Cliff 1985;Heaman and Parrish 1991;Hodges 1991Hodges , 2014Baxter 2010).…”

Section: Introductionmentioning

confidence: 99%

Geological significance of ⁴⁰Ar/³⁹Ar mica dates across a mid-crustal continental plate margin, Connemara (Grampian orogeny, Irish Caledonides), and implications for the evolution of lithospheric collisions

Friedrich

Hodges

2016

Can. J. Earth Sci.

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Abstract:The Connemara region is a world-class example of a regional-scale, high-temperature metamorphic terrain. Its rock record documents formation of a bi-vergent orogenic wedge and associated calkalkaline magmatism in a an arc-continent collisional setting (Grampian orogeny), for which a protracted evolution was inferred based on a >75 Ma spread in U-Pb, Rb-Sr, and K-Ar mineral ages. In contrast, geological field observations imply a simple relationship between syntectonic magmatism, bi-vergent deformation, and Barrovian-type metamorphism. We explore the significance of the spread in apparent cooling ages using 40 Ar/ 39 Ar mica thermochronometers of varying grain sizes and composition, collected across metamorphic grades ranging from staurolite to upper sillimanite. We integrated geological and previously published geochronological evidence to identify a 32 Ma range (ca. 475-443 Ma) of permissible cooling ages and distinguished them from those dates not related to cooling after high-temperature metamorphism. Variations in 40 Ar/ 39 Ar dates at a single locality are ≤10 Ma, implying rapid cooling (≥6-26°C/Ma) following metamorphism and deformation. A distinct cooling age variation (≥15 Ma) occurs on the regional scale, consistent with spatial differences in the metamorphic, magmatic, and deformational evolution across Connemara. This cooling record relates to a lateral thermal gradient (30°C/km) in an evolving arc-continent collision, rather than to differential unroofing of the orogen. Our results imply that the large (≥50 Ma) spread in thermochronometers commonly observed in orogens does not automatically translate into a protracted cooling history, but that only a small number of thermochronometers supply permissible cooling ages.Résumé : La région de Connemara des Calédonides irlandaises est un exemple de classe mondiale de terrain métamorphique de haute température d'envergure régionale. Sa formation est reliée au magmatisme calcoalcalin dans le contexte d'une collision arc-continent, pour laquelle une évolution prolongée a été inférée à la lumière de la distribution sur plus de 75 Ma d'âges U-Pb, Rb-Sr, et K-Ar sur différents minéraux. Une telle évolution ne correspond pas aux observations géologiques sur le terrain, qui indiqueraient plutôt une relation simple entre un magmatisme, une déformation et un métamorphisme de type barrovien syntectoniques. Nous avons examiné la signification de la distribution des âges apparents de refroidissement à l'aide de thermochronomètres 40 Ar/ 39 Ar sur micas de granulométries et compositions variées, prélevés à différents degrés de métamorphisme allant de la zone à staurotide à la zone à sillimanite supérieure. Nous avons intégré les données géologiques et de l'information géochronologique déjà publiée pour délimiter une fenêtre de 32 Ma (de 475 à 443 Ma environ) pour les âges de refroidissement possibles et avons distingué ces derniers des âges non reliés au refroidissement ayant suivi le métamorphisme de haute température. La variation des âges 40 Ar/ 39 Ar en un ...

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U-Pb Garnet, Sphene, Monazite, and Rutile Ages: Implications for the Duration of High-Grade Metamorphism and Cooling Histories, Adirondack Mts., New York

Cited by 329 publications

References 27 publications

Tectonic Evolution of the Adirondack Mountains and Grenville Orogen Inliers within the USA

Tectonic Evolution of the Adirondack Mountains and Grenville Orogen Inliers within the USA

Global events across the Mesoproterozoic–Neoproterozoic boundary: C and Sr isotopic evidence from Siberia

Geological significance of ⁴⁰Ar/³⁹Ar mica dates across a mid-crustal continental plate margin, Connemara (Grampian orogeny, Irish Caledonides), and implications for the evolution of lithospheric collisions

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U-Pb Garnet, Sphene, Monazite, and Rutile Ages: Implications for the Duration of High-Grade Metamorphism and Cooling Histories, Adirondack Mts., New York

Cited by 329 publications

References 27 publications

Tectonic Evolution of the Adirondack Mountains and Grenville Orogen Inliers within the USA

Tectonic Evolution of the Adirondack Mountains and Grenville Orogen Inliers within the USA

Global events across the Mesoproterozoic–Neoproterozoic boundary: C and Sr isotopic evidence from Siberia

Geological significance of 40Ar/39Ar mica dates across a mid-crustal continental plate margin, Connemara (Grampian orogeny, Irish Caledonides), and implications for the evolution of lithospheric collisions

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Geological significance of ⁴⁰Ar/³⁹Ar mica dates across a mid-crustal continental plate margin, Connemara (Grampian orogeny, Irish Caledonides), and implications for the evolution of lithospheric collisions