Interpretation of (U–Th)/He single grain ages from slowly cooled crustal terranes: A case study from the Transantarctic Mountains of southern Victoria Land

Fitzgerald, Paul G.; Baldwin, Suzanne L.; Webb, Laura E.; O’Sullivan, Paul B.

doi:10.1016/j.chemgeo.2005.09.001

Cited by 271 publications

(225 citation statements)

References 72 publications

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“…4 and Table 2). Although a progress has been made in explaining overdispersed and anomalously old (U-Th)/He ages (Fitzgerald et al, 2006;Flowers et al, 2009), no universal mechanism has been found to explain why some samples yield consistent (U-Th)/He data and others do not. For example, U-zoning in the core leads to overestimate of the alpha-ejection correction, but cannot explain the abnormally old ages in our study, because even the uncorrected ages of five of the six grains are older than the intrusion age (~35-36 Ma).…”

Section: Experimental Methodsologymentioning

confidence: 99%

Oligocene-Early Miocene river incision near the first bend of the Yangze River: Insights from apatite (U-Th-Sm)/He thermochronology

Shen¹,

Tian

Li³

et al. 2016

Tectonophysics

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The southeastern Tibetan Plateau is deeply incised by three parallel rivers, the Salween, the Mekong and the Yangtze. The river incision and surface uplift histories of this landscape are hotly debated. This study presents bedrock apatite (U-Th-Sm)/He data from a ~1800m vertical profile, located near the first bend of the Yangtze River. Ages range from 20 to 30Ma, indicating an Oligocene -early Miocene phase of moderate river incision at a rate of 0.10-0.18 mm/yr. This is considerably older than elsewhere in the region, but consistent with a previously proposed phase of Eocene surface uplift inferred from stable isotope geochemistry. We consider the implications of the new data under two different tectonic models. If the surface uplift and river incision resulted from lower crustal flow, the new results require such flow to have commenced at Oligocene -Early Miocene time rather than during the previously proposed Late Miocene. Alternatively, Oligocene to Early Miocene plateau growth might have resulted from transpressional deformation in the southeastern Tibetan Plateau. Highlights:Oligocene -early Miocene river incision Diachronous onset of river incision in the southeastern Tibetan Plateau Oligocene to Early Miocene lower crustal flow or transpressional deformation

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Section: Experimental Methodsologymentioning

confidence: 99%

Oligocene-Early Miocene river incision near the first bend of the Yangze River: Insights from apatite (U-Th-Sm)/He thermochronology

Shen¹,

Tian

Li³

et al. 2016

Tectonophysics

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“…12; e.g. Fitzgerald 2002;Fitzgerald et al 1999Fitzgerald et al , 2006. Thus, no cooling history younger than Late Cretaceous is recorded by the used methods.…”

Section: Aft and Ahe Agesmentioning

confidence: 99%

“…12 Elevation of the samples plotted against their AHe age showing a cluster at around 80 Ma indicating that they passed the PRZ at that time (e.g. Fitzgerald 2002;Fitzgerald et al 1999Fitzgerald et al , 2006. Arrows indicate shifting of the age after recalculating (further details are explained in the text).…”

Section: Aft and Ahe Agesmentioning

confidence: 99%

“…apatite fission track and (U-Th)/ He dating, can provide constraints, because these techniques are suitable to constrain time, amounts and rate of cooling/erosion associated with mountain building, crustal deformation, extensional tectonics and landscape evolution (e.g. Gallagher et al 1998;Farley 2002;Ehlers et al 2003;Stockli et al 2000;Fitzgerald et al 2006). To contribute to the knowledge of the exhumation history of the Sierras Pampeanas as well as an attempt to clarify its relationship to the Andean flat-slab subduction, we followed three different approaches investigating two different elevation profiles in the Sierra de Comechingones.…”

Section: Introductionmentioning

confidence: 99%

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Exhumation and uplift of the Sierras Pampeanas: preliminary implications from K–Ar fault gouge dating and low-T thermochronology in the Sierra de Comechingones (Argentina)

Löbens

Bense

Wemmer

et al. 2010

Int J Earth Sci (Geol Rundsch)

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The Sierras Pampeanas in central and northwestern Argentina constitute a distinct morphotectonic feature between 27°S and 33°S. The last stage of uplift and deformation in this area are interpreted to be closely related to the Andean flat-slab subduction of the Nazca plate beneath the South American plate. K-Ar fault gouge dating and low-temperature thermochronology along two transects within the Sierra de Comechingones reveal a minimum age for the onset of brittle deformation about 340 Ma, very low exhumation rates since Late Paleozoic time, as well as a total exhumation of about 2.3 km since the Late Cretaceous. New Ar-Ar ages (7.54-1.91 Ma) of volcanic rocks from the San Luis volcanic belt support the eastward propagation of the flat-slab magmatic front, confirming the onset of flat-slab related deformation in this region at 11.2 Ma. Although low-temperature thermochronology does not clearly constrain the signal of the Andean uplift, it is understood that the current structural relief related to the Comechingones range has been achieved after the exhumation of both fault walls (circa 80-70 Ma).

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“…8). Again, no correlation between age and elevation as expected for undisturbed elevation profiles (Fitzgerald et al, 2006) is recognizable. The youngest apparent ages (196 Ma and 192 Ma) can be found in the middle part of both slopes (Table 4).…”

Section: Thermochronologymentioning

confidence: 89%

Exhumation history and landscape evolution of the Sierra de San Luis (Sierras Pampeanas, Argentina) - new insights from low - temperature thermochronological data

Bense

Costa

Oriolo

et al. 2017

andgeo

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ABSTRACT. This paper presents low-temperature thermochronological data and K-Ar fault gouge ages from the Sierra de San Luis in the Eastern Sierras Pampeanas in order to constrain its low-temperature thermal evolution and exhumation history. Thermal modelling based on (U-Th)/He dating of apatite and zircon and apatite fission track dating point to the Middle Permian and the Triassic/Early Jurassic as main cooling/exhumation phases, equivalent to ca. 40-50% of the total exhumation recorded by the applied methods. Cooling rates are generally low to moderate, varying between 2-10 °C/Ma during the Permian and Triassic periods and 0.5-1.5 °C/Ma in post-Triassic times. Slow cooling and, thus, persistent residence of samples in partial retention/partial annealing temperature conditions strongly influenced obtained ages. Thermochronological data indicate no significant exhumation after Cretaceous times, suggesting that sampled rocks were already at or near surface by the Cretaceous or even before. As consequence, Cenozoic cooling rates are low, generally between 0.2-0.5 °C/Ma which is, depending on geothermal gradient used for calculation, equivalent to a total Cenozoic exhumation of 0.6-1.8 km. K-Ar fault gouge data reveal long-term brittle fault activity. Fault gouge ages constrain the end of ductile and onset of brittle deformation in the Sierra de San Luis to the Late Carboniferous/Early Permian. Youngest K-Ar illite ages of 222-172 Ma are interpreted to represent the last illite formation event, although fault activity is recorded up to the Holocene. RESUMEN. Historia de la exhumación y evolución del paisaje de la sierra de San Luis (Sierras Pampeanas, Argentina)-nuevas perspectivas a partir de datos termocronológicos de baja temperatura. Esta contribución presenta datos de termocronología de baja temperatura y edades de illitas generadas en zonas de fallas de la sierra de San Luis, en las Sierras Pampeanas Orientales de Argentina, con el propósito de aportar al conocimiento de la historia de su exhumación y evolución termal de baja temperatura. El modelado termal basado en dataciones de (U-Th)/He, apatita, circón y trazas de fisión sugiere que las principales fases de exhumación y enfriamiento ocurrieron durante el Pérmico medio y Triásico/Jurásico inferior, contribuyendo con aproximadamente 40-50% de la exhumación total registrada por los métodos utilizados. Las tasas de enfriamiento son, en general, bajas a moderadas, variando entre 2-10 °C/Ma durante el Pérmico y Triásico y 0,5-1,5 °C/Ma después del este último período. El lento enfriamiento y la persistente residencia de las muestras analizadas en condiciones térmicas de retención parcial (partial annealing) ha influenciado notoriamente las edades obtenidas. Los datos termocronológicos indican que no ha habido una exhumación 276 Exhumation history and LandscapE EvoLution of thE siErra dE san Luis (siErras pampEanas, argEntina)... significativa después del Cretácico o incluso antes. Consecuentemente, las tasas de enfriamiento durante el Cenozoico, son bajas, ge...

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Interpretation of (U–Th)/He single grain ages from slowly cooled crustal terranes: A case study from the Transantarctic Mountains of southern Victoria Land

Cited by 271 publications

References 72 publications

Oligocene-Early Miocene river incision near the first bend of the Yangze River: Insights from apatite (U-Th-Sm)/He thermochronology

Oligocene-Early Miocene river incision near the first bend of the Yangze River: Insights from apatite (U-Th-Sm)/He thermochronology

Exhumation and uplift of the Sierras Pampeanas: preliminary implications from K–Ar fault gouge dating and low-T thermochronology in the Sierra de Comechingones (Argentina)

Exhumation history and landscape evolution of the Sierra de San Luis (Sierras Pampeanas, Argentina) - new insights from low - temperature thermochronological data

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