The influence of natural radiation damage on helium diffusion kinetics in apatite

Shuster, David L.; Flowers, Rebecca M.; Farley, K. A.

doi:10.1016/j.epsl.2006.07.028

Cited by 604 publications

(592 citation statements)

References 38 publications

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“…The apatite (U-Th)/He age of 44.7±3.7 Ma provides further support to the above interpretation considering the even lower temperature range of the apatite He partial retention zone (~85-40°C; Wolf et al, 1998;Shuster et al, 2006). The apatite cooled through the ~85-40°C temperature range during the Eocene, which is coherent with the modeled cooling path from the apatite fission-track data for the Dos Amigos porphyry (Fig.…”

Section: Discussionsupporting

confidence: 70%

Determinaciones geocronológicas y termocronológicas para la mineralización de cobre porfídico en la zona de alteración de Domeyko, norte de Chile.

Maksaev

Almonacid

Munizaga

et al. 2010

Andgeo

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ABsTrACT. At Domeyko, 40 km south of Vallenar in northern Chile (28°57'S-70°53'W), the Dos Amigos and Tricolor porphyry copper centers are located within a north-south-elongated hydrothermal alteration zone 6x1.5 km of surface dimensions. The centers are related to tonalite to granodiorite porphyry stocks displaying potassic alteration, which are surrounded by Lower Cretaceous andesitic volcanic rocks with sericitic, kaolinite-illite and propylitic alteration zones. The western boundary of the alteration zone is marked by the post-mineralization Cachiyuyo Batholith of granodioritic to dioritic composition. U-Pb zircon ages for the Dos Amigos porphyry are of 106.1±3.5 and 104.0±3. 39 Ar data establish a minimum Late Cretaceous age for this activity. A fission track age of 59.8±9.8 Ma of apatite from the Dos Amigos porphyry indicates cooling through the temperature range of the apatite partial annealing zone (~125-60°C) during the Paleocene; and an (U-Th)/He age of 44.7±3.7 Ma of apatite from the same porphyry sample shows cooling through the temperature range of the apatite He partial retention zone (~85-40°C) during the Eocene. These ages correspond to the exhumation of the porphyry, and the latter provides a maximum age for the supergene enrichment processes that formed the chalcocite blanket currently mined at Dos Amigos.Keywords: Porphyry copper, Andes, Chile, Geochronology, Thermochronology, Coastal Cordillera. 145 Maksaev et al./ Andean Geology 37 (1): 144-176, 2010 resuMen. Determinaciones geocronológicas y termocronológicas para la mineralización de cobre porfídico en la zona de alteración de Domeyko, norte de Chile. En Domeyko, a 40 km al sur de la ciudad de Vallenar, en el norte de Chile (28°57'S-70°53'O), se ubican los pórfidos cupríferos Dos Amigos y Tricolor dentro de una zona de alteración hidrotermal elongada en sentido norte-sur de 6x1,5 km. Estos están relacionados con stocks porfídicos tonalíticos a granodioríticos con alteración potásica, rodeados por zonas de alteraciones sericítica, caolinita-illita y propilítica, las cuales afectaron principalmente rocas volcánicas del Cretácico Inferior. El límite oeste de la zona de alteración lo constituye el Batolito Cachiyuyo postmineral de composición granodiorítica a diorítica. Edades U-Pb en circón para el pórfido Dos Amigos son de 106,1±3,5 Ma y 104,0±3,5 Ma y de 108,5±3,4 Ma para el pórfido Tricolor. El Batolito Cachiyuyo adyacente dio edades U-Pb en circón de 99,6±1,9 y 99,1±1,9 Ma y edades 40 Ar/ 39 Ar en biotita de 96,9±3,9 y 94,8±0,9 Ma. De acuerdo a estas edades el emplazamiento del batolito fue posterior a los pórfidos Dos Amigos y Tricolor, consistente con las relaciones geológicas. Aunque la mineralización de cobre está relacionada espacialmente y genéticamente con los stocks porfídicos del Cretácico Inferior (Albiano), la mayoría de las micas datadas Ar establecen con certeza una edad mínima Cretácico Tardío para ella. Una edad de trazas de fisión en apatita de 59,8±9,8 Ma para el pórfido Dos Amigos indica enfriamiento a través del ...

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Section: Discussionsupporting

confidence: 70%

Determinaciones geocronológicas y termocronológicas para la mineralización de cobre porfídico en la zona de alteración de Domeyko, norte de Chile.

Maksaev

Almonacid

Munizaga

et al. 2010

Andgeo

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“…The potential for increased He diffusivity from high eU and very old zircons is not relevant here because of the extremely young (U-Th)/He ages of the zircons in this study. However, the above data do indicate that grains with very low eU may have slightly younger ages, consistent with slightly higher He diffusivity in grains with low radiation damage, similar to observations in apatite (Shuster et al, 2006), and consistent with decreasing anisotropy of He diffusion (Farley, 2007) with increasing radiation damage. …”

Section: Figure 2 a Continuous Profile Ofsupporting

confidence: 60%

Detrital zircon U-Pb-He double dating: A method of quantifying long- and short-term exhumation rates in collisional orogens

Wang

Campbell

Reiners

et al. 2014

Sci. China Earth Sci.

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A U-Pb-He double-dating method is applied to detrital zircons with core-rim structure from the Ganges River in order to determine average short-and long-term exhumation rates for the Himalayas. Long-term rates are calculated from the U/Pb ages of metamorphic rims of the grains that formed during the Himalayan orogeny and their crystallization temperatures, which are calculated from the Ti-in-zircon thermometer. Short-term rates are calculated from (U-Th)/He ages of the grains with appropriate closure temperatures. The results show that short-term rates for the Himalayas, which range from 0.70  0.09 to 2.67  0.40 km/Myr and average 1.75  0.59 (1) km/Myr, are higher and more varied than the long-term rates, which range from 0.84  0.16 to 1.85  0.35 km/Myr and average 1.26  0.25 (1) km/Myr. The differences between the long-term and short-term rates can be attributed to continuous exhumation of the host rocks in different mechanisms in continental collision orogen. The U/Pb ages of 44.0 ± 3.7 to 18.3 ± 0.5 Ma for the zircon rims indicate a protracted episode of ~25 Myr for regional metamorphism of the host rocks at deeper crust, whereas the (U-Th)/He ages of 42.2 ± 1.8 to 1.3 ± 0.2 Ma for the zircon grains represent a protracted period of ~40 Myr for exposure of the host rocks to shallower crustal level. In particular, the oldest (U-Th)/He ages of the zircon grains are close to the oldest U/Pb ages for the rims, indicating that some parcels of the rocks that contain zircons were rapidly exhumed from deep to shallow levels in the stage of collisional orogeny. On the other hand, some parcels of the rocks may have been carried upwards by thrust faults in the post-collisional stage. The parcels could be carried upwards by the thrust faults that steepen as they near the surface, or by transient movement faults so that areas of rapid exhumation became areas of slow exhumation and visa versa on a time scale of a few Myr in order to maintain the continuous exhumation. In this regard, the Ganges River must be preferentially sampling areas that are currently undergoing above average rates of uplift.zircon, U-Pb-He double-dating method, Himalayas, exhumation rate, collisional orogen Citation:Wang C Y, Campbell I H, Reiners P W, et al. 2014. Detrital zircon U-Pb-He double dating: A method of quantifying long-and short-term exhumation rates in collisional orogens.

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“…While both models discussed in this paper are justified by laboratory data (e.g., Shuster et al 2006; Shuster and) , implementing either model, or other models for the (UTh)/He system in apatite (e.g., Gautheron et al 2009) , requires the assumption that what has been determined in the lab can be accurately extrapolated to geologic timescales and temperatures. Because laboratory experiments are limited to durations orders of magnitude shorter than geologic timescales, we commonly increase experimental temperatures to achieve a similar net effect.…”

Section: Extrapolating From Laboratory Conditions To Geologic Timescalesmentioning

confidence: 99%

“…Future experiments on the effects of reheating temperature and duration on He diffusion kinetics in a range of apatite samples would test these outlined assumptions, particularly the scaling of the functions via the evolving c 3 _E a and c 3 _D 0 parameters. For example, experiments could be conducted on very young and very old apatite samples or apatites with syntheticallygenerated radiation damage ( Shuster et al 2006) . Such experiments would help evaluate whether the effects of thermal annealing on He diffusion kinetics depend on the amount of preexisting damage.…”

Section: Edddependent Annealingmentioning

confidence: 99%

A helium-based model for the effects of radiation damage annealing on helium diffusion kinetics in apatite

Willett

Fox

Shuster

2017

Earth and Planetary Science Letters

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Widely used to study surface processes and the development of topography through geologic time, (UTh)/He thermochronometry in apatite depends on a quantitative description of the kinetics of 4He diffusion across a range of temperatures, timescales, and geologic scenarios. Empirical observations demonstrate that He diffusivity in apatite is not solely a function of temperature, but also depends on damage to the crystal structure from radioactive decay processes. Commonlyused models accounting for the influence of thermal annealing of radiation damage on He diffusivity assume the net effects evolve in proportion to the rate of fission track annealing, although the majority of radiation damage results from recoil. While existing models adequately quantify the net effects of damage annealing in many geologic scenarios, experimental work suggests different annealing rates for the two damage types. Here, we introduce an alphadamage annealing model (ADAM) that is independent of fission track annealing kinetics, and directly quantifies the influence of thermal annealing on He diffusivity in apatite. We present an empirical fit to diffusion kinetics data and incorporate this fit into a model that tracks the competing effects of radiation damage accumulation and annealing on He diffusivity in apatite through geologic time. Using timetemperature paths to illustrate differences between models, we highlight the influence of damage annealing on data interpretation. In certain, but not all, geologic scenarios, the interpretation of lowtemperature thermochronometric data can be strongly influenced by which model of radiation damage annealing is assumed. In particular, geologic scenarios involving 12 km of sedimentary burial are especially sensitive to the assumed rate of annealing and its influence on He diffusivity. In cases such as basement rocks in Grand Canyon and the Canadian Shield, (UTh)/He ages predicted from the ADAM can differ by hundreds of Ma from those predicted by other models for a given thermal path involving extended residence between ~40 80 ºC.

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The influence of natural radiation damage on helium diffusion kinetics in apatite

Cited by 604 publications

References 38 publications

Determinaciones geocronológicas y termocronológicas para la mineralización de cobre porfídico en la zona de alteración de Domeyko, norte de Chile.

Determinaciones geocronológicas y termocronológicas para la mineralización de cobre porfídico en la zona de alteración de Domeyko, norte de Chile.

Detrital zircon U-Pb-He double dating: A method of quantifying long- and short-term exhumation rates in collisional orogens

A helium-based model for the effects of radiation damage annealing on helium diffusion kinetics in apatite

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