Chemical Composition of Nuclei of Z &gt; 22 in Cosmic Rays using Meteoritic Minerals as Detectors

Lal, D.; Rajan, R. S.; Tamhane, A. S.

doi:10.1038/221033a0

Cited by 133 publications

(20 citation statements)

References 10 publications

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“…Confined tracks are revealed when etchant travels down a pathway from the exposed surface and intersects a track in which both ends are within the solid crystal. When the etchant pathway is another fission track, the confined track is referred to as a track-in-track (TINT; Lal et al 1969), while if the pathway is a fracture or cleavage it is termed a track-in-cleavage (TINCLE, Bhandari et al 1971).…”

Section: Length Revelationmentioning

confidence: 99%

Inter-laboratory comparison of fission track confined length and etch figure measurements in apatite

Ketcham

Carter

Hurford

2015

American Mineralogist

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Section: Length Revelationmentioning

confidence: 99%

Inter-laboratory comparison of fission track confined length and etch figure measurements in apatite

Ketcham

Carter

Hurford

2015

American Mineralogist

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“…After AFM grinding and normal polishing, zircons were etched with a KOH:NaOH = 1:1 (mol) at 248° ± 1°C [ Yamada et al , 1995a], until the width of horizontal confined tracks (HCTs) was ∼1 μ m. The etching duration for each sample was determined so that as many HCTs with an ∼1 μ m width as possible could be observed for all grains of each sample. FTLs were measured for HCTs throughout this study, including both track‐in‐track and track‐in‐cleavages [e.g., Lal et al , 1969]. The length of HCTs were measured by taking photographs of tracks using a Nikon DXM1200 digital camera installed on the E‐1000 microscope with a 100 times dry objective and counting the track lengths on the photos.…”

Section: Sample Preparation and Analysismentioning

confidence: 99%

Postcollisional exhumation history of the Tanzawa Tonalite Complex, inferred from (U‐Th)/He thermochronology and fission track analysis

Yamada

Tagami

2008

J. Geophys. Res.

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[1] The Tanzawa Mountains in the South Fossa Magna region, in the middle of the Japan Arc, were formed due to collision of the Izu-Bonin Arc against the Japan Arc during the last several million years. The Tanzawa Tonalite Complex is exposed in the Tanzawa Mountains and is inferred to represent middle crust of the Izu-Bonin Arc. We performed new thermochronometry, consisting of (U-Th)/He dating, fission track dating, and fission track length analysis for the complex to investigate the exhumation history of the Tanzawa Tonalite Complex caused by arc-arc collision. Typical (U-Th)/He ages were 2.0 ± 0.2 Ma on apatite, 3.3 ± 0.2 Ma on zircon, and 4.5 to 6.9 Ma on zircon using the fission track method. The mean fission track length was 9.7 ± 0.6 mm (2 SE). The cooling rate of the tonalite has been calculated to be in the range of 20°-60°C Ma À1 from $7 to 3.3 Ma, $80°C Ma À1 from 3.3 to 2.0 Ma, and $30°C Ma À1 from 2.0 to 0 Ma assuming a surface temperature of 10°C. The exhumation rate has been calculated to be 0.5 to 1.5 mm a À1 from $7 to 3.3 Ma, $2 mm a À1 from 3.3 to 2.0 Ma, and $0.8 mm a À1 from 2.0 to 0 Ma with an assumed geothermal gradient of 40°C km À1 . The exhumation rate has not changed significantly despite the simultaneous tectonic changes around the Tanzawa Mountains after $7 Ma.

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“…The low albedo of cometary nuclei and Kuiper-belt objects suggests that in addition to strongly absorbing finely divided materials and ices and other inorganic materials darkened intrinsically or by free radicals arising from radiation damage, they may contain dust particles coated with dark radiation polymerized polyaromatic components deposited from the interstellar medium (Greenberg and Li 1997). Until incorporated into cometary interiors, micronsized particles of primordial materials in space accumulate radiation damage from the galactic cosmic ray background and the solar wind (Lal et al 1969). This radiation-induced lattice damage represents an accumulation of latent energy because atomic displacement defects in solids typically store about 1 eV each (Devanathan et al 1998).…”

Section: Introductionmentioning

confidence: 99%

Xenomict energy in cold solids in space

Seitz¹,

Raymond

Kissel

et al. 2006

Naturwissenschaften

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Minerals on earth whose crystalline order has been reduced by radioactive decay of contained atoms are termed "metamict." They are rare and few because in most crystalline solids, atoms and vacancies are relatively mobile at terrestrial temperatures, and radiation damage tends to be self-annealing. This is not the case in the extreme cold of deep space. Below roughly 100 K, reduced vacancy mobility allows cosmic ray and solar wind induced lattice defects to endure and accumulate for eons, reaching energy densities of up to MJ kg −1 in some materials. We examine the possible effects of the release of energy stored in cold deep-space materials when solid-state defects recombine upon warming due to impacts, gravitational infall, or perihelion. Dimensional analysis suggests energetic defect recombination in radiation-damaged "xenomict" solids in comets, and planetesimals may, in some circumstances, raise internal temperatures enough to melt ice and volatilize frozen gases. We speculate that this may account for some cometary outbursts and Deep Impact experiment results. Calorimetric experiments on appropriately irradiated natural and synthetic materials are needed to further quantify these mechanisms.

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Chemical Composition of Nuclei of Z > 22 in Cosmic Rays using Meteoritic Minerals as Detectors

Cited by 133 publications

References 10 publications

Inter-laboratory comparison of fission track confined length and etch figure measurements in apatite

Inter-laboratory comparison of fission track confined length and etch figure measurements in apatite

Postcollisional exhumation history of the Tanzawa Tonalite Complex, inferred from (U‐Th)/He thermochronology and fission track analysis

Xenomict energy in cold solids in space

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