Comparative study of sup 222 Rn, sup 40 Ar, sup 39 Ar and sup 37 Ar leakage from rocks and minerals: Implications for the role of nanopores in gas transport through natural silicates

Journal Article · Tue Mar 01 04:00:00 EST 1988 · Geochimica et Cosmochimica Acta; (USA)

DOI:https://doi.org/10.1016/0016-7037(88)90327-4· OSTI ID:5180773

Krishnaswami, S; Seidemann, D E ^[1]

---

1. Yale Univ., New Haven, CT (USA)

The authors have measured the leakage of radiogenic {sup 222}Rn and {sup 40}Ar and reactor-produced {sup 39}Ar and {sup 37}Ar in samples of granites, plagioclase, orthoclase, cleavelandite and hornblende to assess the role of nanopores in gas transport through them. The {sup 39}Ar and {sup 37}Ar were produced by fast neutron irradiation of the samples in vacuum sealed ampoules. The leakage of all three Ar isotopes was barely measurable. In contrast, the leakage of {sup 222}Rn ranged between 1.45-18.1% orders of magnitude higher than that of the Ar isotopes. The extremely low Ar isotope leakage suggests that the samples studied are not permeated by extensive nanopore networks which intersect grain surfaces. The relatively high {sup 222}Rn loss from these samples, therefore, has to be attributed to preferential enrichment of {sup 226}Ra ({sup 238}U) on grain surfaces or to the existence of U-Th accessory minerals in or around grain boundaries from which substantial quantities of {sup 222}Rn escape.

• DOE Contract Number: FG02-87ER60576
• OSTI ID: 5180773
• Journal Information: Geochimica et Cosmochimica Acta; (USA), Journal Name: Geochimica et Cosmochimica Acta; (USA) Vol. 52:3; ISSN GCACA; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
ALPHA DECAY RADIOISOTOPES
AMPHIBOLE
ARGON 37
ARGON 39
ARGON 40
ARGON ISOTOPES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CHEMICAL ANALYSIS
CHEMICAL COMPOSITION
CHEMISTRY
COMPARATIVE EVALUATIONS
CRYSTAL STRUCTURE
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FELDSPARS
GAS ANALYSIS
GEOCHEMISTRY
GRANITES
HEAVY NUCLEI
HORNBLENDE
IGNEOUS ROCKS
ISOTOPE RATIO
ISOTOPES
LIGHT NUCLEI
MICROSTRUCTURE
MINERALS
NUCLEI
PLUTONIC ROCKS
POROSITY
QUANTITATIVE CHEMICAL ANALYSIS
RADIO-RELEASE ANALYSIS
RADIOISOTOPES
RADON 222
RADON ISOTOPES
ROCKS
SILICATE MINERALS
STABLE ISOTOPES
YEARS LIVING RADIOISOTOPES