Application of /sup 40/Ar//sup 39/Ar thermochronology to the study of sedimentary basins; an example from the North Sea

Conference · Tue Jan 01 04:00:00 EST 1985 · Geol. Soc. Am., Abstr. Programs; (United States)

OSTI ID:6453366

Phelps, D W; Harrison, T

/sup 40/Ar//sup 39/Ar age spectra analyses of detrital potassium feldspars from the North Sea demonstrate that the technique can be used to date the provenance of sandstones and to reconstruct the thermal history of sedimentary basins. Potassium feldspar separates from four Mesozoic deltaic sandstones from the southern Viking Graben all yield plateau ages that cluster around 400 Ma, suggesting derivation from nearby Caledonian-ages crystalline basement. Potassium feldspars from a Paleocene turbidite, also from the southern Viking Graben, yield a minimum age of Late Precambrian. Facies relationships suggest that the Paleocene turbidite was sourced from the Precambrian Shetland platform. Two samples of the Permian Rotliegende sandstone from the Sole Pit basin were also analyzed. Potassium feldspar separates from both samples yield complex age spectra indicating components from both Precambrian and Caledonian-aged crystalline rocks. The nearby London-Brabant Massif is a likely source of the Precambrian feldspars. Recent /sup 40/Ar rad loss (2 to 4%) was detected in one sample from the southern Viking Graben. Following the methods of Harrison and McDougall (1982), an activation energy of 36 kcal/mol was calculated. With this activation energy, the observed amount of Ar loss should have occurred in only 3 or 4 Ma at the present-day temperature of 115/sup 0/C. A more geologically reasonable temperature history that satisfies the /sup 40/Ar//sup 39/Ar systematics requires that the present-day temperature has been maintained for less than 2 Ma, and that the temperature rose above 90/sup 0/C within the past 5 Ma.

• Research Organization: Exxon Production Research Company, Houston, TX (USA)
• OSTI ID: 6453366
• Report Number(s): CONF-8510489-
• Conference Information: Journal Name: Geol. Soc. Am., Abstr. Programs; (United States) Journal Volume: 17
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580100 -- Geology & Hydrology-- (-1989)
580400* -- Geochemistry-- (-1989)
AGE ESTIMATION
ARGON 39
ARGON 40
ARGON ISOTOPES
ATLANTIC OCEAN
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CHEMICAL ANALYSIS
CHEMICAL COMPOSITION
CHEMISTRY
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FELDSPARS
GEOCHEMISTRY
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
GEOTHERMOMETRY
ISOTOPE DATING
ISOTOPE RATIO
ISOTOPES
LIGHT NUCLEI
MINERALS
NORTH SEA
NUCLEI
QUANTITATIVE CHEMICAL ANALYSIS
RADIOISOTOPES
ROCKS
SANDSTONES
SEAS
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
STABLE ISOTOPES
SURFACE WATERS
YEARS LIVING RADIOISOTOPES