The organic geochemistry of the Alum Shale, Sweden

Thesis/Dissertation · Mon Jan 01 04:00:00 EST 1990

OSTI ID:5801702

Dahl, J E.P.

Organic matter in the Alum Shale of Sweden has been affected post-depositionally by irradiation from U decay. Effects include: (1) lowering of kerogen H/C ratios; (2) decrease in amount of extractable bitumen; (3) increased aromaticity. Higher thermal maturity of Alum Shale bitumen than kerogen in Central Sweden suggest bitumen migration into the shale. The thermal immaturity of both Alum Shale bitumen and kerogen in Eastern Sweden (Gotland and Oland) indicate that Gotland's oil has either migrated from an area of higher thermal maturity or is the result of very localized heating, possibly from an igneous intrusion. Zn, Cu and Pb concentrations in asphaltenes from the Alum Shale show an inverse relationship with thermal maturity. Experimental hydrous pyrolysis of Alum Shale suggest that Zn, Cu and, to a lesser extent Pb, are mobile during petroleum generation in both bitumen and brine, whereas U is immobile. Nitrogen in naturally occurring gases from the Alum Shale of Ostergotland, Sweden is atmospheric in origin based on ratios of N{sub 2}/Ar. Helium is derived from the radioactive decay of U-based on He{sub 3} He{sub 4} ratios. {delta}{sup 34}S values of Alum Shale pyrite show a fractionation with coeval seawater of approximately 35 per mil, which along with high total S concentrations of over 15% in some samples, implies extensive metabolism of organic matter during early diagenesis by sulfate reducing bacteria. Pyrite {delta}{sup 34}S values are lighter than coexisting organic sulfur in the kerogen by an average of near 7 per mil. The difference is believed to be the result of rite formation earlier and at a relatively shallower sediment depth than organo-sulfur compounds due to the greater reactivity of iron with bacterially released hydrogen sulfide than organic matter.

• Research Organization: California Univ., Los Angeles, CA (USA)
• OSTI ID: 5801702
• Country of Publication: United States
• Language: English

Related Subjects

04 OIL SHALES AND TAR SANDS
040200* -- Oil Shales & Tar Sands-- Reserves
Geology
& Exploration
040500 -- Oil Shales & Tar Sands-- Properties & Composition
ACTINIDES
ALKANES
ARGON
AROMATICS
ASPHALTENES
ASPHALTS
BACTERIA
BITUMENS
BITUMINOUS MATERIALS
BRINES
CARBONACEOUS MATERIALS
CHALCOGENIDES
CHEMICAL COMPOSITION
CHEMICAL REACTIONS
CHEMISTRY
COPPER
DECAY
DECOMPOSITION
DIAGENESIS
ELEMENTS
ENVIRONMENTAL TRANSPORT
EUROPE
EVEN-EVEN NUCLEI
FLUIDS
GASES
GEOCHEMISTRY
GEOLOGIC DEPOSITS
HELIUM
HYDROCARBONS
HYDROGEN COMPOUNDS
HYDROGEN SULFIDES
IRON COMPOUNDS
IRON SULFIDES
IRRADIATION
ISOTOPE RATIO
ISOTOPES
KEROGEN
LEAD
LIGHT NUCLEI
MASS TRANSFER
MATERIALS
MATURATION
METALS
METHANE
MICROORGANISMS
MINERAL RESOURCES
MINERALS
NITROGEN
NONMETALS
NUCLEI
OIL SHALE DEPOSITS
ORGANIC COMPOUNDS
ORGANIC MATTER
ORIGIN
OTHER ORGANIC COMPOUNDS
PYRITE
PYROLYSIS
RARE GASES
RESOURCES
SCANDINAVIA
STABLE ISOTOPES
SULFATE-REDUCING BACTERIA
SULFIDE MINERALS
SULFIDES
SULFUR 34
SULFUR COMPOUNDS
SULFUR CONTENT
SULFUR ISOTOPES
SWEDEN
TAR
THERMOCHEMICAL PROCESSES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
URANIUM
WESTERN EUROPE
ZINC