The influence of bottom water oxygenation and reactive iron content on sulfur incorporation into bitumens from Jurassic marine shales

Journal Article · Tue Jun 01 04:00:00 EDT 1993 · American Journal of Science; (United States)

DOI:https://doi.org/10.2475/ajs.293.6.569· OSTI ID:6368726

Raiswell, R; Bottrell, S H; Al-Biatty, H J; Tan, M MD ^[1]

---

1. Leeds Univ. (United Kingdom)

Sulfur isotope studies of bitumens (dichloromethane- extractable) from jurassic marine shales indicate that most sulfur is derived, at least initially, from diagenetic sulfate reduction. Under euxinic or semi-euxinic conditions sulfur incorporation in the Jet Rock and Posidonienschiefer bitumens appears to post-date formation of most reactive syngenetic pyrite but occurs contemporaneously with the formation small concentrations of later pyrite, relatively depleted in [sup 32]S. The most reactive iron minerals were mainly pyritized before any significant incorporation of sulfur occurred, and subsequent solidification reactions only occurred in response to prolonged contact between dissolved sulfide and residual, poorly reactive iron minerals (forming in the later pyrite) and organic matter (incorporating sulfur into bitumen). In these circumstances, which are typical of most euxinic or semi-euxinic sediments, the abundance of reactive iron is not the main control on the incorporation of sulfur (0.8 wt percent in the Jet Rock, 1.5 wt percent in the Posidonienschiefer) into bitumen. Consistent with this, variable concentrations of bitumen S occur in the Alum Shales (2.48 and 0.86 wt percent) which have uniform reactive iron contents. In the Alum Shales, the weakly bioturbated and more oxygenated depositional environments appear to favor sulfur incorporation into bitumens, which may occur here via partially oxidized sulfur species. Bitumen compositions suggest that oxygen is eliminated as sulfur is incorporated, possibly due to the dehydration of polar compounds followed by nucleophilic addition of sulfur. 64 refs., 6 figs., 4 tabs.

• OSTI ID: 6368726
• Journal Information: American Journal of Science; (United States), Journal Name: American Journal of Science; (United States) Vol. 293:6; ISSN AJSCAP; ISSN 0002-9599
• Country of Publication: United States
• Language: English

Related Subjects

04 OIL SHALES AND TAR SANDS
040200* -- Oil Shales & Tar Sands-- Reserves
Geology
& Exploration
58 GEOSCIENCES
580000 -- Geosciences
ABUNDANCE
AGE ESTIMATION
BITUMENS
CHEMICAL REACTIONS
DIAGENESIS
ELEMENT ABUNDANCE
ELEMENTS
EVEN-EVEN NUCLEI
GEOLOGIC AGES
GEOLOGY
IRON
ISOTOPE DATING
ISOTOPES
JURASSIC PERIOD
LIGHT NUCLEI
MESOZOIC ERA
METALS
MINERALOGY
MINERALS
NONMETALS
NUCLEI
ORGANIC COMPOUNDS
OTHER ORGANIC COMPOUNDS
OXYGEN
PYRITE
ROCKS
SEDIMENTARY ROCKS
SHALES
STABLE ISOTOPES
STRATIGRAPHY
SULFIDE MINERALS
SULFUR 32
SULFUR CONTENT
SULFUR ISOTOPES
TAR
TRANSITION ELEMENTS