Petroleum potential of Precambrian Nonesuch Formation, Mid-Continent rift system

Conference · Wed Mar 01 04:00:00 EST 1989 · AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States)

OSTI ID:6119476

Hieshima, G B; Zaback, D A; Pratt, L M

The Precambrian Nonesuch Formation crops out in northern Wisconsin and Michigan and is recognized as a possible petroleum source rock based on active oil seeps in copper mines of the White Pine area. Sedimentological and organic geochemical analyses of about 200 samples from outcrops, cores, and mine excavation were undertaken to evaluate the petroleum potential of the Nonesuch Formation. Organic carbon (C/sub org/) contents above 0.3% are restricted to thin intervals of finely laminated calcareous and noncalcareous silty shale. C/sub org/ for finely laminated samples ranges from 0.25% to 2.8% and averages 0.6%. Total sulfur (TS) values range from 0.4% to 2.7%. Using samples containing only framboidal pyrite, a positive covariance between C/sub org/ and TS is recognized, with an approximate C/sub org//TS ratio of 0.5. This value is significantly higher than the Goldhaber/Kaplan, Gautier, or Tuttle ratios for Phanerozoic shales. Nonesuch bitumens are alkane rich and depleted in asphaltenes. Gas chromatography of extracts shows a decreasing distribution of alkanes from C/sub 10/ to C/sub 30/ with a slight enrichment of n-C/sub 17/ and n-C/sub 19/. pristane is abundant in several samples, with pristane/n-C/sub 17/ ratios approaching 1.0. Pristane/phytane ratios range from 2.5 to 6.0 and average 4.1. Biomarkers suggest that the unit is within the middle part of the oil window. If thicker sections of the organic-rich facies are present in the southern extension of the rift or downdip of the outcrop belt under Lake Michigan, the petroleum source potential of the Nonesuch should be good.

• Research Organization: Indiana Univ., Bloomington (USA)
• OSTI ID: 6119476
• Report Number(s): CONF-890404-
• Conference Information: Journal Name: AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States) Journal Volume: 73:3
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
BITUMENS
CARBONACEOUS MATERIALS
CHALCOGENIDES
FEDERAL REGION V
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
GEOLOGIC STRUCTURES
IRON COMPOUNDS
IRON SULFIDES
MATERIALS
MICHIGAN
MINERAL RESOURCES
MINERALS
NORTH AMERICA
ORGANIC COMPOUNDS
OTHER ORGANIC COMPOUNDS
PETROLEUM DEPOSITS
PYRITE
RESOURCES
RIFT ZONES
ROCKS
SEDIMENTARY ROCKS
SHALES
SOURCE ROCKS
SULFIDE MINERALS
SULFIDES
SULFUR COMPOUNDS
TAR
TRANSITION ELEMENT COMPOUNDS
USA
WISCONSIN