Type of Submission
Poster
Keywords
Heavy liquid separation, lithium metatungstate, glacial till prospecting, heavy indicator minerals, Wisconsinan glaciation
Abstract
Glacial till (drift) prospecting has served a major role in corporate mineral exploration, especially for gold and diamond during the past 30 years. It involves analyzing heavy indicator minerals from bulk sampling of various glacial deposits in order to track up ice flow direction to the potential orebody (such as a kimberlite pipe or Cu-Ni deposit), a technique commonly used in Canada but not in the U.S. Heavy minerals including diamond, gold, and native copper have been found in Ohio glacial till; the provenance of these heavy minerals is the Precambrian bedrock north of Ohio. This study utilized standard procedures in sample collection and analysis (sieving, concentration by gold-panning, heavy liquid separation with lithium metatungstate [LMT], magnetic separation and microscopy) with seven samples from a kame of the Late Wisconsinan glaciation in northeastern Greene County, southwest Ohio. Coarse to very coarse sand (2 - 0.5 mm) and fine to medium sand (0.5 - 0.125 mm) fractions from each bulk sample were analyzed for heavy minerals and felsic (quartz and feldspars) concentration. The goal was to determine variability in heavy minerals and felsic component concentrations across samples and between grain-size fractions, in order to suggest improved sampling and analysis techniques.
A variety of heavy minerals, including gold, of igneous and metamorphic provenance were identified in all sample fractions by physical and optical (including fluorescence) properties. Zircon concentration in the fine to medium sand fraction appeared similar across concentrated samples. Statistical analysis showed: significant variation of the coarser to finer grain size ratio between samples, displaying the expected variability in sand sizes in a kame deposit; significant differences in the felsic concentration within each grain size fraction across samples and between size fractions within samples. Taken together, results suggest glacial kame deposits can be useful repositories of heavy indicator minerals, yet due to sediment variability extensive sampling is required if kame deposits are to be used as benchmarks in till prospecting en route to an orebody.
Faculty Sponsor or Advisor’s Name
Dr. John Whitmore
Campus Venue
Stevens Student Center
Location
Cedarville, OH
Start Date
4-1-2015 11:00 AM
End Date
4-1-2015 2:00 PM
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Glacial Till Prospecting in Southwest Ohio: Implications for Improved Sampling
Cedarville, OH
Glacial till (drift) prospecting has served a major role in corporate mineral exploration, especially for gold and diamond during the past 30 years. It involves analyzing heavy indicator minerals from bulk sampling of various glacial deposits in order to track up ice flow direction to the potential orebody (such as a kimberlite pipe or Cu-Ni deposit), a technique commonly used in Canada but not in the U.S. Heavy minerals including diamond, gold, and native copper have been found in Ohio glacial till; the provenance of these heavy minerals is the Precambrian bedrock north of Ohio. This study utilized standard procedures in sample collection and analysis (sieving, concentration by gold-panning, heavy liquid separation with lithium metatungstate [LMT], magnetic separation and microscopy) with seven samples from a kame of the Late Wisconsinan glaciation in northeastern Greene County, southwest Ohio. Coarse to very coarse sand (2 - 0.5 mm) and fine to medium sand (0.5 - 0.125 mm) fractions from each bulk sample were analyzed for heavy minerals and felsic (quartz and feldspars) concentration. The goal was to determine variability in heavy minerals and felsic component concentrations across samples and between grain-size fractions, in order to suggest improved sampling and analysis techniques.
A variety of heavy minerals, including gold, of igneous and metamorphic provenance were identified in all sample fractions by physical and optical (including fluorescence) properties. Zircon concentration in the fine to medium sand fraction appeared similar across concentrated samples. Statistical analysis showed: significant variation of the coarser to finer grain size ratio between samples, displaying the expected variability in sand sizes in a kame deposit; significant differences in the felsic concentration within each grain size fraction across samples and between size fractions within samples. Taken together, results suggest glacial kame deposits can be useful repositories of heavy indicator minerals, yet due to sediment variability extensive sampling is required if kame deposits are to be used as benchmarks in till prospecting en route to an orebody.
