Trace element signature of Late Jurassic siliciclastic-carbonate sedimentary strata from western Montana, southeastern British Columbia and southern Alberta
- Elizabeth City State Univ., NC (United States). Dept. of Geosciences
A trace element signature, a characteristic pattern of enrichment and depletion of trace elements, was determined for a group of siliciclastic-carbonate Oxfordian and Kimmeridgian sedimentary strata, collected from outcrops in western Montana, southeastern British Columbia and southern Alberta. The average values, by petrofacies, of 10 major and 18 trace elements were measured for 40 samples. These data were normalized to Upper Continental Crust (UCC), and plotted against averaged published values of graywackes from the same facies. The rare earth elements (REEs), as well as Ti, Zr, Nb and Y are considered immobile even through diagenesis, and at least low level metamorphism. So these elements should form a reliable part of the geochemical signature. Compared to UCC and average graywacke, Jurassic samples are very depleted in Zr, Nb and Y. Oxfordian samples have slightly higher rare earth element values, i.e. La, Ce and Nd, than either other Jurassic samples or average graywacke. The most likely source of REE values are garnets and tourmaline which occur as inclusions in monocrystalline quartz grains. This pattern, and petrological study, point to a sedimentary source area, deficient in feldspar, heavy minerals and rock fragments. The consistency of the signature throughout this time may indicate slow uplift of a widespread sedimentary source area, or could be an effect of greater mixing and shorter residence time of dissolved materials in an epeiric sea.
- OSTI ID:
- 5809538
- Report Number(s):
- CONF-921058-; CODEN: GAAPBC
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Vol. 24:7; Conference: 1992 annual meeting of the Geological Society of America (GSA), Cincinnati, OH (United States), 26-29 Oct 1992; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
Similar Records
Origin of Paleozoic volcanics, northern Sierra Nevada, California: trace element and isotopic evidence
Critical Minerals and Rare Earth Elements in Powder River Basin Coal and Associated Sediments, Wyoming, USA
Related Subjects
ALBERTA
SEDIMENTARY BASINS
BRITISH COLUMBIA
MONTANA
GEOCHEMISTRY
CARBONATE ROCKS
GEOLOGIC HISTORY
JURASSIC PERIOD
NIOBIUM
PETROLOGY
RARE EARTHS
TITANIUM
TRACE AMOUNTS
YTTRIUM
ZIRCONIUM
CANADA
CHEMISTRY
DEVELOPED COUNTRIES
ELEMENTS
GEOLOGIC AGES
GEOLOGIC STRUCTURES
GEOLOGY
MESOZOIC ERA
METALS
NORTH AMERICA
ROCKS
SEDIMENTARY ROCKS
TRANSITION ELEMENTS
USA
580000* - Geosciences