Fabric analysis and ICP: Under-used geoanalytical techniques of value for plant biostratigraphy, provenance and palaeoecology

Journal Article · Tue Jan 01 00:00:00 EST 1991 · American Journal of Botany; (USA)

OSTI ID:5733504

Bateman, R M ^[1]

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1. Smithsonian Institute, Washington, DC (USA)

Inductively-coupled plasma-arc spectrometry (ICP) is a rapid, automated method of quantifying the bulk geochemistry of artificially vitrified rocks. Measurable elements (cations of atomic No > 10) are partitioned into three categories (major, minor, trace) of decreasing abundance and increasing potential error. Even a basic analysis of the ten major elements plus loss-on-ignition is sufficient to finger-print a sample, yielding a data-set that can be fed directly into a multivariate analysis to compare and classify rocks. Thus, ex situ plant-bearing blocks can be correlated with their source horizons. ICP data also aid indirect correlation of plant-bearing horizons per se. Extensive ICP sampling reveals spatial trends that can be interpreted palaeoenvironmentally (e.g. indicating the direction of a nearby volcano, or distinguishing between biogenic and non-biogenic limestones enclosing permineralized plants). In contrast variables recorded during fabric analysis are physical rather than chemical, particulate rather than bulk, and few rather than many. Two orientations, relative to magnetic north and to the bedding plane, are taken from clast populations; these are summarized as three values (mean dip, resultant vector, vector magnitude) that can be tested against randomness. Although data are traditionally obtained from large (> 2 cm) abiotic clasts, transported fossil plant fragments are equally suitable. Adpressions are oriented by exposing bedding planes, permineralizations by reconstructing beds in the laboratory and then repeatedly transversely cutting blocks to trace the fossils. Singly, fabrics reflect the hydraulic conditions prevailing in the depositional environment immediately prior to burial; in aggregate, they indicate the direction of the source community relative to the depositional sink.

• OSTI ID: 5733504
• Journal Information: American Journal of Botany; (USA), Journal Name: American Journal of Botany; (USA); ISSN 0002-9122
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
58 GEOSCIENCES
RESERVOIR ROCK
MULTI-ELEMENT ANALYSIS
CORRELATIONS
DEPOSITION
ELEMENTS
FOSSILS
GEOCHEMISTRY
GEOLOGIC HISTORY
GEOLOGIC STRATA
MULTIVARIATE ANALYSIS
ORIGIN
PALEONTOLOGY
PLANTS
SPECTROSCOPY
STRATIGRAPHY
CHEMICAL ANALYSIS
CHEMISTRY
GEOLOGIC STRUCTURES
GEOLOGY
MATHEMATICS
STATISTICS
400102* - Chemical & Spectral Procedures
580000 - Geosciences