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Standard modal grain analysis in sandstones

The GAZZI-DICKINSON method

A grain-size independent evaluation of the provenance

of sandstones and geodynamic implications

Materials: petrographic microscope, thin sections stained for carbonates and feldspars

Wilfried H. Winkler (Geological Institute ETH Zurich, Switzerland)

Biogenics and bioclasts

Standard modal grain analysis in sandstones

GAZZI-DICKINSON

Grain types

Monocrystalline Quartz Qm

Polycrystalline Quartz Qp

QT

Tectonic Quartz

QT

Tectonic Quartz

Tectonite quartz-mica TQM

Tectonite quartz-mica TQM

Polycrystalline Mica Mp

K-feldspar K and Plagioclase P

K-feldspar K

Plagioclase P

Chert (sedimentary)

Chert (sedimentary)

Chert (sedimentary)

Chert (sedimentary)

Chert (sedimentary)

Chert (sedimentary)

Volcanic-hypabyssal Lithoclast Lvh

Volcanic-hypabyssal Lithoclast Lvh

Volcanic-hypabyssal Lithoclast Lvh

Volcanic-hypabyssal Lithoclast Lvh

Volcanic-hypabyssal Lithoclast Lvh

Sedimentary lithoclast Ls

Sedimentary lithoclast Ls

Sedimentary

lithoclast Ls

Sedimentary lithoclast Ls

Intrabasinal clasts

Three stepped approach in sandstone provenance evaluation in typical Alpine Flysch

Factors controlling the composition of sandstones:

o source rocks

o grain size

o distance of transport

o climate in source terrane and routing