Qualitative interpretations of the proportions of the framework grains, the ones that support the sediment or sedimentary rocks, have become the traditional manner in which provenance was interpreted.

Much of the development of the use of framework grains (and tourmaline) that exploded in the 1970s and 1980s actually was developed in the late 1940s by Paul Krynine (Penn State).

However, the potential of this approach was not realized until Bill Dickinson and colleagues examined the framework grains in a wide range of geological environments and placed these sediments into a plate tectonic context. (Note: this is also a point of caution for interpretation.)

 One of the classic papers that firmly placed framework grain provenance in a plate tectonic was the of Dickinson and Suczek (1979): Plate Tectonics and Sandstone Composition, AAPG Bulletin, 63, 2164-2182.

Realized that the composition of the sandstones were a function of:

• the character of the sedimentary provenance (i.e. source rock character)

• the nature of the sedimentary processes

• the kind of dispersal patterns that brings the clastic material to a basin

These are likely related by plate tectonic features

broad categories of sandstones can be correlated to tectonic regimes

---

MODES of DETRITAL FRAMEWORK GRAINS

Modes (volumes) of grains are based on the following categories of grains:

Total Lithic Fragments (Lt) = L + Qp

Extraneous constituents (e.g. heavy minerals) are ignored!

Data compiled for 88 separate Phanerozoic sandstone suites

• PreCambrian sandstones ignored due to uncertainty of plate tectonic style

• Only for sandstones with <25% matrix or cement

Provenance types

1. Continental Block Provenance - detritus in marginal basins from shields or platforms, or in fault-bounded basins

Craton Interior Provenance - generally dominated by quartz sands and high Kfs/Pl ratios due to extensive transport and more chance for weathering

Uplifted Basement (Fault-bounded) Provenance - generally dominated by quartzo-feldspathic sands with more lithic sands due to high relief, rapid deposition and minor transport.

2. Magmatic Arc Provenance - detritus deposited in basins in active island arcs or active continental arcs

Undissected  Arc Provenance (continuous volcanic cover) - dominated by volcaniclastic sands with plagioclase-rich lithic (phenocrystic) sand grains and minor quartz (clearly volcanic) .

Dissected Arc Provenance (cogenetic subvolcanic plutonic roots with volcanics)  - generally dominated by intermediate mixtures of feldspathic, volcanic and non-volcanic lithic sands with more plutonic than volcancic quartz.

3. Recycled Orogens Provenance - detritus sourced from deformed and uplifted sequences associated with subduction zones, along collisional orogens and within foreland fold-thrust belts.

Foreland Uplift Provenance (crustal thrusts with foreland basins) - dominated by recycled sedimentary from the fold-thrust belt - quartzose to chert-rich, but variable.

Subduction Complex Provenance - dominated by ophiolitic and oceanic material deposited into the forearc basin or subduction zone trench -  onset of abundant chert fragments with lesser argillite, greenstone and serpentinite.

Collision Orogen Provenance (crustal thrusts with some ophiolitic material) - dominated by sedimentary and metasedimentary lithic sands with a high quartz/feldspar ratio.

Four complementary diagrams are used, involving different grain populations and help define different provenances.

QFL diagram has emphasis on grain stability - and, consequently, on weathering, source area relief and transport mechanisms.

• Continental Block, Magmatic Arc and Recycled Orogen Provenances generally separated

• convergence of quartz-rich fields probably represent multicyclic sands

• several trends within each field

QmFLt diagram emphasizes grain size of source - because volcanics yield more lithic fragments in the sand size range than plutonics.

• Continental Block, Magmatic Arc and Recycled Orogen Provenances generally closer

• convergence of quartz-rich fields probably represent multicyclic sands

• several trends within each field

 

QpLvLs diagram subset of grain populations - reveals the general nature of the polycrystalline lithic fragments

• most useful for magmatic arc suites with arc orogen vs. collision orogen

QmPK diagram emphasizes grain size of source - reveals the general nature of the monocrystalline fragments

• Arcuate trends related to plutonic/volcanic components in magmatic arcs and stability or maturity in continental blocks

Tests of provenance potential

• Deep Sea turbidites in a variety of settings generally consistent

• Sands near the mouths of major rivers generally plot in recycled orogens fields

The type of framework grains and, consequently provenance influence the porosity structure of sandstones

• initial porosity related to angularity and grain size distribution (due to sedimentary processes)

• diagenesis affects the different types of framework grains in a distinct way

• unstable lithic fragments tend to undergo diagenesis and commonly release components that will cement the sediments, and reduce porosity.

• lithic fragments tend to be more readily deformed, and reduce porosity.