A QFL diagram or QFL triangle is a type of

ternary diagram A ternary plot, ternary graph, triangle plot, simplex plot, Gibbs triangle or de Finetti diagram is a barycentric plot on three variables which sum to a constant. It graphically depicts the ratios of the three variables as positions in an equ ...

that shows

compositional data In statistics, compositional data are quantitative descriptions of the parts of some whole, conveying relative information. Mathematically, compositional data is represented by points on a simplex. Measurements involving probabilities, proportions, ...

from

sandstones Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) b ...

and modern

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class of s ...

s, point counted using the Gazzi-Dickinson method. The abbreviations used are as follows: * Q -

quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical form ...

* F -

feldspar Feldspars are a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagioclase'' (sodium-calcium) feldsp ...

* L - lithic fragments In general, the most contentious item counted is

chert Chert () is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin, but may also occur inorganically as a prec ...

, which is usually counted as a lithic fragment, but is sometimes better suited in the Q pole. When this happens, the pole is renamed 'Qt' instead of Q. The importance of a QFL triangle is mainly demonstrated in

tectonic Tectonics (; ) are the processes that control the structure and properties of the Earth's crust and its evolution through time. These include the processes of mountain building, the growth and behavior of the strong, old cores of continents k ...

exercises. As first demonstrated in the 1979 paper by

Bill Dickinson Bill Dickinson (1917 – 7 April 1994) was a Scottish rugby union player and coach. He was appointed the first official national coach of in 1971.Bath, p133 Richard Bath points out that Dickinson's appointment made an "immediate impact" in ...

and Chris Suczek, the composition and

provenance Provenance (from the French ''provenir'', 'to come from/forth') is the chronology of the ownership, custody or location of a historical object. The term was originally mostly used in relation to works of art but is now used in similar senses i ...

of a sandstone is directly related to its tectonic environment of formation. *

Craton A craton (, , or ; from grc-gre, κράτος "strength") is an old and stable part of the continental lithosphere, which consists of Earth's two topmost layers, the crust and the uppermost mantle. Having often survived cycles of merging and ...

sands are clustered near the Q pole. As sandstones, these are known as

quartz arenite A quartz arenite or quartzarenite is a sandstone composed of greater than 90% detrital quartz. Quartz arenites are the most mature sedimentary rocks possible, and are often referred to as ultra- or super-mature, and are usually cemented by sili ...

s. *Transitional continental sands are along the QF line. As sandstones, these are known as

arkose Arkose () or arkosic sandstone is a detrital sedimentary rock, specifically a type of sandstone containing at least 25% feldspar. Arkosic sand is sand that is similarly rich in feldspar, and thus the potential precursor of arkose. Quartz is c ...

s. *Basement

uplift Uplift may refer to: Science * Geologic uplift, a geological process ** Tectonic uplift, a geological process * Stellar uplift, the theoretical prospect of moving a stellar mass * Uplift mountains * Llano Uplift * Nemaha Uplift Business * Uplif ...

sands are near the F pole. This includes "thick-skinned tectonics." As sandstones, these are known as

s. *Recycled orogen sands plot near the Q pole, but with significant F and L components. This includes "thin-skinned tectonics" common in subduction back-arc thrusting. As sandstones, these are known as

lithic sandstone Lithic sandstones, or lithic arenites, or litharenites, are sandstones with a significant (>5%) component of lithic fragments, though quartz and feldspar are usually present as well, along with some clayey matrix. Lithic sandstones can have a s ...

s. *

Arc ARC may refer to: Business * Aircraft Radio Corporation, a major avionics manufacturer from the 1920s to the '50s * Airlines Reporting Corporation, an airline-owned company that provides ticket distribution, reporting, and settlement services * ...

sands plot along the F and L line, with sometimes significant Q components. Clustering near the F pole indicates a dissected arc, and clustering near the L pole indicates an undissected, or new arc. As sandstones, these are known as

s and/or

References

Petrology Sandstone {{petrology-stub

See also

References