Lithic Arenites

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 speckled (salt and pepper) or gray color, and are usually associated with one specific type of lithic fragment (i.e., igneous, sedimentary, or metamorphic).

Tectonically, lithic sandstones often form in a wide variety sedimentary depositional environments (including fluvial, deltaic, and alluvial sediments) associated with active margins. This tectonic setting provides the source of the lithic fragments, either through arc volcanism, thin-skinned faulting, continental collisions, unroofing, and subduction roll-back.

QFR diagram for Folk's sandstone classification: Q = Quartz, F = Feldspar, R = Rock fragments, F/R = Feldspar/Rock ratio. VRF = Volcanic rock fragment, MRF = metamorphic rock fragments, SRF = sedimentary rock fragments, CFR = carbonate rock fragments, Ss and Sh = sandstone fragments and shale fragments. From Wikipedia

Bibliography

• E. WM. Heinrich (1956): Microscopic Petrografy. Mcgraw-hill book company,inc
• M. J. Hibbard (1994): Petrography to Petrogenesis. Prentice Hall editore

Photo
General structure of the rock. PPL image, 2x (Field of view = 7mm)	General structure of the rock. XPL image, 2x (Field of view = 7mm)	General structure of the rock. XPL image, 2x (Field of view = 7mm)
Quartz-feldspar fragments and sedimentary rock fragment (pale beige). PPL image, 10x (Field of view = 2mm)	Quartz-feldspar fragments and sedimentary rock fragment (pale beige). XPL image, 10x (Field of view = 2mm)	Quartz-feldspar fragments and sedimentary rock fragment (pale beige). PPL image, 10x (Field of view = 2mm)
Quartz-feldspar fragments and metamorphic rock fragment (the polymineralic fragment). XPL image, 10x (Field of view = 2mm)	Mylonite fragment. PPL image, 10x (Field of view = 2mm)	Mylonite fragment. XPL image, 10x (Field of view = 2mm)
Quartz-feldspar fragments and metamorphic rock fragment (the polymineralic fragment). XPL image, 10x (Field of view = 2mm)	Schist fragment. XPL image, 10x (Field of view = 2mm)	Quartz-feldspar fragments and metamorphic rock fragment (the polymineralic fragment). XPL image, 10x (Field of view = 2mm)
Quartz-feldspar fragments. XPL image, 10x (Field of view = 2mm)	Quartz-feldspar fragments. XPL image, 10x (Field of view = 2mm)	Quartz-feldspar fragments. XPL image, 10x (Field of view = 2mm)