Geologic units containing mylonite

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Earth material > Tectonite

Mylonite

A compact, chert-like rock without cleavage, but with a streaky or banded structure, produced by the extreme granulation and shearing of rocks that have been pulverized and rolled during overthrusting or intense dynamic metamorphism.

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Alabama

Jacksons Gap Group; Jacksons Gap Group undifferentiated in part (Precambrian to Paleozoic): Jacksons Gap Group undivided - principally graphitic sericite (muscovite)-quartz schist; includes sericite-quartz phyllonite; sericite phyllonite, blastomylonite, porphyroclastic blastomylonite schist, and mylonite quartzite occur principally along margins in south and form most of unit northeast of Jacksons Gap, Tallapoosa County.
Mylonitic and Cataclastic Rocks in the Brevard, Towaliga, and Goat Rock Fault Zones (Precambrian to Paleozoic): Mylonitic and Cataclastic Rocks in the Brevard, Towaliga, and Goat Rock Fault Zones - blastomylonite, mylonite gneiss, locally includes mylonite schist and mylonite quartzite in Towaliga fault zone.
Mylonitic and Cataclastic Rocks in the Brevard, Towaliga, and Goat Rock Fault Zones (Precambrian to Paleozoic): Mylonitic and Cataclastic Rocks in the Brevard, Towaliga, and Goat Rock Fault Zones - crushed schistose rock; includes sericite-graphite-rich rocks.
Mylonitic and Cataclastic Rocks in the Brevard, Towaliga, and Goat Rock Fault Zones (Precambrian to Paleozoic): Mylonitic and Cataclastic Rocks in the Brevard, Towaliga, and Goat Rock Fault Zones - mylonite and blastomylonite; contains minor ultramylonite, mylonite schist, and mylonite gneiss.

Arizona

Tertiary to Early Proterozoic gneissic rocks (Early Proterozoic to Tertiary): Gneissic rocks with complex histories, typically with well developed, light-colored granitoid layers and dark-colored biotite- and amphibole-rich layers. Protoliths are of Tertiary to Proterozoic age. This unit includes variably mylonitic gneisses in metamorphic core complexes that have been exhumed from middle crustal levels by large-displacement middle Tertiary normal faults, and gneiss exposed at scattered locations near the Colorado River in southwestern Arizona. These rocks are interpreted to record Proterozoic, Mesozoic, and Tertiary metamorphism and deformation. (15-1800 Ma)

Connecticut

Mylonite along Paleozoic faults (Upper or Middle Paleozoic): Mylonite along Paleozoic faults - Mylonite, blastomylonite, and blastomylonitic gneiss, composed of intensely granulated quartz, plagioclase, biotite, and epidote, in places with hornblende or microcline and commonly with secondary minerals. In places has later been silicified (compare unit Jsi)..
Silicified rock and mylonite along Mesozoic faults (probably mainly Jurassic): Silicified rock and mylonite along Mesozoic faults - Close network of quartz veins and veinlets cutting each other and older rock, which is mostly replaced by very fine grained quartz. In places, incompletely replaced rock shows strongly mylonitic texture.

Georgia

Flinty Crush Rock (Age not given): Flinty Crush Rock
Mylonite and ultramylonite (Age not given): Mylonite and ultramylonite

Idaho

Biotite schist, hornfels, amphibolite, and mylonite; Middle Proterozoic rocks of the Prichard Formation, metamorphosed near the Cretaceous Kaniksu batholith; northern Belt province (Eocene to Middle Proterozoic): Intermediate Precambrian age metasediments; generally low-to-medium grade; argillite, siltite and minor quartzite of northern Idaho.

Massachusetts

Mylonite along Connecticut Valley border fault (Lower Jurassic): Mylonite along Connecticut Valley border fault.

North Carolina

Metamorphosed Granitic Rock (Late Proterozoic): Metamorphosed Granitic Rock (680-710 my) - massive to foliated, locally mylonitic. Beech, Crossnore, Brown Mountain, Lansing, and other granitic rocks.

South Carolina

Mylonite gneiss (Late Paleozoic): Mylonite gneiss
Mylonitic rocks of Brevard fault zone (Late Paleozoic): Mylonitic and phyllonitic equivalents of Chauga River Formation and other adjacent rock units
Mylonitic rocks of Modoc Fault Zone (Late Paleozoic): Mylonitic rocks of Modoc Fault Zone: mylonite gneiss

Virginia

Mylonite, Mylonite Gneiss, and Cataclastic Rocks (Proterozoic - Paleozoic ?): Mylonite, mylonite gneiss, and cataclastic rocks.

Washington

Pre-Upper Jurassic metamorphic rocks of the medium and high-grade zone (Early Jurassic-Triassic): Schist, amphibolite, and minor lime-silicate rocks, marble, quartzite, and metaconglomerate.

Wisconsin

Fault rocks (Archean to Early Proterozoic): Fault rocks - Mylonitic rocks of uncertain lithology in Eau Pleine shear zone