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Geologic units containing skarn
A rock of complex mineralogic composition formed by contact metamorphism and metasomatism of carbonate rocks. It is typically coarse-grained and rich in garnet, iron-rich pyroxene, epidote, wollastonite, and scapolite.
This category is also used for skarn (tactite) and tactite.
- Early Tertiary to Late Cretaceous granitic rocks (Late Cretaceous to Early Tertiary)
- Porphyritic to equigranular granite to diorite emplaced during the Laramide orogeny. Larger plutons are characteristically medium-grained, biotite +/- hornblende granodiorite to granite. Smaller, shallow-level intrusions are typically porphyritic. Most of the large copper deposits in Arizona are associated with porphyritic granitic rocks of this unit, and are thus named 'porphyry copper deposits'. (50-82 Ma)
- Jurassic to Cambrian metamorphosed sedimentary rocks (Cambrian to Jurassic)
- Highly faulted and folded rocks of units Jv, J_, and Pz, deformed and metamorphosed in Jurassic, Cretaceous and Tertiary time. This unit is restricted to west-central Arizona. (160-540 Ma)
- Limestone, slate; Upper Triassic greenschist-facies metamorphic rocks; western Idaho, Blue Mountains island-arc complex; (Late Triassic)
- Upper Triassic shale overlying reefal limestone and dolomite in west-central Idaho.
- Quartzite and biotite schist in fault contact; Middle Proterozoic metasedimentary rocks; southern Belt province (Middle Proterozoic)
- Intermediate Precambrian age metasediments; dominantly quartzite with minor micaceous layers and mica schists of northern Idaho
- Schist, quartzite, marble, skarn, and mafic gneiss; Jurassic to Mississippian amphibolite-facies rocks; southwestern Idaho, western accreted island-arc complex (Jurassic to Mississippian)
- Metamorphic complex of probable Paleozoic units of southwestern Idaho.