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Geologic units containing quartz syenite

California

Mesozoic granitic rocks, unit 3 (Sierra Nevada, Death Valley area, Northern Mojave Desert and Transverse Ranges) (Permian to Tertiary; most Mesozoic)

Mesozoic granite, quartz monzonite, granodiorite, and quartz diorite

Idaho

Monzogranite, syenogranite, and syenite; Eocene phaneritic to porphro-aphanitic intrusions of the pink monzogranite suite; Challis magmatic belt (Eocene)

Eocene intrusions of predominantly felsic (pink granite) composition

Syenite, granite, quartz syenite, and gabbro; Ordovician to Cambrian plutons; east-central Idaho (Ordovician to Cambrian)

Intrusive rock of eastern Idaho; appears older than Cretaceous; possibly Precambrian

Syenite, monzonite, quartz syenite; Late to Early Cretaceous syenitic intrusions; northern Idaho (Cretaceous)

Cretaceous syenitic to monzonitic intrusions

Syenite, quartz syenite, monzodiorite, quartz diorite, gabbro, pyroxenite, and hornblendite; Late Proterozoic plutons; east-central Idaho (Late Proterozoic)

Younger or Intermediate Precambrian age intrusive rock undifferentiated.

Massachusetts

Cape Ann Complex (Lower Silurian or Upper Ordovician)

Cape Ann Complex - Alkalic granite to quartz syenite containing ferro-hornblende. Intrudes Zdigb. Most of Cape Ann Complex forms Cape Ann peninsula of northeastern MA. Consists of alkalic granite to quartz syenite (its main phase), Beverly Syenite, and Squam Granite, all of which form a pluton covering 385 sq km. Intrudes Late Proterozoic greenschist, diorite, and gabbro that earlier workers assigned to Marlboro Formation, Salem Gabbro-Diorite, or Middlesex Fells Volcanic Complex. Dennen (1975) considered masses of diorite and gabbro within and adjacent to Cape Ann Complex to be cogenetic with it and equivalent in age to Nahant Gabbro and gabbro at Salem Neck. Authors recommend that usage of term Salem Gabbro-Diorite be restricted to these masses of diorite and gabbro in and around Cape Ann pluton that are younger than Dedham Granite and cogenetic with Cape Ann Complex. Gabbro at Salem Neck is probably representative. Radiometric ages straddle Late Ordovician-Early Silurian boundary. Age is based on Rb-Sr whole rock isochron of 426 +/-6 Ma (Zartman and Marvin, 1971) and U-Pb zircon date of 450 +/-25 Ma (Zartman, 1977) (Wones and Goldsmith, 1991).

Maine

Carboniferous alkali feldspar quartz syenite (Carboniferous)

Carboniferous alkali feldspar quartz syenite - alkali feldspar-biotite quartz syenite

Cretaceous alkali feldspar quartz syenite (Cretaceous)

Cretaceous alkali feldspar quartz syenite - Cretaceous alkali feldspar-biotite quartz syenite

Devonian granite-quartz diorite (Devonian)

Devonian granite-quartz diorite: biotite granite, biotite granodiorite, biotite tonalite, biotite quartz syenite, biotite quartz monzodiorite, and biotite quartz diorite.

Devonian granite-quartz monzonite (hornblende accessory mineral) (Devonian)

Devonian granite-quartz monzonite (hornblende accessory mineral) Devonian hornblende-biotite granite to quartz monzonite- hornblende-biotite granite, hornblende-biotite granodiorite, hornblende-biotite tonalite, hornblende-biotite alkali feldspar quartz syenite, hornblende-biotite quartz syenite, and hornblende-biotite quartz monzonite.

Devonian granodiorite - quartz diorite (Devonian)

Devonian granodiorite - quartz diorite - Devonian biotite granodiorite to biotite quartz diorite - biotite granodiorite, biotite tonalite, biotite quartz syenite, biotite quartz monzodiorite, and biotite quartz diorite.

Devonian granodiorite - quartz monzodiorite (hornblende accessory mineral) (Devonian)

Devonian granodiorite - quartz monzodiorite (hornblende accessory mineral) - Devonian hornblende-biotite granodiorite to quartz monzodiorite - hornblende-biotite granodiorite, hornblende-biotite tonalite, hornblende-biotite quartz syenite, and hornblende-biotite quartz monzodiorite.

Devonian granodiorite - quartz syenite (porphyritic texture) (Devonian)

Devonian granodiorite - quartz syenite (porphyritic texture) - Devonian porphyritic biotite granodiorite to quartz syenite - porphyritic biotite granodiorite, porphyritic biotite tonalite, porphyritic alkali feldspar-biotite quartz syenite, and porphyritic biotite quartz syenite.

New Hampshire

Hornblende-biotite quartz syenite to syenite (Late Ordovician)

Hornblende-biotite quartz syenite to syenite.

Hornblende or alkalic amphibole quartz syenite (Jurassic)

Hornblende or alkalic amphibole quartz syenite.

Large mesoperthitic phenocrysts in a pink to gray quartz syenite porphyry of "Albany type" (Cretaceous)

Large mesoperthitic phenocrysts in a pink to gray quartz syenite porphyry of "Albany type" - Alkalic amphibole or fayalite may be present. Part of Ossipee Mountain Complex of Kingsley (1931).

Leucocratic granite to quartz syenite (Jurassic)

Leucocratic granite to quartz syenite.

Porphyritic biotite quartz syenite in central Jefferson dome in Mt. Washington quadrangle (Late Ordovician)

Porphyritic biotite quartz syenite in central Jefferson dome in Mt. Washington quadrangle.

Porphyritic hornblende or alkalic amphibole quartz syenite (Jurassic)

Porphyritic hornblende or alkalic amphibole quartz syenite.

Quartz syenite (Jurassic)

Quartz syenite - Commonly porphyritic and mesoperthitic; contains biotite and, locally, fayalite, hastingsite, hornblende, or ferrohedenbergite.

New Jersey

Hornblende Granite (Middle Proterozoic)

Hornblende Granite - Pinkish-gray- to medium-buff-weathering, pinkish-white or light-pinkish-gray, medium- to coarse-grained, gneissoid to indistinctly foliated granite and sparse granite gneiss composed principally of microcline microperthite, quartz, oligoclase, and hornblende. Some phases are quartz syenite or quartz monzonite. Includes small bodies of pegmatite and amphibolite not shown on map. U-Pb age approximately 1,090 Ma (Drake and others, 1991b).

Hornblende Syenite (Middle Proterozoic)

Hornblende Syenite - Tan- to buff-weathering, pinkish-gray or greenish-gray, medium- to coarse-grained, gneissoid syenite and lesser amounts of quartz syenite containing microcline microperthite, oligoclase, quartz, and hornblende. Some phases are monzonite or monzodiorite.

Vermont

Syenite (Permian-Triassic)

Syenite - Hornblende, biotite, quartz and augite syenites.