Igneous
Rocks of Southeastern ArizonaCochise College
Virtual Geology Museum
Arizona Geology
Geology of Southeastern Arizona
Igneous
Rocks of Southeastern ArizonaRoger Weller, geology instructor
wellerr@cochise.edu last updated: 10/9/07
Johnny Lyon Granodiorite (Precambrian)
location- Johnny Lyon Hills, Dragoon quadrangle
description-medium to coarse-grained, gray to gray-green, hornblende-biotite granodiorite
age-1660 mya
Tungsten King Granite (Precambrian)
location- Dragoon quadrangle
description-medium to coarse grain granite
Whetstone Granite (Precambrian)
location-Whetstone Mountains
description-nonfoliated granite
age-intrudes Pinal Schist
MESOZOIC
Juniper Flat Granite (Triassic or Jurassic)
location- Mule Mountains
description-granite porphyry to porphyritic granite
age-186 mya, 163 mya
views of Juniper Flat Granite
Gleeson Quartz Monzonite (Triassic or Jurassic)
location-Gleeson area, Dragoon Mountains
description-coarse-grained, light-gray to greenish gray quartz monzonite
age-173 mya
Canelo Hills Volcanics (Triassic or Jurassic)
location- Canelo Hills-west of Huachuca Mountains
description-volcanic
sedimentary rocks, interlayered rhyolitic tuffs and lavas,
rhyolitic lavas, and
welded tuffs
age-173 mya
Turquoise Granite (Triassic or Jurassic)
location- near Courtland, Dragoon Mountains
description-greenish-gray to pinkish-gray highly altered granite
Walnut Gap Volcanics (Triassic or Jurassic)
location- Gunnison Hills
description-andesitic and dacitic tuffs, pyroclastic breccias and conglomerates
age-overlain by Glance Conglomerate
Huachuca Quartz Monzonite (Jurassic?)
location- Huachuca Mountains
description-medium to coarse-grained equigranular quartz monzonite
age-164 mya; overlain by Glance Conglomerate
Bronco Volcanics (Upper Cretaceous or Lower Tertiary)
location- Bronco Hill near Tombstone
description- andesite flow breccia, fine-grained quartz latite tuff
Sugarloaf Quartz Latite (Upper Cretaceous or Lower Tertiary)
location- Gleeson area, Dragoon Mountains
description-light
pinkish-gray quartz latite with phenocrysts of biotite, quartz
and feldspar in
an aphanitic groundmass; andesite flows
Schieffelin Granodiorite (Cretaceous)
location- Tombstone area
description-granodiorite to quartz monzonite
age-72.2 mya
Uncle Sam Porphyry (Cretaceous)
location- Tombstone area
description-quartz latite porphyry to quartz monzonite porphyry
age-71.9 mya
Texas Canyon Quartz Monzonite (Tertiary)
location- Little Dragoon Mountains
description-biotite quartz monzonite
age-50 mya
Chiricahua Rhyolite (Tertiary)
location- Pedregosa Mountains
Bonita Park Formation (Cenozoic)
location- Chiricahua National Monument
description-red beds and tuff
Faraway Ranch Formation (Cenozoic)
location- Chiricahua National Monument
description-ignimbrites
age-27.6 mya
Rhyolite Canyon Formation (Miocene)
location- Chiricahua Mountains
description-ash flows
age-24.9 mya
Stronghold Granite (Tertiary)
location- Chiricahua Mountains
description-light-gray to light-pink biotite granite with porphyritic border facies
age-22 mya