tholeiite

Quartz tholeiite basalt lava flows (flow B over flow A, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 4
by James St. John

Autobrecciated amygdaloidal quartz tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 27
by James St. John

Intergranular calcite in autobrecciated amygdaloidal tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 2
by James St. John

Intergranular calcite in autobrecciated amygdaloidal tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 3
by James St. John

Autobrecciated amygdaloidal quartz tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 31
by James St. John

Quartz tholeiite basalt lava flow (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 5
by James St. John

Natural arch in basalt (Gooseberry River Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Gooseberry Falls State Park, Minnesota, USA) 1
by James St. John

Quartz tholeiite basalt lava flow (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 16
by James St. John

Quartz tholeiite basalt lava flows (flow B over flow A, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 3
by James St. John

Agglutinated volcanic bomb in basaltic lapillistone (Middle Tholeiitic Unit, Kidd-Munro Assemblage, Neoarchean, 2.711-2.719 Ga; just east of the Potter Mine, east of Timmins, Ontario, Canada) 9
by James St. John

Natural arch in basalt (Gooseberry River Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Gooseberry Falls State Park, Minnesota, USA) 2
by James St. John

Autobrecciated amygdaloidal quartz tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 7
by James St. John

Autobrecciated amygdaloidal quartz tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 22
by James St. John

Autobrecciated amygdaloidal quartz tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 23
by James St. John

Olivine tholeiite basalt lava flow at Gooseberry Falls - Lower Falls (Gooseberry River Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Gooseberry Falls State Park, Minnesota, USA) 2
by James St. John

Agglutinated volcanic bomb in basaltic lapillistone (Middle Tholeiitic Unit, Kidd-Munro Assemblage, Neoarchean, 2.711-2.719 Ga; just east of the Potter Mine, east of Timmins, Ontario, Canada) 8
by James St. John

Autobrecciated amygdaloidal quartz tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 36
by James St. John

Autobrecciated amygdaloidal quartz tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 25
by James St. John

Autobrecciated amygdaloidal quartz tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 21
by James St. John

Large quartz-laumontite-calcite amygdule in quartz tholeiite basalt lava flow (Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA)
by James St. John

Autobrecciated amygdaloidal quartz tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 4
by James St. John

Autobrecciated amygdaloidal quartz tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 6
by James St. John

Autobrecciated amygdaloidal quartz tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 32
by James St. John

Autobrecciated amygdaloidal quartz tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 16
by James St. John

Intergranular calcite in autobrecciated amygdaloidal tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 1
by James St. John

Autobrecciated amygdaloidal quartz tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 19
by James St. John

Plumose marking on joint surface in tholeiitic basalt (Clam Falls Volcanics, Mesoproterozoic, ~1.1 Ga; Interstate State Park, Taylors Falls, Minnesota, USA) 2
by James St. John

Autobrecciated amygdaloidal quartz tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 11
by James St. John

Polymetallic massive sulfide (Middle Tholeiitic Unit, Kidd-Munro Assemblage, Neoarchean, 2.711 to 2.719 Ga; drill core at the Potter Mine, east of Timmins, Ontario, Canada) 15
by James St. John

Autobrecciated amygdaloidal quartz tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 2
by James St. John

Autobrecciated amygdaloidal quartz tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 30
by James St. John

Quartz tholeiite basalt lava flow (flow A, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 16
by James St. John

Intergranular calcite in autobrecciated amygdaloidal tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 8
by James St. John

Intergranular calcite in autobrecciated amygdaloidal tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 5
by James St. John

Autobrecciated amygdaloidal quartz tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 24
by James St. John

Autobrecciated amygdaloidal quartz tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 28
by James St. John

Autobrecciated amygdaloidal quartz tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 17
by James St. John

Large quartz-laumontite amygdule in quartz tholeiite basalt lava flow (Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 10
by James St. John

Andesite (Larch Mountain Andesite, Lower Pleistocene, 1.43 Ma; Larch Mountain Shield Volcano, Boring Volcanic Field, Oregon, USA) 1
by James St. John

Autobrecciated amygdaloidal quartz tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 37
by James St. John

Quartz tholeiite basalt lava flow (flow A, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 3
by James St. John

Autobrecciated amygdaloidal quartz tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 26
by James St. John

Tholeiitic basalt dike with flow layering & peperite & basaltic lapillistone (Middle Tholeiitic Unit, Kidd-Munro Assemblage, Neoarchean, 2.711-2.719 Ga; just east of the Potter Mine, east of Timmins, Ontario, Canada) 5
by James St. John

Quartz tholeiite basalt lava flow (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 8
by James St. John

Tholeiitic basalts (Clam Falls Volcanics, Mesoproterozoic, ~1.1 Ga; Interstate State Park, Taylors Falls, Minnesota, USA) 4
by James St. John

Autobrecciated amygdaloidal quartz tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 1
by James St. John

Diabase dike (ophitic olivine tholeiite) (anorthosite series, Duluth Complex, Mesoproterozoic, 1099 Ma; Merritt Creek West Skyline Parkway roadcut, Duluth, Minnesota, USA) 3
by James St. John

Hyaloclastic sandstone (probably Pliocene; Interstate 84 roadcut, Portland, Oregon, USA) 1
by James St. John

Quartz tholeiite basalt lava flow (flow A, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 15
by James St. John

Quartz tholeiite basalt lava flow (flow A, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 1
by James St. John

Intergranular calcite in autobrecciated amygdaloidal tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 7
by James St. John

Tholeiitic basalt dike with flow layering & peperite & basaltic lapillistone (Middle Tholeiitic Unit, Kidd-Munro Assemblage, Neoarchean, 2.711-2.719 Ga; just east of the Potter Mine, east of Timmins, Ontario, Canada) 6
by James St. John

Quartz tholeiite basalt lava flow (flow A, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 2
by James St. John

Intergranular calcite in autobrecciated amygdaloidal tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 9
by James St. John

Sulfidic basaltic lapillistone (Middle Tholeiitic Unit, Kidd-Munro Assemblage, Neoarchean, 2.711 to 2.719 Ga; drill core at the Potter Mine, east of Timmins, Ontario, Canada) 2
by James St. John

Large quartz-laumontite amygdule in quartz tholeiite basalt lava flow (Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 11
by James St. John

Autobrecciated amygdaloidal quartz tholeiite basalt aa lava flow top (flow B, Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 8
by James St. John

Basaltic lapillistone (Middle Tholeiitic Unit, Kidd-Munro Assemblage, Neoarchean, 2.711-2.719 Ga; just east of the Potter Mine, east of Timmins, Ontario, Canada) 15
by James St. John

Tholeiitic basalts (Clam Falls Volcanics, Mesoproterozoic, ~1.1 Ga; Interstate State Park, Taylors Falls, Minnesota, USA) 13
by James St. John

Large quartz-laumontite amygdule in quartz tholeiite basalt lava flow (Two Harbors Basalts, North Shore Volcanic Series, Mesoproterozoic, 1097-1098 Ma; Burlington Bay, Two Harbors, Minnesota, USA) 3
by James St. John