Pillow Stone
Pillow Stone
This Timestone is made of pillow basalt breccia (a rock made of broken pieces), formed on the deep sea floor during the enormous outpouring of undersea lava that built Siletzia, the final exotic terrane that completed Oregon as we see it today. Basalt pillows form when lava squirts out of a crack on the sea floor only to freeze in the cold deep water. Small pieces break off as the pillows grow, piling up to make a breccia, which is a rock made of broken fragments. This pillow breccia was then cemented together with white and pink calcite.
The base for this piece is serpentine from an older exotic terrane, a rock that forms in subduction zones when water carried by the subducting ocean crust mixes with the peridotite that makes up the mantle. Serpentinite is much less dense than the surrounding rock, and rises slowly towards the surface, forcing its way through solid rock.Stone from Coos County, base from Curry County
The Birth of Cascadia
a plume of hot rock (hotspot) arises west of Oregon, building a gigantic volcanic island which collides with the continent and shifts the subduction zone to the west
(56-49 million years ago)
This Timestone is made of pillow basalt breccia (a rock made of broken pieces), formed on the deep sea floor during the enormous outpouring of undersea lava that built Siletzia, the final exotic terrane that completed Oregon as we see it today. Basalt pillows form when lava squirts out of a crack on the sea floor only to freeze in the cold deep water. Small pieces break off as the pillows grow, piling up to make a breccia, which is a rock made of broken fragments. This pillow breccia was then cemented together with white and pink calcite.
The base for this piece is serpentine from an older exotic terrane, a rock that forms in subduction zones when water carried by the subducting ocean crust mixes with the peridotite that makes up the mantle. Serpentinite is much less dense than the surrounding rock, and rises slowly towards the surface, forcing its way through solid rock.Stone from Coos County, base from Curry County
The Birth of Cascadia
a plume of hot rock (hotspot) arises west of Oregon, building a gigantic volcanic island which collides with the continent and shifts the subduction zone to the west
(56-49 million years ago)
