Geologist explains basaltic pillow lava formation (pillow basalt). Expand description for more details about pillow lavas or visit http://HUGEfloods.com Use High-Definition (HD) option to improve video quality. Pillow lavas form when basaltic lava encounters water. Active pillows have been video recorded in Hawaii as the ongoing Kilauea eruption sends active basalt lava flows into the Pacific Ocean. In continental settings, pillows are formed when flood basalts bury landscapes dominated by large freshwater lakes and streams. The Columbia River Basalt Group of Washington and Oregon (USA) is a stack of more than 300 individual lava flows. The flows issued forth from deep fissures that began forming 17 million years ago in southeast Washington and northeast Oregon. Some of the flows have well-developed pillow structures in the basal sections - which proves the existence of lakes between eruptions. Thousands of years are estimated between eruptions of basalt lava from the fissures.
This episode begins with Nick standing in Sand Hollow (46.93049 -119.95038) at one of the region's most impressive Pillow Basalt road cuts - where Washington Route 26 begins its climb east out of the Columbia River Gorge near Vantage, WA. The Ginkgo and Sand Hollow basalt flows are featured - 15 million year old lavas. Lake Vantage existed 15 million years ago.
The episode then switches to Nick at the mouth of Potholes Coulee (47.15033 -119.98147) southeast of Quincy, WA. Details within a pillow zone exposed by the Ice Age Floods are studied. Palagonite between the pillows proves to be a collection of small, angular blocks of volcanic glass (obsidian) which implies sudden, explosive events as the 2,000 degree lava encounters lake water. Petrified logs on display in nearby Ginkgo Petrified Forest State Park have all been found within the palagonite zone in the base of the Ginkgo Flow. The water-logged logs escaped the incinerator of the Ginkgo Flow - and eventually became petrified as silica from the lava soaked into the wood.

Filmed in November, 2012.
Episode written by Nick Zentner and Tom Foster.
Video, Sound, & Editing: Tom Foster