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This could be accomplished by sheet flow, which can travel at velocities of 1 to 8 metres per second (2.2 to 17.9 mph) without turbulence and minimal cooling, suggesting that the Ginkgo flow occurred in less than a week.

The cooling/hydraulics analyses are supported by an independent indicator; if longer periods were required, external water from temporarily dammed rivers would intrude, resulting in both more dramatic cooling rates and increased volumes of pillow lava.

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Some time during a 10–15 million-year period, lava flow after lava flow poured out, eventually reaching a thickness of more than 1.8 km (5,900 ft).

As the molten rock came to the surface, the Earth's crust gradually sank into the space left by the rising lava.

The Latah Formation sediments of Washington and Idaho are interbedded with a number of the Columbia River Basalt Group flows, and outcrop across the region.

Absolute dates, subject to a statistical uncertainty, are determined through radiometric dating using isotope ratios such as (800,000 sq mi) in Russia.

Erosion resulting from the Missoula Floods has extensively exposed these lava flows, laying bare many layers of the basalt flows at Wallula Gap, the lower Palouse River, the Columbia River Gorge and throughout the Channeled Scablands.

The Columbia River Basalt Group is thought to be a potential link to the Chilcotin Group in south-central British Columbia, Canada.In the middle Miocene, 17 to 15 Ma, the Columbia Plateau and the Oregon Basin and Range of the Pacific Northwest were flooded with lava flows.Both flows are similar in both composition and age, and have been attributed to a common source, the Yellowstone hotspot.The Columbia River Basalt Group flows exhibit essentially uniform chemical properties through the bulk of individual flows, suggesting rapid placement.Ho and Cashman (1997) characterized the 500 km (310 mi)-long Ginkgo flow of the Columbia River Basalt Group, determining that it had been formed in roughly a week, based on the measured melting temperature along the flow from the origin to the most distant point of the flow, combined with hydraulics considerations.Using tomographic images based on seismic waves, relatively narrow, deeply seated, active convective plumes have been detected under Yellowstone and several other hot spots.

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