Reshuffling the Columbia River Basalt chronology—Picture Gorge Basalt, the earliest- and longest-erupting formation
نویسندگان
چکیده
منابع مشابه
Structures, textures, and cooling histories of Columbia River basalt flows
Flood basalt flows of the Columbia River Basalt Group commonly exhibit well-developed colonnade and entablature structures formed during cooling of individual flows. The colonnade refers to the well-defined columnar structure of many flows, which appears in the lowermost 10% to 30% and, in places, the uppermost 10% to 20%. Entablature refers to those parts of a flow that have smaller column dia...
متن کاملStructural Model for the Columbia River Basalt Near Riggins, Idaho by
Imnaha Basalt and Grande Ronde Basalt (RI) of the Columbia River Basalt Group form a small synclinal basin immediately west of Riggins, Idaho. The displacement of the margins of the basalt outcrop, of the synclinal axis, and of a dike of Saddle Mountains(?) Basalt define a pattern best explained by a model of west-northwest to eastsoutheast and north-northwest to south-southeast dextral strike-...
متن کاملA Major KREEP-Basalt—Mare Basalt unconformity on the Moon
The lunar regolith records both the geological history and processes of the Moon and also that of particles from the Sun and galaxy. Such a record extends back to the age of the rock unit upon which the regolith is developed, but complex impact gardening and processing makes this record difficult to recover and interpret. Ancient rock units, such as lava flows, begin to have regolith developed ...
متن کاملUsing paleosols of the Picture Gorge Basalt to reconstruct the middle Miocene climatic optimum
The Picture Gorge Subgroup of the Columbia River Basalt preserves numerous, minimally altered, interfl ow paleosols that were formed during the middle Miocene climatic optimum. These paleosols are used to reconstruct a high-resolution paleoclimate record. Between 16.0–15.4 Ma ago, mean annual precipitation (MAP) was 500–900 mm/year and mean annual temperature (MAT) was 8–16°C, which is consiste...
متن کاملBasalt weathering across scales
Weathering of silicate minerals impacts many geological and ecological processes. For example, the weathering of basalt contributes significantly to consumption of atmospheric carbon dioxide (CO2) and must be included in global calculations of such consumption over geological timeframes. Here we compare weathering advance rates for basalt (wD β ), where D and β indicate the scale at which the r...
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ژورنال
عنوان ژورنال: Geology
سال: 2020
ISSN: 0091-7613,1943-2682
DOI: 10.1130/g47122.1