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A flood basalt (or plateau basalt [1]) is the result of a giant volcanic eruption or series of eruptions that covers large stretches of land or the ocean floor with basalt lava. Many flood basalts have been attributed to the onset of a hotspot reaching the surface of the Earth via a mantle plume . [ 2 ]
The Columbia River Basalt Group (including the Steen and Picture Gorge basalts) extends over portions of four states. The Columbia River Basalt Group (CRBG) is the youngest, smallest and one of the best-preserved continental flood basalt provinces on Earth, covering over 210,000 km 2 (81,000 sq mi) mainly eastern Oregon and Washington, western Idaho, and part of northern Nevada. [1]
Map of the Mackenzie Large Igneous Province and its sub-features. The Coppermine River Group are shown as "Coppermine River volcanics". The Coppermine River Group is a sequence of Mesoproterozoic continental flood basalts forming part of the Mackenzie Large Igneous Province in the Northwest Territories and Nunavut, Canada.
The Deccan Traps shown as a dark purple spot on the geologic map of India Crystals of epistilbite and calcite in a vug in Deccan Traps basalt lava from Jalgaon District, Maharashtra. Within the Deccan Traps, at least 95% of the lavas are tholeiitic basalts. [26]
During late Miocene and early Pliocene times, a flood basalt engulfed about 63,000 square miles (160,000 km 2) of the Pacific Northwest, forming a large igneous province. [2] Over a period of perhaps 10 to 15 million years, lava flow after lava flow poured out, ultimately accumulating to a thickness of more than 6,000 feet (1.8 km). [2]
Representative continental flood basalts (also known as traps) and oceanic plateaus, together forming a listing of large igneous provinces: [1] Era Period [ a ]
The main source of rock in this formation is basalt, but both mafic and felsic rocks are present, so this formation is officially called a Flood Basalt Province. The inclusion of mafic and felsic rock indicates multiple other eruptions that occurred and coincided with the one-million-year-long set of eruptions that created the majority of the ...
The basalt samples at Paraná and Etendeka have an age of about 132 Ma, during the Valanginian stage of the Early Cretaceous. [3] Indirectly, the rifting and extension are probably the origin of the Paraná and Etendeka traps and it could be the origin of the Gough and Tristan da Cunha Islands as well, as they are connected by the Walvis Ridge (Gough/Tristan hotspot).