Flood Basalt Provinces anyone tell me what formed them, and over how longer period?

Answer 1

Depends on where you are talking. The USA east coast once was joined by Africa, over 300,000,000 years ago. When it started breaking up, and moving apart, what is now the mid-Atlantic volcanic rift line between tectonic plates was right at the Eastern coast of America. First the African continent jammed itself into the eastern seaboard, raising up the Allegheny and Blue Ridge mountain ranges from PA down thru VA to GA. That created alot of the volcanic action in the collision and subsequent compression pressures and flows resulting from the collision ( about 500,000,000 million years ago ). then more occurred as they started pulling apart. Virginia has some 1.1 billion year old volcanic gneiss and basaltic rock formations from that period, some of the oldest exposed bedrock.

- The Gremlin Guy -

Answer 2

are result of a giant volcanic eruption or series of eruptions that coats large stretches of land or the ocean floor with basalt lava.

Answer 3

BASALT BEING A VOLCANIC ROCK IS OUR FIRST CLUE. THEREFORE THE WERE FORMED BY REPEATED VOLCANIC ERUPTIONS. AND IT OCCURRED SOME 250 MILLION YEARS AGO.

Answer 4

basalt is volcanic isn't it?

Answer 5

http://en.wikipedia.org/wiki/Flood_basalt