Search results
Results From The WOW.Com Content Network
The Midcontinent Rift System (MRS) or Keweenawan Rift is a 2,000 km (1,200 mi) long geological rift in the center of the North American continent and south-central part of the North American plate. It formed when the continent's core, the North American craton , began to split apart during the Mesoproterozoic era of the Precambrian , about 1.1 ...
The New Madrid seismic zone (NMSZ), sometimes called the New Madrid fault line (or fault zone or fault system), is a major seismic zone and a prolific source of intraplate earthquakes (earthquakes within a tectonic plate) in the Southern and Midwestern United States, stretching to the southwest from New Madrid, Missouri.
Between the two zones is the Missouri Gravity Low, or MGL, a mass of low density granite including the Missouri batholith up to 370 miles long and 60 miles wide, identified in gravity surveys. Igneous activity ended around 1.3 billion years ago, with the intrusion of numerous dikes and sills into newly crystallized rhyolite and granite.
(The ridge also has a secondary rift valley running its length.) The width is an average taken along the spreading ridges (Georgia–Senegal, Brazil – Bight of Benin, etc.). The greatest depth is the Romanche Trench. (The Puerto Rico Trench is not part of the rift system.) Great Rift Valley: 6,000 km (3,700 mi) 220 km (140 mi) 2 km (1 mi)
The Midcontinent Rift is the largest-known continental rift in the world. The rift began as a hot spot of basaltic magma underneath the Lake Superior region; it extruded layers of lava up to 20 km (12 mi) thick and extending up to 100 km (60 mi) on either side of the rift. The deposited lava along the North Shore of Lake Superior is 7,620 m (5 ...
Over 1,100 mya, a rift formed and lava emerged from cracks along the edges of the rift valley. This Midcontinent Rift System extended from the lower peninsula of Michigan north to the current Lake Superior, southwest through the lake to the Duluth area, and south through eastern Minnesota down into what is now Kansas. [5]
The Midcontinent Rift System, a late Precambrian rift in central North America; The Midland Valley in Scotland; The Fundy Basin, a Triassic rift basin in southeastern Canada; The Cambay, Kachchh, and Narmada rifts [25] in northwestern Deccan volcanic province of India [26]
The Stenian period Midcontinent Rift System that is still visible at the surface in the area of Lake Superior. The Mississippi embayment with the associated New Madrid Seismic Zone is an example of an ancient aulacogen that dates back to the breakup of the ancient continent, Rodinia .