Non-volcanic passive margins (NVPM) constitute one end member of the transitional crustal types that lie beneath passive continental margins; the other end member being volcanic passive margins (VPM). Transitional crust welds continental crust to oceanic crust along the lines of continental break-up. Both VPM and NVPM form during rifting, when a continent rifts to form a new ocean basin. NVPM are different from VPM because of a lack of volcanism. Instead of intrusive magmatic structures, the transitional crust is composed of stretched continental crust and exhumed upper mantle. NVPM are typically submerged and buried beneath thick sediments, so they must be studied using geophysical techniques or drilling. NVPM have diagnostic seismic, gravity, and magnetic characteristics that can be used to distinguish them from VPM and for demarcating the transition between continental and oceanic crust.
Read more about Non-volcanic Passive Margins: Typical Characteristics
Famous quotes containing the words passive and/or margins:
“She has taken her passive pigeon poor,
She has buried him down and down.
He never shall sally to Sally
Nor soil any roofs of the town.”
—Gwendolyn Brooks (b. 1917)
“Everything is becoming science fiction. From the margins of an almost invisible literature has sprung the intact reality of the 20th century.”
—J.G. (James Graham)