Earth Materials. John O'Brien. Читать онлайн. Newlib. NEWLIB.NET

Автор: John O'Brien
Издательство: John Wiley & Sons Limited
Серия:
Жанр произведения: География
Год издания: 0
isbn: 9781119512219
Скачать книгу
west‐east in a trough that represents a modern foreland basin.

      Continental collision inevitably produces a larger continent. It is now recognized that supercontinents such as Pangea and Rodinia were formed as the result of collisional tectonics. Collisional tectonics only requires converging plates whose leading edges are composed of lithosphere that is too buoyant to be easily subducted. In fact all the major continents display evidence of being composed of a collage of terranes that were accreted by collisional events at various times in their histories.

      1.5.4 Transform plate boundaries

Image described by caption.

      Source: Courtesy of NASA;

      (b) Satellite image of southern Asia showing indentation of Eurasia by India, the uplift of Himalayas and Tibetan Plateau and the mountains that “wrap around” India.

      Source: From UNAVCO.

Schematic illustration of transform faults offsetting ridge segments on the eastern Pacific Ocean floor off Central America.

      Source: William Haxby, with the permission of Columbia University Earth Institute; Copyright Marine Geoscience Data System.

      Plates cannot simply diverge and converge; they must be able to slide past each other in opposite directions in order to move at all. Transform plate boundaries serve to accommodate this required sense of motion. Small amounts of igneous rocks form along transform plate boundaries, especially hybrid boundaries that have a component of divergence or convergence as well. They produce much smaller volumes of igneous and metamorphic rocks than are formed along divergent and convergent plate boundaries. Because they neither create nor destroy large volumes of crust/lithosphere, these boundaries are sometimes referred to as conservative plate boundaries.

Schematic illustration of (a) the fracture zones, transform faults and ridge segments in the eastern Pacific Ocean and western North America. (b) The San Andreas Fault System is a continental transform fault plate boundary.

      Source: Courtesy of USGS.

Image described by caption.

      Source: Tarduno et al. (2009). © The American Association for the Advancement of Science;

      (b) Mantle plume feeding surface volcanoes of Hawaiian Chain.

      Source: From USGS.