Fold (geology) - Fold Types

Fold Types

  • Anticline: linear, strata normally dip away from axial center, oldest strata in center.
  • Syncline: linear, strata normally dip toward axial center, youngest strata in center.
  • Antiform: linear, strata dip away from axial center, age unknown, or inverted.
  • Synform: linear, strata dip toward axial centre, age unknown, or inverted.
  • Dome: nonlinear, strata dip away from center in all directions, oldest strata in center.
  • Basin: nonlinear, strata dip toward center in all directions, youngest strata in center.
  • Monocline: linear, strata dip in one direction between horizontal layers on each side.
  • Chevron: angular fold with straight limbs and small hinges
  • Recumbent: linear, fold axial plane oriented at low angle resulting in overturned strata in one limb of the fold.
  • Slump: typically monoclinal, result of differential compaction or dissolution during sedimentation and lithification.
  • Ptygmatic: Folds are chaotic, random and disconnected. Typical of sedimentary slump folding, migmatites and decollement detachment zones.
  • Parasitic: short wavelength folds formed within a larger wavelength fold structure - normally associated with differences in bed thickness
  • Disharmonic: Folds in adjacent layers with different wavelengths and shapes

(A homocline involves strata dipping in the same direction, though not necessarily any folding.)

Read more about this topic:  Fold (geology)

Famous quotes containing the words fold and/or types:

    “I mourn the safe and motherly old middle-class queen, who held the nation warm under the fold of her big, hideous Scotch-plaid shawl and whose duration had been so extraordinarily convenient and beneficent. I felt her death much more than I should have expected; she was a sustaining symbol—and the wild waters are upon us now.”
    —Henry James (1843–1916)

    “Our major universities are now stuck with an army of pedestrian, toadying careerists, Fifties types who wave around Sixties banners to conceal their record of ruthless, beaverlike tunneling to the top.”
    —Camille Paglia (b. 1947)