Abstract
Oceanic transform fault plate boundaries accommodate large-scale, strike-slip displacements. They link combinations of convergent (subduction zones) and divergent (spreading centers) boundaries. Depending on the details of the linked boundaries, the length of transform faults may increase, decrease or remain the same with continued plate motions. Transform fault plate boundaries may terminate abruptly in other plate boundary configurations such as triple junctions. As plate boundaries change their orientation with respect to plate motions, convergent or divergent boundaries may transition along strike into transform faults. Transform faults may be converted to other types of plate boundaries as a result of inevitable reconfigurations of poles of rotation. The most common type of oceanic transform fault occurs at near-orthogonal offsets along mid-ocean ridge spreading centers at oceanic fracture zones. Strike-slip movement is limited to the plate boundary linking the tips of offset ridge segments. Nontransform limbs of fracture zones are intra-plate contacts in relatively old lithosphere extending beyond spreading center offsets. Long-lived (millions of years) ridge-ridge transforms have predictable tectonic displacement histories within lithosphere with persistent thermal and mechanical influences. The morphology and tectonics of oceanic transform faults is largely a function of the age contrast across these boundaries determined by both ridge offset length and slip rate. A variation on this type of plate boundary occurs where spreading centers propagate and recede resulting in migrating transform boundaries. In these situations, transform deformation occurs in crust and lithosphere that did not form in an established transform domain and slip duration is limited by the propagation rate. Transform migration can leave an area of deformed lithosphere in its wake.
Original language | English (US) |
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Title of host publication | Encyclopedia of Geology |
Subtitle of host publication | Volume 1-6, Second Edition |
Publisher | Elsevier |
Pages | 930-946 |
Number of pages | 17 |
Volume | 3 |
ISBN (Electronic) | 9780081029091 |
DOIs | |
State | Published - Jan 1 2020 |
Keywords
- Lithosphere plate boundary
- Migrating transform
- Nontransform zone
- Oceanic fracture zone
- Oceanic lithosphere
- Relative plate motions
- Ridge-ridge transform
- Seafloor spreading
- Transform fault
- Transform zone
ASJC Scopus subject areas
- General Environmental Science