39°26′N29°50′W / 39.44°N 29.83°W /39.44; -29.83
TheAzores triple junction (ATJ) is a geologictriple junction where the boundaries of three tectonic plates intersect: theNorth American plate, theEurasian plate and theAfrican plate. This triple junction is located along theMid-Atlantic Ridge (MAR) amidst theAzores islands, nearly due west of theStrait of Gibraltar. It is classified as anR-R-R triple junction of the T type (for its shape), as it is an intersection of the Mid-Atlantic Ridge running north–south and theTerceira Rift which runs east-southeast.
The spreading rate along the MAR does not change abruptly at the ATJ, instead decreasing from 22.9±0.1 mm/yr at 40°N to 19.8±0.2 mm/yr at 38°N. This means the ATJ is not a simple triple junction where three tectonic plates meet at a point. The transitional range of spreading rates instead indicates the presence of amicroplate, commonly referred to as theAzores Microplate, although the observed behaviour can also be explained in terms of a diffuse boundary.[1] Its northern boundary intersects the MAR between 39.4°N and 40.0°N and its southern between 38.2°N and 38.5°N. The microplate moves about 2 mm/yr east-northeast along its Nubian (African plate) boundary.[2]
{{cite journal}}: CS1 maint: multiple names: authors list (link)| Triple trench | |
|---|---|
| Triple ridge | |
| Triple fault | |
| Trench–trench–ridge | |
| Fault–fault–trench | |
| Ridge–fault–fault | |
| Ridge–trench–fault | |
| See also | |
