The Vulcan structure is a 350 kilometres (217.5 mi) long major convergent boundary

Convergent boundary

In plate tectonics, a convergent boundary, also known as a destructive plate boundary , is an actively deforming region where two tectonic plates or fragments of lithosphere move toward one another and collide...

 between the Medicine Hat Block and the Loverna Block, Archean

Archean

The Archean , also spelled Archeozoic or Archæozoic) is a geologic eon before the Paleoproterozoic Era of the Proterozoic Eon, before 2.5 Ga ago. Instead of being based on stratigraphy, this date is defined chronometrically...

 basement

Basement (geology)

In geology, the terms basement and crystalline basement are used to define the rocks below a sedimentary platform or cover, or more generally any rock below sedimentary rocks or sedimentary basins that are metamorphic or igneous in origin...

 rock structures which lie between the Wyoming craton

Wyoming craton

The Wyoming craton is a craton located in the west-central United States and western Canada – more specifically, in Montana, Wyoming, southern Alberta, southern Saskatchewan, and parts of northern Utah...

 and Hearne craton on the western edge of the North American craton

Laurentia

Laurentia is a large area of continental craton, which forms the ancient geological core of the North American continent...

. It lies under the Western Canadian Sedimentary Basin

Western Canadian Sedimentary Basin

The Western Canadian Sedimentary Basin is a vast sedimentary basin underlying of Western Canada including southwestern Manitoba, southern Saskatchewan, Alberta, northeastern British Columbia and the southwest corner of the Northwest Territories. It consists of a massive wedge of sedimentary rock...

.

The Vulcan structure has intrigued geologists because it is a region of low gravity

Gravity anomaly

A gravity anomaly is the difference between the observed acceleration of Earth's gravity and a value predicted from a model.-Geodesy and geophysics:...

 and contains an east-trending magnetic anomaly

Magnetic anomaly

In geophysics, a magnetic anomaly is a local variation in the Earth's magnetic field resulting from variations in the chemistry or magnetism of the rocks. Mapping of variation over an area is valuable in detecting structures obscured by overlying material...

 which cuts across the magnetic field of southern Alberta

Alberta

Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...

 at a high angle. The Vulcan structure was the target of one of the first deep-crustal seismic profiles in the late 1960s. Geologists have offered several explanations for what the structure is: failed Proterozoic

Proterozoic

The Proterozoic is a geological eon representing a period before the first abundant complex life on Earth. The name Proterozoic comes from the Greek "earlier life"...

 rift

Rift

In geology, a rift or chasm is a place where the Earth's crust and lithosphere are being pulled apart and is an example of extensional tectonics....

, intraplate collision zone

Collision zone

A collision zone occurs when tectonic plates meeting at a convergent boundary both bear continental lithosphere. As continental lithosphere is usually not subducted due to its relative low density, the result is a complex area of orogeny involving folding and thrust faulting as the blocks of...

, Proterozoic suture

Suture (geology)

In structural geology, a suture is a major fault zone through an orogen or mountain range. Sutures separate terranes, tectonic units that have different plate tectonic, metamorphic and paleogeographic histories...

, or continental collision zone.