Essential Geological Terms: Tectonics, Landforms, and Earth Structure

Essential Geological Terms: Tectonics and Landforms

Orogeny or Orogenic Movement

A set of geological processes that cause the formation and folding of mountain ranges.

Ancient Massif (Old Massif)

Mountainous terrain formed by crystalline and metamorphic materials from the Primary Era (Paleozoic or Precambrian). It exhibits rigid behavior against internal Earth forces, tending to fracture rather than fold under tectonic thrusts.

Peneplain

A large landform, gently undulating and characterized by a low slope. It results from a long cycle of erosion during periods of tectonic calm, leading to widespread leveling of the relief.

Tectonic Style (Structural Form)

A set of characteristics defining a tectonic structure and the mechanisms causing its deformation. Several styles exist:

• Germanic Style: Formed primarily by faults.
• Saxonian Style: Formed by the fracturing of the crust into blocks.
• Jura Style: Characterized by folding.

High-Altitude Plateau

A plateau of great extent, located at a high altitude.

Ice Age (Glacial Period)

A climatic process characterized by generalized planetary cooling, leading to the expansion of ice sheets across large areas of the Earth's surface.

Geosyncline

A large marine sedimentation basin where materials eroded from surrounding reliefs accumulate.

Tectonic Plateau

A plateau located at a specific elevation, uplifted by tectonic movements. Mountainous ridges often form, separating the plateau from surrounding areas.

Fault

A fracture in the Earth's crust caused by tectonic stress, resulting in the displacement of one portion of the crust relative to another.

Appalachian Relief (Folded Mountain Relief)

A landform resulting from differential erosion, where hard layers are highlighted, forming peaks, while soft layers are eroded, forming valleys through which the river network flows.

Intermontane Depression (Basin)

An area, often full of undergrowth, located between mountain systems. It is composed of sedimentary materials derived from the surrounding mountains.

Witness Hill (Mesa or Butte)

High formations topped by a horizontal surface. They form through river erosion in soft layers, leaving the resistant upper layer exposed as a "witness" of the former elevation.

Countryside (Campiña)

A lowland area with sub-plateau characteristics. The elimination of the overlying limestone layer exposes a relief composed of softer materials, typically soft clay. These areas are often highly utilized for agriculture.

Karst Relief

Relief formed by the dissolution of soluble rocks (such as limestone) by water. This dissolution creates characteristic features, often resulting in very close walls or fissures within the rock structure.

Craton (Basement or Zócalo)

A set of ancient landmasses, typically consisting of granite and metamorphic rocks, upon which younger sedimentary materials lie. They usually have great extension and tend to fracture rather than fold. They form the base of a mountain range.