Geometric Elements

Advanced Tectonics
James S. Aber

The following examples are taken from metamorphic and igneous rocks and
unconsolidated sediment in western Norway. All images © J.S. Aber.

Planar Elements

Interlayered felsic gneiss and amphibolite showing three sets of planar fractures exposed at Glasskartunnel. Layers and fractures are planar elements that cause the rock to break into rectangular blocks. Highway 14 in Bergen, Norway.
Amphibolite pod within gneiss, approximately 5 m across. White veins are secondary infillings of planar fractures within the dark amphibolite pod. Highway 14, Bergen, Norway.
Block of augen gneiss. Augens (eyes or knots) of feldspar are contained within banded metamorphic rock. The bands, known as foliation, are planar features. Askøy island, near Bergen, Norway.

Linear Elements

Large glacial groove on crystalline bedrock surface. Scale pole is laid parallel to the linear groove; pole is 2 m long. Island of Herdla, near Bergen, Norway.
Small fold above a fault in late Pleistocene glaciomarine sediment. The yellow pen marks the linear axis of the fold, and the fault is a planar structure. Island of Herdla, near Bergen, Norway.

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Notice: Advanced tectonics is presented for the use and benefit of students enrolled at Emporia State University. Others are welcome to view the course webpages. Any other use of text, imagery or curriculum materials is prohibited without permission of the instructor. Text and images © J.S. Aber (2016).