Geomorphology and Quaternary Geology Flashcards

Stream terraces form primarily as a result of:

Answer: Stream incision following a change in base level or sediment supply

Stream terraces are abandoned floodplains left elevated when a river incises downward due to falling base level or decreased sediment supply.

Which process describes the downslope movement of water-saturated soil and debris as a coherent mass over a curved failure surface?

Answer: Rotational slump

A rotational slump involves movement along a concave-upward failure surface, with the mass rotating backward as it slides.

Pleistocene pluvial lakes, such as Lake Bonneville, formed primarily because of:

Answer: Increased precipitation and reduced evaporation under cooler climates

Pluvial lakes expanded during glacial intervals due to cooler, wetter conditions that reduced evaporation and increased precipitation.

What is the term for a crescent-shaped sand dune with horns pointing downwind?

Answer: Barchan

Barchan dunes are crescent-shaped with the concave side downwind, forming where sand supply is limited and wind direction is consistent.

Drumlins are elongated glacial landforms that indicate:

Answer: The direction of former glacial flow

Drumlins are streamlined subglacial landforms whose long axes parallel the direction of ice flow, with the blunt end facing up-ice.

Which luminescence dating technique uses heat to release trapped electrons from mineral grains to determine burial age?

Answer: Thermoluminescence (TL)

Thermoluminescence (TL) dating releases trapped electrons by heating mineral grains, measuring light emitted to calculate the time since last exposure to heat or light.

A wave-cut platform is best described as:

Answer: A subhorizontal bedrock surface eroded by wave action at the base of a sea cliff

Wave-cut platforms are flat or gently sloping bedrock surfaces formed by wave erosion at the base of retreating sea cliffs.