Unit 4 Definitions Flashcards
Entrained
The Process by which surface sediment is incorporated into a fluid flow, as part of erosion
Englacial Debris
Debris dispersed throughout the interior of a glacier
Subglacial Debris
Debris released from ice at the base of a glacier.
Supraglacial Debris
Debris Carried on the surface of a glacier.
Attrition
An erosional process where rocks and pebbles are carried in the flow of a river, knocking into each other, causing rocks to erode or break, getting smaller.
Stratification
The layering that occurs in most sedimentary rocks, and in rocks formed at the earth’s surface.
Sorting
The distribution of grain size of sediments, in deposits or sedimentary rocks.
Lateral Moraine
Sharp-crested pile of glacially transported rocks and debris, dropped by ice as it melts.
Medial Moraine
Formed when two tributary glaciers come together.
Recessional Moraine
A secondary terminal moraine deposited during a temporary glacial standstill.
Terminal Moraine
An accumulation of glacial debris pushed forward by the leading glacial snout, and dumped at the outermost point edge of any given ice advance.
Push Moraine
A moraine which forms when the terminus advance of a lowland glacier pushes unstratified glacial sediment in front of it.
Drumlin
Oval shaped hills, composed of glacial drift, formed beneath a glacier or ice sheet, aligned in the direction of ice flow.
Esker
Ridges made of sand and gravel, deposited by glacial meltwater flowing through tunnels within and underneath glaciers.
Kame
A moundlike hill of poorly sorted drift, deposited near the terminus of a glacier.
Kettlehole
An enclosed topographic depression, formed at the surface of outwash deposits in recently deglaciated areas.
Proglacial Lake
A lake formed by the damming action of a moraine during the retreat of a melting glacier, a glacial ice dam, or meltwater, trapped against an ice sheet.
Varves
Successive Layers of fine sediment, deposited by meltwater streams into glacial lakes.
