Flashcards
PW 8
Flashcards do conjunto (21)
- 1Where can glaciofluvial activity occur?-Supraglacial
-Englacial
-Subglacial
-Proglacial - 2What leads to entrainment and re-deposition of matieral?-Fluctuations in flow regime and this produces secondary glacial sedimentary deposits
- 3What does entrainment and transport depend upon?-Discharge
-Season
-Hydrological configuration
-Environment of transport - 4What are the characteristics of typical fluvial environments?-Sediment re-worked from glacial tills
-Clasts well rounded
-Assorted sediment sizes from fines to gravel
-Sediment sorting depending upon stream power to transport and deposit
-Internal structures range from massive, planar stratification- cross bedding, depending upon water flow characteristics - 5What happens when the capacity of a stream declines?-Material is deposited
- 6What do the following deposits show us?Horizontal deposits
-Horizontal bedding producing laminations
-Each laminae represents fluctuations in flow velocity or sediment supply
-Slow moving, shallow water
Cross bedding
-Ripples
-Dunes
Structureless - 7What is an example of a glaciofluvial landform?-Ice marginal kame deposits
-Sediment deposited between ice margin and lateral valley slope
-Ice retreats to leave terrace of fluvial material
-Proglacial braided rivers
-Networks of shifting sediment-floored channels and bars on outwash plains
-Develop in response to marked seasonal fluctuations in discharge
-Distinct changes in facies architecture from proximal to distal locations - 8Compare proximal characteristicd and distal characteristics
- 9What are the types of glacial lakes?-Past glacial lakes
-Non-glacier contact water bodies
-Terminating ice margins
-Subglacial - 10What are glacial water terminating ice margins?-Lakes receiving direct inputs from glaciers
-Dynamic, unstable environments - 11What are past glacial lakes?-Those which used to be fed by glaciers
- 12What are non-glacier-contact lakes?-Glacier fed but no direct ice contact
- 13How is sediment inputted to ice marginal water bodies?-Ice contact
-Glacier margins
-Iceberg meltout
-Suspended sediment
-Non glacial sources
-Rivers
-Slope processes - 14What are the mechanisms for glaciolacustrine sediment deposition?-Direct deposition from glacier ice
-Deposition from subglacial rivers entering below water level
-Sedimentation from suspension
-Gravity from suspension
-Gravity flows
-Lake show sedimentation - 15How can the way in which melt water enter a lake change?-Thermal stratification of lake water
-The manner in which melt water enters a lake depends upon the density of the meltwater relative to that of the lake - 16How does sediment come from meltwater discharge?
- 17How can ice be in contact with sediments?-Drop
-Dump
-Grounding - 18What are the types of re-sedimentation from gravity flows?-Creep
-Slow intergranular frictional sliding with quasi-static grain contact
-Slide
-Transitional or rotational coherent mass with minor internal deformation
-Slump
-Coherent mass with considerable internal deformation
-Flow with plastic behaviour
-Rounded mass, non-turbulent, with transient large scale turbulent churning
-Flow with fluvial behaviour
-Fully turbulent - 19Why do these happen?-Instabilities on steep slopes lead to slow failure and mass movement of sediment
- 20What are typical glaciolacustrine landforms?-Shorelines/ strandlines carved by wave action at the shore of a large lake
-Detla moraines - 21What do glaciolacustrine facies include?-Deltaic sediments, basin margin
-Glacial meltwaters enter a lake, rapid depositon of the heaviest material produces a delta
-Overflow causes large delta
-Underflow plumes form small deltaic fans
-Lake bottom sediments
-Annual couplets formed through meltwater input
-Ablation season, meltwater plumes and coarse sediments
-Winter season, sedimentation from suspension settling clay
-Vary based on proximity to distal iceberg activity
Informações
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- FlashCards sobre PW 8, criado por erossmae em 25-08-2015.
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- erossmae
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