EES Glaciers, groundwater, and streams test

you know all of this stuff tbh

what type of period are we in today?

interglacial period

glacier

masses of ice which forms on land over 100s of years , slowly moving and accumulating, transporting and depositing rocks and sediment

how much water do glaciers presently contain on earth?

2.15%

what are the types of glaciers?

-valley (alpine) glaciers

-continental ice sheets

characteristics of valley/ alpine glaciers

-vary in size

-found in mountainous regions

-when these erode stream valleys, they both deepen and straighten them

characteristics of continental ice sheets

-enormous glaciers that flow out in all DRNS from one or more snow accumulation centers

-completely bury underlying landscape

-two left on earth today (Greenland and Antarctica)

Ice shelves

Flat masses of floating ice that extend seaward but remain attached to land

how do glaciers originate and move?

when winter snowfall exceeds summer melt and snow accumulation yearly

how does firn form?

as snow melts it refreezes, becoming granular = firn ~50% air

how does the upper half of a glacier act?

behaves in a brittle fashion, breaking as ice moves

how does the portion below 50m behave?

the weight of the ice causes it to flow in a plastic action

what parts of a glacier move the slowest?

the sides and bottom due to friction

what is a fast glacial movement called?

glacial surge

crevasse

a large fracture that developes in the upper brittle portion of glacial ice

zone of ablation

where snow and ice are melting

what is happening when glaciers are moving forward?

-accumulation> waste

-advancing

what is happening when glaciers are moving backwards

• accumulation< waste

• -retreating

what is the glacial budget when stationary?

balanced budget

glacial abrasion

when glacier has rocks in it and it rubs the ground, sometimes making striations

plucking

when glacier erodes when ice freezes in bedrock projections and pulls them loose

calving

forming of ice bergs

• ~20% exposed ice

glacial features by erosion:

-U shaped valley/ glacial trough

• arete

• cirque/ tarn

• horn

• hanging valley

arete

sharp ridges formed by two glaciers “to stop”

cirque

bowl shaped depressions formed by a valley glacier (basically an empty hole)

tarn

isolated lake forms in a cirque formed by a glacier

horn

located at peaks of mountains that have glaciated by valley glaciers

hanging valley

a smaller valley that is elevated above a bigger valley

glacial erratic’s

huge boulders derived from distant source areas, transported to their current location

till

unsorted sediment deposited directly by the glaciers

stratified drift

sorted sediment deposited by glacial meltwater, well sorted

deposits comprised of till

end

ground

terminal

medial

lateral

drumlin

asymmetrical hills of till formed by the plastic ice at the bottom of a glacier

groundwater

all subsurface water that completely fills the pores and other open spaces in rocks, sediments and soil

(responsible for forming caverns and an important source of drinking water)

transpiration

water in plants is released as water vapor

porosity

% of a materials total volume that is pore space

permeability

capacity of rocks, soils, or sediments to transmit fluids

what is permeability depended on?

porosity but also on the size of pores and their interconnections.

(a porous rock with poorly connected pores would be impermeable)

aquifers

rocks, sediments, or soils that are permeable or capable of transmitting groundwater

aquicludes

impermeable rocks, sediments, or soils that are incapable of transmitting groundwater

ex) unfractured shales, clays, many metamorphic and intrusive igneous rocks

zone of aeration

where water initially infiltrates, most of the pores are filled with air

zone of saturation

a zone where the pores are filled with water

how are caves made?

carbonic acid (from ppt reacts with CO2 in atmosphere) dissolves calcite in limestone

features formed by groundwater flow

-caves

-hot springs

-natural springs

-sink holes

-geysers

-disappearing streams

streams

found wherever the water table intersects the surface, water by itself flows out of the springs.

(any body of water confined within a channel regardless of size)

hot springs

where water temp is higher than human body temp (37 deg C)

geysers

hot springs which periodically eject hot water and steam with tremendous force

sinkholes

depressions in the ground formed by the dissolution of the underlying soluble rock or the collapse of a cave roof

how is the size of a stream described?

by its discharge: its volume of water flowing past a certain point in a time period

drainage basin

region from which the stream draws water from

• AKA watersheds

common drainage patterns

-dendritic

-radial

-rectangular

-trellis

saltation

where material of intermediate size may be carried in short hops along the stream bed

traction load

where heavier material may be rolled, dragged, or pushed along the bottom of a stream bed

dissolved load

substances dissolved in the water make up this load

suspended load

materials traveling in the water column (this is what makes streams cloudy)

bed load

larger particles along the sediment floor

baselevel

lowest elevation to which a stream can erode downwards

gradient

the steepness of a stream

delta

a large fan-shaped pile of sediment forms if a stream is carrying alot of sediment when it gets to the mouth of still waters

where do dendritic streams form

develops on uniform bedrock

where do radial streams form

on a volcano

where do rectangular springs form

develops on highly jointed bedrock (90 deg angles)

where do trellis streams form

develops on alternating weak and resistant bedrock