geology Flashcards
Explaining the past Geology
1) skeletons fall lay there and eventually squeezing out water and compacting
2) *calcium carbonate crystallized around the fragments
Explaining the past Tectonic processes
The plate on the uk sits shifted away from the tropics
Convection currents beneath the plate uplifted rocks and the rock that moves the highest forms fault scarps
Explaining the past Glaciation
altering river valleys, making them deeper and widening them into u-shaped troughs
As they melt glaciers leave features like waterfalls
Igneous rocks
oldest rock, hard rock, formed from lava’s and magmas.
sedimentary rocks
some are resistant, most not, formed from sediments
metamorphic rock
sedimentary rocks that have been heated by igneous rock.
hard rock
north and west uplands (type of landscape)
older, resistant igneous rocks, more faults
south and east lowlands (type of landscape)
younger, weaker sedimentary rocks, less faults
weathering
is the physical, chemical or biological breakdown of solid rock by the action of weather.
Lake district freeze thaw weathering
rain water gets into cracks in the rock, freezes and expands by 10%. expansion widens the crack and eventually the rock breaks into pieces. This creates *scree.
Landslides in the lake district
wettest region adds to wight to weatherd rock
The Weald (a low land landscape)
Has undulating hills, once an dome of folded rock called an *anticline, Erosion has left alternate *strata of more and less resistant rock to form a landscape known as *scarp and vale topography
softer clays form the vales
The Weald (weathering)
Chalk is an alkali so is effected by solution
Tree and scrub roots break up solid rock
The Weald (post glacier river)
1) clay is impermeable so rivers are common in vales
2) In the last ice age water in the chalk froze making it impermeable, then fresh water formed rivers, water seeped through again and water dried away
The weald (slope processes)
slow in the district mainly soil creep (its caused by rain dislodging soil particles)
