Lab 1 Flashcards
what is a layer
strata/bed
what is stratigraphy
branch of geology concerned with the arrangement of strata through time
what is the principle of superposition
what is on top is youngest
principle of original horizontality
rocks that are now tilted were once deposited in horizontal layers
How do you tell if a strata is younger from the left side or right side
hard to tell without fossils
1) use roots
2) graded bedding
- sediments deposited in wading current
3) mud cracks
- way up is direction that mud crack widens
cross cutting relationship
a geographical feature that curs another is the younger of the two features
rule of inclusion
inclusions (on rock type contained in another rock type) are older than the rock they are imbedded in
what is thermal contact metamorphism
heat from magma and lava pass into rock
dike vs sill
dike: cross cuts strata (up)
sill: cuts through strata (sideways)
sill vs lava flow
sill has contact metamorphism all round
lava flow only has contact metamorphism on the botton
angular uncomfority
strata is at different angle than below
unconformities
represents break in deposition or the erosion of sedimentary strata
noncomformity
start below erosion surface are either metamorphic or plutonic ingneous rocks
discomformity
strata are parallel on either side
paracomformity
similar but erosion surface Is FLAT
