Chapter 6 Flashcards
(148 cards)
To asses previous enviromental conditions
look at them globally
Sediment of ocean floors accumulates
very slowly
Can trace changes in enviroment through time by studying
o Cores taken from the sea bed
o Fluctuations in the species
Morphology of single species through the sequence
Oxygen isotope technique
Cores come from stratified sheets of ice where the oxygen isotopic composition gives a guide to climate oscillations
Isostatic uplift/tectonic movement
the weight of ice is removed as the temp rise at the end of the ice age
WHY is the height of a raised beach above the present shoreline not always a straightforward indication of the former sea level height
o The land has been raised up through isostatic uplift
Raised beaches
- Location can be an indicator of earlier coastlines
Raised Beaches stratigraphy rather than vertical
can occur in horizontal stratigraphy rather than vertical
Coral reefs
Provides the position of previous shorelines and their organisms give info on local marine environment
Geoarchaeology
Area of study that uses methods and concepts of earth science to examine processes of earth formation and soil/sediment patterns
geoarchaeology aims
achieve the fullest possible reconstruction of the local area and set into the context of the region
Reconstruct glaciated landscapes is done through
varves, rivers and caves
VARVES
- Receive annual layers of sediment deposited after the spring thaw
Thick layers in varves
warm years with increased glacial melt
Thin layers in varves
cold conditions with less glacial melt
factors that affect varve readings
lakes that are
too shallow
have sediments that are easily disturbed
Form varves from other factors, violent storms
river show rapid change through
Erosion
Deposition of sediments
why are rivers important
often human occupation is close to a river and provided crucial rise of irrigation agriculture and urban civilization
Limestone caves
important because it can conserve a wide range of evidence about humans and the enviroment
The growth of tree rings varies with the climate
More moisture available = wider the annual rings
Growth was slow = which implies dense local forest cover
Growth was fast = which implies light forest cover
can record sudden and dramatic shocks to the climate
Tree rings
Sediments
the global term for material deposited on the earth’s surface
soils
the life-supporting, biologically and physically weathered upper layers of those sediments
Geomorphology
study of the form and development of the landscape