Environmental change 2 Flashcards
archive measures
long records of environmental change (ice cores, lake sediments)
collecting past climate data
temp/rainfall use meteorological equipment
problem with past climate data
temp, rainfall data only records few 100 years and most events we want to study are 1000 years
proxy measures
indirect measurement of past climate
biological proxy
preserved plants/animals, need to be preserved in anoxic conditions (peat bog/lake)
pollen spores
chemically strong, construct past climates, sporopollenin on outer wall
plant macrofossils
fossil nuts/seeds, reconstruct past vegetation, seeds are best as surrounded by wood to stop decay
beetles
coleoptera respond fast to climate change and chitinous skeleton is preserved
megafauna
UK had lions/rhinos, bones/teeth are evidence and show evolution
positive/negatives of proxies
respond at different rates, need different sample sizes
geomorphological
landforms
depositional indicators
moraines, drumlins, raised beaches
erosional indicators
corries, u shaped valleys
what do sediments do
deconstruct past depositional environments (low energy means temperate)
ocean proxy
oxygen isotopes
ocean archives
sediment sequences on seafloor
what has lots of evidence in oceans
deep ocean basin
landscape archive
moraines/drumlins
sediment archives
fossils
ice cores
contains lots of things, continuous measurement but ice compresses record
proxies of ice cores
oxygen isotopes, warmer temp means O18 is evaporated and stored, provide past greenhouse gas measurements
loess archives
windblown sediment, records alternatives between soil/loess, soil in warm loess in cold, tells about rainfall
lake basins archives
sediment accumulates, tells about temp/rainfall
proxies and archives
proxies (biological, pollen, macrofossils, megafauna, beetles), archives (ice cores, sedime nts)
