Final Exam Flashcards
Heinrich Events
Characterized by finding higher percentage of coarse grained material thought to have been transported by ice-rafted debris and deposited when the debris melts
What can Iceberg tracks or striations tell us
How far the ice-bergs got before they melted
What size is an iceberg
>5m across
Bergy bits
5-2m across
Growlers
<2m across
Red beds
hematite-stained grains
from heinrich events
Flux
the rate of flow of a property per unit area
[quantity]*[time]-1*[area]-1
Hardest part of flux is time
Ice-rafted debris in the North Atlantic
appears in marine sediments for several thousand years
events correlated with Greenland ice core
Where they show up is related to currents and rates of calving
Armadas of icebergs
foraminifera as a temperature indicator
left coiling (sinistral) = cold
right coiling (dextral) = warm
distribution also affected by temperature (latitude)
Mg/Ca
based on the idea that Mg is substituted for Ca in foraminifera lattice- reflects temperatures
Higher Mg/Ca ratios correlate with higher calcification temperatures
More Mg = higher temperatures
Oxygen isotopes at equilibrium
depend only on the temperature of precipitation and 18O/16O of the ambient water
Range of foram delta 18O values
0ºC = +4 per mil
20ºC = -2 per mil
colder temps means more positive
Paleo-temperature Equation
T°C = 16.9-4.2*(d18OCaCO3 - d18Owater )+0.1*(d18OCaCO3 - d18Owater )2
This is one of several equations available. Can change per species.
Vienna Standard Mean Ocean Water (VSMOW)
distilled ocean water collected from around the globe
Pee Dee Belemnite (PBD)
Carbonate from a fossil from the Pee Dee formation in South Carolina
CLIMAP
Climate: Long range Investigation Mapping, and Prediction
major project in 70s and 80s to produce map of climate conditions during the last glacial maximum
Most data from atlantic, lacking in Pacific. Not good for global representation.
Surface currents during LGM according to CLIMAP
surface currents were stronger
driven by winds which are dependent on horizontal temperature gradients
ice rim and polar front much closer to equator, temperature difference between ice and tropics was compressed into much shorter distance than present
Steeper temperature gradient = strong winds = stronger ocean currents
Currents during LGM according to CLIMAP
Coastal and equatorial upwelling was intensified
Productivity decreased at high latitudes because of ice cover
Productivity increased at mid latitudes because of intensified mixing
Productivity increased in the subtropics because of upwelling
Tertiary Oxygen Isotope Record
Overall cooling since the Cretaceous- from 18O benthic foram record
MM and EO on graph show what?
about where the cooling periods occurred involving high latitudes and deep ocean water masses
MM = midmiocene
EO = Eocene/oligocene
Cooling steps increase in frequency closer to present

Tertiary period
66Ma- 2.58Ma
Planktonic and Benthic foram records
planktonic is the top, benthic is the bottom
shows separate trends for low latitudes, but similar trends for high latitudes
So- cooling is high latitude and deep water phenomenon

Temperature gradients during Tertiary
increased since Oligocene (30-35mya)
caused stronger winds which increased coastal and equatorial upwelling
Evidence in increasing diatom supply in N Pacific and Antarctic
Ocean Hemisphere Partitioning
Plate tectonics affect configuration and circulation of the oceans
creation and destructions of gateways






































