Exam review, Paleoclimates Flashcards
what are the climatic conditions (in terms of general trends) of the Pleistocene
VERY COLD (large fluctuations still within the cold temperatures)
when did the Pleistocene happen
1.8 mya - 12 kya
what are the subsections of the Pleistocene
lower
middle
upper
when was the lower Pleistocene
1.8 mya to 780 kya):
what is the lower Pleistocene characterized by
characterized by steadily decreasing global temperatures
when was the middle Pleistocene
780 kya to 126 kya
what is the middle Pleistocene characterized by
characterized by generally low, yet wildly fluctuating temperatures
when was the upper Pleistocene
126 kya to 12 kya
what did upper Pleistocene correspond to
corresponding to the end of the last major Ice Age (Last Glacial Maximum)
what is the Paleoclimates: Milankovitch Cycles responsible for
Earth’s glacial and interglacial periods within the Late Pleistocene have been caused primarily by cyclical changes in the Earth’s circumnavigation of the Sun
what do the Milankovitch Cycles affect
These changes affect the seasonality and location of solar energy around the Earth, thus impacting contrasts between the seasons
what are the three changes in Milankovitch Cycles
eccentricity, obliquity (axil tilt), precission
what does eccentricity do
changes to the shape of the Earth’s orbit around the Sun. Orbital shape ranges between more and less elliptical on a cycle of about 100,000 years. Greater variation in Sun’s energy reaching Earth when orbital shape is more elliptical
what is obliquity (axil tilt)
is the inclination of the Earth’s axis in relation to its plane of orbit around the Sun. Oscillations in the degree of Earth’s axial tilt occur on a periodicity of 41,000 years from 21.5 to 24.5 degrees. Affects the severity of the Earth’s seasons
what is Precession
is the Earth’s slow wobble as it spins on axis. This wobble has a periodicity of 23,000 years. Contributes to differences in seasons felt by the Northern and Southern hemispheres
