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CHAPTER 8 • Insolation Control of Monsoons 153

way. Instead, it appears that plateau uplift sensitizes the 7. How do tectonic uplift and orbital variations
monsoon system to insolation forcing in such a way combine to affect the long-term intensity of
that the combined monsoon response to uplift and inso- monsoons?
lation is stronger than a simple linear combination of the
two effects.
Additional Resources
Key Terms Basic Reading

orbital monsoon anoxic (p. 143) Companion Web site at www.whfreeman.com
hypothesis (p. 139) thermocline (p. 145) /ruddiman2e, pp. 9–11, 15–18, 21–24, 32.
nonlinear response clipping (p. 148) Kutzbach, J. E. 1981. “Monsoon Climate of the Early
Holocene: Climate Experiment with Earth’s Orbital
(p. 140) orbital tuning (p. 149) Parameters for 9000 Years Ago.” Science 214: 59–61.
threshold level (p. 141)
Ruddiman, W. F. 2005. Plows, Plagues and Petroleum,
sapropels (p. 143) Chapter 5. Princeton, NJ: Princeton University
Press.
Review Questions www.classzone.com/book/earth_science/terc/content
/visualization, Chapter 24: Monsoon Circulations.
1. In what way is the orbital monsoon hypothesis an
extension of processes driving modern monsoons?
Advanced Reading
2. Why does the intensity of 23,000-year monsoon Olsen, P. E. 1986. “A 40-Million-Year Lake Record of
peaks vary at intervals of 100,000 and 413,000 years? Early Mesozoic Orbital Climatic Forcing.” Science
234: 842–48.
3. How did the Mediterranean Sea acquire a Pokras, E. M., and A. C. Mix. 1987. “Earth’s
freshwater lid during times when very little Precession Cycle and Quaternary Climatic Changes
precipitation was falling in that region?
in Tropical Africa.” Nature 326: 486–87.
4. Explain how the opposed July/February timing Rossignol-Strick, M., W. Nesteroff, P. Olive, and C.
of past monsoon changes in China and Brazil Vergnaud-Grazzini. 1982. “After the Deluge:
lends strong support to the orbital monsoon Mediterranean Stagnation and Sapropel
hypothesis. Formation.” Nature 295: 105–10.
Ruddiman, W. F., 2006. “Viewpoint: What Is the
5. Does peak monsoon strength lag behind summer
insolation forcing? Timing of the Orbital Monsoon?” Quaternary
Science Reviews 25: 657–58.
6. What similarities exist between monsoon changes Yuan, D., et al. 2004. “Timing, Duration, and
in Pangaea 200 Myr ago and those in North Africa Transitions of the Last Interglacial Monsoon.”
during the last several hundred thousand years? Science 304: 575–78.