"Anoxic Events" and Volcanism
275
Plateau east of New Guinea, which is some 40 km thick and has the size of Texas. A
"superplume" event may be responsible for its origin. According to recent theories,
the basalt forming the plateau derived from a great hot blob of magma that rose from
the core-mantle boundary during the early Cretaceous, and arrived at the surface
some time in the Aptian. The release of carbon dioxide to the atmosphere (and
possibly other disturbances related to hydrothermal reactions and heat input) may be
ultimately responsible for anaerobism in the deep sea. The coincidence of major
volcanism, anaerobism (and petroleum formation), and sea level rise certainly is
striking (Fig. 9.22). In addition, as R. L. Larson points out, the frequency of magnetic
reversals is affected: delivery of a plume of magma extracts energy from the coremantle boundary, which halts the processes responsible for reversals.
The last illustration in this chapter emphasis the complexitiy of factors that are
important in ocean history and paleoceanography. Especially the influence of mantle
processes on climate evolution are being hotly discussed in the geologic community.
Is the formation of black shales and related petroleum source rocks really determined
by volcanism? At this time we cannot say. In the next chapter we address the more
descriptive aspects of resources from the ocean floor, including hydrocarbons.
Further Reading
CLIMAP Project Members (1981) Seasonal reconstruction of the Earth's surface at the last glacial
maximum. Geol Soc Am Map Chart Ser MC-36, Boulder, Colo
Warme JE, Douglas RG, Winterer EL (eds) (1981) The Deep Sea Drilling Project: a decade of
progress. SEPM Spec Publ 32, Soc Econ Paleontol Mineral, Tulsa, Okla
Berger A, Imbrie J, Hays J, Kukla G, Saltzman B (eds) (1984) Milankovitch and climate, 2 vols.
Reidel, Dordrecht
Kennett JP (ed) (1985) The Miocene Ocean: paleoceanography and biogeography. Geol Soc Am
Mem 163, Boulder, Colo
Sundquist ET, Broecker WS (eds) (1985) The carbon cycle and atmospheric C02: natural variations
Archean to present. Geophys Monogr 32, Am Geophys Union, Washington DC
275
Plateau east of New Guinea, which is some 40 km thick and has the size of Texas. A
"superplume" event may be responsible for its origin. According to recent theories,
the basalt forming the plateau derived from a great hot blob of magma that rose from
the core-mantle boundary during the early Cretaceous, and arrived at the surface
some time in the Aptian. The release of carbon dioxide to the atmosphere (and
possibly other disturbances related to hydrothermal reactions and heat input) may be
ultimately responsible for anaerobism in the deep sea. The coincidence of major
volcanism, anaerobism (and petroleum formation), and sea level rise certainly is
striking (Fig. 9.22). In addition, as R. L. Larson points out, the frequency of magnetic
reversals is affected: delivery of a plume of magma extracts energy from the coremantle boundary, which halts the processes responsible for reversals.
The last illustration in this chapter emphasis the complexitiy of factors that are
important in ocean history and paleoceanography. Especially the influence of mantle
processes on climate evolution are being hotly discussed in the geologic community.
Is the formation of black shales and related petroleum source rocks really determined
by volcanism? At this time we cannot say. In the next chapter we address the more
descriptive aspects of resources from the ocean floor, including hydrocarbons.
Further Reading
CLIMAP Project Members (1981) Seasonal reconstruction of the Earth's surface at the last glacial
maximum. Geol Soc Am Map Chart Ser MC-36, Boulder, Colo
Warme JE, Douglas RG, Winterer EL (eds) (1981) The Deep Sea Drilling Project: a decade of
progress. SEPM Spec Publ 32, Soc Econ Paleontol Mineral, Tulsa, Okla
Berger A, Imbrie J, Hays J, Kukla G, Saltzman B (eds) (1984) Milankovitch and climate, 2 vols.
Reidel, Dordrecht
Kennett JP (ed) (1985) The Miocene Ocean: paleoceanography and biogeography. Geol Soc Am
Mem 163, Boulder, Colo
Sundquist ET, Broecker WS (eds) (1985) The carbon cycle and atmospheric C02: natural variations
Archean to present. Geophys Monogr 32, Am Geophys Union, Washington DC