Pribnow, D. F. C., Kinoshita, M., and Stein, C. A., 2000. Thermal
Data Collection and Heat Flow Recalculations for ODP Legs
101–180. Hanover: Institute for Joint Geoscientific Research,
(CGA).
Revelle, R., and Maxwell, A. E., 1952. Heat flow through
the floor of the eastern North Pacific Ocean. Nature, 170,
199–200.
Schroeder, W., 1984. The empirical age-depth relation and depth
anomalies in the Pacific Ocean. Journal of Geophysical
Research, 89(9873–9883), 1984.
Sclater, J. G., 2003. Ins and outs on the ocean floor. News and Views,
Nature, 421, 590–591.
Sclater, J. G., and Francheteau, J., 1970. The implications of
terrestrial heat flow observations on current tectonic and geochemical models of the crust and upper mantle of the earth. Geophysical Journal of the Royal Astronomical Society, 20,
509–542.
Sclater, J. G., Anderson, R. N., and Bell, M. L., 1971. The elevation
of ridges and the evolution of the central Eastern Pacific. Journal
of Geophysical Research, 76, 7888–7915.
Sclater, J. G., Crowe, J., and Anderson, R. N., 1976. On the reliability of oceanic heat flow averages. Journal of Geophysical
Research, 81, 2997–3006.
Sclater, J. G., Jaupart, C., and Galson, D., 1980. The heat flow
through the oceanic and continental crust and the heat loss of
the earth. Reviews of Geophysics and Space Physics, 18,
269–311.
Sclater, J. G., Parsons, B., and Jaupart, C., 1981. Oceans and continents: similarities and differences in the mechanisms of heat loss.
Journal of Geophysical Research, 86, 11535–11552.
Shapiro, N. M., and Ritzwoller, M. H., 2004. Inferring heat flux distributions guided by a global seismic model: particular application to Antarctica. Earth and Planetary Science Letters, 223,
213–214.
Simmons, G., and Horai, K., 1968. Heat flow data 2. Journal of
Geophysical Research, 73, 6608–6609.
Sleep, N., 1969. Sensitivity of heat flow and gravity to the mechanism of sea-floor spreading. Journal of Geophysical Research,
76(542), 1969.
Staudigal, H., 2003. Hydrothermal alteration processes in the oceanic crust. In Rudnick, R. (ed.), Treatise on Geochemistry.
Amsterdam: Elsevier, Vol. 3, pp. 511–545.
Stein, C., and Stein, S., 1992. A model for the global variation in
oceanic depth and heat flow with lithospheric age. Nature, 359,
123–129.
Turcotte, D. L., and Oxburgh, E. R., 1967. Finite amplitude convection cells and continental drift. Journal of Fluid Mechanics, 28,
29–42.
Vacquier, V., and Von Herzen, R., 1964. Evidence for connection
between heat flow and the Mid-Atlantic ridge magnetic anomaly.
Journal of Geophysical Research, 69, 1093–1101.
Vogt, P. R., 1967. Steady state crustal spreading. Nature, 215,
811–817.
Von Herzen, R., 1959. Heat-flow values from the South-eastern
Pacific. Nature, 183, 882–883.
Von Herzen, R., and Uyeda, S., 1963. Heat flow through the eastern
Pacific Ocean floor. Journal of Geophysical Research, 68,
4219–4250.
Williams, D., and Von Herzen, R., 1974. Heat loss from the earth:
new estimate. Geology, 2, 327–328.
Williams, D., Von Herzen, R. P., Sclater, J. G., and Anderson, R. N.,
1974. The Galapagos spreading center: lithospheric cooling and
hydrothermal circulation. Geophysical Journal of the Royal
Astronomical Society, 38, 609–626.
Wilson, J. T., 1965. A new class of faults and their bearing on continental drift. Nature, 207, 343–347.
Cross-references
Hydrothermalism
Lithosphere: Structure and Composition
Plate Tectonics
Technology in Marine Geosciences
Subsidence of Oceanic Crust
Oceanic Spreading Centers
MARINE IMPACTS AND THEIR CONSEQUENCES
Henning Dypvik
Department of Geosciences, University of Oslo, Oslo,
Norway
Introduction
Asteroid and comet impacts (meteorite impacts) are
important factors in shaping the surface of the terrestrial
planets. The impacts release vast amounts of energy
resulting in sudden increase in temperature and pressure,
structural deformations, and redistribution of target and
bolide (asteroid and comet) material. It is presently well
accepted that impacts, especially into marine environments, have had a major influence on the development
of the Earth. The Earth is covered by 71 % seawater
(7 % shelf seas and 64 % deep oceans), and, consequently,
impacts into marine targets should be the most common.
Asteroids and comets (both generally called bolides,
projectiles, or impactors) impact regularly on the Earth
and other planetary bodies in our solar system, forming
impact craters, expelling ejecta material, and triggering
earthquakes and tsunamis. The impact craters registered
on the Earth range from a few meters to hundreds of kilometers in diameter (http://www.passc.net/EarthImpactDatabase/) mainly determined by bolide size,
composition, and velocity as well as the composition of
the target area and angle of impact (Figure 1). The most
probable impact angle is 45
for asteroids and comets
(Gilbert, 1893; Shoemaker, 1962).
The impacts on dry land form subaerial impact craters,
while submarine or sublacustrine craters are the result of
marine or lacustrine impacts (subaqueous impact craters),
respectively (Dypvik and Jansa, 2003). The marine
impacts/submarine craters can in general be classified into
two broad classes: shallow marine, neritic, and deep
marine, bathyal. The shallow marine cases represent
impacts and related deposits on continental shelves
with water depths down to about 300 m, while the deep
marine impacts are found below 300 m, i.e., beyond the
shelf edge and into the deep ocean. It should be noted that
the critical depth depends on projectile size (D) and water
depth (H). The shallow marine case is realized when
H < D. Even 1,000 m is shallow water for a 10 km
projectile.
460
MARINE IMPACTS AND THEIR CONSEQUENCES
Data Collection and Heat Flow Recalculations for ODP Legs
101–180. Hanover: Institute for Joint Geoscientific Research,
(CGA).
Revelle, R., and Maxwell, A. E., 1952. Heat flow through
the floor of the eastern North Pacific Ocean. Nature, 170,
199–200.
Schroeder, W., 1984. The empirical age-depth relation and depth
anomalies in the Pacific Ocean. Journal of Geophysical
Research, 89(9873–9883), 1984.
Sclater, J. G., 2003. Ins and outs on the ocean floor. News and Views,
Nature, 421, 590–591.
Sclater, J. G., and Francheteau, J., 1970. The implications of
terrestrial heat flow observations on current tectonic and geochemical models of the crust and upper mantle of the earth. Geophysical Journal of the Royal Astronomical Society, 20,
509–542.
Sclater, J. G., Anderson, R. N., and Bell, M. L., 1971. The elevation
of ridges and the evolution of the central Eastern Pacific. Journal
of Geophysical Research, 76, 7888–7915.
Sclater, J. G., Crowe, J., and Anderson, R. N., 1976. On the reliability of oceanic heat flow averages. Journal of Geophysical
Research, 81, 2997–3006.
Sclater, J. G., Jaupart, C., and Galson, D., 1980. The heat flow
through the oceanic and continental crust and the heat loss of
the earth. Reviews of Geophysics and Space Physics, 18,
269–311.
Sclater, J. G., Parsons, B., and Jaupart, C., 1981. Oceans and continents: similarities and differences in the mechanisms of heat loss.
Journal of Geophysical Research, 86, 11535–11552.
Shapiro, N. M., and Ritzwoller, M. H., 2004. Inferring heat flux distributions guided by a global seismic model: particular application to Antarctica. Earth and Planetary Science Letters, 223,
213–214.
Simmons, G., and Horai, K., 1968. Heat flow data 2. Journal of
Geophysical Research, 73, 6608–6609.
Sleep, N., 1969. Sensitivity of heat flow and gravity to the mechanism of sea-floor spreading. Journal of Geophysical Research,
76(542), 1969.
Staudigal, H., 2003. Hydrothermal alteration processes in the oceanic crust. In Rudnick, R. (ed.), Treatise on Geochemistry.
Amsterdam: Elsevier, Vol. 3, pp. 511–545.
Stein, C., and Stein, S., 1992. A model for the global variation in
oceanic depth and heat flow with lithospheric age. Nature, 359,
123–129.
Turcotte, D. L., and Oxburgh, E. R., 1967. Finite amplitude convection cells and continental drift. Journal of Fluid Mechanics, 28,
29–42.
Vacquier, V., and Von Herzen, R., 1964. Evidence for connection
between heat flow and the Mid-Atlantic ridge magnetic anomaly.
Journal of Geophysical Research, 69, 1093–1101.
Vogt, P. R., 1967. Steady state crustal spreading. Nature, 215,
811–817.
Von Herzen, R., 1959. Heat-flow values from the South-eastern
Pacific. Nature, 183, 882–883.
Von Herzen, R., and Uyeda, S., 1963. Heat flow through the eastern
Pacific Ocean floor. Journal of Geophysical Research, 68,
4219–4250.
Williams, D., and Von Herzen, R., 1974. Heat loss from the earth:
new estimate. Geology, 2, 327–328.
Williams, D., Von Herzen, R. P., Sclater, J. G., and Anderson, R. N.,
1974. The Galapagos spreading center: lithospheric cooling and
hydrothermal circulation. Geophysical Journal of the Royal
Astronomical Society, 38, 609–626.
Wilson, J. T., 1965. A new class of faults and their bearing on continental drift. Nature, 207, 343–347.
Cross-references
Hydrothermalism
Lithosphere: Structure and Composition
Plate Tectonics
Technology in Marine Geosciences
Subsidence of Oceanic Crust
Oceanic Spreading Centers
MARINE IMPACTS AND THEIR CONSEQUENCES
Henning Dypvik
Department of Geosciences, University of Oslo, Oslo,
Norway
Introduction
Asteroid and comet impacts (meteorite impacts) are
important factors in shaping the surface of the terrestrial
planets. The impacts release vast amounts of energy
resulting in sudden increase in temperature and pressure,
structural deformations, and redistribution of target and
bolide (asteroid and comet) material. It is presently well
accepted that impacts, especially into marine environments, have had a major influence on the development
of the Earth. The Earth is covered by 71 % seawater
(7 % shelf seas and 64 % deep oceans), and, consequently,
impacts into marine targets should be the most common.
Asteroids and comets (both generally called bolides,
projectiles, or impactors) impact regularly on the Earth
and other planetary bodies in our solar system, forming
impact craters, expelling ejecta material, and triggering
earthquakes and tsunamis. The impact craters registered
on the Earth range from a few meters to hundreds of kilometers in diameter (http://www.passc.net/EarthImpactDatabase/) mainly determined by bolide size,
composition, and velocity as well as the composition of
the target area and angle of impact (Figure 1). The most
probable impact angle is 45
for asteroids and comets
(Gilbert, 1893; Shoemaker, 1962).
The impacts on dry land form subaerial impact craters,
while submarine or sublacustrine craters are the result of
marine or lacustrine impacts (subaqueous impact craters),
respectively (Dypvik and Jansa, 2003). The marine
impacts/submarine craters can in general be classified into
two broad classes: shallow marine, neritic, and deep
marine, bathyal. The shallow marine cases represent
impacts and related deposits on continental shelves
with water depths down to about 300 m, while the deep
marine impacts are found below 300 m, i.e., beyond the
shelf edge and into the deep ocean. It should be noted that
the critical depth depends on projectile size (D) and water
depth (H). The shallow marine case is realized when
H < D. Even 1,000 m is shallow water for a 10 km
projectile.
460
MARINE IMPACTS AND THEIR CONSEQUENCES