dating of middle Frasnian (lower Upper Devonian) Alamo Breccia, Nevada, USA. Palaeogeography Palaeoclimatology
Palaeoecology, 282, 105–118.
NASA, 2012. http://nssdc.gsfc.nasa.gov/planetary/planets/.
Oberbeck, V. R., Marshall, J. R., and Aggarwal, H., 1993. Impacts,
tillites and the breakup of Gondwanaland. The Journal of Geology, 101, 1–19.
Ormö, J., and Lindström, M., 2000. When a cosmic impact strikes
the sea bed. Geological Magazine, 137, 67–80.
Pope, K. O., Baines, K. H., Ocampo, A. C., and Ivanov, B. A., 1997.
Energy, volatile production, and climatic effects of the
Chicxulub Cretaceous/Tertiary impact. Journal of Geophysical
Research, 102, 21645–21664.
Pope, K. O., Ocampo, A. C., Fischer, A. G., Vega, F. J., Ames, D. E.,
King, D. T., Jr., Fouke, B. W., Wachtman, R. J., and Kletetschka,
G., 2005. Chicxulub impact ejecta deposits in southern Quintana
Roo, Mexico and central Belize. In Kenkmann, T., Hörz, F.,
and Deutsch, A. (eds.), Large Meteorite Impacts III. Boulder:
Geological Society of America. Special Paper, Vol. 384,
pp. 171–190.
Riis, F., Kalleson, E., Dypvik, H., Krøgli, S. O., and Nilsen, O.,
2012. The Ritland impact structure, southwestern Norway. Meteoritics and Planetary Science, 46, 748–761.
Schulte, P., et al., 2010. The Chicxulub asteroid impact and mass
extinction at the Cretaceous -Paleogene boundary. Science,
327, 1214–1218.
Shoemaker, E. M., 1962. Interpretation of lunar craters. In Kopal,
Z. (ed.), Physics and Astronomy of the Moon. New York/London: Academic, pp. 283–359.
Shuvalov, V. V., 2002. Numerical modeling of impacts into shallow
seas. In Plado, J., and Pesonen, L. J. (eds.), Impacts in Precambrian Shields. Heidelberg/New York: Springer. Impact Studies,
pp. 323–336.
Shuvalov, V., Dypvik, H., Kalleson, E., Setså, R., and Riis, F.,
2012. Modeling the 2.7 km in diameter, shallow marine
Ritland impact structure. Earth, Moon and Planets, 108,
175–188.
Simonson, B. M., and Glass, B. P., 2004. Spherule layers - records
of ancient impacts. Annual Review of Earth and Planetary Science, 32, 329–391.
Simonson, B. M., Hassler, S. W., Smit, J., and Sumner, D., 2002.
How many late Archean impacts are recorded in the Hamersley
basin of Western Australia? In Lunar and Planetary Science
Conference, League City, TX, 33, #1772.
Smit, J., 1999. The global stratigraphy of the Cretaceous-Tertiary
boundary impact ejecta. Annual Review of Earth and Planetary
Science, 27, 75–113.
Suuroja, K., Suurjoa, S., All, T., and Floden, T., 2002. Kärdla
(Hiiumaa Island, Estonia) – the buried and well preserved Ordovician marine impact structure. Deep Sea Research II, 49,
1121–1144.
Task Force Group, 2000. Report of the Task Force on Potentially
Hazardous Near-Earth Objects. London: Information Unit, British National Space Centre. 56 pp.
Ward, S. N., and Asphaug, E., 2000. Asteroid impact tsunami: a
probabilistic hazard assessment. Icarus, 145, 64–78.
Ward, S. N., and Asphaug, E., 2002. Impact tsunami – Eltanin.
Deep-Sea Research II, 49, 1073–1079.
Warme, J. E., 2004. The many faces of the Alamo impact breccia.
Geotimes, 49, 26–29.
Wünnemann, K., and Lange, M. A., 2002. Numerical modelling of
impact induced modifications of the deep-sea floor. Deep-Sea
Research II, 49, 969–981.
Wünnemann, K., Weiss, R., and Hofmann, K., 2007. Characteristics
of oceanic impact-induced large water waves – re-evaluation of
the tsunami hazard. Meteoritics and Planetary Science, 42,
1893–1903.
Cross-references
Events
Tsunamis
MARINE MICROFOSSILS
Jakub Witkowski
1
, Kirsty Edgar
2
, Ian Harding
3 ,
Kevin McCartney
4 and Marta Bąk
5
1
Institute of Marine and Coastal Sciences, University of
Szczecin, Szczecin, Poland
2
School of Earth Sciences, University of Bristol, Clifton,
UK
3
Ocean and Earth Science, National Oceanography Centre,
University of Southampton, Waterfront Campus,
Southampton, UK
4
Department of Environmental Studies and Sustainability,
University of Maine at Presque Isle, Presque Isle, ME,
USA
5
Faculty of Geology, Geophysics and Environmental
Protection, AGH University of Science and Technology,
Kraków, Poland
Synonyms
Fossil microbiota
Definition
Marine microfossils are fossils of small size (usually
<1 mm) that need to be studied by microscopy to deduce
the morphological characteristics of the organism or skeletal element concerned.
Introduction
Marine microfossils are produced by a variety of microorganisms that may be auto- or heterotrophic or planktic or
benthic. Although most marine microfossils are body fossils
of single-celled organisms (protists), some are small-sized
elements of macrobiota, e.g., conodont elements or sponge
spicules. The vast majority of marine microfossils possess
permineralized skeletons that are composed of one of several common skeletal materials such as calcium carbonate
(foraminifera (Figure 1), calcareous nannofossils), silica
(radiolarians (Figure 2), diatoms (Figure 3), silicoflagellates, ebridians), organic compounds (acritarchs,
chitinozoa, dinoflagellates (Figure 4), scolecodonts), or calcium phosphate (conodonts). Obviously, groups that lack
mineralized or refractory skeletal elements have a considerably lower potential for fossilization.
History of study
The discipline of micropaleontology was founded by
Christian Gottfried Ehrenberg (1795–1876), a German
microscopist who was the first person to systematically
describe microfossils (including diatoms, dinoflagellates,
MARINE MICROFOSSILS
467
Palaeoecology, 282, 105–118.
NASA, 2012. http://nssdc.gsfc.nasa.gov/planetary/planets/.
Oberbeck, V. R., Marshall, J. R., and Aggarwal, H., 1993. Impacts,
tillites and the breakup of Gondwanaland. The Journal of Geology, 101, 1–19.
Ormö, J., and Lindström, M., 2000. When a cosmic impact strikes
the sea bed. Geological Magazine, 137, 67–80.
Pope, K. O., Baines, K. H., Ocampo, A. C., and Ivanov, B. A., 1997.
Energy, volatile production, and climatic effects of the
Chicxulub Cretaceous/Tertiary impact. Journal of Geophysical
Research, 102, 21645–21664.
Pope, K. O., Ocampo, A. C., Fischer, A. G., Vega, F. J., Ames, D. E.,
King, D. T., Jr., Fouke, B. W., Wachtman, R. J., and Kletetschka,
G., 2005. Chicxulub impact ejecta deposits in southern Quintana
Roo, Mexico and central Belize. In Kenkmann, T., Hörz, F.,
and Deutsch, A. (eds.), Large Meteorite Impacts III. Boulder:
Geological Society of America. Special Paper, Vol. 384,
pp. 171–190.
Riis, F., Kalleson, E., Dypvik, H., Krøgli, S. O., and Nilsen, O.,
2012. The Ritland impact structure, southwestern Norway. Meteoritics and Planetary Science, 46, 748–761.
Schulte, P., et al., 2010. The Chicxulub asteroid impact and mass
extinction at the Cretaceous -Paleogene boundary. Science,
327, 1214–1218.
Shoemaker, E. M., 1962. Interpretation of lunar craters. In Kopal,
Z. (ed.), Physics and Astronomy of the Moon. New York/London: Academic, pp. 283–359.
Shuvalov, V. V., 2002. Numerical modeling of impacts into shallow
seas. In Plado, J., and Pesonen, L. J. (eds.), Impacts in Precambrian Shields. Heidelberg/New York: Springer. Impact Studies,
pp. 323–336.
Shuvalov, V., Dypvik, H., Kalleson, E., Setså, R., and Riis, F.,
2012. Modeling the 2.7 km in diameter, shallow marine
Ritland impact structure. Earth, Moon and Planets, 108,
175–188.
Simonson, B. M., and Glass, B. P., 2004. Spherule layers - records
of ancient impacts. Annual Review of Earth and Planetary Science, 32, 329–391.
Simonson, B. M., Hassler, S. W., Smit, J., and Sumner, D., 2002.
How many late Archean impacts are recorded in the Hamersley
basin of Western Australia? In Lunar and Planetary Science
Conference, League City, TX, 33, #1772.
Smit, J., 1999. The global stratigraphy of the Cretaceous-Tertiary
boundary impact ejecta. Annual Review of Earth and Planetary
Science, 27, 75–113.
Suuroja, K., Suurjoa, S., All, T., and Floden, T., 2002. Kärdla
(Hiiumaa Island, Estonia) – the buried and well preserved Ordovician marine impact structure. Deep Sea Research II, 49,
1121–1144.
Task Force Group, 2000. Report of the Task Force on Potentially
Hazardous Near-Earth Objects. London: Information Unit, British National Space Centre. 56 pp.
Ward, S. N., and Asphaug, E., 2000. Asteroid impact tsunami: a
probabilistic hazard assessment. Icarus, 145, 64–78.
Ward, S. N., and Asphaug, E., 2002. Impact tsunami – Eltanin.
Deep-Sea Research II, 49, 1073–1079.
Warme, J. E., 2004. The many faces of the Alamo impact breccia.
Geotimes, 49, 26–29.
Wünnemann, K., and Lange, M. A., 2002. Numerical modelling of
impact induced modifications of the deep-sea floor. Deep-Sea
Research II, 49, 969–981.
Wünnemann, K., Weiss, R., and Hofmann, K., 2007. Characteristics
of oceanic impact-induced large water waves – re-evaluation of
the tsunami hazard. Meteoritics and Planetary Science, 42,
1893–1903.
Cross-references
Events
Tsunamis
MARINE MICROFOSSILS
Jakub Witkowski
1
, Kirsty Edgar
2
, Ian Harding
3 ,
Kevin McCartney
4 and Marta Bąk
5
1
Institute of Marine and Coastal Sciences, University of
Szczecin, Szczecin, Poland
2
School of Earth Sciences, University of Bristol, Clifton,
UK
3
Ocean and Earth Science, National Oceanography Centre,
University of Southampton, Waterfront Campus,
Southampton, UK
4
Department of Environmental Studies and Sustainability,
University of Maine at Presque Isle, Presque Isle, ME,
USA
5
Faculty of Geology, Geophysics and Environmental
Protection, AGH University of Science and Technology,
Kraków, Poland
Synonyms
Fossil microbiota
Definition
Marine microfossils are fossils of small size (usually
<1 mm) that need to be studied by microscopy to deduce
the morphological characteristics of the organism or skeletal element concerned.
Introduction
Marine microfossils are produced by a variety of microorganisms that may be auto- or heterotrophic or planktic or
benthic. Although most marine microfossils are body fossils
of single-celled organisms (protists), some are small-sized
elements of macrobiota, e.g., conodont elements or sponge
spicules. The vast majority of marine microfossils possess
permineralized skeletons that are composed of one of several common skeletal materials such as calcium carbonate
(foraminifera (Figure 1), calcareous nannofossils), silica
(radiolarians (Figure 2), diatoms (Figure 3), silicoflagellates, ebridians), organic compounds (acritarchs,
chitinozoa, dinoflagellates (Figure 4), scolecodonts), or calcium phosphate (conodonts). Obviously, groups that lack
mineralized or refractory skeletal elements have a considerably lower potential for fossilization.
History of study
The discipline of micropaleontology was founded by
Christian Gottfried Ehrenberg (1795–1876), a German
microscopist who was the first person to systematically
describe microfossils (including diatoms, dinoflagellates,
MARINE MICROFOSSILS
467