– Looking around in the Solar System millions of meteorite craters (or impact structures) can be seen at the surfaces of Earthtype planets, moons, asteroids as well as on comets. They have a wide variety of size: from few microns in diameter (at the surfaces without atmosphere) up to impact-generated giant basins 2000km in diameter (South Pole-Aitken basin on Moon). They are situated randomly at different surfaces – leastwise for the  first sight, but after particular investigations it can be recognized that the impact structures are concentrated on older surfaces and become relatively rare on younger ones. In the case  of the Earth’s surface this distribution is complicated by the effects of wide range of erosion types and endogenic processes (e.g. metamorphism, tectonic movements, magmatic, sedimentary infilling etc.). But even here it can be recognized, that the largest meteorite crater density and the oldest forms can be found on the old cratons (shields) of North Europe, North America and Australia (see Fig. 1) in North Europe and America probably because of the exhumation of the ice-dominated surface after the last ice age (Pleistocene). The impact craters in these two regions were formed long before the Pleistocene and they are relatively small (most of them under 20km in diameter). Impact craters became rare in the tropical regions because of the rich vegetation cover and the fast landscape destruction. Ocean floors are other poorly cratered regions. In depths of thousands of meters, smaller meteorites or asteroids can’t impact into the floor-surface because of the drag of the water. Other reasons are the young ages of the seafloors (not older than 200 million years), according to the plate tectonics; the rapid sedimentation and the relatively poorly explored topography of ocean basins. There is a third region too, where meteorite craters are missing (or were not found so far): these are the inland ice sheets and the Antarctica: on the relatively young, moving, melting-refreezing 

and fast-changing ice surfaces where impact craters were deformed and eroded rapidly. As the following article demonstrates, impact craters may have remarkable hydrogeological features too, which can help understanding crater erosion, and identify new, possible meteorite craters. For final confirmation of impact origin, geochemical and geological signatures are needed, e.g. shock metamorphic effects, impact  materials (impactites) and geophysical features, etc., which are characteristic for confirmed impact structures.

BATES, L.R. 1980: Glossary of geology – American Geological Institute, p. 21, 23, 24, 25, 79, 102, 134, 

166, 168, 181, 319, 430, 477, 516, 523, 531, 624, 663

 

BÉRCZI  SZ., GUCSIK  A., HARGITAI  H., HORVAI  F.,KERESZTURI  Á., ILLÉS  E., NAGY  SZ.J. 2005: A Naprendszer kisenciklopédiája. (A Naprendszer formakincse 1): Becsapódások folyamata, nyoma és hatásai. – ELTE – HAS Cosmic Material Research Group, Budapest, 13–16, p. 64 

  

DRESSLER, B.O., REIMOLD, W.U., 2001: Terrestrial impact melt rocks and glasses – Earth-Science Reviews, 56, 208–211, 218–220

 

FRENCH, B.M. 1998: Traces of Catastrophe - A Handbook of Shock Metamorphic Effects in Terrestrial Meteorite Impact Structures. – Lunar and Planetary Institute,Houston, 17–30 

GREELY, R. 1985: Planetary Landscapes. – Allen & Unwin, London, 39–42 

GREELY, R., MALIN, M.C., MURRAY, B. 1981: Earthlike planets (Surfaces of Mercury, Venus, Earth, Moon, Mars). – W.H. Freeman and Company, San Francisco, 

72–74, p. 80 

GUCSIK  A. 2003: Terrestrial impact cratering and shock metamorphism: A review, – The Bulletin of Research Institute of Natural Sciences, Okayama University of Science, No. 29 

GUCSIK A., MIHÁLYI K., SZABÓ J. 2008: Drainage patterns of terrestrial complex meteorite craters: a hydrogeological overwiev – 39th Lunar and Planetary 

Science Conference, abstract, #1200 

LÓCZY  D., VERESS  M., 2005: Geomorfológia I. – Földfelszíni folyamatok és formák. – Dialóg Campus 66–67, p. 116 

MIHÁLYI K., 2007: Meteortípusok és becsapódási formáik, különös tekintettel a Földre. – unpublished diploma theses Department of Physical Geography and 

Geoinformatics, University of Debrecen, 30–31, 33–41, 66–69 

 

MIHÁLYI  K., 2008: Distributions of the terrestrial impact structures. – (manuscript)

 

SAUNDERS, A.D., WHITE, R.V. 2005: Volcanism, impact and mass extinctions: incredible or credible coincidences? – Lithos, 79, p. 306 

SEBE K., KOVÁCS J., TÓTH G., CSISZÁR CS., 2004: Angolmagyar geomorfológiai szótár – Pécs-Szombathely, p.18, 30, 42, 51, 53, 54, 56, 83, 106, 114, 121, 122, 123, 143, 152

SPRAY, J. (PASSC  director), 2008: Earth Impact Database (EID), website: http://www.unb.ca/passc/ImpactDatabase/index.html

TWIDALE, C.R. 2004: River patterns and their meaning –Earth-Science Reviews,  67, 161–166, 173–183, p. 190