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The earliest dinosaurs appeared on earth about 230 million years ago during the geological Triassic Period, and for the next 164 million years evolved into an amazing diversity of life forms.

O., Rullkötter, J., A Comparative Study of Molecular Paleosalinity Indicators: Chromans, Tocopherols and C20 Isoprenoid Thiophenes in Miocene Lake Sediments (Nördlinger Ries, Southern Germany), Aquatic Geochemistry, v.

B., Transformation of planetary material in high-speed collisions (in Russian).

Until recently, impacts by extraterrestrial bodies were regarded as an interesting but, perhaps, not an important phenomenon in the spectrum of geological process affecting the Earth.

Our concept of the importance of impact processes, however, has been changed radically through planetary exploration, which has shown that virtually all planetary surfaces are cratered from the impact of interplanetary bodies.

In many ways the Moon is a geologic Rosetta stone: an airless, waterless body untouched by erosion, containing clues to events that occurred in the early years of the solar system, which have revealed some of the details regarding its origin and providing new insight about the evolution of Earth.

Although they also posed new questions, the thousands of satellite photographs brought back from the Moon have permitted us to map its surface with greater accuracy than Earth could be mapped a few decades ago.It is now clear from planetary bodies that have retained portions of their earliest surfaces that impact was a dominant geologic process throughout the early solar system.For example, the oldest lunar surfaces are literally saturated with impact craters, produced by an intense bombardment which lasted from 4.6 to approximately 3.9 billion years ago, at least a 100 times higher than the present impact flux.Heat generated by early impacts may have led to outgassing of Earth's initial crust, thus, contributing to the primordial atmosphere and hydrosphere.Additionally, the impacting bodies themselves may have contributed to the Earth's budget of volatiles. Ames Structure and Similar Features - A Workshop, pp. In: Giese, P., Prodehl, C and Stein, A., eds., Explosion Seismology in Central Europe; Data and Results, Springer Verlag, New York, pp.

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