We presented some results on the soil redization and yellowization at some of the previous WCSS meetings. Since the last WCSS, more research and survey have been done. More evidences have been collected which support that the catastrophic high temperature be the main cause on soil redization. Here are the four observations:

1. Red Soils Spread Globally

Red soils, in large distributions or small isolated distributions, can be found everywhere: in the southern hemisphere or northern hemisphere, high latitude (e.g. Algonquin Park in Canada) or low latitude, high altitude (e.g. Tibet Plateau in China and Yellow Stone Park in America) or low altitude, upper soil beds or subsoil beds, continents or islands, and dry lands or wet lands.

2. Terra Rossa Exists Commonly

Terra rossa can usually be found in the areas with calcareous stratum distribution. The allitic weathering process should be very slow under the presence of rich alkali-earth metal. It is almost impossible to have enriched ferric oxide. The hematite could only be produced through dehydration under very high temperature.

3. There Is No Relation between Allitic Weathering and the Formation of Red Soils

The clay samples (< 2 µm) containing three color layers, black, yellow and red, were taken from the yellow red soil beds in the mountain areas in the subtropical zone. The yellow and red layers of the samples were analyzed in 1963, 1987 and 2003 respectively. The results show that the ratio of the silica alumina and the ratio of the silica iron alumina had been increasing not decreasing. It indicates that the allitic weathering processing does not exist in the soils in the subtropical and tropical zones. Therefore it is unlikely that the red soils were formed through the process of allitic weathering in these areas.

4. The Fertile Red Soils Spread Widely

According to the theory of allitic weathering and the formation of red soil, the evolution process would produce red soils poor in mineral nutrition eventually. In fact, agricultural crops, fruit trees and economic forests grow very well on this type of soils.

Some papers presented at the International Conference on Catastrophic Events and Mass Extinctions: Impacts and Beyond, 9-12 July 2000, Vienna, Austria, indicated that the asteroid impacts on earth about 65 million years ago had produced extraordinary high temperature reaching thousands or ten thousands of degree Celsius and the energy released had been equivalent to that from several billions of megatons of TNT. It was inevitable at that period of time that the surface soils and sand stones burned to red. With this theory, some unanswered questions in the soil genesis process can readily be solved. The yellowization process of the red soils will be discussed in another paper in the near future.