The question of the Cretaceous-Tertiary (K-T) boundary is here considered in a more wide sense, considering its importance for Impact Geology. The first two sub-principles of uniformitarianism can be seen as similar to the actualist principle and can be both merged with catastrophism as a renewed view of geosciences [as two principles in dialectical opposition for working with regime x rupture processes in Earth Sciences]. Examples from Brazilian basins, especially Pernambuco-Paraiba (PE-PB) basin, are considered with their face value for the study of the K-T boundary. Most of their characteristics also give support to Impact Geology Theory. It is also considered the importance of the initial works on the Brazilian K-T sedimentary boundaries (in a Impact Geology context), which begun 10 years ago giving support to present time trends of researches. At present with the actual state of knowledge in Geosciences it is no longer possible to consider the Earth System as a closed one (Albertão 1991). It is obvious that Earth is an open system subjected to any sort of interactions with other corpses and fields within the Cosmos as many geological and biological evidences indicate everywhere.The question of the Cretaceous-Tertiary (K-T) boundary is here considered in a more wide sense, considering its importance for Impact Geology. The first two sub-principles of uniformitarianism can be seen as similar to the actualist principle and can be both merged with catastrophism as a renewed view of geosciences [as two principles in dialectical opposition for working with regime x rupture processes in Earth Sciences]. Examples from Brazilian basins, especially Pernambuco-Paraiba (PE-PB) basin, are considered with their face value for the study of the K-T boundary. Most of their characteristics also give support to Impact Geology Theory. It is also considered the importance of the initial works on the Brazilian K-T sedimentary boundaries (in a Impact Geology context), which begun 10 years ago giving support to present time trends of researches. At present with the actual state of knowledge in Geosciences it is no longer possible to consider the Earth System as a closed one (Albertão 1991). It is obvious that Earth is an open system subjected to any sort of interactions with other corpses and fields within the Cosmos as many geological and biological evidences indicate everywhere.