Nanogeosciences are the international frontier field for the recent cross-development of geosciences and nanotechnology, also are the combination of nanometer and earth. It is possible to research the morphology, structures, and components of the earth on a nanoscale and further reveal the nanoscale information recorded by the substances on the earth, relying on research means, experience, and achievements of fast-developing nanotechnology and in combination with geoscience. Based on the summarization of the existing academic achievements in ultra-microscopic reasearch on geosciences, the concept of nanogeosciences is put forward. Nanogeosciences are a series of geosciences, taking the matters on different layers of the earth as a research target, to reveal the information of nanoparticles and nanopores and their relationship with geoscientific phenomena and especially genetic types during the geoscientific processes on the basis of nanoscience and geoscience, as well as nanotechnology and geoscientific tools. Nanotechnology has been introduced in various branches of geosciences, at first nanogeology since the 1980s. From the nanogeology to nanogeosciences, nanogeosciences have witnessed three major developmental stages: exploratory research, development of several research directions, and the preliminary formation of the subject based on comprehensive research. Among them, relevant nanophenomena found in the field of geoscience have been observed and relevant geoscientific issues have been explored. In the nanogeosciences, the various branches formed by the combination of nanotechnology and geosciences has analyzed systematically, including: nano-mineralogy, nano-petrology, nano-geochemistry, nano-structural geology, nano-energy geology, nano-ore deposit geology, nano-earthquake geology, nano-environmental geology, nano-atmospheric science, and nano-marine science. The significant and groundbreaking scientific issues, along with the developing trend of nanogeosciences also has discussed, mainly include basic geological study, nano-ore deposit and unconventional energy, nano-mineralogy and coal-based materials, nanoparticles and environmental pollution, and nanostructure and geological disaster. Nanogeosciences are still in its initial stages but with a revolutionary challenge and huge prospects for development in geosciences.