CHAPTER 3

Field work was carried out during several field cam p igns within the states of Morelos and México (see chapter 1). Lithological units were map ped in the field at a scale of 1:10,000 at five localities, recording approximately 30 % of th e 180 km of the Tepoztlán Formation within the study area (Fig. 5). The mapped areas we re chosen on account of their good outcrop conditions and are supposed to be represent ative for the geological conditions of the study area as a whole. The remaining area of the st udy area was mapped through interpretation of arial photographs and satellite i mages. All data were integrated into a geographic information system (GIS) environment. Fu rthermore, eight stratigraphic sections, ranging in thickness from 78 to 378 m, were logged and sampled for petrographical, sedimentological and palaeomagnetic analyses (Fig. 5). The sections provide a large and wellconstrained sample suite covering all major deposit ional units and geological characteristics.