Fil: Lyons, Patrick. Australian Geological Survey Organisation; Australia. Fil: Skirrow, R. Australian Geological Survey Organisation; Australia. As part of the Work Program far the Geoscientific Mapping of the Sierras Pampeanas Argentina-Australia Cooperative Project, this report presents the results of additional whole-rock geochemical analyses done on 22 samples collected from the Sierra Chica and stable isotope analyses done on 40 samples collected from mineralised environments throughout the project area (Figure 1). All samples were collected during 1995 as part of Field Program 2. Whole-rock analyses include majar oxides, trace elements, and Au, the latter done to asses regional background values (Table 4.1). Stable isotopes analyses were done far oxygen, deuterium/hydrogen, and sulfur isotopes (Tables 4.2, 4.3, 4.4). This report presents these analyses in accordance with the Work Program delivery schedule and supplements the previous whole-rock geochemistry report (Lyons and others, 1996). Whole-rock and trace element analyses were done at the Department of Geology laboratory at the Australian National University (ANU) where both majar oxides and trace elements were determined by XRF. Gold analyses were done at Analabs Pty Ltd at their Welshpool laboratory in Western Australia and determined by fire assay. Samples submitted far stable isotope analysis were prepared by AGSO and white mica separation was carried out at AMDEL laboratories in South Australia. Stable isotope analyses were done at CSIRO Division of Petroleum Resources in North Ryde, Sydney.