Estimativa De Densidades A Partir De Dados Gravimétricos Distribuídos Aleatoriamente

In a gravity survey, Bouguer and terrain corrections<br>require the knowledge of subsurface densities. Commonly,<br>rock samples taken from outcrops, boreholes<br>or mines are left in laboratories for specific weight<br>determinations. However, those results may not be<br>representative of subsurface rocks. In spite of that,<br>good estimations can be taken from gravity measurements<br>in site as suggested by many authors. In this<br>paper I present an improved method using the relation<br>between free-air anomaly versus Bouguer and terrain<br>corrections in randomly collected gravity data. The<br>method was applied to a survey released in Crixás,<br>Goiás, Brazil. The results show great correlations to<br>laboratory measured densities and well-known geology:<br>3.2 to 3.4 g/cm3 for mafic/ultramafic rocks and<br>2.4 to 2.9 g/cm3 for gneissic rocks.