THE STUDY OF CRUSTAL STRUCTURES FOR THE IRANIAN PLATEAU BY TERRESTRIAL GRAVITY DATA

Terrestrial gravity data are relatively sparse in the Middle East region. In Iran these data are mainly furnished by Bureau Gravimetric International (BGI) and Iranian National Cartographic Center (NCC). These data seems to be enough for studying the large-scale crustal structures in Iran.

A considerable data preparation phase is needed to correct the data for blunders. Complete Bouguer anomalies are computed over the region by taking account of the Earth’s curvature for topographic correction. Some special problems like negative heights of Caspian Sea level shore have to be treated with more precautions. There are also some marine gravimetric data over Persian Gulf and Oman Sea. The corresponding Bouguer anomalies are computed for these regions as well.

Bouguer anomalies show a minimum value of -289 mgal over Zagros Mountains. This region has the thickest crust in Iran. The maximum value of Bouguer anomlies is seen in the southern part of Caspian Sea. A positive anomaly is also seen in the south east of Iran in the northern part of Oman Sea. Rigorous interpretation of these Bouguer anomalies needs a comparison with other data sources like seismic data.