A palaeomagnetic study and age determinations of Tertiary rocks in Nicaragua, Central America

Palaeomagnetic, K-Ar and Ar-40/Ar-39 measurements have been made to elucida te Nicaragua's plate tectonic history. These show that the Nicaraguan Highl and rotated 90 degrees counterclockwise between 30 and 18 Myr ago, but the Pacific Coastal Plain has not rotated. A lack of data has prevented a direct comparison with the tectonic history of adjacent areas, in particular, the Chords Block, which is the part of th e Caribbean Plate that is geologically most closely related to the Nicaragu an Highland. However, our data suggest that the Caribbean Plate in this par t of Central America was not consolidated until c. 15 Ma.