Paleomagnetism and Geochronology of the Early Cretaceous Dipilto Batholith (NW Nicaragua): Chortís Block Large Rotation With Respect to SW North America

Abstract

AbstractThe Dipilto Batholith is one of the largest plutonic complexes (~1,200 km2) of the Chortís block. It is located at northwestern Nicaragua in Central America. We present paleomagnetic, rock magnetic, and petrographic results from 34 sites (269 samples) of this batholith and some associated dikes. Four U‐Pb (zircon) isotopic ages were obtained from samples collected through the intrusive body in order to gain insight into the timing of silicic magmatism in the southern Chortís block and its possible tectonic and paleogeographic connections with the southwestern North America Plate during the Early Cretaceous. The paleomagnetic analyses of 16 selected sites indicate a large counterclockwise rotation (~101°), with a related paleolatitude of 28.7°N, and isotopic ages ranging from 119.08 ± 0.37 to 112.69 ± 0.44 Ma. Our results imply an updated tectonic model resulted from an inherited peri‐Gondwanan position and open the discussion of at least three possible tectonic scenarios for the Chortís block during the Early Cretaceous: (1) Chortís block with an angle of ~45° with respect to the southwestern margin of North America. This would imply the removal of an in‐between continental or oceanic crust segment by subduction or subduction erosion; (2) Chortís block immediately juxtaposed to the southwestern margin of North America, being part of extension‐compression events of the Guerrero Terrane‐Arperos basin; or (3) Chortís block juxtaposed to North America, but with intraplate deformation resulting in overestimated counterclockwise rotation for a tectonic decoupled block, called herein the “Dipilto block.”