A Gallium Anomaly Utilized in Palaeogeographic Reconstruction of Battle Mountain, Rappahannock County, Virginia

Abstract

This paper explores the geostatistical relationship between volcanic and plutonic rock on Battle Mountain, one of the northernmost units of the Robertson River Igneous Suite in central Virginia (U.S.A.), in an effort to reconstruct the original appearance of the formation after rift volcanism at 704 Ma. This Neoproterozoic anorogenic formation dates from the initial rifting of the supercontinent Rodinia and may be one of the oldest intact visible volcanic formations in Virginia. This paper explores the use of geostatistical trace element analysis in geochemical data related to A-type granitoid rock, as well as mathematical and feed-forward neural network palaeogeographic reconstructions including the use of Markov chains. The paper concludes with evidence and analysis that indicates gallium may be used as a reliable indicator trace element for volcanic A-type rhyolitic rock. Furthermore, the paper indicates a lateral rhyolitic stratovolcano explosive event at approximately 704 Ma with a corresponding rhyo...