A short investigation of the north central portion of the Lang Quadrangle, California

Abstract

This paper consists of a study of the Escondido and Mint Canyon formations and their structural relationships in the Lang Quadrangle, California. The Escondido formation was found to be approximately 4,500 feet thick and folded into a large pitching syncline with a small anticline in the center. This large syncline, which is in fault contact with the basement, is further modified by a series 4 major strike-slip faults in which the east side has moved northwards. The structure of the Mint Canyon formation is that of a syncline of depositional origin lying in depositional contact on the Escondido and the basement. The Mint Canyon is also modified by one of the major strike-slip faults. The age determinations are not satisfactory where the Escondido and the basement are concerned. The basement is believed to be pre-Cretaceous; the Escondido is placed between the Eocene and the Upper Middle Miocene and is suspected to be Middle Miocene in age. The Mint Canyon formation is thought to be Upper-Middle Miocene and Lower Upper Miocene.