The Basal Unit of the Lizard Ophiolite Complex preserves evidence of a protracted deformation and accretion history. The earliest recognizable events record the construction of ocean crust and the generation of the Lizard Ophiolite Complex in a slow-spreading ridge-axis environment. The initial stages of deformation involved the development of a sub-horizontal crustal-scale shear zone and its progressive deformation by ductile thrusting and folding. Subsequent deformation progressed with the out-of-sequence stacking of ocean lithosphere in which detachment, initiated at mid-crustal levels, culminated in mantle decoupling as thrust slices were derived from progressively deeper crustal levels. The progressive emplacement of a coherent slice of ocean lithosphere over previously accreted units and the generation of a dynamothermal aureole are consistent with models suggesting rapid overthrusting of young ocean lithosphere. Evidence from the dynamothermal aureole indicates that syn-emplacement extensional collapse of the complex occurred in response to thrust loading. Foreland-directed offsliding and lateral thrusting mark the final stages in the collapse of the complex.

Scientific editing by David Snyder.
This content is PDF only. Please click on the PDF icon to access.

First Page Preview

First page PDF preview