preorogenic

preorogenic

[¦prē‚ȯr·ə′jen·ik]
(geology)
The initial phase of an orogenic cycle during which geosynclines form.
References in periodicals archive ?
In each cycle, the preorogenic and synorogenic stages and the orogenic belt related to this last were also differentiated and characterized when possible.
From the lithostratigraphic perspective, the Guaraco Norte Formation correlates with preorogenic metamorphic rocks, probably Devonian in age, that outcrop below the Carboniferous sediments in the Cordillera Frontal.
The Andacollo Group has a similar tectonostratigraphic position to those of the Gondwana preorogenic El Plata (Caminos, 1965) and Cerro Agua Negra (Polanski, 1970) formations of the Cordillera Frontal of Mendoza and San Juan, northern of the study area (Fig.
If these rocks are of Upper Devonian age, as we propose in this study, the Guaraco Norte Formation would be a preorogenic succession related to the Chanic cycle and separated from the Gondwanan succession by a major unconformity (Fig.
The Gondwanan subduction in late Carboniferous times developed a first magmatic arc (Coastal Batholith in figure 11E) and a retro-wedge preorogenic basin (Fig.
In the CV, preorogenic sequences continued until the Jurassic, with two other extensional phases (Huarpes and Tunuyan phases) separated by unconformities (Llambias et al.
In the CV, the early to late Carboniferous Andacollo Group is part of the Gondwanan cycle; during its preorogenic stage volcano-sedimentary rocks were deposited and deformed by syn-sedimentary normal faulting, where synextensional unconformities are associated to block tilting during half-graben development.