Time Scale

Reading about the Acadian orogeny in the literature can be extremely confusing because no two geologists seem to agree about the extent of the terranes involved or their positions, let alone the timing of Acadian events,. Stratigraphy, structural deformation, metamorphism, plutonism, biogeography, and ophiolites have all been used in correlation and to distinguish different phases, or pulses, of the orogeny.

Many authors have debated the usefulness of correlating the Acadian orogeny with other orogenies which occurred around the same time, including the Caledonian (Western Europe) and Variscan (Spain) orogenies.

.
Tucker, et al., provide a brief overview of the many conflicting views held by researchers of the timing of the Acadian orogeny. Tucker, et al. point out that while some workers use the term Acadian only in connection with events during Devonian time (choosing to make distinctions between orogenies based on convenient age brackets rather than what process is occurring), others consider it to be a very long term event that overlaps with the Taconic and Alleghanian orogenies in time (viewing the Devonian events merely as the culmination of the orogeny). Still others have suggested that the Acadian was a very short-lived event that occurred either in the late in the Early Devonian (according to some) or early in the Middle Devonian (according to others).

 

*Bold face words are defined in the glossary.

 

Paleozoic Time Scale