EARLY CARBONIFEROUS (MISSISSIPPIAN) CLIMATE CHANGE IN SOUTHERN EURAMERICA
There was a relatively abrupt switch from the cool humid state of the DMT to a warm arid state in the late Tournaisian. Aridity persisted through the Viséan as indicated by accumulation of evaporites and evaporite- and chert-bearing limestones and dolomites across the North American craton. The arid period persisted until near the beginning of the Serpukhovian (late Chesterian) when sea level began to fall and the climate became progressively more humid. By the end of the Serpukhovian sea level fall exposed much of southern Euramerica and led to the Mid-Carboniferous unconformity of near global scope. Sea level fall was accompanied by a relatively gradual development of a humid to perhumid climate state, which became the dominant paleoclimate state through the early and early middle Pennsylvanian (Bashkirian-Moscovian).
Abrupt shifts in climate were in response to changes in ice volume; humid states corresponded to cool periods and low sea level, whereas arid states corresponded to warm periods and high sea level. Change in Mississippian paleoclimate in response to the gradual northward drift of Euramerica tends to be masked by global climate change associated with changes in ice volume.