AULACOGEN

AULACOGEN (from the Greek words aulax (furrow) and genes (generating, generated) * EN: aulacogen; DE: Aulakogen; FR: aulacogene; ES: aulacogeno) is the intraplatform linear rift zone. The simple and complex aulacogens may be distinguished.

The simple aulacogens are the depressions, which are deep (with the subsidence of the foundation sometimes down to 5-10 kilometres), narrow (from the tens to the few hundreds of kilometers), elongated to the hundreds or the few thousands of kilometres, and limited by the faults, which are developing for a long time. The aulacogens can cross the entire platform (the through aulacogens) or fade within it, often reaching the adjacent geosyncline by the other end. As the result of the development, the aulacogens become either the intraplatform narrow linear fold zones (for example, the Danish-Polish aulacogen), or the wide and gently sloping syncline depressions (such as the Dnieper-Donets aulacogen in the Ukrainian syncline).

The complex aulacogens comprise not only the depressions (grabens), but also the uplifts (horsts) (for example, the Wichita zone of the North American platform).

The manifestations of the basaltic (alkaline basaltic) volcanism are sometimes observed in the aulacogens, and often the thick salt bearing strata are accumulating there. The term has been proposed by N.Shatski (1960).