MORPHOLOGY AND STRUCTURAL SETTING OF QUATERNARY TRAVERTINES AT PAMUKKALE, TURKEY

Pamukkale (Cotton Castle), in the west Anatolian sector of the Aegean extensional province, is so named because snow white travertines are accumulating there. Travertine deposition at Pamukkale, one of Turkey's most important tourist destinations, has been in progress for at least the last 400 000 years, and has partially overwhelmed the Roman city and necropolis of Hierapolis. The travertine originates from hot waters that emerge at 35-56-degrees-C from open fissures and at least one fault zone. The five principal morphological varieties of travertine mass are: (1) terraced-mound travertines; (2) fissure-ridge travertines; (3) range-front travertines; (4) eroded-sheet travertines; and (5) self-built channel travertines. The first two varieties are similar to those reported from well known travertines at Tivoli, east of Rome, and Mammoth Hot Springs, Wyoming, but the last three varieties have not previously been reported. The orientations of fissure-ridge travertines directly reflect neotectonic directions of stretching that are north-south in the south and north-east-south-west in the north of the Pamukkale plateau. The deposition of about 10 km2 of travertines at Pamukkale is attributed to the presence beneath Pamukkale of carbonate bedrocks and an anastomosing network of fissures intersecting at numerous nodes that provide conduits for the escape of water. These fissures are parallel to the normal faults framing the west-trending Menderes graben and the north-west trending Gediz graben, whose confluence is near Pamukkale.