Tectonic features and geology of Uzunköy and its surroundings west of Zile (Tokat)

The study area covers a 345 km2 and located to the west of Zile (Tokat). In the area from old to young; Permo-Triassic Tokat metamorphics, Ferhatkaya and Carcurum Formations of Upper Jurassic-Lower Cretaceous Amasya Group, Middle Eocene Çekerek Formation and Mio-Pliocene Kemerkaş Formation outcrop. Tokat metamorphics are represented by phyllites, marble, metavolcanites, metasediments and mica schists, and thought to be metamorphosed at high pressure and low temperature conditions in a subduction zone. Amasya Group, which overlies Tokat metamorphics with an unconformity, is composed of Ferhatkaya and Carcurum formations on the basis of its lithologic and facies properties. Ferhatkaya Formation starts with a thin layer of conglomerate drived from metamorphic materials. The formation is composed mainly of limestones except lower levels, hi places brecciated fabric and often oolitic and psodooolitic fabrics are seen. Limestones of Ferhatkaya Formation deposited in a shallow marine environment. Carcurum Formation is, generally, composed of claystone and mudstone layers in lower levels, while limestones with chert layers and lenses in upper levels. These limestones of Carcurum Formation were deposited in deep marine environment.VI Middle Eocene Çekerek Formation is divided into three members. These are, from bottom to top; Kozluca, Kuzalan limestone and Göynücek Agglomerate members. Kozluca member generally consists of pebblestone, sandstone, mudstone, claystone and marl alternations. Kuzalan limestone member contains limestone lithology with high amount of Nummulites sp. fossils in some levels. Göynücek Agglomerate Member is composed of a matrix made of volcanic materials and basalt and andesite pebbles-blocks. In this unit, silicificated wood, metamorphic rock fragments, recrystalized limestone and limestone blocks, mudstone and claystone lumps and coal seams are commonly observed. The members of Çekerek Formation started to be deposited in a shallow marine conditions during Middle Eocene; thus Kozluca member and in shallower regions Kuzalan limestone member were deposited. Göynücek Agglomerate Member was completed by transition to continental conditions resulted from intense volcanism Mio-Pliocene Kemerkaş Formation overlying Middle Eocene Çekerek Formation with an angular uncomformity, is composed mainly of alternating conglomerate and pebblestone-rough sandstone, mudstone, gypsum interlayers and travertines. This unit was deposited in flood plain, graduation braided river, alluvial fan and lowers lopes of mountain in hot and dry climate conditions according to sediment fabrics and lithologic features. The area was affected mainly by the Alpine orogenic events and the effects of the Early Cimmericien, Oregonian and the Pyreneen orgenic phases have been determined. Thrust in the area were formed as a result of overthrusting of Tokat metamorphics and Amasya Group to Çekerek Formation and of overthrusting members of Çekerek Formation over each other. Thrusts dipping in NNW direction and striking in NE-SW were formed by tectonic movements after Middle Eocene. Fold axis and strikes of overthrust faults indicate that this region were under the effect of strain approximately in N-S and/or NW-SE during the period of Late Alpine Orogeny. Rose and contour diagrams prepared by using field data from the area support this idea. The strain was consequence of thrust movements in north-south strike which occurred from continuing compression since Neo-Tethyan closure. The sequence of geotectonic movements which shaped geotectonic evolution of the area, may be summarized as follows: Neo-Tethyan Ocean were formed by a series of geological events starting from Lias. They started to close during Lower Cretaceous and was consumed during Miocene.vıı There are economic lignite horizons in tuffaceous levels within the Göynücek Agglomerate Member of Çekerek Formation in the study area. In addition limestones of Ferhatkaya Formation can be used as commercial marble. KEY WORDS: Zile, Uzunköy (Büyûkbultu), Büyükkozluca, Kuzalan, Tokat Massif, North Anatolian Fault, Thrust fault, clip, lignite, oolit, continental deposits.