SUBAERIAL CEMENTATION AND SUBSEQUENT DOLOMITIZATION OF LACUSTRINE CARBONATE MUDS AND SANDS FROM PALEOTUZ GÖLÜ (“SALT LAKE”), TURKEY

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Abstract

SUMMARY

Along the eastern coast of the Gez Gölö, a salt lake formerly belonging to the larger “Paleo-Tuz Gölö” in central Anatolia, about 6.5 m of lake sediments of probably Pleistocene age were studied.

The sediment series consists of fine-grained unconsolidated dolomite muds representing the basin sedimentation of the old lake.

Nine lithified beds (oomicrites, intramicrites, intraoomicrites, intrabiomi-crites and dololutites with smaller amounts of allochems) are intercalated. These beds were deposited in very shallow water in the littoral zone of the paleo-lake. There is direct evidence that the beds were occasionally exposed to the air after deposition. This led to desiccation (with mud cracks, breaking up of intraclasts) and subaerial cementation due to the influx of fresh water (rain water, springs).

These now lithified carbonate sedimentary rocks were submerged and subsequently covered with mud. During this sub-aquatic phase the rock beds as well as the unconsolidated muds were dolomitized by an extremely high Mg/Caratio of the lake water which in the present Tuz Gölü amounts to about 150! It cannot be excluded, however, that dolomitization already took place or was initiated during the subaerial phase (“supratidal dolomite”).

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