1:24000 GEOLOGIC MAP OF THE SYLAMORE QUADRANGLE, STONE AND IZARD COUNTIES, ARKANSAS

The geologic map of the Sylamore 7.5 minute quadrangle of Stone and Izard counties Arkansas depicts the surficial geologic units and structural relationships at the 1:24000 scale. In this area over 1700 ft (518m) of carbonate and clastic sedimentary rock of middle Ordovician to late Mississippian age (approximately 470 – 320 Mya) are at the earth’s surface. The area straddles the boundary between the Salem plateau and the Springfield plateau, two of three dissected, imbricate, geologic plateau surfaces that comprise the Ozark Plateaus of northern Arkansas, southern Missouri, southeastern Kansas and eastern Oklahoma.

The structure of the area is characterized by mostly relatively flat-lying strata deformed by a few normal faults and folds. Offsets on faults range from less than 20 ft (6m) to greater than 300 ft (91) and they are oriented mostly west northwest to east southeast, though northeast to southwest trending faults and folds are present.

The geology of the Sylamore quadrangle was mapped in 1973 by EE Glick of the USGS for the 1:500000 scale geologic map of Arkansas. This work builds on the previous mapping but uses a more detailed section and depicts structure in greater detail. The geologic interpretations depicted on the map are based on field observations made between July 2011 and April 2012. The map was produced for the National Cooperative Geologic Mapping Program (STATEMAP).