Digital Geologic Quadrangle Map Arkansas Geological Survey Mountain View Quadrangle, Arkansas Bekki White, State Geologist and Director Geologic Map of the Mountain View Quadrangle, DGM-AR-00604 Stone County, Arkansas Richard S. Hutto and Daniel S. Rains 2013 Correlation of Map Units Description of Map Units Stratigraphic Column Alluvial terrace (Quaternary) - Unconsolidated clay, silt, Holocene Qat Qat Qls Quaternary sand and gravel on either the modern floodplain or the Pleistocene modern floodplain and one or more terrace levels. SystemSeries Member Formation Unconformity 1500 Landslide deposits (Quaternary) - A mass of rock and Qls Ùhc Morrowan Pennsylvanian debris that has moved downslope due to gravity. Only the largest landslide deposits are depicted. 1400 Cane Hill Unconformity Hale Morrowan 400 Pennsylvanian Mpi Hale Formation (Pennsylvanian, Morrowan) – Consists 1300 of two members, the Prairie Grove and the Cane Hill. Only Mp the Cane Hill Member is present on this quadrangle. 1200 Chesterian Cane Hill Member consists of very thin to Ù Imo interval Mf hc medium-bedded, and rarely thick-bedded, very fine 1100 grained, silty sandstone with shale interbeds. The Mbv Mississippian sandstone is buff to brown on freshly broken and 1000 weathered surfaces, characteristically ripple- or 300 Mm Meramecian flat-bedded, and typically weathers to flagstone; locally thick-bedded and cross bedded; Other rare features 900 Unconformity include liesegang boxwork, bioturbation, and plant Pitkin Limestone Mb Osagean fossils. The shale is typically not exposed but mostly 800 Chesterian clayey and black to dark-gray with rare liesegang Mississippian boxwork. Unconformable with the underlying Imo Unconformity 700 interval. Up to 220 feet (67 meters) thick. Su Silurian 200 Fayetteville 600 Shale Unconformity Imo interval (Upper Mississippian, Chesterian) – Mpi Typically consists of thin- to thick-bedded sandstone Of Ordovician 500 intervals interbedded with shale. Sandstone is mostly Batesville Sandstone very fine grained, buff to tan on fresh surfaces, and 400 weathers to brown or grayish-brown; displays Moorefield well-developed, abundant stylolitic surfaces, and 100 well-preserved plant fossils including Calamites, 300 Meramecian St. Francois Mountains Lepidodendron, and Stigmaria; contains coal traces; cross bedded sections are common throughout; honeycomb 200 structure is a common development, and liesegang Boone banding and soft-sediment deformation are preserved 100 Osagean Salem Plateau locally. The shale is mostly black on fresh surfaces, but Silurian Silurian locally gray; charcoal-gray to tan on weathered surfaces; Undifferentiated 0 ft 0 m Springfield contains poorly exposed fossiliferous zones with Fernvale Limestone Plateau fragments of brachiopods, ammonoids, nautiloids, Ozark Dome crinoids, gastropods, and rugosans. Locally there are flat MISSOURI ARKANSAS gypsum laminae less than a quarter inch (6 millimeter) Ordovician thick, limestone lenses typically no more than two feet Boston (0.6 meter) thick, and fossiliferous conglomerate lenses Mountains Plateau up to three feet (1 meter) thick containing ferruginous pebble-size concretions. Conformable with the underlying Mountain View limestone shale with sandstone shale Boston Mountains Quadrangle Pitkin Limestone. 180 - 400 feet (55 - 122 meters) thick. Escarpment and chert siltstone Pitkin Limestone (Upper Mississippian, Chesterian) – Modified from Shepard et al., 2011 Mp Mostly thick-bedded, very finely to coarsely crystalline limestone shale with calcareous ripple-bedded bioclastic limestone with lesser intervals of shale sandstone shale sandstone containing thin, slightly calcareous siltstone interbeds. and shale The limestone is usually light- to medium-gray on freshly Introduction broken surfaces and gray after weathering; contains unconformable surface abundant fossil fragments including crinoid stems and Archimedes; locally oolitic and cross bedded. The shale This map depicts the bedrock and surficial geology and siltstone is black when freshly broken and buff on of the Mountain View 7.5-minute quadrangle. In this References weathered surfaces. Well-developed nearly orthogonal area approximately 1400 feet (427 meters) of Late joint-sets produce rectangular to rhombic siltstone float Ordovician through Pennsylvanian (Morrowan) clastic where the shale and siltstone intervals are weathering at and carbonate sedimentary rocks are near the surface. the surface. Conformable with the underlying Fayetteville Glick E. E., 1973, Preliminary Geologic map of the The bedrock is overlain by a veneer of Quaternary-age Shale. 140 – 400 feet (43 – 122 meters) thick. Mountain View quadrangle, Stone County, regolith. Regional geology of the area is controlled by an Arkansas: Arkansas Geological Commission, uplift centered in the St. Francois Mountains of Geologic Worksheet, 1 sheet, 1:24,000. southeast Missouri known as the Ozark Dome. – Progressively younger rocks form a series of imbricate Fayetteville Shale (Upper Mississippian, Chesterian) Ingram, R. L., 1954, Terminology for the Thickness of Mf Primarily composed of shale with interbedded micrite. plateau surfaces from the core of the uplift southward Stratification and Parting Units in Sedimentary The shale is black when freshly broken, dark-gray when into Arkansas. This map straddles the boundary Rocks: Geological Society of America Bulletin, v. weathered, and clay-rich. The micrite is black on freshly between two of these surfaces: the Springfield Plateau in 65, pp. 937 – 938. broken surfaces and light-gray after weathering; the northern part of the map, and the higher Boston characteristically petroliferous when freshly broken, thin- McFarland, J. D., 2004, Stratigraphic Summary of Mountains Plateau to the south. The Springfield Plateau to medium-bedded, and grades from being almost absent Arkansas: Arkansas Geological Commission, is capped by Mississippian-age rocks deposited in in the lower portion to almost ubiquitous near the upper Information Circular 36, 38p. nearshore shallow marine and fluvial environments contact; Where locally fossiliferous, brachiopods are a between 365 and 330 million years before present. The Rains, D. S., and Hutto R. S., 2012, Geologic Map of the primary constituent. Concretions are abundant locally Boston Mountains Plateau surface is comprised primarily Sylamore quadrangle, Izard and Stone Counties, including up to 4 inch (10 centimeter), bedded, of Pennsylvanian-age rocks deposited in nearshore fluvial Arkansas: Arkansas Geological Survey, Digital light-orange siltstone concretions and cobble-sized and deltaic environments between 330 and 290 million Geologic Map, DGM-AR-00844, 1 sheet, 1:24,000. septarian concretions. Conformable with the underlying years before present. The recognized boundary between Batesville Sandstone. 120 – 400 feet (37 – 122 meters) Shepard, S. L., Dixon, J. C., and Davis, R. K., 2011, Are the plateaus, called the Boston Mountains Escarpment, thick. Ozark Streams Underfit? Using GIS to Re-Examine forms a persistent and prominent cuesta with a steep Dury’s Theory of Underfit Streams: Physical north face that extends from just south of the town of Geography, v. 32, no. 2, pp. 179 - 194. Mountain View on the west side of the quadrangle, to Batesville Sandstone (Upper Mississippian, Irons Mountain on the eastern margin. Mbv The geology of the Mountain View quadrangle was Chesterian) – Primarily sandstone units with lesser mapped in 1973 by E. E. Glick for the 1:500,000-scale intervals of shale between them. Sandstone is tan to gray Geologic Map of Arkansas. This map builds on the to dark-orange-gray on freshly broken surfaces and previous work but uses a more detailed stratigraphic weathers buff to brown; typically either blocky and non-calcareous or rounded, calcareous and cross-bedded; section and depicts structures in greater detail. The Imo shale contacts and structural features on the map are based bedding thickness is highly variable ranging from very primarily on field observations made from July 2012 - thin to thick. The shale intervals are clay-rich, black on April 2013. Locations of data collection sites were freshly broken surfaces, and tan to buff after weathering. recorded with a Garmin GPSmap 76 global positioning Conformable with the Moorefield Formation. 40 – 120 feet satellite receiver. Bedrock inclined at less than 2o is (12 – 37 meters) thick. shown as horizontal. Cane Hill Moorefield Formation (Upper Mississippian, Mm Mermecian) – Consists primarily of shale, sandstone, and Joint Frequency siltstone. The shale is the largest component and is usually dark-gray to black when freshly broken, buff after weathering, and clay-rich. The sandstone is typically 0 330 silty, very fine grained and thick-bedded, but thin to 30 medium beds are interspersed locally; dark-gray when freshly broken and brown to buff after weathering; 300 60 Locally, it is very limey and fossiliferous with abundant, well-preserved brachiopods. The siltstone is usually similar in color and bedding to the sandstone. Near the unconformable contact with the Boone Formation, limey 270 90 siltstone is common. Thickness ranges from 80 – 140 feet (24 - 43 meters). 240 120 Boone Formation (Lower Mississippian, Osagean) - Mb Typically consists of thick-bedded, finely granular to 210 150 coarsely bioclastic limestone interbedded with chert 180 nodules and anastomosing chert beds. The limestone is usually medium- to dark-gray on fresh surfaces and N = 390 light-gray after weathering; common