Honeycomb-weathered sandstone (Dundee Sandstone, Middle Pennsylvanian; cliffs along Walnut Creek Bottom Road, west of Dundee, Ohio, USA) 3 : 無料・フリー素材/写真
Honeycomb-weathered sandstone (Dundee Sandstone, Middle Pennsylvanian; cliffs along Walnut Creek Bottom Road, west of Dundee, Ohio, USA) 3 / James St. John
| ライセンス | クリエイティブ・コモンズ 表示 2.1 |
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| 説明 | Honeycomb-weathered quartzose sandstone in the Pennsylvanian of Ohio, USA. (geology hammer for scale)The Pottsville Group is a Pennsylvanian-aged cyclothemic succession in eastern Ohio that contains nonmarine shales, marine shales, siltstones, sandstones, coals, marine limestones, and chert ("flint"). The lower Pottsville dates to the late Early Pennsylvanian. The upper part dates to the early Middle Pennsylvanian. The Lower-Middle Pennsylvanian boundary is apparently somewhere near the Boggs Member (?).This is the Dundee Sandstone, a moderately thick unit of quartzose sandstone in the Pottsville Group. It is supposedly equivalent to the Massillon Sandstone. In places, the Dundee underlies the Lower Mercer Limestone. In other areas, it underlies the Upper Mercer Limestone. As are other cliff-forming sandstone units in the Upper Paleozoic of Ohio, the Dundee Sandstone is probably an incised valley-fill succession. It consists of about 50 to 70 feet of horizontally-bedded and cross-bedded sandstones. Honeycomb weathering is moderately common and iron banding ("Liesegang banding") is present. One layer rich in granules and pebbles was observed at this outcrop (see above photo) - it pinched out laterally. In addition to quartz, which is the dominant mineral, samples of Dundee Sandstone also contain small amounts of potassium feldspar, limonite, kaolinite, tourmaline, chlorite, zircon, titanite/sphene, and serpentine (Bownocker, 1921). The Dundee was quarried in the past for its quartz sand, which was melted down and used to make various grades of glass.The pitting shown in the above photo is honeycomb weathering, which forms by differential erosion of the exposed sandstone face.Stratigraphy: Dundee Sandstone, Pottsville Group, lower Middle PennsylvanianLocality: roadcut & huge talus blocks of sandstone on the northern side of Walnut Creek Bottom Road (= Tuscarawas County Road 94), west of the town of Dundee, Wayne Township, northwestern Tuscarawas County, northeastern Ohio, USA (40° 35’ 15.22” North latitude, 81° 38’ 49.58” West longitude)---------------Reference cited:Bownocker (1921) - Steel molding sand in Ohio. Ohio Journal of Science 21: 249-266. |
| 撮影日 | 2015-10-31 15:13:39 |
| 撮影者 | James St. John |
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