ASPHALT

Composition. Asphalt is a bituminous substance probably derived from organic matter sometimes found in porous beds such as sand, sandstone, or sandy limestone. In Arkansas there are seven known deposits of asphaltic sands, sandstones, and sandy limestones. They are located in Sevier and Pike counties along the northern edge of the Trinity formation of Lower Cretaceous age, as are shown on the accompanying map. This formation rests on the upturned edges of the Paleozoic (Mississippian) rocks. The origin of these deposits is not entirely known. It may be that they were once oil sands in the Trinity beds and eventually became asphaltic due to the volatilization of the more fluid portion of the petroleum on exposure to the atmosphere, or it is possible that the petroleum originated in the Mississippian beds and saturated the Trinity sands above them. These sands were later eroded and the lighter portions of the petroleum volatilized. The following is an analysis of five of the Arkansas asphalt sands :*

Occurrence. The asphalt deposit two and one-half miles southeast of Pike in Pike County was worked from 1900 to 1906. During those years the Arkansas Asphalt Company mined 4,815 tons valued at $22,368. This was used in Little Rock to pave twelve blocks on West Markham from Main to Cross Streets and also a part of Center Street. Owing to the fact that the asphaltic sand did not receive entirely proper treatment, some of the pavement which was made from it did not prove satisfactory. Some of the asphalt is suitable for laying cold, while some needs to have bitumen added in order to make it suitable for paving. It is possible that, due to the fact that the shipment of the lime and sand is a considerable item of expense, the deposits can best be worked by extracting the bitumen and shipping it to the point where it is expected to be used,

*C. W. Hayes, "The Asphalt Deposits of Pike County, Arkansas."-Engineering and Mining Journal.

and mixing it with locally secured sand and ground limestone at such points.

A deposit of asphaltic dolomite has been found in southwestern Scott County at the northern base of Fourche Mountain. This deposit occurs in the Jackfork sandstone of Mississippian age. There has been no development of this deposit.

None of the asphaltic sand deposits in the State are now being developed.

At the present time nearly, if not all, of the asphalt used in Arkansas is derived from crude oil residues.

Bibliography of Asphalt in Arkansas

1902

Hayes, C. W., "Asphalt Deposits of Pike County, Arkansas."-U. S. Geological Survey Bulletin No. 213, pp. 353-355. may be consulted in public or scientific libraries.

Now out of print, but

Hayes, C. W., "The Asphalt Deposits of Pike County, Arkansas."-Engineering and Mining Journal, 74:782. Obtainable from Engineering and Mining Journal Press, Tenth Avenue at 36th Street, New York.

1918

3.

Miser, H. D., and Purdue, A. H., "Asphalt Deposits and Oil Conditions in Southwestern Arkansas."-U. S. Geological Survey, Bulletin No. 691j, pp. 271-292. Now out of print, but may be consulted in public or scientific libraries.

BAUXITE

Bauxite is a mixture of minerals and is not itself a natural chemical compound. According to chemists, it is probably a mixture of hydrous aluminum oxides, iron hydroxides with hydrous aluminum silicate.

*Following is a table showing the chemical qualities of nine samples of Arkansas bauxite.

Sample No. 1-From 1 north, 12 west, Section 24, north side of the southeast quarter. On Little Rock-Sweet Home turnpike, cut near road.

Sample No. 2-From 1 north, 12 west, Section 25, southwest corner, and Section 36, northwest corner.

Sample No. 3-From 2 south, 14 west, Sections 9 and 10; extending also from 10 into northwest of 15.

west.

west.

Sample No. 4-From 2 south, 14 west, Section 3, southeast of the south

Sample No. 5-From 2 south, 14 west, Section 3, southeast of the south

Sample No. 6-From 2 south, 14 west, Section 16, northeast corner of the southwest quarter, near Sol. Nethercut's.

Sample No. 7-From 1 south, 12 west, Section 9, northwest quarter of the northeast quarter, at the end of the Arch Street pike, and just north of the fork of the road at the point mentioned.

Sample No. 8-From 1 south, 12 west, Section 4, middle of the south side of the northwest quarter of the southwest quarter on the west side of the Arch Street pike leading south from Little Rock. Exposure in the field, a stone's throw from the road.

Sample No. 9-From 1 south, 12 west, Section 9, northeast quarter of the northwest quarter, west of the pike and west of small stream, about 100 feet south of bridge.

Uses of Bauxite

Bauxite is used (1) as a source of metallic aluminum, (2) in the manufacture of abrasives, (3) in the manufacture of aluminum chemicals, (4) as a refractory, and (5) in the manufacture of aluminum.

cement.

Bauxite is at present the only ore used commercially as a source of metallic aluminum. It also provides the source of those abrasives made by the dehydration of bauxite. These are synthetic products such as alundum, aloxite, exolon, and lionite. Bauxite is used in the

*Arkansas Geological Survey.