Bitumen

BITUMEN (bī-tū'mĕn). A mineral pitch widely scattered over the earth, and one of the best waterproofing substances known. It was used with tar to cover the ark of bulrushes (Exod.2.3) and to waterproof Noah’s ark (Gen.6.14). It was also used for mortar in the tower of Babel (Gen.11.3), and to represent a curse on Edom (Isa.34.9). There were great deposits near the Dead Sea and at different places in Mesopotamia. The principal modern source is a great lake of pitch on the island of Trinidad.



Bitumen is a general term for naturally occurring or pyrolytically obtained petroliferous substances ranging from crude oil thru the socalled mineral tars to asphaltite. They are dark to black color, consisting almost entirely of hydrogen and carbon with very little oxygen, nitrogen, and sulfur. Asphaltic-base oils at seepages yield natural bitumen, such as asphalt, rock asphalt, pyro-bitumens, and related compounds. They are prob. formed primarily by evaporation of the lighter and more volatile constituents. Asphalt (or asphaltum) is a semisolid mixture of several hydrocarbons. It is amorphous, of low specific gravity, 1-2 with a black or brownish-black color and pitchy luster. Well-known localities for asphaltum are Asphalt Lake, covering 114 acres on the Island of Trinidad, and the Dead Sea region. It is from the latter that Lacus Asphaltites were long known to the ancients. A similar lake occurs in Venezuela. Asphalt also occurs as a natural cement in sandstones, forming bituminous or asphaltic sandstones.

Herodotus and others described the use of asphalt as a cement for bricks at Babylon, and it still may be seen in the ruins of the wall of Media near Babylon.

Abundant petroleum deposits are known in the Middle E from several geologic periods, viz., Iran and Iraq (Tertiary), Kuwait and Bahrein (Cretaceous), Saudi Arabia (Jurassic), and in Egypt (Carboniferous to Eocene) esp. along the Gulf of Suez. In the latter oil seeps and heavy asphalt are known.

Today asphalt is used for road and roofing materials, water-proofing, blending with rubber, briquetting, pipe coatings, molding compounds, and paints.

Bibliography

C. F. Keil and F. Delitzsch, Biblical Commentary on the Old Testament (1949), V. 2, 142; A. M. Bateman, Economic Mineral Deposits, 2nd Ed. (1950), 732; M. F. Unger, Unger’s Bible Dictionary (1957); R. Said, The Geology of Egypt (1962), 274-281; McGraw-Hill, Encyclopedia of Science and Technology (1966), v. 2, 251; Van Nostrand’s Scientific Encyclopedia, 4th Ed. (1968).

See also

  • Slime