Trace-Element Systematics of Beryllium in Terrestrial Materials

Abstract

Although often studied as key constituent in minerals, the low mass element (Z = 4; M = 9.0012182 amu) beryllium is most commonly encountered as a very low abundance trace metal in rocks and fluids. In terms of atomic structure and valence state, Be is affiliated with alkaline earth elements; but geologically and chemically beryllium shows greater affinities to the major cations Al, Si, and Mn, and the lithophile trace elements Nd and Zr. Low beryllium abundances prevented the precise measurements of Be contents in rocks and fluids until relatively recently. Intense geochemical interest in the cosmogenic radioisotope 10Be has led to advances in the measurement of stable beryllium. High quality Be data now exist for a variety of natural materials found at or near the Earth’s surface. We have a good general understanding of the distribution of beryllium in the solid earth, and in surficial systems. New data for both mineral/melt and mineral/fluid partitioning of beryllium offer the possibility of a detailed assessment of the geochemical behavior of Be in the Earth’s major geologic environments. Goldschmidt and Peters (1932), using a flame-emission method, first measured trace-levels of beryllium in common rocks and minerals. They examined a variety of igneous rocks and their associated minerals, sedimentary rocks, and meteorites. While they were able to recognize differences in Be contents among materials (Be is higher in granites and alkaline igneous rocks than in mafic and ultramafic rocks; is higher still in pegmatitic rocks and minerals, and is not detectable in meteorites), they were unable to make precise measurements on most samples due to the poor sensitivity of their method. Sandell (1952) obtained somewhat more precise Be data on igneous rocks using a fluorimetric method. He confirmed the Be abundance variations reported by Goldschmidt and Peters (1932), and inferred …