Data of Geochemistry * Chapter T. Nondetrital Siliceous Sediments GEOLOGICAL SURVEY PROFESSIONAL PAPER 440-T Data of Geochemistry Michael Fleischer, Technical Editor Chapter T. Nondetrital Siliceous Sediments By EARLE R. CRESSMAN GEOLOGICAL SURVEY PROFESSIONAL PAPER 440-T Tabulation and discussion of chemical analyses of chert with respect to mineralogic composition, petrographic type, and geologic occurrence UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1962 UNITED STATES DEPARTMENT OF THE INTERIOR STEW ART L. UDALL, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director For sale by the Superintendent of Documents, U.S. Government Printing Office Washington 25, D.C. DATA OP GEOCHEMISTRY, SIXTH EDITION Michael Fleischer, Technical Editor The first edition of the Data of Geochemistry, by F. W. Clarke, was published in 1908 as U.S. Geological Survey Bulletin 330. Later editions, also by Clarke, were published in 1911, 1916, 1920, and 1924 as Bul­ letins 491, 616, 695, and 770. This, the sixth edition, has been written by several scientists in the Geological Survey and in other institutions in the United States and abroad, each preparing a chapter on his special field. The current edition is being published in individual chapters, titles of which are listed below. Chapters already published are indicated by boldface type. CHAPTER A. The chemical elements B. Cosmochemistry C. Internal structure and composition of the Earth D. Composition of the earth's crust E. Chemistry of the atmosphere F. Chemical composition of subsurface waters, by Donald E. White, John D. Hem, and G. A. Waring G. Chemical composition of rivers and lakes, by Daniel A. Livingstone H. Chemistry of the oceans I. Geochemistry of the biosphere J. Chemistry of rock-forming minerals K. Volcanic emanations, by Donald E. White and G. A. Waring L. Phase equilibrium relations of the common rock-forming oxides except water M. Phase equilibrium relations of the common rock-forming oxides with water and (or) carbon dioxide N. Chemistry of igneous rocks O. Chemistry of rock weathering and soils P. Chemistry of bauxites and laterites Q. Chemistry of nickel silicate deposits R. Chemistry of manganese oxides S. Chemical composition of sandstones excluding carbonate and volcanic sands, by F. J. Petti John T. Nondetrital siliceous sediments, by Earle R. Cressman U. Chemical composition of shales and related rocks V. Chemistry of carbonate rocks W. Chemistry of iron-rich rocks X. Chemistry of phosphorites Y. Marine evaporites, by Frederick H. Stewart Z. Continental evaporites AA. Chemistry of coal BB. Chemistry of petroleum, natural gas, and miscellaneous carbonaceous substances CC. Chemistry of metamorphic rocks DD. Abundance and distribution of the chemical elements and their isotopes EE. Geochemistry of ore deposits FF. Physical chemistry of sufide systems GG. The natural radioactive elements HH. Geochronology II. Temperatures of geologic processes J J. Composition of fluid inclusions CONTENTS age Chemical composition Continued Page Abstract_______________________________ Tl _______ T10 Definitions____________________________ 1 Iron ___ _________ __ _____ ____ 10 Classification and occurrence______________. 1 _ ____ 12 Bedded nonfragmental siliceous deposits. Relation of iron to manganese. __ _ _ _______ 12 -. ___ 13 Diatomaceous deposits ____________ 2 . ____ 14 Radiolarian deposits______________ 2 Deposits of sponge spicules______. 3 15 _______ 15 Other bedded chert_______________ 4 _______ 15 Nodular chert in carbonate rock. _______ 4 Owoppn 16 Other siliceous deposits._______________ 4 Solubility of silica. ____ ____ _____ _ _ ____ 16 Mineralogic composition.__________________ 5 Origin_________________ ___ ___ ___ _ ____ _______ 17 Chemical composition.____________________ 5 _ ___ _ 18 Major constituents _________________ 6 Index. __________ _ _____ _ __ ___ _ ____ 23 ILLUSTRATIONS FIGURE 1. Frequency diagrams of four types of nonfragmental siliceous sedimentary rocks_________ ___ ___ ________ T7 2. Relation between SiO2 and the ratio SiO2/Al2Os in chert and related rocks._________ ___ _ ___ - 9 3. Relation of Fe2Os to AJ2Os in 46 radiolarian cherts_____ _________________________________ __ ______ 11 4. Relation of iron to manganese in chert and related rocks-____-_---_-------_-_ __ 13 5. Relation of TiO2 to A12O3 in chert and related rocks__________ _____ 14 TABLES Page TABLE 1. Analyses of three nearly pure cherts________________ ____________ ____________ __________ __ T6 2. Spectrochemical analyses of igneous and hydrothermal quartz____________________ _____ 3. Analyses of diatomaceous rocks____________________ ______ 4. Analyses of radiolarian rocks__________________________________ ___ _______ ______ 8 5. Analyses of spicular cherts_________________________________ ___________ ______ 8 6. Analyses of bedded cherts containing few or no siliceous skeletal remains. __________ _________ 10 7. Analyses of chert nodules, lenses, and layers in carbonate rock_________________ ___ ____. 10 8. Analyses of silcrete and other siliceous materials_______________________ _____ _____ . 11 9. Relation of iron and manganese to depth of water in sediments of the equatorial Atlantic Ocean- 12 10. Trace-element content of chert________________________ _________________________ ___ 15 11. Relative abundance of Si isotopes in nonfragmental siliceous sedimentary rocks. 16 12. Relative abundance of oxygen isotopes in nonfragmental siliceous sedimentary rocks - - - 16 DATA OF GEOCHEMISTRY NONDETRITAL SILICEOUS SEDIMENTS By EARLE R. CHESSMAN ABSTRACT textured, light-colored variety with a porcelaneous tex­ Chemical analyses of nondetrital siliceous sediments and sedi­ ture. Diatomaceous, radiolarian, and spicular chert are mentary rocks chert, siliceous earth, siliceous ooze, siliceous varieties that contain conspicious skeletal remains of shale culled from the literature have been grouped according the type specified. Two varieties of radiolarian chert to the following classification: Bedded: frequently described in the literature are lydite (lydian Diatomaceous deposits stone or culm-type), a black radiolarian chert, and Radiolarian deposits radiolarian jasper. Sponge-spicule deposits Diatomite, radiolarite, and spiculite are rocks that Bedded chert containing few or no siliceous skeletal consist largely of diatom f rustules, radiolarian tests, or fragments. sponge spicules, but do not exhibit the characteristic Nodular Mineralogically, the rocks consist of biogenic and chemogenic physical properties of chert; as used in this report, opal, chalcedony, and quartz, singly or as mixtures, admixed these terms include the diatomaceous, radiolarian, and with the same clastic and authigenic minerals that are in the spicular earths. Their equivalents on present sea and associated nonsiliceous sedimentary rocks. Opaline tests con­ lake bottoms are diatom, radiolarian, and spicule ooze. sist originally of truly amorphous silica, but much sedimentary Siliceous shales are rocks that consist mainly of fine­ opal has been shown by many authors to give an X-ray pattern of crlstobalite or tridymite. grained detrital minerals but contain noteworthy Small amounts of Al, Fe, and alkali and alkali-earth elements amounts of nonfragmental silica. Varieties are dia­ may occur within the lattice of the silica minerals; however, tomaceous, radiolarian, and spicular shale and their most of these elements are apparently in the admixed clastic equivalent muds in present sea and lake bottoms. and authigenic minerals, and the chemical composition of the Logically, the siliceous mudstones should not be treated rocks can, for the most part, be interpreted as the result of the mixture of mudstone or sandstone with pure SiO2 or by the in this section, but the distinction between siliceous mud- replacement of calcite or dolomite in carbonate rocks by pure stone and rocks composed dominantly of nonfragmental SiO2. Compositional differences between the rock types reflect silica is not always made; much of the sediment called (1) the association of diatomaceous rocks with pyroclastics, (2) diatom, or radiolarian ooze in the literature actually the association of radiolarian rocks with argillaceous and vol­ consists largely of detrital minerals, and the terms canic rocks of bathyal and possibly abyssal origin, (3) the asso­ lydite and radiolarian jasper have been applied both to ciation of spicular rocks with sublittoral sandstone and lime­ rocks composed almost entirely of nonfragmental silica stone, and (4) the common occurrence of nodular chert in and to siliceous mudstones. limestone of sublittoral origin. Recent work suggests that chert cannot form by direct inor­ Silcrete is a term applied to silicified layers in uncon- ganic precipitation of silica from sea water except locally in solidated surficial material. The name was coined by areas of volcanism and supports the hypothesis that much bedded Lamplugh (1907), who applied it to silicified surface chert has resulted from the accumulation of siliceous skeletal layers in southern Africa. The term is used widely by remains and that most nodular chert has resulted from the South African geologists. replacement of carbonate rock. Many authors report abundant Stratigraphic nomenclature used is that of the pub­ evidence that silica deposited as skeletal remains or in volcanic lished sources and is not necessarily that of the U.S. ash dissolves, migrates, and reprecipitates during diagenesis. Geological Survey. DEFINITIONS CLASSIFICATION AND OCCURRENCE Chert, by most