Mineralogy of Selected Soils from Guam
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Mineralogy of Selected Soils from Guam GEOLOGICAL SURVEY PROFESSIONAL PAPER 403-F Mineralogy of Selected Soils from Guam By DOROTHY CARROLL and JOHN C. HATHAWAY with a section on DESCRIPTION OF SOIL PROFILES By CARL H. STENSLAND GEOLOGY AND HYDROLOGY OF GUAM, MARIANA ISLANDS GEOLOGICAL SURVEY PROFESSIONAL PAPER 403-F A mineralogical study of selected soil samples of Guam, including data on chemical composition, grain-size distribution, and comparison with other areas, as well as a description of soil profiles UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1963 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.G., 20402 CONTENTS Page Page Abstract____________________________ Fl Soil genesis Continued Introduction __________________________ 1 Evidence from chemical composition Continued Outline of geology_-------_---_---_--_- 2 Soils on volcanic parent rocks Continued Ferric oxide____________________________ F28 Soils of Guam_________-___-_-_---_--_- 3 Titania__ _____________________ 28 Methods of examination._______________ 4 Water. ________________________________ 29 Mechanical analysis______________ 4 Soils on limestones__________________________ 29 Chemical analysis________________ 5 Silica__________________________ 29 Mineralogical analysis ____________ 5 Alumina,_ _____________________________ 30 Results of analyses___________________ 7 Ferric oxide____________________________ 30 Mechanical composition ____________ 7 Titania__________________________ 30 Soil reaction. _____________________ 9 Phosphate. ________________________ 30 Chemical composition______________ 9 Evidence from mineralogical composition __________ 30 Atate clay on volcanic rocks _ _ _ _ 9 Soils on volcanic rocks_______________________ 30 Asan clay on volcanic rocks_____ 11 Soils on limestones__________________________ 32 Guam clay on limestones _______ 11 Comparison of soils of Guam with those of similar pa Fossil red latosol_____________ 11 rentage in other selected areas______________________ 36 Chacha clay on limestone_______ 11 Volcanic rock soils______________________________ 36 Chemical characteristics--______ 11 Hawaiian Islands___________________________ 36 Free iron oxide________-__________. 11 Norfolk Island_______________________ 36 Ion-exchange capacity______________ 12 Lismore, New South Wales__________________ 38 Organic matter____________________ 13 Inverell, New South Wales_______________ 38 Mineralogical composition__________ 13 Antrim, Northern Ireland__________________ 38 Sand fractions_______________ 13 Soils on limestones______________________________ 39 Clay and silt fractions_________. 18 Conclusions ________________________________________ 40 Soil genesis.__________________________ 24 References.-..______ _______________________________ 41 Evidence from chemical composition. 24 Description of soil profiles, by Carl H. Stensland______ 43 Soils on volcanic parent rocks. _. 24 Soils on volcanic rocks_________________________ 43 Silica removal____________. 27 Soils on limestone__ ___________________________ 48 Alumina accumulation___. 27 Index.________-_-____---_--------_--__---_------__ 51 ILLUSTRATIONS Page FIGURE 1. Parent rocks of soils on Guam, andesite, basalt, tuffaceous sandstone, and weathered tuff____________________ F4 2. Parent rocks of soils on Guam, pillow basalt-_________-__--_-_-_-___---_---_--_-.------_---------------- 5 3. Localities of soil profiles on Guam_______________________._____-___---_---__--_-_-_---_------_-------- 6 4. Heavy residues of sand fractions of soils on Guam__________-___-___-_-_--__---_-_-_---_-__-----___--_- 16 5. Diagram showing proportion of halloysite to gibbsite and boehmite in the various soil profiles- _____________ 21 6. Differential thermal analyses of clay «2ji) from soils developed on limestones and on volcanic rocks _____ 22 7. Diagram showing percentage of goethite and hematite in the various soil profiles_____-__--__--__---_---_--- 24 8. Chemical composition, recalculated on water-free basis, of profiles of Atate clay and Asan clay on volcanic rocks. 28 9. Diagram showing mineralogical relationships of soils developed on basaltic materials in various localities ____ 33 TABLES Page TABLE 1. Calcium carbonate, magnesium carbonate, and insoluble residues of limestones from Guam_________-__------_ F2 2. Chemical composition of the volcanic rocks of Guam________-_______-___---___-_---_---_---_----------- 7 3. Mechanical composition and pH 6f soils on volcanic rocks and on limestones-____--_----_-_-_--------------- 8 ni IV CONTENTS Page TABLE 4. Major chemical constituents in samples of soil from 13 soil profiles on Guam________________________________ F10 5. Organic carbon, free iron oxide, and ion-exchange capacity of soils on volcanic rocks and on limestones.________ 12 6. Heavy minerals (sp gr >2.8) in the sand fractions (0.25-0.10 mm and 0.10-0.05 mm) of soils from Guam______ 14 7. Mineralogy of the clay and silt fractions of soils.___-_______-_____---_-_---_---___----__----_____________ 18 8. Interpretation of thermal reactions shown by differential thermal analysis curves in figure 6_-___-___-_____-__ 20 9. Average chemical composition of three groups of volcanic rocks that are parent materials of soils on Guam._ __. 25 10. Average chemical composition (water-free basis) of soil profiles developed on volcanic rocks and on limestones from Guam____________________-_____________-_______-_-___---__---____--__-_--__-_-___--_________ 25 11-15. Chemical composition of parent rock and soil profiles: 11. Atate clay on Alutom Formation (profile S54-4)_______--_-___-----__-_-_____-__-_____________-____ 25 12. Atate clay on Alutom Formation (profile S54-5)____-_--__-__-__-_--_-__--__-_-_____-______________ 26 13. Atate clay on Bolanos Pyroclastic Member of the Umatac Formation (profile S54-6)___________________ 27 14. Atate clay on pillow basalt of the Facpi Volcanic Member of the Umatac Formation (profile S54-12)_____ 27 15. Asan clay on Alutom Formation (profile S54-23) _____ ______________________________________________ 27 16. Normative clay mineral composition, calculated from chemical analyses, of soil profiles on volcanic rocks and on limestones- ----____--__-__-__-_______-_____-__----_---------_------__----.__----____-___---_-_--__- 29 17. Changes in chemical composition of the Guam clay (average), presuming that it developed from material similar to the Chacha clay________--_____________________-_--____-____-__-_____--______-_-_-_________---__ 30 18. Weathering sequence of minerals in rocks and soils of Guam. _____________________________________________ 31 19. Comparison of soils developed on basalt and volcanic ash from various selected localities._____-_________--_-_ 37 GEOLOGY AND HYDROLOGY OF GUAM, MARIANA ISLANDS MINERALOGY OF SELECTED SOILS FROM GUAM By DOROTHY CARROLL and JOHN C. HATHAWAY ABSTRACT The principal weathering process in the development of the Data are given for the grain-size distribution, pH, chemical Atate clay is the removal of silica and the consequent accumula composition, organic carbon, free iron oxide, ion exchange ca tion of alumina, iron oxide, and titania. The Guam clay has a pacity, and mineralogy of soil samples from 14 profiles on Guam. more complex genesis as the limestones beneath it vary in their Six of the profiles are developed on limestone and eight on vol content of insoluble residue and in the kinds of minerals present. canic rocks. Most of the soils are described as red latosols and In some limestones the residue consists principally of fresh vol are clayey. The principal soil overlying volcanic rocks, the canic ash minerals, but in others, soil material from the erosion Atate clay, averages 71 percent clay, 23 percent silt, and 6 per of land surfaces is present. cent sand. The principal soil overlying limestone, the Guam The soils developed on volcanic materials on Guam are com clay, averages 59 percent clay, 33 percent silt, and 9 percent pared with other lateritic soils and with fossil laterites. Soils sand. In chemical composition the Atate clay averages 35.5 thus compared are from the Hawaiian Islands, Norfolk Island, percent SiO2, 27.9 percent Al20a, 14.5 percent Fe2O3, and 1.0 Australia, and Northern Ireland. The clay minerals of all these percent TiO2. The Guam clay averages 1.4 percent SiO2, 39.1 soils show a progressive change from montmorillonite > percent A12O3, 20.9 percent Fe203, and 2.0 percent TiO2. Com halloysite * kaolinite » gibbsite. The Atate clay of Guam parison of the SiO2 percentages for weathered rock and surface is a uniform profile that apparently has not reached the same soil of the Atate clay show that silica has been removed during stage of development as have the older soils of the Hawaiian development of the profile. Alumina and ferric oxide accumulate Islands. The ease of the weathering of the tuffs on Guam that in these soils. contain zeolites and glass suggests that these soils have de Normative mineral compositions of representative soil profiles veloped more rapidly than similar soils 011 compact basalts and show that a kaolin mineral, goethite, and a little gibbsite make andesites. The soils overlying limestones are compared with up the bulk of the Atate clay; whereas gibbsite, hematite, and terra rossa type soils of other Pacific islands, the West Indies, a little kaolin mineral are the main "constituents of the Guam and the