Abstract
Basalts from DSDP Site 417 (109 Ma) exhibit the effects of several stages of alteration reflecting the evolution of seawater-derived solution compositions and control by the structure and permeability of the crust. Characteristic secondary mineral assemblages occur in often superimposed alteration zones within individual basalt fragments. By combining bulk rock and single phase chemical analyses with detailed mineralogic and petrographic studies, chemical changes have been determined for most of the alteration stages identified in the basalts.
-
1)
Minor amounts of saponite, chlorite, and pyrite formed locally in coarse grained portions of massive units, possibly at high temperatures during initial cooling of the basalts. No chemical changes could be determined for this stage.
-
2)
Possible mixing of cooled hydrothermal fluids with seawater resulted in the formation of celadonite-nontronite and Fe-hydroxide-rich black halos around cracks and pillow rims. Gains of K, Rb, H2O, increase of Fe3+/FeT, and possibly some losses of Ca and Mg occurred during this stage.
-
3a)
Extensive circulation of oxygenated seawater resulted in the formation of various smectites, K-feldspar, and Fe-hydroxides in brown and light grey alteration zones around formerly exposed surfaces. K, Rb, H2O, and occasionally P were added to the rocks, Fe3+/FeT increased, and Ca, Mg, Si and occasionally Al and Na were lost.
-
3b)
Anoxic alteration occurred during reaction of basalt with seawater at low water-rock ratios, or with seawater that had previously reacted with basalt. Saponite-rich dark grey alteration zones formed which exhibit very little chemical change: generally only slight increases in Fe3+/FeT and H2O occurred.
-
4)
Zeolites and calcite formed from seawater-derived fluids modified by previous reactions with basalt. Chemical changes involved increases of Ca, Na, H2O, and CO2 in the rocks.
-
5)
A late stage of anoxic conditions resulted in the formation of minor amounts of Mn-calcites and secondary sulfides in previously oxidized rocks. No chemical changes were determined for this stage.
Recognition of such alteration sequences is important in understanding the evolution of submarine hydrothermal systems and in interpreting chemical exchange due to seawater-basalt reactions.
Similar content being viewed by others
References
Anderson RN, Hobart MA, Langseth MG (1979) Geothermal convection through oceanic crust and sediments in the Indian Ocean. Science 204:828–832
Andrews AJ (1977) Low temperature fluid alteration of oceanic layer 2 basalts, DSDP Leg 37. Can J Earth Sci 14:911–926
Andrews AJ, Dollase WA, Fleet ME (1983) A Mossbauer Study of Saponite Occurring in Layer 2 Basalt, DSDP Leg 69. In: Initial Reports of the Deep Sea Drilling Project, Vol. 69–70, U.S. Government Printing Office, Washington, D.C.
Bass MN (1976) Secondary Minerals in Oceanic Basalts with Special Reference to Leg 34, DSDP, pp. 393–431. In: Yeats RS, Hart RS (eds) Initial Reports of the Deep Sea Drilling Project, Vol. 34, U.S. Government Printing Office, Washington, D.C.
Berner RA (1975) The role of magnesium in the crystal growth of calcite and aragonite from seawater. Geochim Cosmochim Acta 39:489–504
Berry LG, Mason B (1959) Mineralogy. W.H. Freeman and Company, San Francisco, p 630
Böhlke JK, Honnorez J, Honnorez-Guerstein BM (1980) Alteration of basalts from Site 396B, DSDP: Petrographic and Mineralogic Studies. Contrib Mineral Petrol 73:341–364
Böhlke JK, Honnorez J, Honnorez-Guerstein BM, Muehlenbachs K, Petersen N (1981) Heterogeneous alteration of the upper oceanic crust: Correlation of rock chemistry, magnetic properties, and O-isotopic ratios with alteration patterns in basalts from Site 396B, DSDP. J Geophys Res 86:7935–7950
Böhlke JK, Alt JC, Muehlenbachs K (1984) Oxygen isotope-water relations in altered deep sea basalts: Low temperature mineralogical control. Can J Earth Sci 21:67–77
Byerly GR, Sinton JM (1979) Compositional trends in natural basalt glasses from DSDP Holes 417D and 418A. In: Donnelly T, Francheteau J, Bryan W, Robinson P, Flower M, Salisbury M (eds) 1979. Initial Reports of the Deep Sea Drilling Project, Vol. 51, 52, 53, Part 2. U.S. Government Printing Office, Washington, D.C., 957–972
Colby JW (1971) MAGIC IV, a computer program for quantiative electron microprobe analyses. Bell Laboratories
Deer WA, Howie RA, Zussman J (1964) Rock Forming Minerals, Vol 1–4. Wiley and Sons, New York
Donnelly T, Francheteau J, Bryan W, Robinson P, Flower M, Salisbury M, 1979a. Initial Reports of the Deep Sea Drilling Project, Vol. 51, 52, 53, U.S. Government Printing Office, Washington, D.C.
Donnelly TW, Pritchard RA, Emmerman R, Puchelt H (1979b) The Aging of Oceanic Crust: Synthesis of the Mineralogical and Chemical Results of Deep Sea Drilling Project Legs 51 Through 53, pp 1563–1755. In: Donnelly T, Francheteau J, Bryan W, Robinson P, Flower M, Salisbury M (eds) Initial Reports of the Deep Sea Drilling Project, Vol. 51, 52, 53, Part 2, U.S. Government Printing Office, Washington, D.C.
Donnelly TW, Thompson G, Salisbury M (1979c) The Chemistry of Altered Basalts at Site 417, Deep Sea Drilling Project Leg 51, pp 1319–1330. In: Donnelly T, Francheteau J, Bryan W, Robinson P, Flower M, Salisbury M (eds) Initial Reports of the Deep Sea Drilling Project, Vol. 51, 52, 53, Part 2, U.S. Government Printing Office, Washington, D.C.
Edmond JM, Measures C, McDuff RE, Chan LH, Collier R, Grant B, Gordon LI, Corliss JB (1979) Ridge crest hydrothermal activity and the balances of the major and minor elements in the oceans: The Galapagos data. Earth Planet Sci Lett 45:1–18
Emmerman R, Puchelt H (1979) Major and Trace Element Chemistry of Basalts from Holes 417D and 418A, Deep Sea Drilling Project Legs 51–53, pp. 987–1000. In: Donnelly T, Francheteau J, Bryan W, Robinson P, Flower M, Salisbury M (eds) Initial Reports of the Deep Sea Drilling Project, Vol. 51, 52, 53, U.S. Government Printing Office, Washington, DC.
Ewing JR, Houtz R (1979) Acoustic stratigraphy and structure of the oceanic crust. In: Talwani M, Harrison C, Hayes D (eds) 1–14, Deep Drilling Results in the Atlantic Oceans: Ocean Crust
Flower MFJ, Ohnmacht W, Robinson PT, Marriner G, Schmincke H-U (1979) Lithologic and Chemical Stratigraphy at Deep Sea Drilling Projects Sites 417 and 418. In: Donnelly T, Francheteau J, Bryan W, Robinson P, Flower M, Salisbury M (eds) Initial Reports of the Deep Sea Drilling Project, Vol. 51, 52, 53, Part 2. Washington (U.S. Government Printing Office): 939–956
Gieskes J, Reese H (1979) Interstitial Water Studies, Legs 51–53, In: Donnelly T, Francheteau J, Bryan W, Robinson P, Flower M, Salisbury M (eds) Initial Reports of the Deep Sea Drilling Project, Vol. 51, 52, 53, Part 2. Washington (U.S. Government Printing Office):747–751
Goldsmith JR, Graf DL, Heard HC (1961) Lattice constants of the Ca-Mg carbonates. Am Mineral 46:453–457
Hamano Y (1979) Physical Properties of Basalts from Holes 417D and 418, pp. 1457–1467. In: Donnelly T, Francheteau J, Bryan W, Robinson P, Flower M, Salisbury M (eds) Initial Reports of the Deep Sea Drilling Project, Vol. 51, 52, 53, Part 2, U.S. Government Printing Office, Washington, D.C.
Hawkins DB, Roy R (1963) Experimental hydrothermal studies on rock alteration and clay mineral formation. Geochim Cosmochim Acta 27:1047–1054
Hay RL (1966) Zeolites and zeolitic reactions in sedimentary rocks. Geol Soc Am Spec Paper no. 85, p 130
Hess PC, (1966) Phase equilibria of some minerals in the K2O-Na2O-Al2O3-SiO2-H2O system at 25° C and 1 atmosphere. Am J Sci 264:289–309
Honnorez J (1981) The aging of the oceanic crust at low temperature, pp. 525–587. In: Emiliani C (ed) The Sea, Vol. 7, John Wiley and Sons, New York
Honnorez J, Laverne C, Hubberten H, Emmerman R, Muehlenbachs K (1983) Alteration processes of Layer 2 basalts from DSDP Hole 504B, Costa Rica Rift. In: Initial Reports of the Deep Sea Drilling Project, Vol. 70, U.S. Government Printing Office, Washington, D.C.: 509–546
Honnorez J, Von Herzen RP, Barrett TJ, Becker K, Bender ML, Borella PE, Hubberten H-W, Jones SC, Karato S, Laverne C, Levi S, Migdisov AA, Moorby SA, Schrader EL (1981) Hydrothermal mounds and young ocean crust of the Galapagos: Preliminary deep sea drilling results, Leg. 70. Geol Soc Am Bull 92:457–472
Humphris SE, Melson WG, Thompson RN (1980) Basalt Weathering on the East Pacific Rise and the Galapagos Spreading Center, DSDP Leg 54, pp. 773–787. In: Rosendahl BR, Hekinian R (eds) Initial Reports of the Deep Sea Drilling Project, Vol. 54, U.S. Government Printing Office, Washington, D.C.
Humphris SE, Thompson RN, Marriner GF (1979) The mineralogy and geochemistry of basalt weathering, Holes 417A and 418A. In: Donnelly T, Francheteau J, Bryan W, Robinson P, Flower M, Salisbury M (eds) Initial Reports of the Deep Sea Drilling Project, Vol. 51, 52, 53, Part 2. Washington (U.S. Government Printing Office): 1201–1217
Laverne C, Vivier G (1983) Petrographical and Chemical Study of Basement from the Galapagos Spreading Center, Leg 70. In: Initial Reports of the Deep Sea Drilling Project, Vol. 70, U.S. Government Printing Office. Washington, D.C.: 375–390
Lawrence JR (1979) Temperatures of Formation of Calcite Veins in the Basalts from Deep Sea Drilling Project Holes 417A and 417D, pp. 1183–1184. In: Donnelly T, Francheteau J, Bryan W, Robinson P, Flower M, Salisbury M (eds) Initial Reports of the Deep Sea Drilling Project, Vol. 51, 52, 53, Part 2, U.S. Government Printing Office, Washington, D.C.
Lawrence JR, Gieskes J (1981) Constraints on water transport and alteration in the oceanic crust from the isotopic composition of pore water. J Geophys Res 86:7294–7934
Miyashiro A, Shido F, Ewing M (1971) Metamorphism in the mid-Atlantic Ridge near 24° and 39° N. R Soc Lond Phil Trans A 268:589–604
Mucci A, Morse JW (1983) The incorporation of Mg and Sr into calcite overgrowths: Influences of growth rate and solution compositions. Geochim Cosmochim Acta 47:217–233
Muehlenbachs K, Clayton RN (1972) Oxygen isotope studies of fresh and weathered submarine basalts. Can J Earth Sci 9:172–184
Muehlenbachs K (1979) The Alteration and Aging of the Basaltic Layer of the Sea Floor: Oxygen Isotope Evidence from DSDP/ IPOD Legs 51, 52, and 53. pp 1159–1167. In: Donnelly T, Francheteau J, Bryan W, Robinson P, Flower M, Salisbury M (eds) Initial Reports of the Deep Sea Drilling Project, Vol 51, 52, 53, Part 2, U.S. Government Printing Office, Washington, D.C.
Pertsev NN, Rusinov VL (1979) Mineral asemblages and processes of alterations in basalts at deep sea drilling project Sites 417 and 418. In: Donnelly T, Francheteau J, Bryan W, Robinson P, Flower M, Salisbury M (eds) Initial Reports of the Deep Sea Drilling Project, Vol. 51, 52, 53, Part 2. Washington (U.S. Government Printing Office): 1219–1242
Ross CS, Hendricks SB (1945) Minerals of the montmorillonite group, their origin and relation to soils and clays. U.S.G.S. Prof. Paper. 205-B:23–79
Schrader EL, Stow SH (1983) Geochemistry and Mineralogy of Fresh and Altered Basalts from the Galapagos Rift. In: Initial Reports of the Deep Sea Drilling Project, Vol. 70, U.S. Government Printing Office, Washington, D.C.: 391–408
Shido F, Miyashiro A, Ewing M (1974) Compositional variation in pillow lavas from the mid-Atlantic Ridge. Mar Geol 16:177–190
Sinton JM, Byerly GR (1979) Mineral compositions and crystallization trends in deep sea drilling project Holes 417D and 418A. In: Donnelly T, Francheteau J, Bryan W, Robinson P, Flower M, Salisbury M (eds) Initial Reports of the Deep Sea Drilling Project, Vol. 51, 52, 53, Part 2. Washington (U.S. Government Printing Office): 1039–1054
Staudigel H, Hart SR (1983) Alteration of basaltic glass: Mechanisms and significance for the oceanic crust-seawater budget. Geochim Cosmochim Acta 47:377–350
Staudigel H, Bryan WB, Thompson G (1979) Chemical Variation in Glass-Whole Rock Pairs from Individual Cooling Units in Holes 417D and 418A, pp. 977–986. In: Donnelly T, Francheteau J, Bryan W, Robinson P, Flower M, Salisbury M (eds) Initial Reports of the Deep Sea Drilling Project, Vol. 51, 52, 53, Part 2, U.S. Government Printing Office, Washington, D.C.
Staudigel H, Hart SR, Richardson SH (1981) Alteration of the oceanic crust: Processes and timing. Earth Planet Sci Lett 52:311–327
Ui T, Haramura H, Nagai H (1979) Major Element Chemistry and Microprobe Studies of Basalts from Deep Sea Drilling Project Leg 51, Site 417, pp 1001–1020. In: Donnelly T, Francheteau J, Bryan W, Robinson P, Flower M, Salisbury M (eds) Initial Reports of the Deep Sea Drilling Project, Vol. 51, 52, 53, Part 2, U.S. Government Printing Office, Washington, D.C.
Weaver CE, Pollard LD (1973) The chemistry of clay minerals. Developments in sedimentology. Vol 15, Elsevier, Amsterdam pp 213
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Alt, J.C., Honnorez, J. Alteration of the upper oceanic crust, DSDP site 417: mineralogy and chemistry. Contrib Mineral Petrol 87, 149–169 (1984). https://doi.org/10.1007/BF00376221
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00376221