East African hominin paleoecology: Isotopic evidence from paleosols

Early Hominin Paleoecology

Volumn , Issue , 2013, Pages 59-102

  Quade, Jay ^a   Levin, Naomi E ^b  

^a University of Arizona   (United States)

^b JOHNS HOPKINS UNIVERSITY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 84928704187     PISSN: None     EISSN: None     Source Type: Book    
DOI: 10.5876/9781607322252:C03     Document Type: Chapter

References (109)

1. Aronson, J. L., M. Hailemichael, and S. M. Savin. 2008. “Hominid Environments at Hadar from Paleosol Studies in a Framework of Ethiopian Climate Change.” Journal of Human Evolution 55 (4): 532-50. http://dx.doi.org/10.1016/j.jhevol.2008.04.004. Medline:18571216
2. Behrensmeyer, A. K., J. Quade, T. Cerling, J. Kappelman, I. A. Khan, P. Copeland, L. Roe, J. Hicks, P. Stubblefield, B. J. Willis, et al. 2007. “The Structure and Rate of Late Miocene Expansion of C4 Plants: Evidence from Lateral Variation in Stable Isotopes in Paleosols of the Siwalik Group, Northern Pakistan.” Geological Society of America Bulletin 119 (11-12): 1486-505. http://dx.doi.org/10.1130/B26064.1.
3. Bestland, E. A., and E. S. Krull. 1999. “Palaeoenvironments of Early Miocene Kisingiri Volcano Proconsul Sites: Evidence from Carbon Isotopes, Palaeosols and Hydromagmatic Deposits.” Journal of the Geological Society 156 (5): 965-76. http://dx.doi.org/10.1144/gsjgs.156.5.0965.
4. Bestland, E. A., and G. Retallack. 1993. “Volcanically Influenced Calcareous Palaeosols from the Miocene Kiahera Formation, Rusinga Island, Kenya.” Journal of the Geological Society 150 (2):293-310. http://dx.doi.org/10.1144/gsjgs.150.2.0293.
5. Bobe, R., and A. K. Behrensmeyer. 2004. “The Expansion of Grassland Ecosystems in Africa in Relation to Mammalian Evolution and the Origin of the Genus Homo.” Palaeogeography, Palaeoclimatology, Palaeoecology 207 (3-4): 399-420. http://dx.doi.org/10.1016/j.palaeo.2003.09.033.
6. Bond, W. J., and B. van Wilgen. 2006 [1996]. Plants and Fire. New York: Chapman.
7. Bonnefille, R., A. Vincens, and G. Buchet. 1987. “Palynology, Stratigraphy and Palaeoenviron-ment of a Pliocene Hominid Site (2.9-3.3 M.Y.) at Hadar, Ethiopia.” Palaeogeography, Palaeoclimatology, Palaeoecology 60:249-81. http://dx.doi.org/10.1016/001-0182(87)90035-6.
8. Bonnefille, R., R. Potts, F. Chalie, D. Jolly, and O. Peyron. 2004. “High-Resolution Vegetation and Climate Change Associated with Pliocene Australopithecus afarensis.”Proceedings of the National Academy of Sciences of the United States of America 101 (33): 12125-9. http://dx.doi.org/10.1073/pnas.0401709101. Medline:15304655
9. Cerling, T. E. 1984. “The Stable Isotopic Composition of Modern Soil Carbonate and Its Relation to Climate.” Earth and Planetary Science Letters 71 (2): 229-40. http://dx.doi.org /10.1016/0012-821X(84)90089-X.
10. Cerling, T. E. 1992. “Development of Grasslands and Savannas in East Africa during the Neogene.” Palaeogeography, Palaeoclimatology, Palaeoecology 97 (3): 241-7. http://dx.doi.org/10.1016/0031-0182(92)90211-M.
11. Cerling, T. E., J. R. Bowman, and J. R. O’Neil. 1988. “An Isotopic Study of a Fluvial-Lacustrine Sequence: The Plio-Pleistocene Koobi Fora Sequence; East Africa.” Palaeogeography, Palaeoclimatology, Palaeoecology 63 (4): 335-56. http://dx.doi.org/10.1016/0031-0182(88)90104-6.
12. Cerling, T. E., J. M. Harris, S. H. Ambrose, M. G. Leakey, and N. Solounias. 1997b. “Dietary and Environmental Reconstruction with Stable Isotope Analyses of Herbivore Tooth Enamel from the Miocene Locality of Fort Ternan, Kenya.”Journal of Human Evolution 33 (6): 635-50. http://dx.doi.org/10.1006/jhev.1997.0151. Medline:9467773
13. Cerling, T. E., J. M. Harris, and M. G. Leakey. 2003b. “Isotope Paleoecology of the Nawata and Nachukui Formations at Lothagam, Turkana Basin, Kenya.” In Lothagam: The Dawn of Humanity in Eastern Africa, ed. M. G. Leakey and J. M. Harris, 605-24. New York: Columbia University Press.
14. Cerling, T. E., J. M. Harris, B. J. MacFadden, J. R. Ehleringer, M. G. Leakey, J. Quade, and V. Eisenman. 1997a. “Global Vegetation Change through the Miocene/Pliocene Boundary.” Nature 389 (6647): 153-58. http://dx.doi.org/10.1038/38229.
15. Cerling, T. E., J. M. Harris, and B. H. Passey. 2003a. “Diets of East African Bovidae Based on Stable Isotope Analysis.”Journal of Mammalogy 84 (2): 456-70. http://dx.doi.org /10.1644/1545-1542(2003)084<0456:DOEABB>2.0.CO;2.
16. Cerling, T. E., and R. L. Hay. 1986. “An Isotopic Study of Paleosol Carbonates from Olduvai Gorge.” Quaternary Research 25 (1): 63-78. http://dx.doi.org/10.1016/0033-5894 (86)90044-X.
17. Cerling, T. E., N. E. Levin, J. Quade, J. G. Wynn, D. L. Fox, J. D. Kingston, R. G. Klein, and F. H. Brown. 2010. “Comment on the Paleoenvironment of Ardipithecus ramidus.”Science 328 (5982): H05, author reply H05. http://dx.doi.org/10.1126/science.1185274. Medline:20508112
18. Cerling, T. E., J. Quade, S. H. Ambrose, and N. E. Sikes. 1991b. “Fossil Soils, Grasses, and Carbon Isotopes from Fort Ternan, Kenya: Grassland or Woodland?” Journal of Human Evolution 21 (4): 295-306. http://dx.doi.org/10.1016/0047-2484(91)90110-H.
19. Cerling, T. E., D. K. Solomon, J. Quade, and J. R. Bowman. 1991a. “On the Isotopic Composition of Carbon in Soil Carbon Dioxide.” Geochimica et Cosmochimica Acta 55 (11): 3403-5. http://dx.doi.org/10.1016/0016-7037(91)90498-T.
20. Chadwick, O. A., J. M. Sowers, and R. A. Amundson. 1988. “Morphology of Calcite Crystals in Clast Coatings from Four Soils in the Mojave Desert Region.” Soil Science Society of America Journal53 (1):211-19. http://dx.doi.org/10.2136/sssaj1989.0361599500530 0010038X.
21. Chen, F. C., and W. H. Li. 2001. “Genomic Divergences between Humans and Other Hominoids and the Effective Population Size of the Common Ancestor of Humans and Chimpanzees.” American Journal of Human Genetics 68 (2): 444-56. http://dx.doi.org /10.1086/318206. Medline:11170892
22. Clarke, R. J. 2003. “Newly Revealed Information on the Sterkfontein Member 2 Australopithecus Skeleton.” South African Journal of Science 98:523-6.
23. Collatz, G., J. Berry, and J. Clark. 1998. “Effects of Climate and Atmospheric CO2 Partial Pressure on the Global Distribution of C4 Grasses: Present, Past, and Future.” Oecologia 114 (4): 441-54. http://dx.doi.org/10.1007/s004420050468.
24. Coppens, Y. 1994. “East Side Story: The Origin of Mankind.” Scientific American (May 1994): 62-69.
25. Craig, H., and L. Gordon. 1965. “Deuterium and Oxygen-18 Variation in the Ocean and the Marine Atmosphere.” In Stable Isotopes in Oceanographic Studies and Paleotemperatures, ed. E. Tongiorgi, 9-130. Spoleto.
26. Dansgaard, W. 1964. “Stable Isotopes in Precipitation.” Tellus 16 (4): 436-68. http://dx.doi.org/10.1111/j.2153-3490.1964.tb00181.x.
27. Dart, R. A. 1925. “Australopithecus africanus: The Man Ape of South Africa.” Nature 115 (2884): 195-9. http://dx.doi.org/10.1038/115195a0.
28. Davidson, G. R. 1995. “The Stable Isotopic Composition and Measurement of Carbon in Soil CO2.” Geochimica et Cosmochimica Acta 59 (12): 2485-9. http://dx.doi.org/10.1016/0016-7037(95)00143-3.
29. Debele, B. 1985. “The Vertisols of Ethiopia: Their Properties and Management.” World Soils Reports (UN, FAO, ROME) 56: 31-54.
30. DeMenocal, P. B. 2004. “African Climate Change and Faunal Evolution during the Plio-Pleistocene.” Earth and Planetary Science Letters 220 (1-2): 3-24. http://dx.doi.org/10.1016 /S0012-821X(04)00003-2.
31. Deutz, P., I. P. Montanez, and H. C. Monger. 2002. “Morphology and Stable and Radiogenic Isotope Composition of Pedogenic Carbonates in Late Quaternary Relict Soils, New Mexico, USA: An Integrated Record of Pedogenic Overprinting.”Journal of Sedimentary Research 72 (6): 809-22. http://dx.doi.org/10.1306/040102720809.
32. Dever, L., R. Durand, J.C.H. Fontes, and P. Vachier. 1982. “Geochemie et Teneurs Isotopiques des Systemes Saisonniers de Dissolution de la Calcite dans un Sol sur Craie.” Geochimica et Cosmochimica Acta 46 (10): 1947-56. http://dx.doi.org/10.1016/0016-7037 (82)90132-6.
33. Dulinski, M., and K. Rozanski. 1990. “Formation of i3C/i2C Ratios in Speleothems: A Semi-Dynamic Model.” Radiocarbon 32:7-16.
34. Fantidis, J., and D. H. Ehhalt. 1970. “Variations of the Carbon and Oxygen Isotopic Composition in Stalagmites and Stalactites: Evidence of Non-Equilibrium Isotopic Fractionation.” Earth and Planetary Science Letters 10 (1): 136-44. http://dx.doi.org/10.1016 /0012-821X(70)90075-0.
35. Fox, D., and P. L. Koch. 2004. “Carbon and Oxygen Isotopic Variability in Neogene Paleosol Carbonates: Constraints on the Evolution of C4 Grasslands.” Palaeogeography, Palaeoclimatology, Palaeoecology 207 (3-4): 305-29. http://dx.doi.org/10.1016/j.palaeo.2003.09.030.
36. Friedli, H., H. Lötscher, H. Oeshger, U. Siegenthaler, and B. Stauffer. 1986. “Ice Core Record of I3C/I2C Ratio of Atmospheric CO2 in the Past Two Centuries.” Nature 324 (6094): 237-8. http://dx.doi.org/10.1038/324237a0.
37. Gawthorpe, R. L., and M. R. Leeder. 2000. “Tectono-Sedimentary Evolution of Active Extensional Basins.” Basin Research 12 (3-4): 195-218. http://dx.doi.org/10.1046/j.1365-2117.2000.00121.x.
38. Hailemichael, M., J. L. Aronson, S. Savin, M.J.S. Tevesz, and J. G. Carter. 2002. “ô18O in Mollusk Shells from Pliocene Lake Hadar and Modern Ethiopian Lakes: Implications for the History of the Ethiopian Monsoon.” Palaeogeography, Palaeoclimatology, Palaeoecology 186 (1-2): 81-99. http://dx.doi.org/10.1016/S0031-0182(02)00445-5.
39. Hendy, C. H. 1971. “The Isotopic Geochemistry of Speleothems, I: The Calculation of the Effects of Different Modes of Formation on the Isotopic Composition of Speleothems and Their Applicability as Paleoclimatic Indicators.” Geochimica et Cosmochimica Acta 35 (8): 801-24. http://dx.doi.org/10.1016/0016-7037(71)90127-X.
40. Hendy, C. H., T. A. Rafter, and T. G. MacIntosh. 1972. “The Formation of Carbonate Nodules in Soils of the Darling Downs, Queensland, Australia, and the Date of the Talgai Cranium.” In Proceedings of the 8th International Radiocarbon Dating Conference, Lower Hutt, New Zealand, ed. T. A. Rafter and T. G. Taylor, 417-437. Wellington: Royal Society of New Zealand.
41. Hesla, A.B.I., L.L. Tieszen, and S. K. Imbamba. 1982. “A Systematic Survey of C3 and C4 Photosynthesis in the Cyperaceae of Kenya, East Africa.” Photosynthetica 16:196-205.
42. Hillel, D. 1982. Introduction to Soil Physics. London: Academic Press.
43. Hoorn, C., T. Ohja, and J. Quade. 2000. “Palynological Evidence of Vegetation Development and Climatic Change in the Sub-Himalayan Zone (Neogene, Central Nepal).” Palaeogeography, Palaeoclimatology, Palaeoecology 163 (3-4): 133-61. http://dx.doi.org/10.1016 /S0031-0182(00)00149-8.
44. Hsieh, J. C., O. Chadwick, E. Kelly, and S. Savin. 1998. “Oxygen Isotopic Composition of Soil Water: Quantifying Evaporation and Transpiration.” Geoderma 82 (1-3): 269-93. http://dx.doi.org/10.1016/S0016-7061(97)00105-5.
45. Ivanov, V. V., D. Lemma, B. G. Rozanov, and T. A. Soklova. 1985. “Composition of Ethiopian Upland Soils.” Pochvovendeniye 3:29-39.
46. Kellog, E. A. 1999. “Phylogenetic Aspects of the Evolution of C4 Photosynthesis.” In C4 Plant Biology, ed. R. F. Sage and R. K. Monson, 411-444. San Diego, CA: Academic Press.
47. Kim, S., and J. R. O’Neil. 1997. “Equlilibrium and Nonequilibrium Oxygen Isotope Effects in Synthetic Carbonates.” Geochimica et Cosmochimica Acta 61 (16): 3461-75. http://dx.doi.org/10.1016/S0016-7037(97)00169-5.
48. Kingston, J. D. 1992. “Stable Isotopic Evidence for Hominid Paleoenvironments in East Africa.” PhD dissertation. Harvard University, Cambridge, MA. 162 pp.
49. Kingston, J. D. 1999. “Environmental Determinants in Early Hominid Evolution: Issues and Evidence from the Tugen Hills, Kenya.” In Late Cenozoic Environments and Hominid Avolution: A Tribute to Bill Bishop, ed. P. Andrews and P. Banham, 69-84. London: Geological Society.
50. Kingston, J. D., A. Hill, and B. D. Marino. 1994. “Isotopic Evidence for Neogene Hominid Paleoenvironments in the Kenya Rift Valley.” Science 264 (5161): 955-9. http://dx.doi.org /10.1126/science.264.5161.955. Medline:17830084
51. Kleinsasser, L., J. Quade, W. C. McIntosh, N. E. Levin, S. W. Simpson, and S. Semaw. 2008. “Stratigraphy and Geochronology of the Late Miocene Adu-Asa Formation at Gona, Ethiopia.” In The Geology of Early Humans in the Horn of Africa, ed. J. Quade and J. G. Wynn, 33-65. Geological Society of America Special Paper. Boulder, CO: Geological Society of America.
52. Kumar, S., and S. B. Hedges. 1998. “A Molecular Timescale for Vertebrate Evolution.” Nature 392 (6679): 917-20. http://dx.doi.org/10.1038/31927. Medline:9582070
53. Latorre, C., J. Quade, and W. C. McIntosh. 1997. “The Expansion of C4 Grasses and Global Change in the Late Miocene: Stable Isotope Evidence from the Americas.” Earth and Planetary Science Letters 146 (1-2): 83-96. http://dx.doi.org/10.1016/S0012-821X(96)00231-2.
54. Lear, C. H., H. Elderfield, and P. A. Wilson. 2000. “Cenozoic Deep-Sea Temperatures and Global Ice Volumes from Mg/Ca in Benthic Foraminiferal Calcite.” Science 287 (5451): 269-72. http://dx.doi.org/10.1126/science.287.5451.269. Medline:10634774.
55. Levin, N. 2002. “Isotopic Evidence for Plio-Pleistocene Environmental Change at Gona, Ethiopia.” MS thesis, University of Arizona, Tucson. 47 pp
56. Levin, N. E. 2013. “Compilation of East Africa Soil Carbonate Stable Isotope Data.” Integrated Earth Data Applications. doi: 10.1594/IEDA/100231
57. Levin, N. E., F. H. Brown, A. K. Behrensmeyer, R. Bobe, and T. E. Cerling. 2011. “Paleosol Carbonates from the Omo Group: Isotopic Records of Local and Regional Environmental Change in East Africa.” Palaeogeography, Palaeoclimatology, Palaeoecology 307 (1-4): 75-89. http://dx.doi.org/10.1016/j.palaeo.2011.04.026.
58. Levin, N. E., J. Quade, S. Simpson, S. Semaw, and M. Rogers. 2004. “Isotopic Evidence for Plio-Pleistocene Environmental Change at Gona, Ethiopia.” Earth and Planetary Science Letters 219 (1-2): 93-110. http://dx.doi.org/10.1016/S0012-821X(03)00707-6.
59. Levin, N. E., S. W. Simpson, J. Quade, T. E. Cerling, and S. R. Frost. 2008. “Herbivore Enamel Carbon Isotopic Composition and the Environmental Context of Ardipithecus at Gona, Ethiopia.” In The Geology of Early Humans in the Horn of Africa, ed. J. Quade and J. G. Wynn, 215-234. Geological Society of America Special Paper. Boulder, CO: Geological Society of America.
60. Levin, N. E., E. J. Zipser, and T. E. Cerling. 2009. “Isotopic Composition of Waters from Ethiopia and Kenya: Insights into Moisture Sources for Eastern Africa.”Journal of Geophysical Research 114 (D23): D23306. http://dx.doi.org/10.1029/2009JD012166.
61. Liutkus, C., J. D. Wright, G. M. Ashley, and Nancy E. Sikes. 2005. “Paleoenvironmental Interpretation of Lake-Margin Deposits Using ôI3C and ôl8ü Results from Early Pleistocene Carbonate Rhizoliths: Olduvai Gorge, Tanzania.” Geology 33 (5): 377-80. http://dx.doi.org/10.1130/G2n32.1.
62. Machette, M. N. 1985. “Calcic Soils in the Southwestern United States.” In Soils and Quaternary Geology of the Southwestern United States, ed. D. L. Weide. Geological Society of America. Special (SAUS) 203 pp.
63. Magaritz, M., and A. J. Amiel. 1980. “Calcium Carbonate in a Calcareous Soil from the Jordan Valley, Israel; Its Origin, as Revealed by Stable Carbon Isotope Method.” Soil Science Society of America Journal 44 (5): 1059-62. http://dx.doi.org/10.2136/sssaj1980.03615 995004400050037X.
64. Magaritz, M., A. Kaufman, and D. H. Yaalon. 1981. “Calcium Carbonate Nodules in Soils: l8O/l6O and I3C/I2C Ratios and I4C Contents.” Geoderma 25 (3-4): 157-72. http://dx.doi.org /10.1016/0016-7061(81)90033-1.
65. Morgan, M. E., J. D. Kingston, and B. D. Marino. 1994. “Carbon Isotope Evidence for the Emergence of C4 Plants in the Neogene from Pakistan and Kenya.” Nature 367 (6459): 162-5. http://dx.doi.org/10.1038/367162a0.
66. Pagani, M., K. H. Freeman, and M. A. Arthur. 1999. “Late Miocene Atmospheric CO2 Concentrations and the Expansion of C4 Grasses.” Science 285 (5429): 876-9. http://dx.doi.org/10.1126/science.285.5429.876. Medline:10436153
67. Passey, B. H., N. E. Levin, T. E. Cerling, F. H. Brown, and J. M. Eiler. 2010. “High-Temperature Environments of Human Evolution in East Africa Based on Bond Ordering in Paleosol Carbonates.” Proceedings of the National Academy of Sciences of the United States of America 107 (25): 11245-9. http://dx.doi.org/10.1073/pnas.1001824107. Medline:20534500
68. Pearson, P. N., and M. R. Palmer. 2000. “Atmospheric Carbon Dioxide Concentrations over the Past 60 Million Years.” Nature 406 (6797): 695-9. http://dx.doi.org/10.1038/35021000. Medline:10963587
69. Pickford, M., and B. Senut. 2001. “The Geological and Faunal Context of Late Miocene Hominid Remains from Lukeino, Kenya.” Comptes rendus de l’Académie des Sciences Paris 332:145-52.
70. Pickford, M., B. Senut, and C. Mourer-Chauvire. 2004. “Early Pliocene Tragulidae and Peafowls in the Rift Valley, Kenya: Evidence for Rainforest in East Africa.” Comptes Rendus. Palévol 3 (3): 179-89. http://dx.doi.org/10.1016/jxrpv.2004.01.004.
71. Pilbeam, D. 1996. “Genetic and Morphological Records of the Hominoidea and Hominid Origins: A Synthesis.” Molecular Phylogenetics and Evolution 5 (1): 155-68. http://dx.doi.org/10.1006/mpev.1996.0010. Medline:8673283
72. Plummer, T., L. C. Bishop, P. Ditchfield, and J. Hicks. 1999. “Research on Late Pliocene Oldowan Sites at Kanjera South, Kenya.” Journal of Human Evolution 36 (2): 151-70. http://dx.doi.org/10.1006/jhev.1998.0256. Medline:10068064
73. Poage, M. A., and C. P. Chamberlain. 2001. “Empirical Relationships between Elevation and the Stable Isotope Composition of Precipitation and Surface Waters: Consideration for Studies of Paleoelevation Change.” American Journal of Science 301 (1): 1-15. http://dx.doi.org/10.2475/ajs.301.1.1.
74. Pratt, D. J., P. J. Greenway, and M. D. Gwynne. 1966. “A Classification of East African Rangeland, with an Appendix on Terminology.” Journal of Applied Ecology 3 (2): 369-82. http://dx.doi.org/10.2307/2401259.
75. Quade, J., T. E. Cerling, and J. R. Bowman. 1989a. “Systematic Variations in the Carbon and Oxygen Isotopic Composition of Pedogenic Carbonate along Elevation Transects in the Southern Great Basin, United States.” Geological Society of America Bulletin 101 (4): 464-75. http://dx.doi.org/10.1130/0016-7606(1989)101<0464:SVITCA>2.3.CO;2.
76. Quade, J., T. E. Cerling, and J. R. Bowman. 1989b. “Development of Asian Monsoon Revealed by Marked Ecological Shift during the Latest Miocene in Northern Pakistan.” Nature 342 (6246): 163-6. http://dx.doi.org/10.1038/342163a0.
77. Quade, J., J. Eiler, M. Daeron, and H. Achythan, 2013. “The clumped isotope paleothermo-meter in soils and paleosol carbonate.” Geochimica et Cosmochimica Acta 105, 92-roy
78. Quade, J., N. Levin, S. Semaw, S. Simpson, M. Rogers, and D. Stout. 2004. “Paleoenvironments of the Earliest Stone Toolmakers, Gona, Ethiopia.” Geological Society of America Bulletin 116 (11):1529-44. http://dx.doi.org/10.1130/B25358.1.
79. Quade, J., N. L. Levin, S. W. Simpson, R. Butler, W. McIntosh, S. Semaw, L. Kleinsasser, G. Dupont-Nivet, P. Renne, and N. Dunbar. 2008. “The Geology of Gona, Ethiopia.” In The Geology of Early Humans in the Horn of Africa, ed. J. Quade and J. G. Wynn, 1-31. Geological Society of America Special Paper. Boulder, CO: Geological Society of America.
80. Quade, J., J. A. Rech, C. H. Latorre, J. Betancourt, E. Gleason, and M. Kalin-Arroyo. 2007. “Soils at the Hyperarid Margin: The Isotopic Composition of Soil Carbonate from the Atacama Desert.” Geochimica et Cosmochimica Acta 71 (15): 3772-95. http://dx.doi.org/10.1016/j.gca.2007.02.016.
81. Quinn, R. L., C. J. Lepre, J. D. Wright, and C. S. Feibel. 2007. “Paleogeographic Variations of Pedogenic Carbonate òi3C Values from Koobi Fora, Kenya: Implications for Floral Compositions of Plio-Pleistocene Hominin Environments.”Journal of Human Evolution 53 (5): 560-73. http://dx.doi.org/10.1016/j.jhevol.2007.01.013. Medline:17905411.
82. Rabenhorst, M. C., L. P. Wilding, and L. T. West. 1984. “Identification of Pedogenic Carbonates Using Stable Carbon Isotope and Microfabric Analyses.” Soil Science Society of America Journal 48 (1): 125-32. http://dx.doi.org/10.2136/sssaji984.03615995004800010023x.
83. Richter, J. 1987. The Soil as a Reactor. Catena Paperback. Cremlingen, Germany: Catena-Verlag Publisher.
84. Romanek, C. S., E. T. Grossman, and J. W. Morse. 1992. “Carbon Isotopic Fractionation in Synthetic Aragonite and Calcite: Effects of Temperature and Precipitation Rate.” Geochimica et Cosmochimica Acta 56 (1): 419-30. http://dx.doi.org/10.1016/0016-7037 (92)90142-6.
85. Rozanski, K., L. Araguas-Araguas, and R. Gonfiantini. 1993. “Isotopic Patterns in Modern Global Precipitation.” In Continental Indicators of Climate, Proceedings of Chapman Conference, ed. P. Swart, J. A. McKenzie, and K. C. Lohman, 1-36. Jackson Hole, Wyoming. American Geophysical Union Monograph 78.
86. Sage, R. F. 1999. “Why C4 Photosynthesis?” In C4 Plant Biology, ed. R. F. Sage and R. K. Monson, 3-16. San Diego: Academic Press. http://dx.doi.org/10.1016/B978-012614440-6/50002-1
87. Salem, A. H., D. A. Ray, J. Xing, P. A. Callinan, J. S. Myers, D. J. Hedges, R. K. Garber, D. J. Witherspoon, L. B. Jorde, and M. A. Batzer. 2003. “Alu Elements and Hominid Phylogenetics.” Proceedings of the National Academy of Sciences of the United States of America 100 (22): 12787-91. http://dx.doi.org/10.1073/pnas.2133766100. Medline:14561894
88. Salomons, W., A. Goudie, and W. G. Mook. 1978. “Isotopic Composition of Calcrete Deposits from Europe, Africa and India.” Earth Surface Processes 3 (1): 43-57. http://dx.doi.org/10.1002/esp.3290030105.
89. Sankaran, M., N. P. Hanan, R. J. Scholes, J. Ratnam, D. J. Augustine, B. S. Cade, J. Gignoux, S. I. Higgins, X. Le Roux, F. Ludwig, et al. 2005. “Determinants of Woody Cover in African Savannas.” Nature 438 (7069): 846-9. http://dx.doi.org/10.1038/nature04070. Medline:16341012
90. Sarmiento, G. 1984. The Ecology of Neotropical Savannas. Cambridge, MA: Harvard University Press.
91. Semaw, S., M. J. Rogers, J. Quade, P. R. Renne, R. F. Butler, M. Dominguez-Rodrigo, D. Stout, W. S. Hart, T. Pickering, and S. W. Simpson. 2003. “2.6-Million-Year-Old Stone Tools and Associated Bones from OGS-6 and OGS-7, Gona, Afar, Ethiopia.” Journal of Human Evolution 45 (2): 169-77. http://dx.doi.org/10.1016/S0047-2484(03)00093-9. Medline:14529651
92. Semaw, S., S. W. Simpson, J. Quade, P. R. Renne, R. F. Butler, W. C. McIntosh, N. Levin, M. Dominguez-Rodrigo, and M. J. Rogers. 2005. “Early Pliocene Hominids from Gona, Ethiopia.” Nature 433 (7023): 301-5. http://dx.doi.org/10.1038/nature03177. Medline:15662421
93. Sharp, W. D., K. R. Ludwig, O. A. Chadwick, R. Amundson, and L. L. Glaser. 2003. “Dating of Fluvial Terraces by 230Th/U on Pedogenic Carbonate, Wind River Basin, Wyoming.” Quaternary Research 59 (2): 139-50. http://dx.doi.org/10.1016/S0033-5894 (03)00003-6.
94. Sikes, N. E., R. Potts, and A. K. Behrensmeyer. 1999. “Early Pleistocene Habitat in Member 1 Olorgesailie Based on Paleosol Stable Isotopes.” Journal of Human Evolution 37 (5): 721-46. http://dx.doi.org/10.1006/jhev.1999.0343. Medline:10536089
95. Straight, W. H., R. Barrick, and D. A. Eberth. 2004. “Reflections of Surface Water, Seasonality and Climate in Stable Oxygen Isotopes from Tyrannosaurid Tooth Enamel.” Palaeogeography, Palaeoclimatology, Palaeoecology 206 (3-4): 239-56. http://dx.doi.org/10.1016/j.palaeo.2004.01.006.
96. Szaran, J. 1997. “Achievement of Carbon Isotope Equilibrium in the System HCO3 (solution)-CO2 (gas).” Chemical Geology 142 (1-2): 79-86. http://dx.doi.org/10.1016 S0009-2541(97)00077-6.
97. Talma, A. S., and F. Netterberg. 1983. “Stable Isotope Abundances in Calcretes.” In Residual Deposits: Surface Related Weathering Processes and Materials, ed. R.C.L. Wilson, 221-233. Oxford: Blackwell Scientific Publications.
98. Taub, D. R. 2000. “Climate and the U.S. Distribution of C4 grass Subfamilies and Decarboxylation Variants of C4 Photosynthesis.” American Journal of Botany 87 (8): 1211-5. http://dx.doi.org/10.2307/2656659. Medline:10948007
99. Tidwell, W. D., and E.M.V. Nambudiri. 1989. “Tomlisonia thomassonii, a Permineralized Grass from the Upper Miocene Ricardo Formation, California.” Review of Palaeobotany andPalynology 60 (1-2): 165-77. http://dx.doi.org/10.1016/0034-6667(89)90075-4.
100. Tieszen, L. L., M. M. Senyimba, S. K. Imbamba, and J. H. Troughton. 1979. “The Distribution of C3 and C4 Grasses and Carbon Isotope Discrimination along an Altitudinal and Moisture Gradient in Kenya.” Oecologia 37:337-50.
101. Washburn, S. L. 1978. “The Evolution of Man.” Scientific American 239 (3): 194-8, 201-2, 204 passim. http://dx.doi.org/10.1038/scientificamerican0978-194. Medline:100881
102. White, T. D., S. H. Ambrose, G. Suwa, D. F. Su, D. DeGusta, R. L. Bernor, J. R. Boisserie, M. Brunet, E. Delson, S. Frost, et al. 2009. “Macrovertebrate Paleontology and the Pliocene Habitat of Ardipithecus ramidus.”Science 326 (5949): 87-93. http://dx.doi.org /10.1126/science.1175822. Medline:19810193
103. WoldeGabriel, G., S. H. Ambrose, D. Barboni, R. Bonnefille, L. Bremond, B. Currie, D. DeGusta, W. K. Hart, A. M. Murray, P. R. Renne, et al. 2009. “The Geological, Isotopic, Botanical, Invertebrate, and Lower Vertebrate Surroundings of Ardipithecus ramidus.”Science 326 (5949): 65 (summary), 65e1-65e5 (text). http://dx.doi.org/10.1126/science.1175817. Medline:19810191
104. WoldeGabriel, G., Y. Haile-Selassie, P. R. Renne, W. K. Hart, S. H. Ambrose, B. Asfaw, G. Heiken, and T. White. 2001. “Geology and Palaeontology of the Late Miocene Middle Awash Valley, Afar Rift, Ethiopia.” Nature 412 (6843): 175-8. http://dx.doi.org/10.1038/35084058. Medline:11449271
105. Wynn, J. G. 2000. “Paleosols, Stable Carbon Isotopes, and Paleoenvironmental Interpretation of Kanapoi, Northern Kenya.” Journal of Human Evolution 39 (4): 411-32. http://dx.doi.org/10.1006/jhev.2000.0431. Medline:11006049
106. Wynn, J. G. 2004. “Influence of Plio-Pleistocene Aridification on Human Evolution: Evidence from Paleosols of the Turkana Basin, Kenya.” American Journal of Physical Anthropology 123 (2): 106-18. http://dx.doi.org/10.1002/ajpa.10317. Medline:14730645
107. Wynn, J. G., Z. Alemseged, R. Bobe, D. Geraads, D. Reed, and D. C. Roman. 2006. “Geological and Palaeontological Context of a Pliocene Juvenile Hominin at Dikika, Ethiopia.” Nature 443 (7109): 332-6. http://dx.doi.org/10.1038/nature05048. Medline:16988711
108. Zachos, Z. C., L. D. Stott, and K. C. Lohmann. 1994. “Evolution of Early Cenozoic Marine Temperatures.” Paleoceanography 9 (2): 353-87. http://dx.doi.org/10.1029/93PA03266.
109. Zazzo, A., H. Bocherens, M. Brunet, A. Beauvilain, D. Billiou, H. T. Mackaye, P. Vignaud, and A. Mariotti. 2000. “Herbivore Paleodiet and Paleoenvironmental Changes in Chad during the Pliocene Using Stable Isotope Ratios of Tooth Enamel Carbonate.” Paleobiol 26 (2): 294-309. http://dx.doi.org/10.1666/0094-8373(2000)026<0294:HPAPCI>2.0.CO;2.