The fluvial geochemistry and denudation rate of the Guayana Shield in Venezuela, Colombia, and Brazil

Andreae, 1990, Precipitation chemistry in central Amazonia, J. Geophys. Res., 95, 16,987, 10.1029/JD095iD10p16987

Berner, 1994, GEOCARB II: a revised model of atmospheric CO2 over Phanerozoic time, Amer. J. Sci., 294, 56, 10.2475/ajs.294.1.56

Berner, 1987

Berner, 1983, The carbonatesilicate cycle and its effect on atmospheric carbon dioxide over the past 100 million years, Amer. J. Sci., 283, 641, 10.2475/ajs.283.7.641

Bricen˜o, 1990, Geomorphology of the Gran Sabana, Guayana Shield, southeastern Venezuela, Geomorphol., 3, 125, 10.1016/0169-555X(90)90041-N

Bricen˜o, 1991, Table-mountain geology and surficial geochemistry: Chimanta Massif, Venezuelan Guayana Shield, J. South Amer. Earth Sci., 3, 179, 10.1016/0895-9811(90)90002-I

Brown, 1992, Beryllium isotope geochemistry in tropical river basins, Geochim. Cosmochim. Acta, 56, 1607, 10.1016/0016-7037(92)90228-B

Brown, 1992, Determination of the denudation of Mount Roraima, Venezuela using cosmogenic 10Be and 26Al, EOS, 73, 170

Brown, 1994, The development of iron crust lateritic systems in Burkina Faso, West Africa examined with in-situproduced cosmogenic nuclides, Earth Planet. Sci. Lett., 124, 19, 10.1016/0012-821X(94)00087-5

Chalcraft, 1984, Humid tropical weathering of quartzite in southeastern Venezuela, Z. Geomorph., 28, 321, 10.1127/zfg/28/1984/321

Clapperton, 1993, Nature of environmental changes in South America at the last glacial maximum, Paleogeog. Paleoclim. Paleoecol., 101, 189, 10.1016/0031-0182(93)90012-8

Clapperton, 1993

Colodner, 1993, The geochemical cycle of rhenium: A reconnaissance, Earth Planet. Sci. Lett., 117, 205, 10.1016/0012-821X(93)90127-U

Crowley, 1983, The geologic record of climate changes, Rev. Geophys. Space Phys., 21, 828, 10.1029/RG021i004p00828

Dougan, 1977, The Imataca Complex near Cerro Bolivar, Venezuela: A calc-alkaline Archean protolith, PreCamb. Res., 4, 237, 10.1016/0301-9268(77)90016-X

Edmond, 1970, High precision determination of titration alkalinity and total carbon dioxide content of sea water by potentiometric titration, Deep-Sea Res., 17, 737

Edmond, 1992, Himalayan tectonics, weathering processes and the strontium isotope record in marine limestones, Science, 258, 1594, 10.1126/science.258.5088.1594

England, 1980, Some consequences of the subduction of young slabs, Earth Planet. Sci. Lett., 47, 403, 10.1016/0012-821X(80)90028-X

Foster, 1993, Episodic denudation in East Africa: A legacy of intracontinental tectonism, Geophys. Res. Lett., 20, 2395, 10.1029/93GL02814

France-Lanord, 1993, Evolution of the Himalaya since Miocene time: Isotopic and sedimentologic evidence from the Bengal Fan

Gac, 1980, Géochimie du bassin du Lac Tchad. Bilan de (l'altération, de (érosion et de la sedimentation, Travaux et Documents OSTROM, 123, 1

Galloway, 1982, The composition of precipitation in remote areas of the world, J. Geophvs. Res., 87, 8771, 10.1029/JC087iC11p08771

Garrels, 1971

Gaudette, 1985, Geochronology of the basement rocks, Amazonas Territory, Venezuela and the tectonic evolution of the western Guayana Shield, Geol. Mijnb., 64, 131

Gaudette, 1978, Geology and age of the Parguaza rapakivi granite, Venezuela, GSA Bull., 89, 1335, 10.1130/0016-7606(1978)89<1335:GAAOTP>2.0.CO;2

Gibbs, 1983, The Guayana Shield reviewed, Episodes, 7, 10.18814/epiiugs/1983/v6i2/003

Gibbs, 1993, The Geologv of the Guiana Shield; Oxford Monog, Geol. Geophys. No. 22

Gibbs, 1982, Zircon U-Pb ages of Guayana greenstone-gneiss terrane, PreCamb. Res., 17, 199, 10.1016/0301-9268(82)90024-9

Gibbs, 1986, The Archean-Proterozoic transition: evidence from the geochemistry of metasedimentary rocks of Guayana and Montana, Geochim. Cosmochim. Acta, 50, 2125, 10.1016/0016-7037(86)90067-0

Gilbert, 1917, Hydraulic-mining debris in the Sierra Nevada, USGS Prof. Paper L05

Gong, 1987, Environmental effects of human activities on rivers in the Huanghe-Huaihe-Haihe plain, China, Geograf. Annal., 69, 181, 10.2307/521376

Gruau, 1985, RbSr and SmNd geochronology of Lower Proterozoic granite-greenstone terranes in French Guayana, South America, PreCamb. Res., 30, 63, 10.1016/0301-9268(85)90029-4

Harrison, 1992, Raising Tibet, Science, 255, 1663, 10.1126/science.255.5052.1663

Hoffman, 1993, Orographic precipitation. erosional unloading and tectonic style, Geology, 21, 195, 10.1130/0091-7613(1993)021<0195:OPEUAT>2.3.CO;2

Holland, 1978

Hu, 1982, Major ion chemistry of some large Chinese rivers, Nature, 298, 550, 10.1038/298550a0

Johnsson, 1990, Overlooked sedimentary particles from tropical weathering environments, Geology, 18, 107, 10.1130/0091-7613(1990)018<0107:OSPFTW>2.3.CO;2

Johnsson, 1988, First-cycle quartz arenites in the Orinoco River basin, Venezuela and Colombia, J. Geol., 96, 263, 10.1086/629219

Kalliokoski, 1965, Geology of the north-central Guayana Shield, GSA Bull., 76, 1027, 10.1130/0016-7606(1965)76[1027:GONGSV]2.0.CO;2

King, 1962

Klinkhammer, 1990, Determination of barium in marine waters by isotope dilution inductively coupled plasma mass spectrometry, Anal. Chim. Acta, 232, 323, 10.1016/S0003-2670(00)81249-0

Lasaga, 1980, The kinetic treatment of geochemical cycles, Geochim. Cosmochim. Acta, 44, 815, 10.1016/0016-7037(80)90263-X

Lee, 1986, Bismuth in the Atlantic and North Pacific: A natural analogue for plutonium and lead?, Earth Planet. Sci. Lett., 76, 254, 10.1016/0012-821X(86)90077-4

Lewis, 1981, The chemistry and phytoplankton of the Orinoco and Caroni rivers, Venezuela, Arch. Hydrobiol., 91, 521

Lewis, 1986, Organic carbon in the Caura River, Venezuela, Limnol. Oceanog., 31, 653, 10.4319/lo.1986.31.3.0653

Lewis, 1987, Major element chemistry, weathering and element yields for the Caura River drainage, Venezuela, Biogeochem., 4, 159, 10.1007/BF02180153

Lichtner, 1988, The quasi-stationary state approximation to coupled mass transport and fluid-rock interaction in a porous medium, Geochim. Cosmochim. Acta, 52, 143, 10.1016/0016-7037(88)90063-4

Lopez, 1975, Study of the weathering of basic, intermediate and acidic rocks under humid tropical conditions, Colo. School Mines, Quart., 40, 209

Mackay, 1993, Air temperature, snow cover, creep of frozen ground, and the time of ice-wedge cracking, western Arctic coast, Can. J. Earth Sci., 30, 1720, 10.1139/e93-151

McKee, 1989, The Waters and Sediments of the Rio Orinoco and its Major Tributaries, Venezuela and Colombia, Chapter B, Sedimentary structures and textures of Rio Orinoco channel sands, Venezuela and Colombia, USGS Water-Supply Paper, 2326B, B1

Meade, 1969, Errors in using modern stream-load data to estimate natural rates of denudation, GSA Bull., 80, 1265, 10.1130/0016-7606(1969)80[1265:EIUMSD]2.0.CO;2

Meade, 1988, Movement and storage of sediment in river systems, 165

Meade, 1994, Suspended sediments of the modern Amazon and Orinoco rivers, Quat. Intl., 10.1016/1040-6182(94)90019-1

Meade, 1990, Suspended-sediment budget for the Orinoco River, 55

Meade, 1990, Movement and storage of sediment in rivers of the United States and Canada, Vol. O-1, 255

Measures, 1983, The geochemical cycle of 9Be: A reconnaissance, Earth Planet. Sci. Lett., 66, 101, 10.1016/0012-821X(83)90129-2

Menard, 1961, Some rates of regional erosion, J. Geol., 69, 154, 10.1086/626726

Meybeck, 1979, Concentrations des eaux fluviales en elements majeurs et apports en solution aux oceans, Rev. Geol. Dyn. Geog. Phys., 21, 215

Meybeck, 1987, Global chemical weathering from surficial rocks estimated from river dissolved loads, Amer. J. Sci., 287, 401, 10.2475/ajs.287.5.401

Meyer, 1993, Diamonds and their sources in the Venezuelan portion of the Guyana Shield, Econ. Geol., 88, 989, 10.2113/gsecongeo.88.5.989

Milliman, 1983, World-wide delivery of river sediment to the oceans, J. Geol., 91, 1, 10.1086/628741

Molnar, 1988, A review of the geophysical constraints on the deep structure of the Tibetan Plateau, the Himalaya and the Karakoram, and their tectonic implications, Phil. Trans. Roy. Soc. London, A326, 33, 10.1098/rsta.1988.0080

Molnar, 1978, Interarc spreading and Cordilleran tectonics as alternates related to the age of subducted oceanic lithosphere, Earth Planet. Sci. Lett., 41, 330, 10.1016/0012-821X(78)90187-5

Molnar, 1990, Late Cenozoic uplift of mountain ranges and global climate change: chicken or egg?, Nature, 346, 29, 10.1038/346029a0

Montes, 1985, pH of bulk precipitation during 3 consecutive annual courses in the Trachypogon savannas of the Orinoco Llanos, Venezuela, Tellus, 37B, 304, 10.1111/j.1600-0889.1985.tb00078.x

Montgomery, 1979, Uranium-lead geochronology of the Archean Imataca Series, Venezuelan Guayana Shield, Contrib. Mineral. Petrol., 69, 167, 10.1007/BF00371859

Montgomery, 1978, Total-rock U-Pb and Rb-Sr systematics in the Imataca Series, Guayana Shield, Venezuela, Earth Planet. Sci. Lett., 39, 281, 10.1016/0012-821X(78)90204-2

Murnane, 1990, Germanium and silicon in rivers of the Orinoco drainage basin, Nature, 344, 749, 10.1038/344749a0

Négrel, 1993, Erosion sources determined by inversion of major and trace element ratios and strontium isotope ratios in river water; the Congo Basin case, Earth Planet. Sci. Lett., 120, 59, 10.1016/0012-821X(93)90023-3

Newton, 1987, The relationship between surface water chemistry and geology in the North Branch of the Moose River, Biogeochem., 3, 21, 10.1007/BF02185183

Nixon, 1992, Venezuela kimberlites, J. Volcanol. Geotherm. Res., 50, 101, 10.1016/0377-0273(92)90039-G

Nordin, 1985, The sediment load of rivers, Vol. 2, 183

Nordin, 1980, The flux of organic carbon to the oceans; some hydrological considerations, 173

Nordin, 1989, The Waters and Sediments of the Rio Orinoco and its Major Tributaries, Venezuela and Colombia, Chap. A Sand waves, bars and wind-blown sands of the Rio Orinoco, Venezuela and Colombia, USGS Water-Supply Paper 2326A, A 1-A74

Onstott, 1989, 40Ar/39Ar thermochronometry of the Imataca complex, Venezuela, PreCamb. Res., 42, 255, 10.1016/0301-9268(89)90014-4

Palmer, 1989, The strontium isotope budget of the modern ocean, Earth Planet. Sci. Lett., 92, 11, 10.1016/0012-821X(89)90017-4

Palmer, 1992, Controls over the strontium isotopic composition of river water, Geochim. Cosmochim. Acto, 56, 2099, 10.1016/0016-7037(92)90332-D

Palmer, 1993, Uranium in river water, Geochim. Cosmochim. Acta, 57, 4947, 10.1016/0016-7037(93)90131-F

Priem, 1971, Isotopic ages of the TransAmazonian acidic magmatism and the Nickerie Metamorphic Episode in the Precambrian basement of Suriname, South America, GSA Bull., 82, 1667, 10.1130/0016-7606(1971)82[1667:IAOTTA]2.0.CO;2

Priem, 1973, Age of the Precambrian Roraima Formation in northeastern South America: Evidence from isotopic dating of Roraima pyroclastic volcanic rocks in Suriname, GSA Bull., 84, 1677, 10.1130/0016-7606(1973)84<1677:AOTPRF>2.0.CO;2

Priem, 1982, Geochronology of the Precambrian in the Amazonas region of southeastern Colombia (Western Guayana Shield), Geol. Mijnb., 61, 229

Raymo, 1992, Tectonic forcing of late Cenozoic climate, Nature, 359, 117, 10.1038/359117a0

Reeder, 1972, Hydrochemistry of the surface waters of the Mackenzie River drainage basin, Canada, 1, Factors controlling the inorganic composition, Geochim. Cosmochim. Acta, 36, 825, 10.1016/0016-7037(72)90053-1

Reid, 1975, Stratigraphy of the diamondbearing Roraima Group, Estado Bolivar, Venezuela, Colo. School Mines, Quart., 70, 61

Richter, 1992, Sr isotopic evolution of seawater: The role of tectonics, Earth Planet. Sci. Lett., 109, 11, 10.1016/0012-821X(92)90070-C

Rogers, 1984, Early poststabilisation sedimentation and later growth of shields, Geol., 12, 607, 10.1130/0091-7613(1984)12<607:EPSALG>2.0.CO;2

Ruddiman, 1989, Forcing of late Cenozoic Northern Hemisphere climate by plateau uplift in Southern Asia and the American West, J. Geophys. Res., 94, 18,409, 10.1029/JD094iD15p18409

Sarin, 1989, Major ion chemistry of the Ganga-Brahmaputra river system: Weathering processes and fluxes to the Bay of Bengal, Geochim. Cosmochim. Acta, 53, 997, 10.1016/0016-7037(89)90205-6

Saunders, 1983, Rates of surface processes on slopes, slope retreat and denudation, 8, 473

Savage, 1991, Petrology of modern sands of the Rios Guaviare and Inirida, Southern Colombia: tropical climate and sand composition, J. Geol., 99, 289, 10.1086/629489

Schorin, 1987, Geochemistry of a ferruginous bauxite from southeast Venezuela, Chem. Geol., 64, 127, 10.1016/0009-2541(87)90158-6

Schumm, 1963, The Disparity between Present Rates of Denudation and Orogeny; USGS Prof. Paper 454-H.

Shoemaker, 1990, Ages of Australian meteorite craters-a preliminary report, Meteoritics, 25, 409

Sidder, 1990, Mineral Occurrences of the Guiana Shield, Venezuela; USGS, Open-File Report 90-16

Sidder, 1990, Geology, Geochemistry and Mineral Resources of the Upper Caura River Area, Bolivar State, Venezuela; USGS Open-File Report 90-231

Sidder, 1991, Geology of the Venezuelan Guayana Shield and its Relation to the Entire Guayana Shield; USGS Open-File Rept. 91-141

Snelling, 1969, The geochronology of Guayana, Geol. Mijnb., 48, 201

Stallard, 1980, Major Element Chemistry of the Amazon River System

Stallard, 1987, Cross-channel mixing and its effect on sedimentation in the Orinoco river, Water Resour. Res., 23, 1977, 10.1029/WR023i010p01977

Stallard, 1981, Geochemistry of the Amazon I. Precipitation chemistry and the marine contribution to the dissolved load at the time of peak discharge, J. Geophys. Res., 86, 9844, 10.1029/JC086iC10p09844

Stallard, 1983, Geochemistry of the Amazon 2. The influence of geology and weathering environment on the dissolved load, J. Geophys. Res., 89, 9671, 10.1029/JC088iC14p09671

Stallard, 1987, Geochemistry of the Amazon 3. Weathering chemistry and limits to dissolved inputs, J. Geophys. Res., 92, 8293, 10.1029/JC092iC08p08293

Tan, 1993, Carbon isotope geochemistry of the Orinoco Basin, Estuar. Coast. Shelf Sci., 36, 541, 10.1006/ecss.1993.1033

Trimble, 1977, The fallacy of stream equilibrium in contemporary denudation studies, Amer. J. Sci., 277, 876, 10.2475/ajs.277.7.876

Twidale, 1982

Twidale, 1990, The origin and implications of some erosional landforms, J. Geol., 98, 343, 10.1086/629409

Twidale, 1993, Remnants of Gondwana in the Australian landscape, 573

USGS, 1993, Geology and Mineral Resource Assessment of the Venezuelan Guayana Shield, USGS Bull. 2062

Vegas-Vilarrubia, 1988, A physicochemical survey of blackwater rivers from the Orinoco and Amazon basins in Venezuela, Archiv fur Hydrobiol., 111, 491, 10.1127/archiv-hydrobiol/111/1988/491

Walker, 1981, A negative feedback mechanism for the long-term stabilization of Earth's surface temperature, J. Geophys. Res., 86, 9776, 10.1029/JC086iC10p09776

Wedepohl, 1969, Composition and abundance of common igneous rocks, Vol 1, 227

Weibezahn, 1985

Weibezahn, 1990, Hidroquiímica y sólidos suspendidos en el alto y medio Orinoco, 151

Yee, 1987, Selenium in the tributaries of the Orinoco in Venezuela, Nature, 326, 686, 10.1038/326686a0

Young, 1983, The tempo of geomorphological change: Evidence from southeastern Australia, J. Geol., 91, 221, 10.1086/628758