Beryllium-10

Records of cosmogenic radionuclides 10Be, 26Al and 36Cl in corals: First studies on coral erosion rates and potential of dating very old corals

Lal, D., CD Gallup, BLK Somayajulu, L. Vacher, MW Caffee, AJT Jull, RC Finkel, RC Speed, and A. Winters. 2005. Records of cosmogenic radionuclides be-10, al-26 and cl-36 in corals: First studies on coral erosion rates and potential of dating very old corals. Geochimica Et Cosmochimica Acta 69 (24) (DEC 15): 5717-28.

Abstract: 
We present results of measurements of cosmogenic 10Be, 26Al and 36Cl, and the indigenous (intrinsic) concentrations of the stable elements Be, Al and Cl in 120–200 kyr old corals from Barbados and Puerto Rico. The concentration levels of these radionuclides in the corals lie in the range 104 to 108 atoms/g. A comparison of the measured nuclide concentrations with those expected to be produced in the corals by nuclear interactions of energetic cosmic radiation shows that (i) the radionuclides 26Al and 36Cl are derived from in situ cosmic ray interactions in the corals after their formation, but that (ii) the radionuclide 10Be owes its provenance in the coralline lattice primarily due to incorporation of dissolved beryllium in seawater in the lattice structure of the corals.

Determination of predevelopment denudation rates of an agricultural watershed (Cayagua´s River, Puerto Rico) using in-situ-produced 10Be in river-borne quartz

Brown, E. T., R. F. Stallard, M. C. Larsen, D. L. Bourlès, G. M. Raisbeck, and F. Yiou. 1998. Determination of predevelopment denudation rates of an agricultural watershed (cayaguas river, puerto rico) using in-situ-produced 10Be in river-borne quartz. Earth and Planetary Science Letters 160 (3-4): 723-8.

Abstract: 
Accurate estimates of watershed denudation absent anthropogenic effects are required to develop strategies for mitigating accelerated physical erosion resulting from human activities, to model global geochemical cycles, and to examine interactions among climate, weathering, and uplift. We present a simple approach to estimate predevelopment denudation rates using in-situ-produced cosmogenic 10Be in fluvial sediments. Denudation processes in an agricultural watershed (Cayagua´s River Basin, Puerto Rico) and a matched undisturbed watershed (Icacos River Basin) were compared using 10Be concentrations in quartz for various size fractions of bed material. The coarse fractions in both watersheds bear the imprint of long subsurface residence times. Fine material from old shallow soils contributes little, however, to the present-day sediment output of the Cayagua´s. This confirms the recent and presumably anthropogenic origin of the modern high denudation rate in the Cayagua´s Basin and suggests that pre-agricultural erosional conditions were comparable to those of the present-day Icacos.

Denudation rates determined from the accumulation of in situ-produced loBe in the Luquillo Experimental Forest, Puerto Rico

Brown, E. T., R. F. Stallard, M. C. Larsen, G. M. Raisbeck, and F. Yiou. 1995. Denudation rates determined from the accumulation of in situ-produced 10Be in the luquillo experimental forest, puerto rico. Earth and Planetary Science Letters 129 (1-4): 193-202.

Abstract: 
We present a simple method for estimation of long-term mean denudation rates using in situ-produced cosmogenic 10Be in fluvial sediments. Procedures are discussed to account for the effects of soil bioturbation, mass wasting and attenuation of cosmic rays by biomass and by local topography. Our analyses of 10Be in quartz from bedrock outcrops, soils, mass-wasting sites and riverine sediment from the Icacos River basin in the Luquillo Experimental Forest, Puerto Rico, are used to characterize denudation for major landform elements in that basin. The 10Be concentration of a discharge-weighted average of size classes of river sediment corresponds to a long-term average denudation of = 43 m Ma^-1, consistent with mass balance results.

Denudation rates determined from the accumulation of in situ-produced 10Be in the luquillo experimental forest, Puerto Rico

Brown, E.T., Stallard, R.F., Larsen, M.C., Raisbeck, G.M., Yiou,
F., 1995b. Denudation rates determined from the accumulation of in
situ-produced Be in the Luquillo Experimental Forest, Puerto
Rico. Earthand Planetary Science Letters 129, 193}202.

Abstract: 
We present a simple method for estimation of long-term mean denudation rates using in situ-produced cosmogenic 10Be in fluvial sediments. Procedures are discussed to account for the effects of soil bioturbation, mass wasting and attenuation of cosmic rays by biomass and by local topography. Our analyses of 10Be in quartz from bedrock outcrops, soils, mass-wasting sites and riverine sediment from the Icacos River basin in the Luquillo Experimental Forest, Puerto Rico, are used to characterize denudation for major landform elements in that basin. The 10Be concentration of a discharge-weighted average of size classes of river sediment corresponds to a long-term average denudation of ≈ 43 m Ma−1, consistent with mass balance results.

Determination of predevelopment denudation rates of an agricultural watershed (Cayaguás River, Puerto Rico) using in-situ-produced 10Be in river-borne quartz

Brown, E.T., Stallard, R.F., Larsen, M.C., Bourles, D.L., Raisbeck,
G.M., Yiou, F., 1998b. Determination fo predevelopment denudation
rates of an agricultural watershed (Cayaguas River, Puerto
Rico) using in-situ-produced Be in river-borne quartz. Earthand
Planetary Science Letters 160 (3-4), 723}728.

Abstract: 
Accurate estimates of watershed denudation absent anthropogenic effects are required to develop strategies for mitigating accelerated physical erosion resulting from human activities, to model global geochemical cycles, and to examine interactions among climate, weathering, and uplift. We present a simple approach to estimate predevelopment denudation rates using in-situ-produced cosmogenic 10Be in fluvial sediments. Denudation processes in an agricultural watershed (Cayaguás River Basin, Puerto Rico) and a matched undisturbed watershed (Icacos River Basin) were compared using 10Be concentrations in quartz for various size fractions of bed material. The coarse fractions in both watersheds bear the imprint of long subsurface residence times. Fine material from old shallow soils contributes little, however, to the present-day sediment output of the Cayaguás. This confirms the recent and presumably anthropogenic origin of the modern high denudation rate in the Cayaguás Basin and suggests that pre-agricultural erosional conditions were comparable to those of the present-day Icacos.
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