Journal articles: 'Bedrock weathering'

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Shen, Xianda, Chloe Arson, Ken L. Ferrier, Nicole West, and Sheng Dai. "Mineral Weathering and Bedrock Weakening: Modeling Microscale Bedrock Damage Under Biotite Weathering." Journal of Geophysical Research: Earth Surface 124, no. 11 (November 2019): 2623–46. http://dx.doi.org/10.1029/2019jf005068.

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Ott, Richard F., Sean F. Gallen, and Darryl E. Granger. "Cosmogenic nuclide weathering biases: corrections and potential for denudation and weathering rate measurements." Geochronology 4, no. 2 (July 6, 2022): 455–70. http://dx.doi.org/10.5194/gchron-4-455-2022.

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Abstract. Cosmogenic radionuclides (CRNs) are the standard tool to derive centennial-to-millennial timescale denudation rates; however, it has been demonstrated that chemical weathering in some settings can bias CRNs as a proxy for landscape denudation. Currently, studies investigating CRN weathering biases have mostly focused on the largely insoluble target mineral quartz in felsic lithologies. Here, we examine the response of CRN build-up for both soluble and insoluble target minerals under different weathering scenarios. We assume a simple box model in which bedrock is converted to a well-mixed regolith at a constant rate, and denudation occurs by regolith erosion and weathering either in the regolith or along the regolith–bedrock interface, as is common in carbonate bedrock. We show that weathering along the regolith–bedrock interface increases CRN concentrations compared to a no-weathering case and how independently derived weathering rates or degrees can be used to correct for this bias. If weathering is concentrated within the regolith, insoluble target minerals will have a longer regolith residence time and higher nuclide concentration than soluble target minerals. This bias can be identified and corrected using paired-nuclide measurements of minerals with different solubility coupled with knowledge of either the bedrock or regolith mineralogy to derive denudation and long-term weathering rates. Similarly, single-nuclide measurements on soluble or insoluble minerals can be corrected to determine denudation rates if a weathering rate and compositional data are available. Our model highlights that for soluble target minerals, the relationship between nuclide accumulation and denudation is not monotonic. We use this understanding to map the conditions of regolith mass, weathering, and denudation rates at which weathering corrections for cosmogenic nuclides become large and ambiguous, as well as identify environments in which the bias is mostly negligible and CRN concentrations reliably reflect landscape denudation. We highlight how measurements of CRNs from soluble target minerals, coupled with bedrock and regolith mineralogy, can help to expand the range of landscapes for which centennial-to-millennial timescale denudation and weathering rates can be obtained.

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Worthington, Stephen R. H., Gareth J. Davies, and E. Calvin Alexander. "Enhancement of bedrock permeability by weathering." Earth-Science Reviews 160 (September 2016): 188–202. http://dx.doi.org/10.1016/j.earscirev.2016.07.002.

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Grocholski, B. "Bedrock weathering runs to the hills." Science 350, no. 6260 (October 29, 2015): 524. http://dx.doi.org/10.1126/science.350.6260.524-c.

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Shen, CD, J. Beer, S. Ivy-Ochs, Y. Sun, W. Yi, P. W. Kubik, M. Suter, Z. Li, S. Peng, and Y. Yang. "10Be, 14C Distribution, and Soil Production Rate in a Soil Profile of a Grassland Slope at Heshan Hilly Land, Guangdong." Radiocarbon 46, no. 1 (2004): 445–54. http://dx.doi.org/10.1017/s0033822200039758.

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Concentrations of organic carbon, carbon isotopes (13C and 14C), atmospheric 10Be in soil, and in situ 10Be in bedrock and weathering rock were determined in a study of a profile of a grassland slope at the Heshan Hilly Land Interdisciplinary Experimental Station, Chinese Academy of Sciences, in Guangdong Province, China. A good linear relationship between depth and the 14C apparent age of the organic carbon demonstrates that the rock weathering process and the accumulation process of organic matter in the slope are relatively stable. Both 14C and 10Be results show that about 34% of soil in the grassland slope has been eroded during the past 3800 yr. The 10Be results for interstitial soil from weathered rocks show that the 90-cm-thick weathering rock layer above the bedrock has evolved over a period of 1.36 Myr. The concentrations of in situ 10Be in the weathered rock and bedrock are 10.7 × 104 atoms/g and 8.31 × 104 atoms/g, respectively. The weathering rate of the bedrock, equivalent to the soil production rate, was estimated at 8.8 × 10-4 cm/yr, and the exposure ages of the weathered rock and the bedrock were 72 kyr and 230 kyr, respectively.

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Riebe, Clifford S., Russell P. Callahan, Sarah B. M. Granke, Bradley J. Carr, Jorden L. Hayes, Marlie S. Schell, and Leonard S. Sklar. "Anisovolumetric weathering in granitic saprolite controlled by climate and erosion rate." Geology 49, no. 5 (January 12, 2021): 551–55. http://dx.doi.org/10.1130/g48191.1.

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Abstract Erosion at Earth’s surface exposes underlying bedrock to climate-driven chemical and physical weathering, transforming it into a porous, ecosystem-sustaining substrate consisting of weathered bedrock, saprolite, and soil. Weathering in saprolite is typically quantified from bulk geochemistry assuming physical strain is negligible. However, modeling and measurements suggest that strain in saprolite may be common, and therefore anisovolumetric weathering may be widespread. To explore this possibility, we quantified the fraction of porosity produced by physical weathering, FPP, at three sites with differing climates in granitic bedrock of the Sierra Nevada, California, USA. We found that strain produces more porosity than chemical mass loss at each site, indicative of strongly anisovolumetric weathering. To expand the scope of our study, we quantified FPP using available volumetric strain and mass loss data from granitic sites spanning a broader range of climates and erosion rates. FPP in each case is ≥0.12, indicative of widespread anisovolumetric weathering. Multiple regression shows that differences in precipitation and erosion rate explain 94% of the variance in FPP and that >98% of Earth’s land surface has conditions that promote anisovolumetric weathering in granitic saprolite. Our work indicates that anisovolumetric weathering is the norm, rather than the exception, and highlights the importance of climate and erosion as drivers of subsurface physical weathering.

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Murphy, Brendan P., Joel P. L. Johnson, Nicole M. Gasparini, Gregory S. Hancock, and Eric E. Small. "Weathering and abrasion of bedrock streambed topography." Geology 46, no. 5 (March 22, 2018): 459–62. http://dx.doi.org/10.1130/g40186.1.

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Lebedeva, Marina I., and Susan L. Brantley. "Weathering and erosion of fractured bedrock systems." Earth Surface Processes and Landforms 42, no. 13 (July 20, 2017): 2090–108. http://dx.doi.org/10.1002/esp.4177.

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Bédard, Pierre. "Postglacial and pre-last-glacial weathering of till on the high plateaus of central Gaspésie, Quebec, Canada." Canadian Journal of Earth Sciences 30, no. 9 (September 1, 1993): 1853–60. http://dx.doi.org/10.1139/e93-163.

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Geochemical data from mineral exploration surveys are used to assess postglacial and pre-last-glacial weathering on the high plateaus of central Gaspésie by comparing the distribution of 30 elements in the B and C horizons of a thin soil developed on glacial deposits. Under postglacial weathering, Fe2O3, TiO2, P2O5, Cr, Li, U, and V are immobile relative to Al2O3, whereas the other elements are mobile and have been depleted to various degrees from the B horizon. Loss-on-ignition value is the only parameter showing a significant enrichment from the C to the B horizons. The apparently high degree of geochemical weathering of the glacial deposits in respect to their source bedrock lithologies suggests that the deposits also contain previously weathered material. The spatial distribution of the geochemical weathering index values calculated for the C horizon shows no clear relation to the underlying bedrock formations. The high values are located on topographic highs, with maxima over deeply weathered bedrock occurrences, and the low values are located in glacial valleys. The spatial distribution of this weathering index in the glacial deposits shows the geochemical signature of a pre-last-glacial weathered mantle.

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Napieralski, Stephanie A., Heather L. Buss, Susan L. Brantley, Seungyeol Lee, Huifang Xu, and Eric E. Roden. "Microbial chemolithotrophy mediates oxidative weathering of granitic bedrock." Proceedings of the National Academy of Sciences 116, no. 52 (December 16, 2019): 26394–401. http://dx.doi.org/10.1073/pnas.1909970117.

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The flux of solutes from the chemical weathering of the continental crust supplies a steady supply of essential nutrients necessary for the maintenance of Earth’s biosphere. Promotion of weathering by microorganisms is a well-documented phenomenon and is most often attributed to heterotrophic microbial metabolism for the purposes of nutrient acquisition. Here, we demonstrate the role of chemolithotrophic ferrous iron [Fe(II)]-oxidizing bacteria in biogeochemical weathering of subsurface Fe(II)-silicate minerals at the Luquillo Critical Zone Observatory in Puerto Rico. Under chemolithotrophic growth conditions, mineral-derived Fe(II) in the Rio Blanco Quartz Diorite served as the primary energy source for microbial growth. An enrichment in homologs to gene clusters involved in extracellular electron transfer was associated with dramatically accelerated rates of mineral oxidation and adenosine triphosphate generation relative to sterile diorite suspensions. Transmission electron microscopy and energy-dispersive spectroscopy revealed the accumulation of nanoparticulate Fe–oxyhydroxides on mineral surfaces only under biotic conditions. Microbially oxidized quartz diorite showed greater susceptibility to proton-promoted dissolution, which has important implications for weathering reactions in situ. Collectively, our results suggest that chemolithotrophic Fe(II)-oxidizing bacteria are likely contributors in the transformation of rock to regolith.

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Verdian, Joseph P., Leonard S. Sklar, Clifford S. Riebe, and Jeffrey R. Moore. "Sediment size on talus slopes correlates with fracture spacing on bedrock cliffs: implications for predicting initial sediment size distributions on hillslopes." Earth Surface Dynamics 9, no. 4 (August 27, 2021): 1073–90. http://dx.doi.org/10.5194/esurf-9-1073-2021.

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Abstract. The detachment of rock fragments from fractured bedrock on hillslopes creates sediment with an initial size distribution that sets the upper limits on particle size for all subsequent stages in the evolution of sediment in landscapes. We hypothesize that the initial size distribution should depend on the size distribution of latent sediment (i.e., fracture-bound blocks in unweathered bedrock) and weathering of blocks both before and during detachment (e.g., disintegration along crystal grain boundaries). However, the initial size distribution is difficult to measure because the interface across which sediment is produced is often shielded from view by overlying soil. Here we overcome this limitation by comparing fracture spacings measured from exposed bedrock on cliff faces with particle size distributions in adjacent talus deposits at 15 talus–cliff pairs spanning a wide range of climates and lithologies in California. Median fracture spacing and particle size vary by more than 10-fold and correlate strongly with lithology. Fracture spacing and talus size distributions are also closely correlated in central tendency, spread, and shape, with b-axis diameters showing the closest correspondence with fracture spacing at most sites. This suggests that weathering has not modified latent sediment either before or during detachment from the cliff face. In addition, talus at our sites has not undergone much weathering after deposition and is slightly coarser than the latent sizes because it contains unexploited fractures inherited from bedrock. We introduce a new conceptual framework for understanding the relative importance of latent size and weathering in setting initial sediment size distributions in mountain landscapes. In this framework, hillslopes exist on a spectrum defined by the ratio of two characteristic timescales: the residence time in saprolite and weathered bedrock and the time required to detach a particle of a characteristic size. At one end of the spectrum, where weathering residence times are negligible, the latent size distribution can be used to predict the initial size distribution. At the other end of the spectrum, where weathering residence times are long, the latent size distribution can be erased by weathering in the critical zone.

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Patterson, C. J., and T. J. Boerboom. "The significance of pre-existing, deeply weathered crystalline rock in interpreting the effects of glaciation in the Minnesota River valley, U.S.A." Annals of Glaciology 28 (1999): 53–58. http://dx.doi.org/10.3189/172756499781821995.

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AbstractMinnesota is largely underlain by Precambrian crystalline bedrock that was weathered to an average depth of 30 m prior to Late Cretaceous time. The fresh-rock— weathered-rock interface is irregular, with as much as 45 m of relief. Weathering exploited joints, locally isolating meter-sized volumes of rock known as corestones. Variable amounts of residuum were removed through glaciation to leave (1) saprolite overlain by an in-situ Late Cretaceous soil profile; (2) partially eroded saprolite; and (3) undulating fresh rock surfaces (commonly mantled by rounded boulders) that display striae and glacial or fluvial polish.Significant subglacial erosion of fresh bedrock is not required to form smoothly undulating bedrock surfaces with closed depressions; they may also form through removal of weathered bedrock and exposure of the weathering front. Large rounded boulders are not always shaped during transport; they may represent chemically rounded corestones resting at or near the bedrock source.Unambiguous evidence for glacial erosion includes striae and streamlining of bedrock parallel to striae. Polish on rock can be created fluvially, and smoothed grooves and ridges in the rock may be chemically produced. Many rounded boulders found in glacial till and strewn on bedrock surfaces probably originated as corestones.

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Andersen, Jane Lund, Annina Margreth, Ola Fredin, Henriette Linge, Bradley W. Goodfellow, Johan C. Faust, Jochen Knies, et al. "Rapid post-glacial bedrock weathering in coastal Norway." Geomorphology 397 (January 2022): 108003. http://dx.doi.org/10.1016/j.geomorph.2021.108003.

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SUMNER, Tamaki, Takuya INOUE, Yoshiya HITOMI, and Yasuyuki SHIMIZU. "MODELING OF BEDROCK EROSION CONSIDERING WET-DRY WEATHERING." Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering) 74, no. 4 (2018): I_1045—I_1050. http://dx.doi.org/10.2208/jscejhe.74.i_1045.

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Dorn, Ronald I. "Necrogeomorphology and the life expectancy of desert bedrock landforms." Progress in Physical Geography: Earth and Environment 42, no. 5 (September 5, 2018): 566–87. http://dx.doi.org/10.1177/0309133318795839.

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This paper presents the first estimates for the life expectancy of the very surface of bedrock desert landforms, such as bornhardts, cliff faces, fault scarp, inselbergs, ridge crests, and slickrock. The correlative dating method of varnish microlaminations yields minimum ages for the timing of the last spalling event caused by the physical weathering process of dirt cracking. Minimum percentage of a bedrock surface spalled per thousand years is a metric that can be estimated using multiple varnish lamination ages. Understanding rates of surface spalling provides a quantitative measure of Gilbert’s (1877: 105) weathering-limited ‘rate of disintegration’, because this metric directly links to the rock disintegration process of dirt cracking. Rates of percent surface spalled then translate into estimates of how long it takes for the very surface of a desert bedrock landform to die. For a variety of example landforms in the southwestern USA, the maximum time required to completely resurface a desert bedrock landform by spalling from dirt cracking ranges from 89 to 600 ka.

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Francis, Oliver R., Tristram C. Hales, Daniel E. J. Hobley, Xuanmei Fan, Alexander J. Horton, Gianvito Scaringi, and Runqiu Huang. "The impact of earthquakes on orogen-scale exhumation." Earth Surface Dynamics 8, no. 3 (July 8, 2020): 579–93. http://dx.doi.org/10.5194/esurf-8-579-2020.

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Abstract. Individual, large thrusting earthquakes can cause hundreds to thousands of years of exhumation in a geologically instantaneous moment through landslide generation. The bedrock landslides generated are important weathering agents through the conversion of bedrock into mobile regolith. Despite this, orogen-scale records of surface uplift and exhumation, whether sedimentary or geochemical, contain little to no evidence of individual large earthquakes. We examine how earthquakes and landslides influence exhumation and surface uplift rates with a zero-dimensional numerical model, supported by observations from the 2008 Mw 7.9 Wenchuan earthquake. We also simulate the concentration of cosmogenic radionuclides within the model domain, so we can examine the timescales over which earthquake-driven changes in exhumation can be measured. Our model uses empirically constrained relationships between seismic energy release, weathering, and landsliding volumes to show that large earthquakes generate the most surface uplift, despite causing lowering of the bedrock surface. Our model suggests that when earthquakes are the dominant rock uplift process in an orogen, rapid surface uplift can occur when regolith, which limits bedrock weathering, is preserved on the mountain range. After a large earthquake, there is a lowering in concentrations of 10Be in regolith leaving the orogen, but the concentrations return to the long-term average within 103 years. The timescale of the seismically induced cosmogenic nuclide concentration signal is shorter than the averaging time of most thermochronometers (>103 years). However, our model suggests that the short-term stochastic feedbacks between weathering and exhumation produce measurable increases in cosmogenically measured exhumation rates which can be linked to earthquakes.

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Brown, G. H., M. Sharp, and M. Tranter. "Subglacial chemical erosion: seasonal variations in solute provenance, Haut Glacier D’Arolla, Valais, Switzerland." Annals of Glaciology 22 (1996): 25–31. http://dx.doi.org/10.3189/1996aog22-1-25-31.

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This paper determines the provenance of solute in bulk meltwaters draining Haut Glacier d’Arolla, Valais, Switzerland, during the 1989 ablation season. Dissolved species are partitioned into components derived from sea salt, acid aerosol, dissolution of atmospheric CO2, and lithogenic sources, namely carbonates, sulphides and aluminosillicates. A major conclusion is that trace geochemically reactive minerals in the bedrock contribute the bulk of the solute found in runoff. Seasonal changes in solute provenance and in the dominant chemical weathering process are observed. Whereas the chemical weathering of aluminosillicate minerals by carbonation reactions remains relatively constant during the ablation season, the chemical erosion of carbonates shows distinct seasonal variations, reflecting changes in the nature of the subglacial drainage system. Subglacial drainage structure and bedrock type are key controls on the extent of subglacial chemical weathering.

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Brown, G. H., M. Sharp, and M. Tranter. "Subglacial chemical erosion: seasonal variations in solute provenance, Haut Glacier D’Arolla, Valais, Switzerland." Annals of Glaciology 22 (1996): 25–31. http://dx.doi.org/10.1017/s0260305500015172.

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This paper determines the provenance of solute in bulk meltwaters draining Haut Glacier d’Arolla, Valais, Switzerland, during the 1989 ablation season. Dissolved species are partitioned into components derived from sea salt, acid aerosol, dissolution of atmospheric CO2, and lithogenic sources, namely carbonates, sulphides and aluminosillicates. A major conclusion is that trace geochemically reactive minerals in the bedrock contribute the bulk of the solute found in runoff. Seasonal changes in solute provenance and in the dominant chemical weathering process are observed. Whereas the chemical weathering of aluminosillicate minerals by carbonation reactions remains relatively constant during the ablation season, the chemical erosion of carbonates shows distinct seasonal variations, reflecting changes in the nature of the subglacial drainage system. Subglacial drainage structure and bedrock type are key controls on the extent of subglacial chemical weathering.

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Nunley, J., R. Donahoe, M. Stock, and A. Ward. "Microscopic techniques leading to the discovery of endolithic plant communities in a stream ecosystem." Proceedings, annual meeting, Electron Microscopy Society of America 49 (August 1991): 328–29. http://dx.doi.org/10.1017/s0424820100085940.

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The chemical weathering of rock is generally assumed to occur primarily at the water/rock interface and to be dominated by inorganic mechanisms. A previous study aimed at using microscopic techniques to study the weathering of sandstone bedrock in a stream ecosystem suggested the operation of biotic processes inside these rocks. Examination of rock samples by a variety of microscopic techniques led to the discovery of endolithic plant communities. Endolithic microbial communities are known to exist in hot and cold desert, freshwater, and marine environments, occurring in a variety of bedrock types. However, endolithic organisms have not been previously documented in stream ecosystems.

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St. Clair, J., S. Moon, W. S. Holbrook, J. T. Perron, C. S. Riebe, S. J. Martel, B. Carr, C. Harman, K. Singha, and D. d. Richter. "Geophysical imaging reveals topographic stress control of bedrock weathering." Science 350, no. 6260 (October 29, 2015): 534–38. http://dx.doi.org/10.1126/science.aab2210.

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Liankai, Zhang, Ji Hongbing, Wang Shijie, Luo Gang, Liu Xiuming, Wei Xiao, Nguyen QuocDinh, and Nguyen DaiTrung. "Geochemical Implications of Rare Earth Elements in Terra Rossa in Tropical Karst Area: A Case Study in Northern Vietnam." Applied Sciences 10, no. 3 (January 26, 2020): 858. http://dx.doi.org/10.3390/app10030858.

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Research on weathered crusts on carbonate rock is essential for paleoenvironmental studies in karst areas. Terra rossa, widely distributed in tropical karst areas, has not been studied in terms of its material sources and geochemistry. Two typical terra rossa profiles on dolomite (SC profile located at Sang Cai, Hoa Binh province) and limestone (TG profile located at Tong Gia, Lao Cai province) in Northern Vietnam were selected to examine the geochemical characteristics and the evolutionary processes of rare earth elements (REEs). Chondrite and bedrock normalized patterns indicated that these two profiles are in situ weathering crusts, meaning they are the residual material remaining after chemical weathering of the lower carbonate rocks. The average value of total REE in the SC profile is 381.19 ppm, which is 30 times higher than the bedrock. In the TG profile, the value is 386.26 ppm, 13 times higher than the bedrock. Compared with the profiles in nearby subtropical areas in Southeast China, the REE enrichment coefficients of terra rossa in Northern Vietnam are much higher. The REE depletion was also different between the SC and TG profiles. The light and heavy REE fractionations in the SC profile are higher than in the TG profile. Paleoclimate inversion analysis shows that the SC profile experienced a stable oxidation condition, whereas the TG profile was subjected to several reducing environments since a weathering crust formed.

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Rempe, Daniella M., and William E. Dietrich. "Direct observations of rock moisture, a hidden component of the hydrologic cycle." Proceedings of the National Academy of Sciences 115, no. 11 (February 28, 2018): 2664–69. http://dx.doi.org/10.1073/pnas.1800141115.

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Recent theory and field observations suggest that a systematically varying weathering zone, that can be tens of meters thick, commonly develops in the bedrock underlying hillslopes. Weathering turns otherwise poorly conductive bedrock into a dynamic water storage reservoir. Infiltrating precipitation typically will pass through unsaturated weathered bedrock before reaching groundwater and running off to streams. This invisible and difficult to access unsaturated zone is virtually unexplored compared with the surface soil mantle. We have proposed the term “rock moisture” to describe the exchangeable water stored in the unsaturated zone in weathered bedrock, purposely choosing a term parallel to, but distinct from, soil moisture, because weathered bedrock is a distinctly different material that is distributed across landscapes independently of soil thickness. Here, we report a multiyear intensive campaign of quantifying rock moisture across a hillslope underlain by a thick weathered bedrock zone using repeat neutron probe measurements in a suite of boreholes. Rock moisture storage accumulates in the wet season, reaches a characteristic upper value, and rapidly passes any additional rainfall downward to groundwater. Hence, rock moisture storage mediates the initiation and magnitude of recharge and runoff. In the dry season, rock moisture storage is gradually depleted by trees for transpiration, leading to a common lower value at the end of the dry season. Up to 27% of the annual rainfall is seasonally stored as rock moisture. Significant rock moisture storage is likely common, and yet it is missing from hydrologic and land-surface models used to predict regional and global climate.

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Millot, Romain, Joachim Tremosa, and Philippe Négrel. "Chemical weathering of a granitic watershed: coupling Lithium isotopes and reactive transport modeling, preliminary results." E3S Web of Conferences 98 (2019): 12014. http://dx.doi.org/10.1051/e3sconf/20199812014.

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In the present study, we report lithium concentrations and Li isotopic compositions for different samples within a granitic watershed (Margeride, France). We investigate unweathered bedrock and samples displaying different stages of weathering in order to characterize Li isotopic fractionation. This was achieved by coupling lithium isotope geochemistry and reactive transport modeling during granite weathering at the scale of this watershed. The following manuscript reports methodology and the preliminary data.

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Aghamiri, Rasoul (Reza), and David W. Schwartzman. "Weathering rates of bedrock by lichens: a mini watershed study." Chemical Geology 188, no. 3-4 (September 2002): 249–59. http://dx.doi.org/10.1016/s0009-2541(02)00105-5.

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Muhardi, M., M. Anwar, and K. Kaharudin. "Application of Induced Polarization and Resistivity Methods to Identify Subsurface Layers in Bauxite Deposits Area of Kendawangan, West Kalimantan." Jurnal Pendidikan Fisika Indonesia 18, no. 1 (June 2, 2022): 75–82. http://dx.doi.org/10.15294/jpfi.v18i1.29230.

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Kendawangan Sub-district, Ketapang Regency is one of the areas in West Kalimantan Province containing minerals of economic value, namely bauxite deposits. This study has applied both induced polarization and resistivity methods. It aims to identify subsurface layers in the Kendawangan bauxite deposit area based on resistivity and chargeability distribution. Measurements in the field apply a north-south line using the dipole-dipole configuration, have a length of 144 m, and electrode distance of 3 m. The results showed that the subsurface layer in the study area identified the presence of bauxite deposits. In addition, it showed that the subsurface layers were topsoil, bauxite deposits, saprolite, and bedrock. Topsoil has a thickness of about 1 m, and it is a product of the weathering process. The bauxite deposit has a thickness of about 9 m, and it contains the minerals aluminum oxide, quartz, hematite, and titanium oxide. Saprolite has a thickness of about 2 - 4 m, and it contains aluminum silica (kaolinite) and minerals quartz, titanium oxide, zircon, and it is a weathering product of bedrock. The bedrock is at a depth of more than 10 m, which is interpreted as volcanic tuff, sandstone, and claystone.

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Akingboye, Adedibu Sunny, Isaac Babatunde Osazuwa, and Muraina Zaid Mohammed. "Electrical Resistivity Tomography for Sustainable Groundwater Development in a Complex Geological Area." Materials and Geoenvironment 66, no. 2 (June 1, 2019): 121–28. http://dx.doi.org/10.2478/rmzmag-2019-0004.

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AbstractElectrical resistivity tomography (ERT) was used for delineating significant subsurface hydrogeological features for sustainable groundwater development in Etioro-Akoko area, Southwestern Nigeria. This study was necessitated by challenges posed on groundwater supplies from wells and boreholes in Etioro-Akoko and the neighbouring fast growing towns and villages. Field data were acquired over the area with ABEM Lund Resistivity Imaging System and were subsequently processed and inverted through RES2DINVx64 software. Results showed four distinct subsurface layers: topsoil, weathered layer, fractured bedrock and fresh bedrock (basal unit). Localised bedrock depressions occasioned by fracturing and deep weathering of less stable bedrock minerals were delineated with resistivity and thickness values ranging from 50 to 650 Ωm and 12 to ---gt--- 25 m, respectively. The localised depressions mirrored uneven bedrock topography and served as the preferential groundwater storage and hydrogeological zones in the area. The two hydrogeological zones significant for groundwater development included overburden-dependent aquifers and fractured dependent bedrock aquifers. It was, therefore, concluded that groundwater storage potential was depended on hydrogeological zones particularly at major localised bedrock depressions where fractures and groundwater recharges/discharges were evident. Wells and boreholes were proposed at bedrock depressions with thickness value not less than 12 and ---gt--- 25 m, respectively, for enhanced groundwater sustainability and quality assurance in the area.

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Welivitiya, W. D. Dimuth P., Garry R. Willgoose, Greg R. Hancock, and Sagy Cohen. "Exploring the sensitivity on a soil area-slope-grading relationship to changes in process parameters using a pedogenesis model." Earth Surface Dynamics 4, no. 3 (August 1, 2016): 607–25. http://dx.doi.org/10.5194/esurf-4-607-2016.

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Abstract. This paper generalises the physical dependence of the relationship between contributing area, local slope, and the surface soil grading using a pedogenesis model and allows an exploration of soilscape self-organisation. A parametric study was carried out using different parent materials, erosion, and weathering mechanisms. These simulations confirmed the generality of the area-slope-d50 relationship. The relationship is also true for other statistics of soil grading (e.g. d10,d90) and robust for different depths within the profile. For small area-slope regimes (i.e. hillslopes with small areas and/or slopes) only the smallest particles can be mobilised by erosion and the area-slope-d50 relationship appears to reflect the erosion model and its Shield's Stress threshold. For higher area-slope regimes, total mobilization of the entire soil grading occurs and self-organisation reflects the relative entrainment of different size fractions. Occasionally the interaction between the in-profile weathering and surface erosion draws the bedrock to the surface and forms a bedrock outcrop. The study also shows the influence on different depth-dependent in-profile weathering functions in the formation of the equilibrium soil profile and the grading characteristics of the soil within the profile. We outline the potential of this new model and its ability to numerically explore soil and landscape properties.

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Wan, Jiamin, Tetsu K. Tokunaga, Wendy Brown, Alexander W. Newman, Wenming Dong, Markus Bill, Curtis A. Beutler, et al. "Bedrock weathering contributes to subsurface reactive nitrogen and nitrous oxide emissions." Nature Geoscience 14, no. 4 (April 2021): 217–24. http://dx.doi.org/10.1038/s41561-021-00717-0.

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SUMNER, Tamaki, Takuya INOUE, and Yasuyuki SHIMIZU. "EFFECTS OF WET-DRY WEATHERING IN MEANDERING CHANNELS OF BEDROCK RIVERS." Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering) 77, no. 2 (2021): I_745—I_750. http://dx.doi.org/10.2208/jscejhe.77.2_i_745.

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INOUE, Takuya, Satomi YAMAGUCHI, and Jungo FUNAKI. "BEDROCK EROSION BY SALTATING BEDLOAD WITH WETTING AND DRYING WEATHERING PROCESS." Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering) 71, no. 4 (2015): I_853—I_858. http://dx.doi.org/10.2208/jscejhe.71.i_853.

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31

Emberson, Robert, Niels Hovius, Albert Galy, and Odin Marc. "Chemical weathering in active mountain belts controlled by stochastic bedrock landsliding." Nature Geoscience 9, no. 1 (November 30, 2015): 42–45. http://dx.doi.org/10.1038/ngeo2600.

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Achyuthan, Hema. "Palaeohydrology and Bedrock Weathering in the Arid Tracts of Jaisalmer, Rajasthan." Gondwana Research 4, no. 4 (October 2001): 559. http://dx.doi.org/10.1016/s1342-937x(05)70361-0.

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Gabet, Emmanuel J., Robin Edelman, and Heiko Langner. "Hydrological controls on chemical weathering rates at the soil-bedrock interface." Geology 34, no. 12 (2006): 1065. http://dx.doi.org/10.1130/g23085a.1.

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34

Chan, Marjorie A., W. Adolph Yonkee, Dennis I. Netoff, Winston M. Seiler, and Richard L. Ford. "Polygonal cracks in bedrock on Earth and Mars: Implications for weathering." Icarus 194, no. 1 (March 2008): 65–71. http://dx.doi.org/10.1016/j.icarus.2007.09.026.

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Afifi, Afifa A., O. P. Bricker, and J. C. Chemerys. "Experimental chemical weathering of various bedrock types at different pH-values." Chemical Geology 49, no. 1-3 (June 1985): 87–113. http://dx.doi.org/10.1016/0009-2541(85)90149-4.

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Domínguez-Villar, David, Laura Razola, Rosa M. Carrasco, Carrie E. Jennings, and Javier Pedraza. "Weathering phases recorded by gnammas developed since last glaciation at Serra da Estrela, Portugal." Quaternary Research 72, no. 2 (September 2009): 218–28. http://dx.doi.org/10.1016/j.yqres.2009.05.004.

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AbstractThe morphometrical analysis of gnammas (weathering pits) in granite landscapes has been used to establish the relative chronology of recent erosive surfaces and to provide the weathering history in a region. To test the validity of gnammas as relative chronometer indicators, and the reliability of the obtained weathering record, two sites have been studied in Serra da Estrela, Portugal. The first site is within the limits of the glacier that existed in these mountains during the last glaciation, whereas the second site is located in an unglaciated sector of the mountains, which preserves a longer record of weathering in the bedrock surface. The number of gnamma weathering phases recorded in the latter site (8) is larger than those from the former (6). Correlation between both measurement stations based on morphometrical criteria is excellent for the younger six weathering phases (1 to 6). Consequently, the parameter used for relative chronology (δ-value) has been verified to be age dependent, although absolute values are modulated by microclimate due to altitude variations. The weathering record was essentially duplicated once the surfaces at both sites were exposed, demonstrating the reliability of gnamma evolution as a post-glacial environmental indicator for the region.

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Kuznetsova, Yulia, Valentin Golosov, Anatoly Tsyplenkov, and Nadezhda Ivanova. "Quantifying channel bank erosion of a small mountain river in Russian wet subtropics using erosion pins." Proceedings of the International Association of Hydrological Sciences 381 (August 1, 2019): 79–86. http://dx.doi.org/10.5194/piahs-381-79-2019.

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Abstract. Channel bank erosion was monitored using erosion pin arrays in a small mountain stream located in the Tsanyk River basin near the Caucasian Black sea coast. The study area is characterized by high precipitation, low mountainous topography, and flysch bedrock. Erosion pins arrays were installed at six key sections each with different bank lithology and morphology. Bank lithology (bedrock or alluvial deposits), morphology (vertical or concave) and orientation towards the local flow direction were the dominant factors controlling the rate of bank retreat and/or collapse. In contrast to alluvial banks, bedrock slopes are predominantly affected by chemical weathering processes in a wet subtropical climate. Results on sediment mobilization and volume removed are presented for different bank types. Variability in channel bank recessional dynamics is discussed in the context of hydrometeorological data (2016–2018) and an extreme flood.

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Gao, Cunhai. "Buried bedrock valleys and glacial and subglacial meltwater erosion in southern Ontario, Canada." Canadian Journal of Earth Sciences 48, no. 5 (May 2011): 801–18. http://dx.doi.org/10.1139/e10-104.

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Morphometric features from a recently compiled bedrock topography map by the Ontario Geological Survey suggest a glacial erosion origin for the buried large bedrock valleys and troughs in southern Ontario. The bedrock valleys at Milverton, Wingham and Mount Forest are tunnel valleys, resulting from subglacial meltwater erosion beneath the Huron ice lobe, probably during or shortly after the Late-Wisconsinan glacial maximum. Diagnostic features for this interpretation include abrupt valley beginning and termination, uneven longitudinal valley profiles and up-slope gradients. The Dundas bedrock valley is the western extension of the Lake Ontario Basin. No comparable bedrock valleys were found to connect it to the Milverton valley for a joint drainage system as previously suggested. The Laurentian bedrock trough is the southeastward extension of the Georgian Bay Basin, both developed along shale bedrock between the Precambrian shield highlands and the Niagara Escarpment, resulting from long-term mechanical weathering associated with Pleistocene glacial erosion. This bedrock low has a floor that exceeds 50 km in width and is 26 m and more below the current water level of Georgian Bay. It could drain Georgian Bay should the drift cover be removed. There is no evidence to suggest that a preglacial river channel, if it existed, is still preserved in the floor of the Laurentian trough as previously suggested. The framework for an intensely glacially sculpted bedrock surface differs from the previous view for simple modification of a preglacial landscape and is, therefore, important in regional subsurface geological mapping and groundwater studies.

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Neal, C. "Boron water quality for the Plynlimon catchments." Hydrology and Earth System Sciences 1, no. 3 (September 30, 1997): 619–26. http://dx.doi.org/10.5194/hess-1-619-1997.

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Abstract. Boron concentrations in rainfall, throughfall and stemflow for Spruce stands, mist, streamwater and groundwater are compared with chloride to assess atmospheric sources and catchment input-output balances for the Plynlimon catchments. In rainfall, boron concentration averages about 4.5 μg-B l-1 and approximately two thirds of this comes from anthropogenic sources. In through-fall and stemflow, boron concentrations are approximately a factor of ten times higher than in rainfall. This increase is associated with enhanced scavenging of mist and dry deposition by the trees. As the sampling sites were close to a forest edge, this degree of scavenging is probably far higher than in the centre of the forest. The throughfall and stemflow concentrations of boron show some evidence of periodic variations with time with peak concentrations occurring during the summer months indicating some vegetational cycling. In mist, boron concentrations are almost twenty times higher than in rainfall and anthropogenic sources account for about 86% of this. Within the Plynlimon streams, boron concentrations are about 1.4 to 1.7 times higher than in rainfall. However, after allowance for mist and dry deposition contributions to atmospheric deposition, it seems that, on average, about 30% of the boron input is retained within the catchment. For the forested catchments, felling results in a disruption of the biological cycle and a small increase in boron leaching from the catchment results in the net retention by the catchment being slightly reduced. Despite the net uptake by the catchment, there is clear evidence of a boron component of weathering from the bedrock. This is shown by an increased boron concentration in a stream influenced by a nearby borehole which increased groundwater inputs. The weathering component for boron is also observed in Plynlimon groundwaters as boron concentrations and boron to chloride ratios are higher than for the streams. For these Goundwaters, increases in boron concentrations are matched linearly by increases in the concentration of the principal ase cation weathering component in the bedrock, calcium. However, the bedrock weathering term is not uniform as the ratio of boron to calcium concentration varies for the different boreholes sampled.

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Krám, Pavel, Juraj Farkaš, Anna Pereponova, Chukwudi Nwaogu, Veronika Štědrá, and Jakub Hruška. "Bedrock Weathering and Stream Water Chemistry in Felsic and Ultramafic Forest Catchments." Procedia Earth and Planetary Science 10 (2014): 52–55. http://dx.doi.org/10.1016/j.proeps.2014.08.010.

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Wei, Zhanyu, Honglin He, and Feng shi. "Weathering history of an exposed bedrock fault surface interpreted from its topography." Journal of Structural Geology 56 (November 2013): 34–44. http://dx.doi.org/10.1016/j.jsg.2013.08.008.

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42

Anderson, Suzanne Prestrud, William E. Dietrich, and George H. Brimhall. "Weathering profiles, mass-balance analysis, and rates of solute loss: Linkages between weathering and erosion in a small, steep catchment." GSA Bulletin 114, no. 9 (September 1, 2002): 1143–58. http://dx.doi.org/10.1130/0016-7606(2002)114<1143:wpmbaa>2.0.co;2.

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Abstract In a headwater catchment in the Oregon Coast Range, we find that solid-phase mass losses due to chemical weathering are equivalent in the bedrock and the soil. However, the long-term rate of mass loss per unit volume of parent rock is greater in the soil than in the rock. We attribute this finding to the effects of biotic processes in the soil and to hydrologic conditions that maximize contact time and water flux through the mineral matrix in the soil. This result stems both from earlier work in which we demonstrated that rock and soil contribute equally to the solute flux and from arguments presented here that the basin is in dynamic equilibrium with respect to erosion and uplift. The silica flux of 10.7 ± 7.1 t·km−2·yr−1 from the basin is several times larger than the flux from older soils elsewhere, but comparable to the flux from sites with similar physical erosion rates. This result argues that physical denudation or uplift rates play an important role in setting the chemical denudation rate. Physical processes appear to influence chemical-weathering rates in several ways. First, they limit chemical evolution by removing material, thus setting the residence time within the weathered rock and the soil. Second, bioturbation mixes rock fragments into the more reactive soil and maintains high soil porosity, allowing free circulation of water. Because the weathering in the soil is more intense than in the rock, we argue that the chemical denudation rate will diminish where uplift rates—and, hence, physical-denudation rates—are great enough to lead to a bedrock-dominated landscape. Chemical denudation rates will increase with physical-denudation rates, but only as long as the landscape remains mantled by soil.

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Chang, Cheng, Howard Omar Beckford, and Hongbing Ji. "Indication of Sr Isotopes on Weathering Process of Carbonate Rocks in Karst Area of Southwest China." Sustainability 14, no. 8 (April 18, 2022): 4822. http://dx.doi.org/10.3390/su14084822.

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Based on the determination of the major and trace element content, and the Sr isotope composition of soils from limestone and dolomite profiles in the karst area of Southwest (SW) China, this study discussed the distribution and migration characteristics of the elements and the influencing factors of Sr isotope fractionation, in order to better understand the chemical weathering and pedogenesis process, as well as to explore the material source of laterite. The chemical weathering analysis results (Chemical Index of Alteration, mass balance coefficient, and A-CN-K ternary) indicate that the weathering intensity of dolomite profile PB is higher than that of limestone profiles CZ and CY. The correlation analysis between Sr isotopes and P2O5 suggests that in addition to illite, apatite in the dolomite profile also affects the 87Sr/86Sr composition. Sr content and 87Sr/86Sr demonstrate two stages in the weathering process of the carbonate, carbonate dissolution stage, and residual silicate weathering stage. As the carbonate minerals dissolve at the beginning of weathering, the Sr content decreases and 87Sr/86Sr increases slightly. After the decomposition of carbonate, the Sr content remains unchanged and 87Sr/86Sr increases. Finally, the study suggests that the material source of laterite is more likely to be underlying bedrock rather than the aeolian source.

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Wright, C. "Faulting and overburden and bedrock seismic velocities at Buchans and Gullbridge, Newfoundland, from seismic refraction measurements: applications to shallow geology and exploration." Canadian Journal of Earth Sciences 33, no. 8 (August 1, 1996): 1201–12. http://dx.doi.org/10.1139/e96-091.

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P-wave arrival times from seismic reflection surveys recorded at two mine sites in Newfoundland were used to estimate lateral variations in seismic velocity in uppermost bedrock. The abundant information on medium- to long-wavelength lateral variations in seismic velocity in bedrock is a by-product of refraction statics analyses, which has rarely been fully exploited to constrain shallow geological interpretation. Local minima in seismic velocity in bedrock are associated with faults, showing that subvertical features that do not produce observable reflections can also be mapped. Significant variations in seismic velocity also indicate variations in lithology or formation boundaries. Variations in overburden and weathering thicknesses are accurately defined at Gullbridge where the careful choice of shot–receiver configuration allows estimates of both lateral and vertical variations in the seismic velocities of glacial overburden. The information on overburden properties is of value in drift prospecting for minerals and in studies of Quaternary geology.

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Lehmann, Benjamin, Frédéric Herman, Pierre G. Valla, Georgina E. King, Rabiul H. Biswas, Susan Ivy-Ochs, Olivia Steinemann, and Marcus Christl. "Postglacial erosion of bedrock surfaces and deglaciation timing: New insights from the Mont Blanc massif (western Alps)." Geology 48, no. 2 (November 22, 2019): 139–44. http://dx.doi.org/10.1130/g46585.1.

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Abstract Since the Last Glacial Maximum, ∼20 k.y. ago, Alpine glaciers have retreated and thinned. This transition exposed bare bedrock surfaces that could then be eroded by a combination of debuttressing or local frost cracking and weathering. Quantification of the respective contributions of these processes is necessary to understand the links between long-term climate and erosion in mountains. Here, we quantified the erosion histories of postglacial exposed bedrock in glacial valleys. Combining optically stimulated luminescence and terrestrial cosmogenic nuclide (TCN) surface exposure dating, we estimated the erosion rate of bedrock surfaces at time scales from 101 to 104 yr. Bedrock surfaces sampled from the flanks of the Mer de Glace (Mont Blanc massif, European Alps) revealed erosion rates that vary from 3.5 ± 1.2 ⋅ 10−3 mm/yr to 4.3 ± 0.6 mm/yr over ∼500 m of elevation, with a negative correlation between erosion rate and elevation. The observed spatial variation in erosion rates, and their high values, reflect morphometric (elevation and surface slope) and climatic (temperature and snow cover) controls. Furthermore, the derived erosion rates can be used to correct the timing of deglaciation based on TCN data, potentially suggesting very rapid ice thinning during the Gschnitz stadial.

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Clapp, Erik M., Paul R. Bierman, Kyle K. Nichols, Milan Pavich, and Marc Caffee. "Rates of Sediment Supply to Arroyos from Upland Erosion Determined Using in Situ Produced Cosmogenic 10Be and 26Al." Quaternary Research 55, no. 2 (March 2001): 235–45. http://dx.doi.org/10.1006/qres.2000.2211.

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AbstractUsing 10Be and 26Al measured in sediment and bedrock, we quantify rates of upland erosion and sediment supply to a small basin in northwestern New Mexico. This and many other similar basins in the southwestern United States have been affected by cycles of arroyo incision and backfilling several times in the past few millennia. The sediment generation (275 ± 65 g m−2 yr−1) and bedrock equivalent lowering rates (102 ± 24 m myr−1) we determine are sufficient to support at least three arroyo cycles in the past 3,000 years, consistent with rates calculated from a physical sediment budget within the basin and regional rates determined using other techniques. Nuclide concentrations measured in different sediment sources and reservoirs suggest that the arroyo is a good spatial and temporal integrator of sediment and associated nuclide concentrations from throughout the basin, that the basin is in steady-state, and that nuclide concentration is independent of sediment grain size. Differences between nuclide concentrations measured in sediment sources and reservoirs reflect sediment residence times and indicate that subcolluvial bedrock weathering on hillslopes supplies more sediment to the basin than erosion of exposed bedrock.

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Oeser, Ralf A., and Friedhelm von Blanckenburg. "Do degree and rate of silicate weathering depend on plant productivity?" Biogeosciences 17, no. 19 (October 14, 2020): 4883–917. http://dx.doi.org/10.5194/bg-17-4883-2020.

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Abstract. Plants and their associated below-ground microbiota possess the tools for rock weathering. Yet the quantitative evaluation of the impact of these biogenic weathering drivers relative to abiogenic parameters, such as the supply of primary minerals, water, and acids, is an open question in Critical Zone research. Here we present a novel strategy to decipher the relative impact of these drivers. We quantified the degree and rate of weathering and compared these to nutrient uptake along the “EarthShape” transect in the Chilean Coastal Cordillera. These sites define a major north–south gradient in precipitation and primary productivity but overlie granitoid rock throughout. We present a dataset of the chemistry of Critical Zone compartments (bedrock, regolith, soil, and vegetation) to quantify the relative loss of soluble elements (the “degree of weathering”) and the inventory of bioavailable elements. We use 87Sr∕86Sr isotope ratios to identify the sources of mineral nutrients to plants. With rates from cosmogenic nuclides and biomass growth we determined fluxes (“weathering rates”), meaning the rate of loss of elements out of the ecosystems, averaged over weathering timescales (millennia), and quantified mineral nutrient recycling between the bulk weathering zone and the bulk vegetation cover. We found that neither the degree of weathering nor the weathering rates increase systematically with precipitation from north to south along the climate and vegetation gradient. Instead, the increase in biomass nutrient demand is accommodated by faster nutrient recycling. In the absence of an increase in weathering rate despite a five-fold increase in precipitation and net primary productivity (NPP), we hypothesize that plant growth might in fact dampen weathering rates. Because plants are thought to be key players in the global silicate weathering–carbon feedback, this hypothesis merits further evaluation.

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Maavara, Taylor, Erica R. Siirila-Woodburn, Fadji Maina, Reed M. Maxwell, James E. Sample, K. Dana Chadwick, Rosemary Carroll, et al. "Modeling geogenic and atmospheric nitrogen through the East River Watershed, Colorado Rocky Mountains." PLOS ONE 16, no. 3 (March 24, 2021): e0247907. http://dx.doi.org/10.1371/journal.pone.0247907.

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There is a growing understanding of the role that bedrock weathering can play as a source of nitrogen (N) to soils, groundwater and river systems. The significance is particularly apparent in mountainous environments where weathering fluxes can be large. However, our understanding of the relative contributions of rock-derived, or geogenic, N to the total N supply of mountainous watersheds remains poorly understood. In this study, we develop the High-Altitude Nitrogen Suite of Models (HAN-SoMo), a watershed-scale ensemble of process-based models to quantify the relative sources, transformations, and sinks of geogenic and atmospheric N through a mountain watershed. Our study is based in the East River Watershed (ERW) in the Upper Colorado River Basin. The East River is a near-pristine headwater watershed underlain primarily by an N-rich Mancos Shale bedrock, enabling the timing and magnitude of geogenic and atmospheric contributions to watershed scale dissolved N-exports to be quantified. Several calibration scenarios were developed to explore equifinality using >1600 N concentration measurements from streams, groundwater, and vadose zone samples collected over the course of four years across the watershed. When accounting for recycling of N through plant litter turnover, rock weathering accounts for approximately 12% of the annual dissolved N sources to the watershed in the most probable calibration scenario (0–31% in other scenarios), and 21% (0–44% in other scenarios) when considering only “new” N sources (i.e. geogenic and atmospheric). On an annual scale, instream dissolved N elimination, plant turnover (including cattle grazing) and atmospheric deposition are the most important controls on N cycling.

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Zhao, Yanpu, Jan R. Wijbrans, Hua Wang, Pieter Z. Vroon, Jianghao Ma, and Yanqiong Zhao. "Chemical Weathering and CO2 Consumption Inferred from Riverine Water Chemistry in the Xi River Drainage, South China." International Journal of Environmental Research and Public Health 20, no. 2 (January 13, 2023): 1516. http://dx.doi.org/10.3390/ijerph20021516.

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Hydrochemistry and strontium isotope data were analysed in water samples from the Xi River Drainage system to reveal the spatial and seasonal variations in chemical weathering, associated CO2 consumption fluxes, and their control factors. The main ions were Ca2+, Mg2+, and HCO3−, which are characteristic of a drainage system on carbonate-dominated bedrock. The dissolved loads were derived from four major end-member reservoirs: silicate, limestone, dolomite, and atmosphere. The silicate weathering rates (SWRs) increased downstream from 0.03 t/km2/year to 2.37 t/km2/year. The carbonate weathering rates (CWRs) increased from 2.14 t/km2/year in the upper reaches, to 32.65 t/km2/year in the middle reaches, and then decreased to 23.20 t/km2/year in the lower reaches. The SWR values were 281.38 and 113.65 kg/km2/month during the high- and low-water periods, respectively. The CWR values were 2456.72 and 1409.32 kg/km2/month, respectively. The limestone weathering rates were 2042.74 and 1222.38 kg/km2/month, respectively. The dolomite weathering rates were 413.98 and 186.94 kg/km2/month, respectively. Spatial and seasonal variations in chemical weathering were controlled mainly by lithology, vegetation, and climate (temperature, water discharge, and precipitation). The CO2 consumption flux by chemical weathering was estimated at 189.79 × 109 mol/year, with 156.37 × 109 and 33.42 × 109 mol/year for carbonate and silicate weathering, respectively. The CO2 fluxes by chemical weathering are substantially influenced by sulfuric acid in the system. The CO2 flux produced by sulfuric acid weathering was estimated at 30.00 × 109 mol/year in the basin. Therefore, the Xi River Basin is a CO2 sink with a net consumption of CO2 flux of 3.42 × 109 mol/year.

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Lee, Gwang-Ryul. "동일 기반암 지역에서 산지와 곡지 암석의 풍화 특성 비교." JOURNAL OF THE GEOMORPHOLOGICAL ASSOCIATION OF KOREA 23, no. 1 (March 31, 2016): 1–16. http://dx.doi.org/10.16968/jkga.23.1.1.

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Journal articles on the topic 'Bedrock weathering'

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