Uplift, denudation, and their causes and constraints over geological timescales

Gallagher, Kerry

doi:10.1016/b978-0-444-53042-4.00022-4

Cited by 15 publications

(14 citation statements)

References 101 publications

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“…High clay distribution was obtained in the northeastern (arable farm) part of the area under study. This may be attributed to the structural factor like land denudation (Kerry, 2012). Also, well-reflected changes were observed in the spatial distribution for Available P, Nitrogen, and CEC.…”

Section: Discussionmentioning

confidence: 73%

Predictive Mapping of Soil Properties for Precision Agriculture Using Geographic Information System (GIS) Based Geostatistics Models

John¹,

Lawani²,

Esther³

et al. 2019

MAS

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In precision Agriculture, geostatistical methods as a predictive tool have been extensively utilized. The approach estimates soil properties spatial variability and dependency. This study was carried out in Ovia north east Local Government Area of Edo State of Nigeria in order to map soil properties (Sand, Clay, pH, OC, P, N and CEC) and redict their spatial variability. Twenty-nine (29) soil samples were collected randomly from Typic Kandiudults soil type under three different land use, teak forest plantation, shrub, and arable farm. The soil samples were air-dried and passed through a 2 mm sieve before being analyzed for pH(CaCl2), SOC, Sand, Clay, Phosphorus, Nitrogen, and CEC. Generated data were statistically and geostatistically computed to explain the spatial variability of soil properties. The traditional method of soil analysis and interpretation are tedious, time-consuming with escalating budgets thus geostatical approach. Available phosphorus yielded large variability with CV=57.08% followed by clay content with CV=49.03%. Spherical, Gaussian, Hole Effect model, Stable, Exponential and Circular models were fitted for all the soil parameters. The result revealed that soil pH, Sand content, TN and CEC were moderate spatially autocorrelated with nugget/sill value of 0.32, 0.21, 0.49 and 0.30 respectively.  SOC also gave a moderate spatially autocorrelated with nugget/sill value of 0.44. And Clay and Available phosphorus were strong spatially autocorrelated with nugget/sill value of 0.15 and 0.13 respectively. Cross-validation of the output maps using the semivariogram showed that the interpolation models are superior to assuming mean for any unsampled area. The output maps will help soil users within the area to proffer best management technology to improve crop, fiber and water production.   

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Section: Discussionmentioning

confidence: 73%

Predictive Mapping of Soil Properties for Precision Agriculture Using Geographic Information System (GIS) Based Geostatistics Models

John¹,

Lawani²,

Esther³

et al. 2019

MAS

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“…In this paper, we focus on estimating net erosion from compaction data. If a reference porosity-depth curve (describing normal compaction) can be established for a given lithology, the depth difference between that and the porosity derived from well log data is an estimate of net erosion ( Figure 1) (see Gallagher, 2012, and references therein). normal compaction) is the basis of this approach (Athy, 1930;Magara, 1980;Sclater & Christie, 1980).…”

Section: Introductionmentioning

confidence: 99%

“…After an erosion event in the geological past, the sediments underlying the associated unconformity will today exhibit lower porosity than expected at the present day burial depth. If a reference porosity-depth curve (describing normal compaction) can be established for a given lithology, the depth difference between that and the porosity derived from well log data is an estimate of net erosion (Figure 1) (see Gallagher, 2012, and references therein).…”

Section: Introductionmentioning

confidence: 99%

Estimating uncertainties on net erosion from well‐log porosity data

2019

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Estimating the amount of erosion experienced by a sedimentary basin during its geological history plays a key role in basin modelling. In this paper, we present a novel probabilistic approach to estimate net erosion from porosity-depth data from a single well. Our approach uses a Markov chain Monte Carlo algorithm which readily allows us to deal with imprecise knowledge of the lithology-dependent compaction parameters in a joint inversion scheme using multiple lithologies. The results using synthetic data highlight the advantages of our approach over conventional techniques for net erosion estimation: (a) uncertainties on compaction parameters can be effectively mapped into a probabilistic solution for net erosion; (b) posterior uncertainties are easy to quantify; (c) the joint inversion scheme can automatically reconcile porosity data from different lithologies. Our results also underscore the critical role of prior assumptions on controlling the retrieved estimates for net erosion. Using real data from a well in the Barents Sea, we simulate three possible scenarios of variable prior assumptions on compaction parameters to demonstrate the general applicability of our approach. Strong prior assumptions on the compaction parameters led to unrealistic estimates of net erosion for the target well, indicating the assumptions are probably inappropriate. Our preferred strategy for this dataset is to include additional data to constrain the normal compaction trend of the sediments. This provides a net erosion estimate for the target well of about 2300 m with a standard deviation of 140 m which is in line with previous studies. Finally, we discuss potential guidelines to deal with real applications in which data from normally compacted sediments are not available. One is to use our algorithm as a hypothesis-testing tool to evaluate the results under a large set of assumed compaction parameters. A second is to infer compaction parameters and net erosion simultaneously from the target well porosity data. Although appealing and successful with synthetic data, this strategy provides results which are strongly dependent on the calibration data and the geological history of the sediments sampled by the target well. Highlights• A probabilistic approach to estimate net erosion from well-log compaction data is presented. • Uncertainties in the compaction model are effectively propagated in the solution for net erosion. • The novel methodology is tested against synthetic data and real data from a well in the Barents Sea.

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“…De acordo com Bishop (1995), esse processo corresponde à transferência parcial ou total do fl uxo de um rio para outro, podendo ocorrer em diferentes escalas espaciais. Rearranjos podem estar relacionados a mudanças no nível de base e permitem a fusão de sistemas fl uviais previamente desconectados ou a divisão/desvio de um sistema já existente (GALLAGHER, 2012). A captura fl uvial é o mais notável tipo de rearranjo e se caracteriza pela transferência de área entre bacias, porém, com a preservação das linhas de drenagem (BISHOP, 1995).…”

Section: Introductionunclassified

Evolução Da Rede De Drenagem E Evidências De Antigas Conexões Entre as Bacias Dos Rios Grande E São Francisco No Sudeste Brasileiro

Rezende

Salgado²,

Castro

2018

Rev. Bras. Geomorfol.

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Resumo:O presente trabalho investigou a evolução da rede de drenagem na alta/média bacia do Rio Grande, com foco em evidências de antigas conexões entre esta bacia e a bacia do Rio São Francisco no sudeste brasileiro. Foi executada a análise conjunta de registros sedimentares, anomalias de drenagem, eixos de soerguimento e dados termocronológicos disponíveis. Feições como um baixo divisor anômalo, um cotovelo de drenagem, uma garganta e um antigo eixo de soerguimento evidenciam que o alto curso do Rio Grande, hoje pertencente à bacia hidrográfi ca do Rio Paraná, encontrava-se previamente direcionado para norte, rumo ao Cráton do São Francisco. O divisor ancestral entre as duas bacias hidrográfi cas coincidia com o eixo soerguido de direção geral NNW-SSE ao longo das intrusões alcalinas Neocretáceas que bordejam a nordeste a Unidade geotectônica Bacia do Paraná. O rompimento do divisor ancestral e a consequente captura fl uvial provavelmente ocorreram após um soerguimento generalizado no Mioceno Médio, que causou a superimposição da drenagem a partir de uma paleosuperfície mais regular e a abertura de depressões. O baixo divisor anômalo na região de Pimenta-MG corresponde a um expressivo registro morfológico do paleovale que conectava as duas bacias atualmente separadas. Taxas médias de incisão de longo-termo foram estimadas em cerca de 10 m/Ma, com base no posicionamento das formações Marília e Itaqueri adjacentes ao médio vale do Rio Grande. Informações sobre o Artigo

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Uplift, denudation, and their causes and constraints over geological timescales

Cited by 15 publications

References 101 publications

Predictive Mapping of Soil Properties for Precision Agriculture Using Geographic Information System (GIS) Based Geostatistics Models

Predictive Mapping of Soil Properties for Precision Agriculture Using Geographic Information System (GIS) Based Geostatistics Models

Estimating uncertainties on net erosion from well‐log porosity data

Evolução Da Rede De Drenagem E Evidências De Antigas Conexões Entre as Bacias Dos Rios Grande E São Francisco No Sudeste Brasileiro

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