Identifying Changes in Sediment Texture along an Ephemeral Gravel-Bed Stream Using Electrical Resistivity Tomography 2D and 3D
| Autor: | Pedro Pérez-Cutillas, Marcos A. Martínez-Segura, Pedro Martínez-Pagán, Marco D. Vásconez-Maza, Carmelo Conesa-García |
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| Rok vydání: | 2021 |
| Předmět: |
010504 meteorology & atmospheric sciences
Sorting (sediment) Borehole Mineralogy 010502 geochemistry & geophysics lcsh:Technology 01 natural sciences Texture (geology) lcsh:Chemistry borehole samples ephemeral gravel-bed stream General Materials Science Electrical resistivity tomography lcsh:QH301-705.5 Instrumentation 0105 earth and related environmental sciences Bed load Fluid Flow and Transfer Processes lcsh:T Process Chemistry and Technology Ephemeral key General Engineering deposition patterns Substrate (marine biology) lcsh:QC1-999 Computer Science Applications climate change lcsh:Biology (General) lcsh:QD1-999 lcsh:TA1-2040 electrical resistivity tomography Alluvium lcsh:Engineering (General). Civil engineering (General) lcsh:Physics Geology |
| Zdroj: | Applied Sciences Volume 11 Issue 7 Applied Sciences, Vol 11, Iss 3030, p 3030 (2021) |
| ISSN: | 2076-3417 |
| DOI: | 10.3390/app11073030 |
| Popis: | Differences in deposit geometry and texture with depth along ephemeral gravel-bed streams strongly reflect fluctuations in bedload which are due to environmental changes at the basin scale and to morphological channel adjustments. This study combines electrical resistivity tomography (ERT) with datasets from borehole logs to analyse the internal geometry of channel cross-sections in a gravel-bed ephemeral stream (southeast Spain). The survey was performed through longitudinal and transverse profiles in the upper channel stretch, of 14 to 30 m in length and 3 to 6 m in depth, approximately. ERT values were correlated with data on sediment texture as grain size distribution, effective grain sizes, sorting, and particle shape (Zingg’s classification). The alluvial channel-fills showed the superposition of four layers with uneven thickness and arrangement: (1) the softer rocky substrate (< 1000 Ω.m) (2) a thicker intermediate layer (1000 to 2000 Ω.m) and (3) an upper set composed of coarse gravel and supported matrix, ranging above 2000 Ω.m, and a narrow subsurface layer, which is the most resistive (> 5000 Ω.m), corresponding to the most recent armoured deposits (gravel and pebbles). The ERT results coupled with borehole data allowed for determining the horizontal and vertical behaviour of the materials in a 3D model, facilitating the layer identification. |
| Databáze: | OpenAIRE |
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