Journal articles: 'Sub-surface geology'

1

Dartnell, L. R., L. Desorgher, J. M. Ward, and A. J. Coates. "Martian sub-surface ionising radiation: biosignatures and geology." Biogeosciences 4, no. 4 (July 30, 2007): 545–58. http://dx.doi.org/10.5194/bg-4-545-2007.

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Abstract. The surface of Mars, unshielded by thick atmosphere or global magnetic field, is exposed to high levels of cosmic radiation. This ionising radiation field is deleterious to the survival of dormant cells or spores and the persistence of molecular biomarkers in the subsurface, and so its characterisation is of prime astrobiological interest. Here, we present modelling results of the absorbed radiation dose as a function of depth through the Martian subsurface, suitable for calculation of biomarker persistence. A second major implementation of this dose accumulation rate data is in application of the optically stimulated luminescence technique for dating Martian sediments. We present calculations of the dose-depth profile in the Martian subsurface for various scenarios: variations of surface composition (dry regolith, ice, layered permafrost), solar minimum and maximum conditions, locations of different elevation (Olympus Mons, Hellas basin, datum altitude), and increasing atmospheric thickness over geological history. We also model the changing composition of the subsurface radiation field with depth compared between Martian locations with different shielding material, determine the relative dose contributions from primaries of different energies, and discuss particle deflection by the crustal magnetic fields.

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Dartnell, L. R., L. Desorgher, J. M. Ward, and A. J. Coates. "Martian sub-surface ionising radiation: biosignatures and geology." Biogeosciences Discussions 4, no. 1 (February 9, 2007): 455–92. http://dx.doi.org/10.5194/bgd-4-455-2007.

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Abstract. The surface of Mars, unshielded by thick atmosphere or global magnetic field, is exposed to high levels of cosmic radiation. This ionizing radiation field is deleterious to the survival of dormant cells or spores and the persistence of molecular biomarkers in the subsurface, and so its characterisation is of prime astrobiological interest. Previous research has attempted to address the question of biomarker persistence by inappropriately using dose profiles weighted specifically for cellular survival. Here, we present modelling results of the unmodified physically absorbed radiation dose as a function of depth through the Martian subsurface. A second major implementation of this dose accumulation rate data is in application of the optically stimulated luminescence technique for dating Martian sediments. We present calculations of the dose-depth profile from galactic cosmic rays in the Martian subsurface for various scenarios: variations of surface composition (dry regolith, ice, layered permafrost), solar minimum and maximum conditions, locations of different elevation (Olympus Mons, Hellas basin, datum altitude), and increasing atmospheric thickness over geological history. We also model the changing composition of the subsurface radiation field with depth compared between Martian locations with different shielding material, determine the relative dose contributions from primaries of different energies, and briefly treat particle deflection by the crustal magnetic fields.

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Dirmeyer, Paul, and Holly Norton. "Indications of Surface and Sub-Surface Hydrologic Properties from SMAP Soil Moisture Retrievals." Hydrology 5, no. 3 (July 25, 2018): 36. http://dx.doi.org/10.3390/hydrology5030036.

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Variability and covariability of land properties (soil, vegetation and subsurface geology) and remotely sensed soil moisture over the southeast and south-central U.S. are assessed. The goal is to determine whether satellite soil moisture memory contains information regarding land properties, especially the distribution karst formations below the active soil column that have a bearing on land-atmosphere feedbacks. Local (within a few tens of km) statistics of land states and soil moisture are considered to minimize the impact of climatic variations, and the local statistics are then correlated across the domain to illuminate significant relationships. There is a clear correspondence between soil moisture memory and many land properties including karst distribution. This has implications for distributed land surface modeling, which has not considered preferential water flows through geologic formations. All correspondences are found to be strongest during spring and fall, and weak during summer, when atmospheric moisture demand appears to dominate soil moisture variability. While there are significant relationships between remotely-sensed soil moisture variability and land properties, it will be a challenge to use satellite data for terrestrial parameter estimation as there is often a great deal of correlation among soil, vegetation and karst property distributions.

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Dragoset, Bill, and Scott MacKay. "Surface Multiple Attenuation and Sub-Salt Imaging." Exploration Geophysics 24, no. 3-4 (September 1993): 463–72. http://dx.doi.org/10.1071/eg993463.

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Basa, T., J. T. Greensmith, and C. Vita-Finzi. "The sub-surface Holocene Middle sands of Dungeness." Proceedings of the Geologists' Association 108, no. 2 (January 1997): 105–12. http://dx.doi.org/10.1016/s0016-7878(97)80033-8.

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Tague, C. L., J. S. Choate, and G. Grant. "Parameterizing sub-surface drainage with geology to improve modeling streamflow responses to climate in data limited environments." Hydrology and Earth System Sciences Discussions 9, no. 7 (July 18, 2012): 8665–700. http://dx.doi.org/10.5194/hessd-9-8665-2012.

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Abstract. Hydrologic models are one of the core tools used to project how water resources may change under a warming climate. These models are typically applied over a range of scales, from headwater streams to higher order rivers, and for a variety of purposes, such as evaluating changes to aquatic habitat or reservoir operation. Most hydrologic models require streamflow data to calibrate subsurface drainage parameters. In many cases, long-term gage records may not be available for calibration, particularly when assessments are focused on low order stream reaches. Consequently, hydrologic modeling of climate change impacts is often performed in the absence of sufficient data to fully parameterize these hydrologic models. In this paper, we assess a geologic-based strategy for assigning drainage parameters. We examine the performance of this modeling strategy for the McKenzie River watershed in the US Oregon Cascades, a region where previous work has demonstrated sharp contrasts in hydrology based primarily on geological differences between the High and Western Cascades. Based on calibration and verification using existing streamflow data, we demonstrate that: (1) a set of streams ranging from 1st to 3rd order within the Western Cascade geologic region can share the same drainage parameter set, and (2) streams from the High Cascade geologic region, however, require a distinctive parameter set. Further, we show that a watershed comprised of a mixture of High and Western Cascade geology can be modeled without additional calibration by transferring parameters from these distinctive High and Western Cascade end-member parameter sets. Using this geologically-based parameter transfer scheme, our model predictions for all watersheds capture dominant historic streamflow patterns, and are sufficiently accurate to resolve geo-climatic differences in how these different watersheds are likely to respond to simple warming scenarios.

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Alsop, G. I., S. Marco, and T. Levi. "Recognising surface versus sub-surface deformation of soft-sediments: Consequences and considerations for palaeoseismic studies." Journal of Structural Geology 154 (January 2022): 104493. http://dx.doi.org/10.1016/j.jsg.2021.104493.

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Nguyen, Manh Duc, Nguyen Van Thang, Akihiko Wakai, Go Sato, Jessada Karnjana, Hoang Viet Hung, Lanh Si Ho, Indra Prakash, Hoc Tran Quang, and Binh Thai Pham. "Identification, Monitoring, and Assessment of an Active Landslide in Tavan-Hauthao, Sapa, Laocai, Vietnam – A Multidisciplinary Approach." Journal of Disaster Research 16, no. 4 (June 1, 2021): 501–11. http://dx.doi.org/10.20965/jdr.2021.p0501.

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The active landslide located in the Tavan-Hauthao, Sapa district, Laocai province, Vietnam was investigated using geophysical methods (2D Electrical Resistivity and Tomography), geotechnical investigations, and a ground survey to assess the geologic condition of the sliding block and surrounding ground. Landslide displacement was measured using 15 surface monitoring points. Numerical modeling was done to assess the behavior of an active landslide. This multi-disciplinary approach helped in interpreting landslide stratigraphy, geotechnical characteristics of the sliding groundmass, depth, and nature of the sliding plane. The surface area of the slide is approximately 1200 m2. Studying this active landslide is important as it affects the road No. 152, which is an important road connecting the Sapa Ancient Rock Field. This study involved surface topographical survey, surface and sub-surface geological, and geotechnical investigations including Standard Penetration Test and Electrical Resistivity Tomography. Geologic and geotechnical data were used to characterize an active landslide block, which is composed of different soil layers underlaid by granitic rock. The surface electrical-resistivity measurements across the Sapa landslide resulted in inverted-resistivity sections with distinct resistivity contrasts that correlated well with the geology and geo-hydrology observed in boreholes.

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Bogunovic, Dragan, and Vladislav Kecojevic. "Equipment CO_{2 emission in surface coal mining}." International Journal of Mining and Mineral Engineering 1, no. 2 (2009): 172. http://dx.doi.org/10.1504/ijmme.2009.023133.

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10

Hovland, M., H. G. Rueslåtten, H. K. Johnsen, B. Kvamme, and T. Kuznetsova. "Salt formation associated with sub-surface boiling and supercritical water." Marine and Petroleum Geology 23, no. 8 (September 2006): 855–69. http://dx.doi.org/10.1016/j.marpetgeo.2006.07.002.

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11

Budiono, Kris, and Godwin Latuputty. "SUBSURFACE GEOLOGICAL CONDITION OF SEVERAL LAND COASTAL ZONE IN INDONESIA BASED ON THE GSSI GROUND PROBING RADAR (GPR) RECORD INTERPRETATION." BULLETIN OF THE MARINE GEOLOGY 23, no. 1 (February 15, 2016): 9. http://dx.doi.org/10.32693/bomg.23.1.2008.6.

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The GSSI Ground Penetrating radar have been used to profile the shallow depth of subsurface geology of several area of Land Coastal zone in Indonesia Analysis of a large data base of GPR profile from natural subsurface geological condition along the land coast line have allowed identification of reflection configuration that characterize this type of sub surface geological environment. In many contamination problem, the geological information of coastal area is sparse and drill-core description only gives a limited picture of the geometry of inhomogeneties. The Ground-Probing Radar (GPR) method is a promising tool for resolving changes of physical properties in subsurface geological condition at the scale of natural inhomogeneties arising from changing lithology composition. The objective of present work are to examine whether and to what extent the characteristic lithofacies of subsurface lithology can be recognised as mapable reflection pattern on ground probing radar (GPR) reflection profiles in order to gain information about the subsurface geometry of subsurface geology in coastal area. Key word: Subsurface geology, coastal zone, Ground Probing Radar Ground probing radar produksi GSSI telah dipergunakan untuk membuat penampang geologi bawah permukaan dangkal di beberapa kawasan pantai Indonesia. Analisa data dasar penampang GPR dari geologi bawah permukaan di kawasan pantai dapat memperlihatkan konfigurasi reflector yang mencerminkan jenis lingkungan geologi bawah permukaan. Dalam masalah kontaminasi, informasi geologi di daerah pantai yang dihasilkan dari pemboran inti hanya dapat memperlihatkan gambaran yang sederhana tentang geometri ketidakseragaman. Metoda ground probing radar merupakan alat bantu yang menjanjikan untuk menanggulangi masalah sifat fisik kondisi geologi bawah permukaan pada skala ketidak seragaman yang sebenarnya dari perubahan komposisi litologi. Tujuan utama dari penelitian ini adalah untuk menguji sampai sejauh mana karakteristik litofasies dari litologi bawah permukaan dapat dilihat sebagai pola refleksi yang dapat dipetakan dalam penampang GPR dengan maksud untuk mendapatkan informasi geometri geologi bawah permukaan di daerah pantai. Kata kunci: Geologi bawah permukaan, zona pantai, â€œGround probing radarâ€

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Jelmert, Tom A., and Tommy Toverud. "Analytical modeling of sub-surface porous reservoir compaction." Journal of Petroleum Exploration and Production Technology 8, no. 4 (June 11, 2018): 1129–38. http://dx.doi.org/10.1007/s13202-018-0479-7.

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13

Sikdar, P. K., and P. Sahu. "Understanding wetland sub-surface hydrology using geologic and isotopic signatures." Hydrology and Earth System Sciences Discussions 6, no. 2 (April 8, 2009): 3143–73. http://dx.doi.org/10.5194/hessd-6-3143-2009.

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Abstract. This paper attempts to utilize hydrogeoloy and isotope composition of groundwater to understand the present hydrological processes prevalent in a freshwater wetland, source of wetland groundwater, surface water/groundwater interaction and mixing of groundwater of various depth zones in the aquifer. This study considers East Calcutta Wetlands (ECW) – a freshwater peri-urban inland wetland ecosystem located at the lower part of the deltaic alluvial plain of South Bengal Basin and east of Kolkata city. This wetland is well known over the world for its resource recovery systems, developed by local people through ages, using wastewater from the city. Geological investigations reveal that the sub-surface geology is completely blanketed by the Quaternary sediments comprising a succession of silty clay, sand of various grades and sand mixed with occasional gravels and thin intercalations of silty clay. Aquifer within the depths of 80 m to 120 m has the maximum potential to supply water. Groundwater mainly flows from east to west and is being over-extracted to the tune of 65×103 m3/day. δ18O and δD values of shallow and deep groundwater are similar indicating resemblance in hydrostratigraphy and climate of the recharge areas. Groundwater originates mainly from monsoonal rain with some evaporation prior to or during infiltration and partly from bottom of ponds, canals and infiltration of groundwater withdrawn for irrigation. Relatively high tritium content of the shallow groundwater indicates local recharge, while the deeper groundwater with very low tritium is recharged mainly from distant areas. At places the deeper aquifer has relatively high tritium, indicating mixing of groundwater of shallow and deep aquifers. Metals such as copper, lead, arsenic, cadmium, aluminum, nickel and chromium are also present in groundwater of various depths. Therefore, aquifers of wetland and surrounding urban areas which are heavily dependent on groundwater are vulnerable to pollution and hence surface water-groundwater interaction should be minimized by regulating tubewell operation time, introducing treated surface water supply system and artificially recharging the aquifer.

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Sikdar, P. K., and P. Sahu. "Understanding wetland sub-surface hydrology using geologic and isotopic signatures." Hydrology and Earth System Sciences 13, no. 7 (July 28, 2009): 1313–23. http://dx.doi.org/10.5194/hess-13-1313-2009.

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Abstract. This paper attempts to utilize hydrogeology and isotope composition of groundwater to understand the present hydrological processes prevalent in a freshwater wetland, source of wetland groundwater, surface water/groundwater interaction and mixing of groundwater of various depth zones in the aquifer. This study considers East Calcutta Wetlands (ECW) – a freshwater peri-urban inland wetland ecosystem located at the lower part of the deltaic alluvial plain of South Bengal Basin and east of Kolkata city. This wetland is well known over the world for its resource recovery systems, developed by local people through ages, using wastewater of the city. Geological investigations reveal that the sub-surface geology is completely blanketed by the Quaternary sediments comprising a succession of silty clay, sand of various grades and sand mixed with occasional gravels and thin intercalations of silty clay. At few places the top silty clay layer is absent due to scouring action of past channels. In these areas sand is present throughout the geological column and the areas are vulnerable to groundwater pollution. Groundwater mainly flows from east to west and is being over-extracted to the tune of 65×103 m3/day. δ18O and δD values of shallow and deep groundwater are similar indicating resemblance in hydrostratigraphy and climate of the recharge areas. Groundwater originates mainly from monsoonal rain with some evaporation prior to or during infiltration and partly from bottom of ponds, canals and infiltration of groundwater withdrawn for irrigation. Relatively high tritium content of the shallow groundwater indicates local recharge, while the deep groundwater with very low tritium is recharged mainly from distant areas. At places the deep aquifer has relatively high tritium, indicating mixing of groundwater of shallow and deep aquifers. Metals such as copper, lead, arsenic, cadmium, aluminium, nickel and chromium are also present in groundwater of various depths. Therefore, aquifers of wetland and surrounding urban areas which are heavily dependent on groundwater are vulnerable to pollution. In the area south of ECW isotope data indicates no interaction between shallow and deep aquifer and hence this area may be a better location to treat sewage water than within ECW. To reduce the threat of pollution in ECW's aquifer, surface water-groundwater interaction should be minimized by regulating tubewell operation time, introducing treated surface water supply system and artificial recharging of the aquifer.

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Shu, D. M., and A. K. Bhattacharyya. "Prediction of sub-surface subsidence movements due to underground coal mining." Geotechnical and Geological Engineering 11, no. 4 (December 1993): 221–34. http://dx.doi.org/10.1007/bf00466365.

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Chaney, RC, KR Demars, EC Leong, HK Cheong, and TC Pan. "A Device for the Measurement of Sub-Surface Ground Vibrations." Geotechnical Testing Journal 19, no. 3 (1996): 286. http://dx.doi.org/10.1520/gtj10354j.

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Kivior, Irena, Stephen Markham, and Leslie Mellon. "Mapping Sub-Surface Geology from Magnetic Data in the Hides area, Western Papuan Fold Belt, PNG." ASEG Extended Abstracts 2016, no. 1 (December 2016): 1–7. http://dx.doi.org/10.1071/aseg2016ab165.

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Dehkhoda, Sevda, and Michael Hood. "An experimental study of surface and sub-surface damage in pulsed water-jet breakage of rocks." International Journal of Rock Mechanics and Mining Sciences 63 (October 2013): 138–47. http://dx.doi.org/10.1016/j.ijrmms.2013.08.013.

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Rudolph, E. M., D. W. Hedding, and W. Nel. "The surface geology of the Prince Edward Islands: refined spatial data and call for geoconservation." South African Journal of Geology 124, no. 3 (September 1, 2021): 627–38. http://dx.doi.org/10.25131/sajg.124.0014.

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Abstract Volcanological maps of the sub-Antarctic Prince Edward Islands were first published in 1968, with a revised surface geology map of Marion Island produced in 2006. These maps have been widely used in terrestrial studies on the Prince Edward Islands but they have limitations in spatial accuracy and detail. Using high-resolution satellite imagery and digital elevation data, more spatially accurate data for both Prince Edward and Marion Island’s surface geology are presented here. In particular, Marion Island’s volcanology on the western coast, including the 1980s lava flow, and the newly exposed Central Highland following the disappearance of extensive ice and snow cover is mapped with greater detail and verified through field observations. The spatial data are downloadable as ESRI layer packages, which can assist in future investigations of island biotic-abiotic processes and interactions and enable improvements in spatial modelling. In addition, this paper highlights geological features and specimens from the Prince Edward Islands as unique examples of geodiversity in a South African context. An overview of these features are provided in terms of their geoheritage value to enable a more comprehensive geoconservation strategy be incorporated into the Prince Edward Islands Management Plan.

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Firdaus, Yulinar, Ali Albab, Subarsyah Subarsyah, Dida Kusnida, Riza Rahardiawan, Imam Setiadi, Shaska R. Zulivandama, Tumpal B. Nainggolan, and Nazar Nurdin. "Acoustic And Geochemical Evidences Of Shallow Gas Distribution Offshore Waropen Basin, Papua, Indonesia." Bulletin of the Geological Society of Malaysia 71 (May 31, 2021): 113–23. http://dx.doi.org/10.7186/bgsm71202110.

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Sub-Bottom Profiling (SBP) records and results of geochemical analysis of 12 surficial sediment cores from various water depths collected from the offshore Waropen Basin-Papua are presented. Presence of gas is clearly observed on sub-bottom profiler records. Shallow gas was identified through acoustic response due to gas accumulation and gas escape on sub-bottom profiles. Acoustic evidences of gas accumulations within near surface geology consist of high amplitude reflections and associated acoustic blanking, gas plumes and morphological features like pockmarks. Total organic carbon analysis of 12 surface sediment cores varies between 0.5% to 1.3% which indicate that the sediments have an abundance of organic matters. Gas chromatographic analysis of hydrocarbon composition detected only methane, a biogenic origin of shallow gas. Acoustic and geochemical evidence in the Waropen Basin indicates extensive shallow gas accumulations in the Late Quaternary sediments, some trapped within these deposits and some escape from seabed into the water column which then created a high distribution of pockmarks.

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Gaikwad, Ravindra, and Vijay Bhagat. "Multi-criteria Prioritization for Sub-watersheds in Medium River Basin using AHP and Influence Approaches." Hydrospatial Analysis 2, no. 1 (December 27, 2018): 61–82. http://dx.doi.org/10.21523/10.21523/gcj3.18020105.

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Watershed is unique bio-physical unit of the Earth surface and source of resources to the human, animal and plants. AHP based multi-criteria analysis is suitable for prioritization of sub-watersheds in medium river basin for planning, management and development. Twenty five criterion i.e. area, morphimery, geology, slope, soil, rainfall and population density were selected for prioritization of medium watersheds of Upper Mula basin in Maharashtra (India). Correlation analysis is suitable for ranking the criterion selected for prioritization. Texture Ratio (25.94%), drainage texture (12.97%), stream order (8.65%), total stream length (6.49%) and ruggedness number (5.19%) show higher influences on development of watershed structure in the study area. Further, criterion like geology, rainfall, soil and population were show considerable influence in prioritization of sub-watersheds in medium river basin. Influences were estimated based on weights calculated using AHP technique. Values of influences were normalized using distribution of particular criterion within sub-watersheds. Watersheds are classified into high, moderate and low priorities. The methodology formulated in this study can be effective tool for quick prioritization of medium and major watersheds for planning and management for development.

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Gaikwad, Ravindra, and Vijay Bhagat. "Multi-criteria Prioritization for Sub-watersheds in Medium River Basin using AHP and Influence Approaches." Hydrospatial Analysis 2, no. 1 (December 27, 2018): 61–82. http://dx.doi.org/10.21523/gcj3.18020105.

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Watershed is unique bio-physical unit of the Earth surface and source of resources to the human, animal and plants. AHP based multi-criteria analysis is suitable for prioritization of sub-watersheds in medium river basin for planning, management and development. Twenty five criterion i.e. area, morphimery, geology, slope, soil, rainfall and population density were selected for prioritization of medium watersheds of Upper Mula basin in Maharashtra (India). Correlation analysis is suitable for ranking the criterion selected for prioritization. Texture Ratio (25.94%), drainage texture (12.97%), stream order (8.65%), total stream length (6.49%) and ruggedness number (5.19%) show higher influences on development of watershed structure in the study area. Further, criterion like geology, rainfall, soil and population were show considerable influence in prioritization of sub-watersheds in medium river basin. Influences were estimated based on weights calculated using AHP technique. Values of influences were normalized using distribution of particular criterion within sub-watersheds. Watersheds are classified into high, moderate and low priorities. The methodology formulated in this study can be effective tool for quick prioritization of medium and major watersheds for planning and management for development.

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Wang, Shuang, Xinlei Sun, Lanbo Liu, and Jianye Zong. "Sub-surface structures and site effects extracted from ambient noise in metropolitan Guangzhou, China." Engineering Geology 268 (April 2020): 105526. http://dx.doi.org/10.1016/j.enggeo.2020.105526.

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LIMA, ALEXANDRE DE OLIVEIRA, FRANCISCO PINHEIRO LIMA-FILHO, NILDO DA SILVA DIAS, PRISCILA REGINA DO ARAGÃO REGO, FLÁVIO FAVARO BLANCO, and MIGUEL FERREIRA NETO. "MECHANISMS CONTROLLING SURFACE WATER QUALITY IN THE COBRAS RIVER SUB-BASIN, NORTHEASTERN BRAZIL." Revista Caatinga 30, no. 1 (March 2017): 181–89. http://dx.doi.org/10.1590/1983-21252017v30n120rc.

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ABSTRACT Stream water quality is dependent on many factors, including the source and quantity of the streamflow and the types of geology and soil along the path of the stream. This study aims to evaluate the origin and the mechanisms controlling the input of ions that effect surface water quality in the sub -basin of the Rio das Cobras, Rio Grande do Norte state, Northeastern Brazil. Thirteen ponds were identified for study: three in the main river and ten in the tributaries between, thus covering the whole area and lithology of the sub -basin. The samples were collected at two different times (late dry and rainy periods) in the hydrological years 2009 and 2010, equating to total of four collection times. We analyzed the spatial and seasonal behavior of water quality in the sub-basin, using Piper diagrams, and analyzed the source of the ions using Guibbs diagram and molar ratios. With respect to ions, we found that water predominate in 82% sodium and 76% bicarbonate water (cations and anions, respectively). The main salinity control mechanism was related to the interaction of the colloidal particles (minerals and organic sediment) with the ions dissolved in water. Based on the analysis of nitrates and nitrites there was no evidence of contamination from anthropogenic sources.

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Tague, C. L., J. S. Choate, and G. Grant. "Parameterizing sub-surface drainage with geology to improve modeling streamflow responses to climate in data limited environments." Hydrology and Earth System Sciences 17, no. 1 (January 29, 2013): 341–54. http://dx.doi.org/10.5194/hess-17-341-2013.

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Abstract. Hydrologic models are one of the core tools used to project how water resources may change under a warming climate. These models are typically applied over a range of scales, from headwater streams to higher order rivers, and for a variety of purposes, such as evaluating changes to aquatic habitat or reservoir operation. Most hydrologic models require streamflow data to calibrate subsurface drainage parameters. In many cases, long-term gage records may not be available for calibration, particularly when assessments are focused on low-order stream reaches. Consequently, hydrologic modeling of climate change impacts is often performed in the absence of sufficient data to fully parameterize these hydrologic models. In this paper, we assess a geologic-based strategy for assigning drainage parameters. We examine the performance of this modeling strategy for the McKenzie River watershed in the US Oregon Cascades, a region where previous work has demonstrated sharp contrasts in hydrology based primarily on geological differences between the High and Western Cascades. Based on calibration and verification using existing streamflow data, we demonstrate that: (1) a set of streams ranging from 1st to 3rd order within the Western Cascade geologic region can share the same drainage parameter set, while (2) streams from the High Cascade geologic region require a different parameter set. Further, we show that a watershed comprised of a mixture of High and Western Cascade geologies can be modeled without additional calibration by transferring parameters from these distinctive High and Western Cascade end-member parameter sets. More generally, we show that by defining a set of end-member parameters that reflect different geologic classes, we can more efficiently apply a hydrologic model over a geologically complex landscape and resolve geo-climatic differences in how different watersheds are likely to respond to simple warming scenarios.

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Mushkin, A., and A. R. Gillespie. "Estimating sub-pixel surface roughness using remotely sensed stereoscopic data." Remote Sensing of Environment 99, no. 1-2 (November 2005): 75–83. http://dx.doi.org/10.1016/j.rse.2005.02.018.

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Wu, Zhaohao, Lin Bi, Deyun Zhong, Ju Zhang, Qiwang Tang, and Mingtao Jia. "Orebody Modeling Method Based on the Coons Surface Interpolation." Minerals 12, no. 8 (August 6, 2022): 997. http://dx.doi.org/10.3390/min12080997.

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This paper presents a surface modeling method for interpolating orebody models based on a set of cross-contour polylines (geological polylines interpreted from the raw geological sampling data) using the bi-Coons surface interpolation method. The method is particularly applicable to geological data with cross-contour polylines acquired during the geological and exploration processes. The innovation of this paper is that the proposed method can automatically divide the closed loops and automatically combine the sub-meshes. The method solves the problem that it is difficult to divide closed loops from the cross-contour polylines with complex shapes, and it greatly improves the efficiency of modeling based on complex cross-contour polylines. It consists of three stages: (1) Divide closed loops using approximate planes of contour polylines; each loop is viewed as a polygon combined with several polylines, that is the n-sided region. (2) After processing the formed n-sided regions, Coons surface interpolation is improved to complete the modeling of every single loop (3) Combine all sub-meshes to form a complete orebody model. The corresponding algorithm was implemented using the C++ programing language on 3D modeling software. Experimental results show that the proposed orebody modeling method is useful for efficiently recovering complex orebody models from a set of cross-contour polylines.

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Hemamalini, C. G., M. Arjun, S. Mathan Kumar, P. R. Mohan Krishna, and S. Prithivi Krishna. "Sub surface investigation using electrical resistivity method-A case study from srm institution, Ramapuram, Chennai (T.N), India." Bulletin of Pure & Applied Sciences- Geology 37f, no. 1 (2018): 54. http://dx.doi.org/10.5958/2320-3234.2018.00004.5.

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Sarate, Omprakash S. "Sub-surface coal seams of Bhupalpalli and Golapalli areas of Godavari valley coalfield and their petrographic characteristics." Journal of the Geological Society of India 87, no. 2 (February 2016): 153–60. http://dx.doi.org/10.1007/s12594-016-0383-z.

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Kornprobst, Jacques, Michel Piboule, and Abdelhalim Tabit. "Diversite des clinopyroxenites a grenat associees aux massifs ultramafiques orogeniques; eclogites, ariegites, griquaites et grospydites; une discussion." Bulletin de la Société Géologique de France III, no. 2 (March 1, 1987): 345–51. http://dx.doi.org/10.2113/gssgfbull.iii.2.345.

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Abstract Chemical composition of rocks belonging to the garnet clinopyroxenite clan (eclogites, griquaites, grospydites) are plotted in the Al 2 O 3 -FeO-MgO diagram. Compositions of eclogites from metamorphic series define a trend corresponding to liquids resulting from the low-pressure cotectic precipitation of ol+cpx+pl. These data support the igneous nature of the material and suggest that the original rocks experienced crystallization of the crust. Garnet clinopyroxenite inclusions from kimberlites and alkali basalts as well as garnet clinopyroxenite lenses from high temperature peridotite bodies define a different trend that can be interpreted as resulting from cpx+gt precipitation from a basic melt. The unusual position of these latter rocks justify that the term "griquaite" be applied to them. Corundum and/or kyanite bearing eclogites from metamorphic series as well as "grospydites" included in kimberlites or alkali basalts, or found as lenses in ultramafic bodies), plot toward the Al-rich apex of the Al-F-M diagram, but show different SiO 2 /Al 2 O 3 : the term "grospydite" appears fully justified to describe the latter, and distinguish them from the former (metamorphic) ones. The origin of grospydites is still in debate: they may be the products of high pressure crystallization of basic liquids. or of metasomatic crystallization of gabbros recycled within the mantle. The coexistence within the Beni Bousera massif in northern Morocco of griquaites and grospydites indicates the large heterogeneity of this upper mantle fragment. This heterogeneity can only be explained by a complex geodynamic evolution characterized by either 1) the succession of two distinct episodes of basic melt production; or 2) a cyclical mechanism implying the subduction in the mantle of a lithospheric fragment followed by the adiabatic ascension of this fragment towards the surface.

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Fattah Agha, Banaz Adeeb, and Omer S. Al-Tamimi. "Using Pumping Tests and Two Techniques of the Water Balance to Assess the Aquifer Hydraulic Characteristics and the Groundwater Recharge of Shewasoor Sub-Basin Kirkuk, NE Iraq." Iraqi Geological Journal 55, no. 1B (February 28, 2022): 82–93. http://dx.doi.org/10.46717/igj.55.1b.8ms-2022-02-24.

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Shewasoor sub-Basin represents one of the hydrogeological sub-basins of the Lower Zab River and covers an area of 160 km². It is located between longitude (44º 31' 23.9" – 44º 37' 75") and latitudes (35º 45' 28.9"–35º 48' 59"). The basin is bounded from the north and northeast by the Taqtaq anticline and Chamchamal anticline represents the western and southwest boundaries, while the southeast boundary is a surface water divide with the Al- Khassah River sub-basin. The groundwater distribution levels and movement maps show that the water depths range between 414-862 m a.s.l, and it moves in line with the movement of water surface drainage, as it moves from the east, southeast, south, and southwest (recharge areas) towards the northwest regions, while the water depths vary from the ground level between relatively deep in the southwestern part to medium and shallow in the rest of the parts. An evaluation of the hydraulic characteristic and groundwater recharge by two techniques of the water balance for aquifers of the study area has been carried out. The results showed that the hydraulic properties, transmissivity value ranges between 5.6 - 169 m²/day, the hydraulic conductivity values range between 0.67 - 5.1 m/day, and the storage coefficient values, ranging from the lowest value (0.0013) to the highest value (0.27). The results reflected that the types of the aquifers are unconfined and semi-confined as well as heterogeneous and anisotropic. after analyzing and calculating the climatological parameters of Koya meteorological station as the nearest station to the Shewassor area, showed the water surplus is equal to 333.94 mm which represent 53.8% of the annual rainfall value (628.3mm) and the surface water is equal to 138.5mm as a runoff. 199.44mm (31.74%) out of the annual rainfall is percolated to recharge the aquifers of Shewasoor, while water table fluctuation method WTF showed there are two zones of specific yield in the study area and the groundwater recharge is 232.06mm, so can be said that the 215.8mm is the average of the groundwater recharge in Shewasoor sub-basin. Finally, and by using the groundwater flow net analyzing technique that the amount of groundwater discharged from the study area is about 12 million m3 (MCM) and the renewal groundwater storage is 19.42 million m3 (MCM), which means there is 7.39 million m3 is groundwater can be invested as a safe investment.

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Ondréas, Hélène, Carla Scalabrin, Yves Fouquet, and Anne Godfroy. "Recent high-resolution mapping of Guaymas hydrothermal fields (Southern Trough)." BSGF - Earth Sciences Bulletin 189, no. 1 (2018): 6. http://dx.doi.org/10.1051/bsgf/2018005.

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Insights into the factors controlling fluid circulation through the crust and the nature of fluid venting at the seafloor are first steps in understanding their effect on ocean properties and climate change. New data on the seafloor morphology, sub-surface sedimentary stratification, and water column of the sedimented Southern Trough hydrothermal field (Guaymas basin) were acquired during the BIG cruise in 2010. These data provide accurate and high-resolution information on the geological context of the vents, on the distribution of acoustic anomalies in the water column, and on the possible nature of the fluid generating these echoes. More than 40 hydrothermal edifices were observed. The southern zone of the study area hosts hydrothermal sites that differ from the northern area. The southern vents are located inside or at the edge of small sub-circular depressions and the relationship between active edifices and collapsed areas involves different steps in the continous hydrothermal setting. Sub-bottom data show surface and sub-surface events, with some reflection layers possibly indicating subsurface hydrothermal precipitates or lithification with an estimated age of approximately 10 000 to 20 000 years. Based on the position and maximum altitude of the acoustic anomalies above the seafloor, two types of fluid emission echoes are distinguished: 1) anomalies reaching a maximal altitude of ∼350 m above the seafloor and seen both at the northern and southern fields and 2) strong, narrow and straight anomalies reaching 1334 or 1702 m above the seafloor that are only present in the southern hydrothermal fields of the studied area. We suggest that there are two types of echoes reflecting different fluid escapes based on the physical conditions of fluid venting and degassing and their relationship to geologic features: hydrothermal fluids or hydrothermal fluid mixed with hydrocarbon gas, oil or condensates rising through the water column. The collapsed depressions observed in the southern part facilitate the release of light hydrocarbon (gas, oil, and condensates) soluble at a high temperature and transported by hydrothermal fluids towards the shallow sedimentary levels where they accumulate. These light hydrocarbons rapidly migrate at high levels in the water column. This contrasts with the northern fields where hydrothermal circulation linked to deeper faults, re-mobilize heavier non-soluble hydrocarbons which do not migrate at high levels in the water column.

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Hilar, Matous, and Nhu The Tuan. "EVALUATION OF THE SURFACE SETTLEMENT ABOVE THE PRAGUE METRO LINE A EXTENSION CONSTRUCTED BY TWO SHIELDS." Acta Polytechnica 56, no. 6 (December 31, 2016): 448–54. http://dx.doi.org/10.14311/ap.2016.56.0448.

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The new section of the Prague metro V.A is located in the west part of Prague, between stations Dejvická and Motol Hospital. The new metro section is 6.2km long and has four new stations. Majority of the two running tunnels that are 6.2km long were excavated by two EPB (Earth Pressure Balance) shields (2 × 4.8 km), it was the first use of modern tunnelling machines in the Czech Republic. Surface settlement above the running tunnels caused by the EPB shields was regularly monitored. The following paper is focused on an evaluation of the mentioned surface settlement using a volume loss. Consequently, numerical modelling of various cross-sections was executed. Modelling was realised by a finite element method in 2D, using the software Plaxis. Two different approaches were applied for modelling of the 3D effect in 2D. Important parameters Mstage and Cref were derived for the selected cross-sections by back analyses (comparison of the numerical modelling results with the results of monitoring). The results of realised numerical modelling and the volume loss evaluation can be used for a preparation and realisation of similar tunnels in similar geology (for example, construction of the Prague metro line D, which will probably also be excavated by the EPB shields).

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Frost, F. B., and J. P. Dumble. "The Application of Ground Conductivity and Offset Wenner Resistivity Soundings to Optimise the Investigation of a 300 ha Site in the West Midlands." Geological Society, London, Engineering Geology Special Publications 2, no. 1 (1986): 241–45. http://dx.doi.org/10.1144/gsl.1986.002.01.44.

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AbstractIn order to evaluate quickly and cost effectively the detailed shallow sub-surface geology of a 300 ha area in the West Midlands, geophysical techniques were used in conjunction with shell and auger drilling. Since the area contains one of the largest landfill sites of its type in Europe and is crossed by a river which is abstracted for drinking water within a short distance downstream, it was important to determine the geology and hydrogeology in some detail.Previous geological surveys of the area, which included the drilling of over 80 boreholes for sand and gravel extraction, indicated the presence of up to 5 m of highly variable sandy overburden overlying Keuper Marl. It was apparent from an initial desk study that despite the large number of boreholes the geology had been completely misinterpreted.A ground conductivity map was produced using a Geonics EM-31 which rapidly gave a picture of the general structure and identified targets for drilling and Offset Wenner resistivity soundings. The geophysics revealed the presence of a major buried channel cutting deeply into the marl, which was later confirmed in several places by drilling. Surface outcrops of clay or marl could be identified using the ground conductivity values alone.The use of the geophysical techniques has considerably reduced the cost and time of the investigation and has allowed the major effort to be concentrated in problem areas.

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Townson, W. G. "THE SUBSURFACE GEOLOGY OF THE WESTERN OFFICER BASIN — RESULTS OF SHELL'S 1980-1984 PETROLEUM EXPLORATION CAMPAIGN." APPEA Journal 25, no. 1 (1985): 34. http://dx.doi.org/10.1071/aj84003.

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The Officer Basin described in this paper includes four Proterozoic to Lower Palaeozoic sub-basins (Gibson, Yowalga, Lennis, Waigen) which extend in a northwest to southeast belt across 200 000 sq. km of central Western Australia. These sub-basins are bounded by Archaean to Proterozoic basement blocks and are almost entirely concealed by a veneer of Permian and Cretaceous sediments. Depth to magnetic basement locally exceeds eight kilometres.Until recently, information on the sub-surface geology was limited to shallow levels, based on the results of a petroleum exploration campaign in the 1960s and the work of State and Federal Geological Surveys. In 1980, the Shell Company of Australia was awarded three permits (46 200 sq. km) covering the Yowalga and Lennis Sub-basins. The results of 4700 km of seismic data and three deep wildcat wells, combined with gravity, aeromagnetic, Landsat, outcrop and corehole information, has led to a better understanding of the regional subsurface geology.The Lennis Sub-basin appears to contain Lower to Middle Proterozoic sediments, whereas the Yowalga Sub- basin is primarily an Upper Proterozoic to Lower Cambrian sequence which comprises a basal clastic section, a middle carbonate and evaporite sequence and an upper clastic section. Widespread Middle Cambrian basalts cap the Upper Proterozoic to Lower Cambrian prospective sequence. Late Proterozoic uplift resulted in salt- assisted gravity tectonics leading to complex structural styles, especially in the basin axis.Despite oil shows, organic matter in the oil and gas generation windows and reservoir-quality sandstones with interbedded shales, no convincing source rocks or hydrocarbon accumulations have yet been located. The area remains, however, one of the least explored basins in Australia.

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Hillis, Richard R. "Does the in situ stress field control the orientation of open natural fractures in sub-surface reservoirs?" Exploration Geophysics 28, no. 1-2 (March 1997): 80–87. http://dx.doi.org/10.1071/eg997080.

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Albadran, Badir N., and Usama Q. Khaleefah. "Islands of the Tectonic Origin in the Shatt Al-Arab River, Southern Iraq." Iraqi Geological Journal 55, no. 2B (August 31, 2022): 153–61. http://dx.doi.org/10.46717/igj.55.2b.13ms-2022-08-29.

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Several factors control the formation of river islands, such as tectonic factors, sedimentation, erosion, and human activities. This research is concerned with islands in the Shatt Al-Arab channel, which are likely to be traced back to tectonic factors in their formation. The islands of the Shatt Al-Arab River are distributed along its axis starting from the islands of Sindbad and Muhammadiyah, 15 km to the north of the city center of Basra, to the islands of Shatit, Al-Dawasir and Minauhi, 70 km south of the city center of Basrah. This study area is part of the Mesopotamia Plain, southern Iraq. The fieldwork period extended from the beginning of September 2012 to June 2013, which included making subsurface sections (longitudinal and transverse) of the bottom of the Shatt Al-Arab channel using the Sub-bottom profile Strata box device, imaging the topography of the river bottom in a side scan sonar, collecting the bottom sediments by a grab sampler. The volumetric analysis method uses the Master Sizer device based on the Folk classification to calculate the volumetric gradient of sediments. The study showed that the tectonic factor has a prominent role in the growth island Maino and as a result of the presence of sub-surface structures for the structure of the Siba, which appeared to affect the subsurface layers of the river bed near the island as it appeared in the survey sections of the Strata box device. There are some islands that more than one factor emerged as a reason for their formation and development, as in the islands of Muhammadiyah and Umm al-Rasas, where tectonic and sedimentary factors interfered in their formation and development due to the influence of sub-surface structures as well as the influence of nearby rivers such as the Karma and Karun Rivers.

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Ivana, Jessica, L. Supriatna, and Tri Rani Puji Astuti. "Identification of Potential Groundwater Recharge Zone Using Remote Sensing and GIS in Upstream Cibeet Sub-watershed, Bogor, West Java." IOP Conference Series: Earth and Environmental Science 1111, no. 1 (December 1, 2022): 012025. http://dx.doi.org/10.1088/1755-1315/1111/1/012025.

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Abstract The Upstream Cibeet sub-watershed is part of the Citarum watershed and Cibeet sub-watershed with an area of 69.35 km2. Hydrologically, the upstream part of the watershed usually functions as a recharge area, and its development should be geared towards land conservation and erosion mitigation. Parameters of rainfall, soil type and texture, geology, lineament density, drainage density, geomorphology, and land cover are used in predicting the most potential catchment area. Thematic maps were made for each parameter. Weighting is carried out using the Analytical Hierarchy Process (AHP) with the following results: rainfall 0 %, soil type and texture 34.62 %, geology 24.98 %, lineament density 17.66 %, drainage density 8.57 %, geomorphology 9.34 %, and land cover 4.83 %. The integration of each thematic map resulted in a map with four zonations, namely zone of poor (4.93 %), fair (32.67 %), good (60.58 %), and very good (1.81 %) recharge potential. Based on the groundwater table contour, groundwater mimics the surface topography and flows from the south to the north and northeast part of the study area. Geological structures in the study area possess a NE-SW and NW-SE trend with a normal oblique regime. Structural damage zones are predicted to function as conduits for water movement, especially in volcanic and intrusion lithology.

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Mahesh, S., Srikanta Murthy, B. Chakraborty, and M. D. Roy. "Fossil charcoal as Palaeofire indicators: Taphonomy and morphology of charcoal remains in sub-surface Gondwana sediments of South Karanpura coalfield." Journal of the Geological Society of India 85, no. 5 (May 2015): 567–76. http://dx.doi.org/10.1007/s12594-015-0251-2.

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K, Manjunatha, Giridhara G, and Jegadeeswaran N. "Oxidation performance of CNT-reinforced Cr3C2-NiCr coatings sprayed by HVOF method." Journal of Mines, Metals and Fuels 69, no. 12A (April 28, 2022): 214. http://dx.doi.org/10.18311/jmmf/2021/30106.

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The high-temperature oxidation performance of thermal sprayed nanocomposite coatings is discussed in the present study. The three combinations 3, 5, and 7% wt. of CNT reinforced Cr3C2-25% NiC coatings sprayed by HVOF on SAE-213 T12 boiler tube alloy steel working at 6000C in silicon tubular furnace following 1hour heating and 20 minutes cooling in atmospheric temperature for 50 cycles. Thermally developed oxidized layer formation influences in structural variations on surface morphology, phases of elements of uncoated and CNT coated sample were analysed using SEM/EDS and XRD techniques. The thermogravimetric approach was used to estimate the kinetics of oxidation on all samples the weight gain measurement has been studied. The weight accumulation of bare substrate has a higher rate of oxidation than the CNT coated samples. The weight gain of the samples oxidation mechanism generally represents parabolic in nature. The oxidation growth rate minimizes when CNT reinforced in coatings and oxidizing scale deposited on CNT coated surface significantly lower than uncoated samples. The developed Cr2O3, NiO, and Fe2O3 oxidized layers were provided intensifying oxidation resistance.

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H S, Nithin, Pradeep D G, Nishchitha K M, Mahantayya Mathapati, Chikodi ., and Anand Babu K. "Comparative study on high temperature oxidation behaviour of CoCrAlY coatings by various reinforcement composition profile analysis." Journal of Mines, Metals and Fuels 69, no. 12A (April 28, 2022): 207. http://dx.doi.org/10.18311/jmmf/2021/30104.

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In this article, high temperature oxidation behaviour of plasma sprayed carbides and oxides reinforced composite CoCrAlY coatings were investigated at 700°C. CoCrAlY was reinforced with Al2O3+YSZ, CeO2, WC-Co, Cr3C2-NiCr individually to produce four different coatings. SEM, EDS and XRD are used to analyze the oxide scales formed during oxidation process on the coatings surface. From the results it is found that, all these coatings exhibited parabolic weight gain nature, indicating presence of protective oxide scale on coating surface, whereas changes in total weight gain is observed. CoCrAlY+Al2O3+YSZ coatings exhibited higher oxidation resistance than other coatings. The distribution of thermodynamically stable á- Al2O3 in the coating is shown slow-scale growth kinetics during the oxidation.

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Simms, Michael J. "The sub-basaltic surface in northeast Ireland and its significance for interpreting the Tertiary history of the region." Proceedings of the Geologists' Association 111, no. 4 (January 2000): 321–36. http://dx.doi.org/10.1016/s0016-7878(00)80088-7.

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Lyon, Eva C., Michael M. McGlue, Edward W. Woolery, Sora L. Kim, Jeffery R. Stone, and Susan R. H. Zimmerman. "Sublacustrine geomorphology and modern sedimentation in a glacial scour basin, June Lake, eastern Sierra Nevada, U.S.A." Journal of Sedimentary Research 89, no. 10 (October 21, 2019): 919–34. http://dx.doi.org/10.2110/jsr.2019.52.

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ABSTRACT Small sub-alpine glacial lakes are often targeted as Holocene paleoclimate archives, but their evolution as landforms and depositional basins is understudied. At June Lake in the eastern Sierra Nevada of California (USA), bathymetry, surface sediment composition, and seismic stratigraphy are studied to assess the modern sedimentary system and gain insight into the basin's origins. A basin-wide seismic survey reveals sublacustrine morphological features that attest to the role of ice in scouring the June Lake basin, including a prominent abraded bedrock shoal and an adjacent overdeepened depression. The seismic survey reveals four acoustically distinct stratigraphic units that reflect the history of sedimentation following glacial scouring. The youngest of these is represented in the recovered lacustrine core records as hemipelagically deposited, organic-rich, laminated diatomaceous oozes alternating with coarse tephra beds. The organic-rich oozes are characterized by low carbon and nitrogen stable-isotope values and occur in profundal areas of the modern lake floor. These sediments suggest an algae-dominated productivity regime and preservation of organic matter at depth. With no perennial streams entering June Lake, surface-sediment grain-size distribution and geochemistry are controlled by water depth and basin morphology. Additional modern facies types include poorly sorted coarse detrital landslide deposits below steep basin walls and volcaniclastic sandy gravel in windward littoral areas. These data provide a modern facies model for sedimentation in ice-scoured, hydrologically closed sub-alpine lakes and a baseline for future paleoclimate studies using June Lake sediment cores.

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Yadav, Jangbahadur Prasad. "Dharan Water Supply System - Alarming Issues and Future." Journal of Advanced Research in Civil and Environmental Engineering 10, no. 1 (March 2, 2023): 1–11. http://dx.doi.org/10.24321/2393.8307.202301.

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This study examines the critical issue of water scarcity in the Dharan Sub-metropolitan city, analyzing the various factors that are driving factors driving water demand and proposing strategies and ensuring water security. This study finds that factors replace with the rapid expansion of residential areas, increasing population, steeper slopes, changing lifestyles, natural hazards, technical and management leakage are major contributors to the growing water shortages in the area, leading to a situation of water instability. However, the study also identifies that factor such as precipitation, geology, soil types, potential water sources in the area offer opportunities for stabilizing the water supply in Dharan Sub-metropolitan. This study highlights the combined effect of these various active factors that led to an increase in per capita demand of water from 71 to 100 lpcd. This increasing water demand and shrinking of surface water led to Interrupted Water pumping and overexploitation. Additionally, the study indicates that due to high level of Non-Revenue Water (NRW) up-to 40%, certain parts of the city’s residents are facing major difficulties in accessing clean drinking water. The study also finds that positive changes in precipitation, supportive soil types and geology in the city of Dharan increases the potential for water recharge and harvesting. In order to achieve a sustainable and climate-resilient water supply, the study recommends implementing Water management tools likewise protective measures for critical water zones, stabilizing stream banks and gullies for surface water source improvement, artificial recharge of the city through Climate Adaptive Recharge Pits (CARP) and slope interception methods, as well as community-based water harvesting for groundwater source improvement. Furthermore, the study suggests establishing R&D unit involving national and local level experts and stakeholders for better planning and management.

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E. Daudu, Joy, S. Ali, and A. D. Shehu. "Application of spectral analysis to determine the magnetic source depths in ibarapa district, oyo state, sw nigeria." Global Journal of Geological Sciences 20, no. 1 (August 31, 2022): 85–93. http://dx.doi.org/10.4314/gjgs.v20i1.8.

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The method of spectral analysis was applied to the total aeromagnetic intensity data covering the district of Ibapara, located on the Nigeria Basement Complex in Oyo State, SW Nigeria. Prior to the spectral analysis, inclined magnetisation was converted to vertical, reduced to the pole and filtered out in order to more correctly reflect spatial location and morphology of magnetic sources over geological bodies, and enhance the effects of shallower sources over deeper ones. The data was divided into blocks and sub-blocks, and was spectrally analysed for the depths to the deep- and shallow-seated magnetic sources. The Curie-point-depths computed from these depths vary between 20.8 and 32.73 km, indicating that the magnetized basement rocks are at different elevations and are probably block faulted. The correlation of shallow Curie-point-depth with the Older Granites inferred that the low Curie-point-depth is due to magmatic intrusion in the highly deformed migmatite unit, the main geologic unit. The surface heat flows derived from the Curie-point-depths vary between 40.82 and 62.84 with a mean of 50.10 mW m-2, with areas having high surface heat flow presumed to be areas of recent intrusions where the elevated heat has transformed appropriate minerals to sapphire, tourmaline and aquamarine. Correlations of the surface heat flows and the average geothermal gradients on one hand and the Curie-point-depth on the other, unlike global compilation, yielded close empirical relations that are attributed to homogeneous geology of the area.

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Hadimuljono, Jonathan Setyoko, and Desi Yensusnimar. "Heavy Oil Seapage Characteristic in Cipari Area, Banyumas Central Java." Scientific Contributions Oil and Gas 44, no. 3 (March 4, 2022): 161–71. http://dx.doi.org/10.29017/scog.44.3.709.

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Oil seepage in Cipari, Banyumas, Central Java, has long been known. Although, Its occurrence had been reported in several publications, it's properties and characteristic, have not been explained in detail. Therefore, through field geology observation and laboratory analysis, this paper attempts to describe the oil seep characteristic, possible source rock origin, and its relationship with geological features in the surrounding area. Picnometer analysis resulted that this oil seep can be classified as heavy oil with 12n API Gravity. Gas Chromatography (GC) Gas Chromatography Mass Spectometry (GCMS) analysis revealed that Cipari oil seep is heavily biodegraded. Possible source rock of the oil seep was interpreted based on bicadinane and oleanane biomarkers, which indicated that source was deposited in fluvio-deltaic/transitional environment. Based on regional geology reference of Banyumas sub-Basin, it is inferred that the source rocks possibly shale or claystone of Paleogene sediment which was thermally mature, and deposited in transition to marine environment. Deep seated fault that extent from Majenang to Karangbolong areas is probably the main migration pathway of the oil seepage from the kitchen or deep reservoir to the surface. The Cipari anticline outcrop, which associated with faults and fractures, become the place where the oil seep occurs in the surface. Heavy biodegradation of the oil seep may possibly be accelerated by hydrothermal system during migration from the reservoir/kitchen area to the surface.

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Mohammad, Rizwan, and Solanki Dayaram. "Evaluation of Irrigation Quality of Sub-Surface Water Resources of Jobat Area, Alirajpur (M.P.) W. India: Insight to Hydro-Geochemical Analysis." Bulletin of Pure & Applied Sciences- Geology 40f, no. 2 (2021): 260–70. http://dx.doi.org/10.5958/2320-3234.2021.00023.8.

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Zainal, S. A., W. R. Daud, M. I. Rosli, S. Harun, Zulfan Adi Putra, and M. R. Bilad. "Development of An Integrated Surface and Sub-Surface Simulation Model in A Single Simulation Platform." Indonesian Journal of Science and Technology 5, no. 1 (January 29, 2020): 109–24. http://dx.doi.org/10.17509/ijost.v5i1.17439.

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An integrated model between surface and sub-surface is typically done by interconnecting many process modelling platforms. PROSPER and GAP are the common steady state modelling platforms for sub-surface while VMGSim and HYSYS are typical steady state surface modelling platforms. A major issue of using multiple simulation platforms is the compatibility of thermodynamic physical properties calculations among the platforms. This situation makes the simulations difficult to converge to a consistent thermo physical properties values. This is due to different interaction parameters applied in each platform that impact flashing and the physical property values even though the same property package such as Peng Robinson is used. To overcome this convergence problem, a single simulation platform within iCON (PETRONAS’s standard process simulation software, co-developed with VMG-Schlumberger) has been developed. This allows the use of one thermodynamic package across the integrated model. PROSPER sub-surface pressure-flow relationship results were automatically correlated and connected to surface models within the iCON environment. This integrated model was validated with data from operations and yielded about 1.23% average error tolerance. Based on this validated model, an optimization envelope can be developed with all possible well lineup configurations. This envelope covers set points for the operations where CAPEX free optimization can readily be applied.

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Cooper, Andrew, Alan Smith, Gavin Rishworth, Carla Dodd, Matt Forbes, Hayley Cawthra, and Callum Anderson. "Microbialites of modern siliciclastic rock coasts." Journal of Sedimentary Research 92, no. 7 (July 11, 2022): 619–34. http://dx.doi.org/10.2110/jsr.2021.071.

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ABSTRACT Contemporary microbialite formation has been documented on rock coasts in a variety of geomorphic, oceanographic, and climatic settings. Based on a synthesis of these diverse occurrences plus new observations, a generalized model is presented. At each locality microbialite development is associated with discharge of mineralized freshwater in the coastal zone. Microbialite formation in the high intertidal and supratidal zones of rock coasts occurs in a variety of sub-environments (cliff face, shore platform surface, platform surface pools, boulder beach, and sand beach) and forms a variety of laminated rock encrustations and oncoids. Allochthonous microbialites occur on the backshore as breccias of reworked microbialite clasts, oncoids transported from rock pools, and partly encrusted boulders. The microbialite-influenced rock coast is a distinct type of siliciclastic environment that offers potential comparison for ancient microbialite occurrences. It has preservation potential in both transgressive and regressive settings. Potential ancient examples are suggested.

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Agarwal, Neeraj, Rashmi Sharma, and Raj Kumar. "Impact of along-track altimeter sea surface height anomaly assimilation on surface and sub-surface currents in the Bay of Bengal." Ocean Modelling 169 (January 2022): 101931. http://dx.doi.org/10.1016/j.ocemod.2021.101931.

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Journal articles on the topic 'Sub-surface geology'

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