High-resolution estimates of rates of depositional processes from an alluvial fan succession in the Miocene of the Ebro Basin, northern Spain

2017 ◽  
Vol 440 (1) ◽  
pp. 159-173 ◽  
Author(s):  
Gary Nichols
Keyword(s):  
High Resolution ◽  
Alluvial Fan ◽  
Northern Spain ◽  
Ebro Basin ◽  
Depositional Processes

High-resolution root zone soil moisture-based indices for drought monitoring in the Ebro basin

2021 ◽  
Author(s):  
Vivien-Georgiana Stefan ◽  
Maria-José Escorihuela ◽  
Pere Quintana-Seguí
Keyword(s):  
Remote Sensing ◽  
Soil Moisture ◽  
High Resolution ◽  
Root Zone ◽  
Cost Effective ◽  
Strong Relationship ◽  
Drought Indices ◽  
Ebro Basin ◽  
Small Areas ◽  
Cost Effective Approach

<h3>Agriculture is an important factor on water resources, given the constant population growth and the strong relationship between water availability and food production. In this context, root zone soil moisture (RZSM) measurements are used by modern irrigators in order to detect the onset of crop water stress and to trigger irrigations. Unfortunately, in situ RZSM measurements are costly; combined with the fact they are available only over small areas and that they might not be representative at the field scale, remote sensing is a cost-effective approach for mapping and monitoring extended areas. A recursive formulation of an exponential filter was used in order to derive 1 km resolution RZSM estimates from SMAP (Soil Moisture Active Passive) surface soil moisture (SSM) over the Ebro basin. The SMAP SSM was disaggregated to a 1 km resolution by using the DISPATCH (DISaggregation based on a Physical And Theoretical scale CHange) algorithm. The pseudodiffusivity parameter of the exponential filter was calibrated per land cover type, by using ISBA-DIF (Interaction Soil Biosphere Atmosphere) surface and root zone soil moisture data as an intermediary step. The daily 1 km RZSM estimates were then used to derive 1 km drought indices such as soil moisture anomalies and soil moisture deficit indices (SMDI), on a weekly time-scale, covering the entire 2020 year. Results show that both drought indices are able to capture rainfall and drying events, with the weekly anomaly being more responsive to sudden events such as heavy rainfalls, while the SMDI is slower to react do the inherent inertia it has. Moreover, a quantitative comparison with drought indices derived from a model-based RZSM estimates has also been performed, with results showing a strong correspondence between the different indices. For comparison purposes, the weekly soil moisture anomalies and SMDI derived using 1 km SMAP-derived SSM were also estimated. The analysis shows that the anomalies and SMDI based on the RZSM are more representative of the hydric stress level of the plants, given that the RZSM is better suited than the SSM to describe the moisture conditions at the deeper layers, which are the ones used by plants during growth and development.</h3><h3>The study provides an insight into obtaining robust, high-resolution remote-sensing derived drought indices based on remote-sensing derived RZSM estimates. The 1 km resolution proves an improvement from other currently available drought indices, such as the European Drought Observatory’s 5 km resolution drought index, which is not able to capture as well the spatial variability present within heterogeneous areas. Moreover, the SSM-derived drought indices are currently used in a drought observatory project, covering a region in the Tarragona province of Catalonia, Spain. The project aims at offering irrigation recommendations to water agencies, and the introduction of RZSM-derived drought indices will further improve such advice.</h3>

scholarly journals Agricultural impacts on streams near Nitrate Vulnerable Zones: A case study in the Ebro basin, Northern Spain

PLoS ONE ◽  
2019 ◽  
Vol 14 (11) ◽  
pp. e0218582 ◽  
Author(s):  
Rubén Ladrera ◽  
Oscar Belmar ◽  
Rafael Tomás ◽  
Narcís Prat ◽  
Miguel Cañedo-Argüelles
Keyword(s):  
Northern Spain ◽  
Ebro Basin ◽  
Agricultural Impacts ◽  
Vulnerable Zones

An integrated high-resolution geophysical and geologic visualization of a Lake Bonneville shoreline deposit (Utah, USA)

2019 ◽  
Vol 7 (2) ◽  
pp. T265-T282 ◽  
Author(s):  
Katelynn M. Smith ◽  
John H. McBride ◽  
Stephen T. Nelson ◽  
R. William Keach ◽  
Samuel M. Hudson ◽  
...  
Keyword(s):  
High Resolution ◽  
Late Pleistocene ◽  
Depositional Environment ◽  
Three Dimensional ◽  
Sedimentary Facies ◽  
Basin And Range ◽  
Basin And Range Province ◽  
Lake Bonneville ◽  
Depositional Processes ◽  
Gravel Bar

Pilot Valley, located in the eastern Basin and Range, Western Utah, USA, contains numerous shorelines and depositional remnants of Late Pleistocene Lake Bonneville. These remnants present excellent ground-penetrating radar (GPR) targets due to their coherent stratification, low-clay, low-salinity, and low moisture content. Three-dimensional GPR imaging can resolve fine-scale stratigraphy of these deposits down to a few centimeters, and when combined with detailed outcrop characterization, it provides an in-depth look at the architecture of these deposits. On the western side of Pilot Valley, a well-preserved late Pleistocene gravel bar records shoreline depositional processes associated with the Provo (or just post-Provo) shoreline period. GPR data, measured stratigraphic sections, cores, paleontological sampling for paleoecology and radiocarbon dating, and mineralogical analysis permit a detailed reconstruction of the depositional environment of this well-exposed prograding gravel bar. Contrary to other described Bonneville shoreline deposits, calibrated radiocarbon ages ranging from 16.5 to 14.3 (ka, BP) indicate that the bar was stable and active during an overall regressive stage of the lake, as it dropped from the Provo shoreline (or just post-Provo level). Our study provides a model for an ancient pluvial lakeshore depositional environment in the Basin and Range province and suggests that stable, progradational bedforms common to the various stages of Lake Bonneville are likely not all associated with periods of shoreline stability, as is commonly assumed. The high-resolution GPR visualization demonstrates the high degree of compartmentalization possible for a potential subsurface reservoir target based on ancient shoreline sedimentary facies.

The Elswick Field, Bowland Basin, UK Onshore

2020 ◽  
Vol 52 (1) ◽  
pp. 62-73 ◽  
Author(s):  
Mathew Hampson ◽  
Heather Martin ◽  
Lucy Craddock ◽  
Thomas Wood ◽  
Ellie Rylands
Keyword(s):  
Electricity Generation ◽  
Alluvial Fan ◽  
Reservoir Quality ◽  
Gas Field ◽  
Water Contact ◽  
Depositional Processes ◽  
Well Field ◽  
Domal Structure ◽  
Single Well ◽  
Sandstone Formation

AbstractThe Elswick Field is located within Exploration Licence EXL 269a (Cuadrilla Resources Ltd is the operator) on the Fylde peninsula, West Lancashire, UK. It is the first producing onshore gas field to be developed by hydraulic fracture stimulation in the region. Production from the single well field started in 1996 and has produced over 0.5 bcf for onsite electricity generation. Geologically, the field lies within a Tertiary domal structure within the Elswick Graben, Bowland Basin. The reservoir is the Permian Collyhurst Sandstone Formation: tight, low-porosity fluvial desert sandstones, alluvial fan conglomerates and argillaceous sandstones. The reservoir quality is primarily controlled by depositional processes further reduced by diagenesis. Depth to the reservoir is 3331 ft TVDSS with the gas–water contact at 3400 ft TVDSS and with a net pay thickness of 38 ft.

Multiscale seismic imaging of active fault zones for hazard assessment: A case study of the Santa Monica fault zone, Los Angeles, California

Geophysics ◽  
1998 ◽  
Vol 63 (2) ◽  
pp. 479-489 ◽  
Author(s):  
Thomas L. Pratt ◽  
James F. Dolan ◽  
Jackson K. Odum ◽  
William J. Stephenson ◽  
Robert A. Williams ◽  
...  
Keyword(s):  
High Resolution ◽  
Los Angeles ◽  
Hazard Assessment ◽  
Seismic Reflection ◽  
Seismic Profile ◽  
Strike Slip ◽  
Alluvial Fan ◽  
Depth Range ◽  
Seismic Reflection Profile ◽  
Santa Monica

High‐resolution seismic reflection profiles at two different scales were acquired across the transpressional Santa Monica Fault of north Los Angeles as part of an integrated hazard assessment of the fault. The seismic data confirm the location of the fault and related shallow faulting seen in a trench to deeper structures known from regional studies. The trench shows a series of near‐vertical strike‐slip faults beneath a topographic scarp inferred to be caused by thrusting on the Santa Monica fault. Analysis of the disruption of soil horizons in the trench indicates multiple earthquakes have occurred on these strike‐slip faults within the past 50 000 years, with the latest being 1000 to 3000 years ago. A 3.8-km-long, high‐resolution seismic reflection profile shows reflector truncations that constrain the shallow portion of the Santa Monica Fault (upper 300 m) to dip northward between 30° and 55°, most likely 30° to 35°, in contrast to the 60° to 70° dip interpreted for the deeper portion of the fault. Prominent, nearly continuous reflectors on the profile are interpreted to be the erosional unconformity between the 1.2 Ma and older Pico Formation and the base of alluvial fan deposits. The unconformity lies at depths of 30–60 m north of the fault and 110–130 m south of the fault, with about 100 m of vertical displacement (180 m of dip‐slip motion on a 30°–35° dipping fault) across the fault since deposition of the upper Pico Formation. The continuity of the uncomformity on the seismic profile constrains the fault to lie in a relatively narrow (50 m) zone, and to project to the surface beneath Ohio Avenue immediately south of the trench. A very high‐resolution seismic profile adjacent to the trench images reflectors in the 15 to 60 m depth range that are arched slightly by folding just north of the fault. A disrupted zone on the profile beneath the south end of the trench is interpreted as being caused by the deeper portions of the trenched strike‐slip faults where they merge with the thrust fault.

High-resolution Stratigraphy of Holocene Lagoon Terraces of Southern Brazil

2015 ◽  
Vol 83 (1) ◽  
pp. 52-65 ◽  
Author(s):  
Natália B. dos Santos ◽  
Ernesto L.C. Lavina ◽  
Paulo S.G. Paim
Keyword(s):  
High Resolution ◽  
Sea Level ◽  
Radiometric Dating ◽  
Sea Level Changes ◽  
Relative Sea Level ◽  
Base Level ◽  
Depositional Processes ◽  
Close Relationship ◽  
Northern Portion ◽  
Depositional Architecture

AbstractThe northern portion of the coastal plain of the Rio Grande do Sul State (southernmost Brazil) comprises an outer sandy barrier that protects a complex lagoon system formed during the Holocene. The terraces of three different lagoons (Gentil, Malvas and Pinguela) formed along their margins record the depositional processes and the relative base level changes over the past 5000 yr. Therefore, our main objective was to characterize and quantify base level fluctuations from the study of these terraces, to correlate them to sea-level changes and to describe the depositional architecture related to the distinct sea-level stages (high-resolution sequence stratigraphy). Satellite images, topographic and GPR profiles, auger holes and radiometric dating were used. The main results indicate a close relationship between relative base level and relative sea-level changes, a stillstand period just after the last transgressive maximum (4840–4650 cal yr BP) and a subsequent overall relative sea-level fall of about 3 m. Both a normal (highstand systems tract) and a forced regression (falling-stage systems tract) controlled the geological record preserved in the terraces. The highstand (older terrace) is characterized by agradational bedding, whereas the falling stage comprises three progradational sets (terraces) bounded by erosive surfaces related to smaller-scale sea-level drops.

Syntectonic alluvial fan sedimentation, southern Pyrenees

1987 ◽  
Vol 124 (2) ◽  
pp. 121-133 ◽  
Author(s):  
G. J. Nichols
Keyword(s):  
Drainage Basin ◽  
Alluvial Fan ◽  
The Other ◽  
Early Miocene ◽  
Tectonic Activity ◽  
Late Oligocene ◽  
Ebro Basin ◽  
Northern Margin ◽  
Thrust Front ◽  
Topographic High

AbstractThe Aguero fanglomerate body developed in late Oligocene to early Miocene time at the northern margin of the Ebro Basin where the emergent southern Pyrenean thrust front created a topographic high. Tectonic activity in the thrust belt strongly influenced the sequences and structures within the fan deposits. The fan deposits display an initial coarsening-up sequence. Intraformational unconformities subdivide the proximal sediments into a series of wedges. These result from a continued uplift along the thrust front during the initial stages of fan development. A major intraformational unconformity marks the top of this sequence and the start of a fining-up sequence. Further tectonic activity in the thrust front is indicated by a syn-depositional synclinal fold which decreases in amplitude up sequence. Rejuvenation of fan sedimentation to form a second coarsening-up sequence reflects renewed activity in the thrust front. This second sedimentation event resulted in a plus 200 m thickness of massive conglomerates. The geographical limits of fan sedimentation can be determined because the fan deposits are lithologically distinct from the other Ebro Basin molasse in the area. The area of the drainage basin of the fan can also be estimated by consideration of the clast types present in the fan deposits. The fan and drainage basin areas are estimated to be 6 km2 and 10 km2 respectively.

scholarly journals Agricultural impacts on streams near Nitrate Vulnerable Zones: a case study in the Ebro basin, northern Spain

2019 ◽  
Author(s):  
Rubén Ladrera ◽  
Oscar Belmar ◽  
Rafael Tomás ◽  
Narcís Prat ◽  
Miguel Cañedo-Argüelles
Keyword(s):  
Riparian Forest ◽  
Agricultural Practices ◽  
Agricultural Activity ◽  
Northern Spain ◽  
Ebro Basin ◽  
Macroinvertebrate Assemblages ◽  
Management Actions ◽  
Wide Range ◽  
Nitrate Concentrations ◽  
Vulnerable Zones

AbstractAgricultural intensification during the last century has produced river degradation across Europe. From the wide range of pressures derived from agricultural activities that impact rivers, diffuse agricultural pollution has received most of the attention from managers and scientists. The aim of this study was to determine the main pressures exerted by intensive agriculture around Nitrate Vulnerable Zones (NVZs), which are areas of land that drain into waters polluted by nitrates according to the European Nitrate Directive (91/676/EEC). The study area was located in the NW of La Rioja (Northern Spain), which has the highest levels of nitrate concentrations within the Ebro basin. The relationships between forty environmental variables and the taxonomic and functional characteristics of macroinvertebrate assemblages (which are good indicators of water quality) were analyzed in 11 stream reaches differentially affected by upstream agricultural activity. The streams affected by a high percentage of agricultural area had significantly greater nitrate concentrations and distinct macroinvertebrate assemblages dominated by pollution tolerant taxa. Hydromorphological alteration (i.e. channel simplification, riparian forest degradation and sediment inputs), which is closely linked to agricultural practices, was the main factor affecting macroinvertebrate assemblages. Good agricultural practices should be implemented in streams affected by NVZs to reverse stream degradation, in consonance with the European Water Framework Directive (WFD). Management actions in these areas should not focus exclusively on nitrate reduction, but also on restoring riparian and aquatic habitats.

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