Results of geoelectrical soundings for mapping of a marine clay along the Tangkak-Pagoh highway Johor, Malaysia

1989 ◽  
Vol 20 (2) ◽  
pp. 117
Author(s):  
A.G. Rafek ◽  
A.R. Samsudin
Keyword(s):  
Apparent Resistivity ◽  
Fine Sand ◽  
Convex Curve ◽  
Marine Clay ◽  
Borehole Data ◽  
Individual Layer ◽  
The North ◽  
Geoelectrical Resistivity ◽  
Good Agreement ◽  
Clay Horizon

Geoelectrical resistivity soundings conducted along the north-south expressway in the Tangkak-Pagoh area during its construction enabled the mapping of a marine clay which was present in alluvium. The apparent resistivity curves of the marine clay area, were characterised by low apparent resistivity values falling to almost zero, and a characteristic shape which was different from areas of weathered metasediments and weathered granite adjacent to this area. Apparent resistivities for both metasediments and granite were intermediate to high, with a distinct upward convex curve for metasediments and a flat upward convex curve for granite. Quantitative interpretation was able to distinguish between an upper and a lower clay horizon, which have differentconsistency and fine sand content. The thickness of the upper clay horizon, which varies between 8.0 m to 9.0 m according to borehole data showed good agreement with that obtained by resistivity soundings. The base of the lower clay horizon remained undetected by the resistivity soundings because of its very low specific resistivity. Using the thickness of weathered layers as observed along the road cuttings as a guide, good agreement between field data and calculated values was obtained in determining the specific resistivities and individual layer thicknesses for the granite and metasediment weathering profiles.

The mineralogical composition of some Scottish soils

1925 ◽  
Vol 15 (3) ◽  
pp. 257-271 ◽  
Author(s):  
James Hendrick ◽  
George Newlands
Keyword(s):  
Mineralogical Composition ◽  
Fine Sand ◽  
Plant Food ◽  
Sand Fraction ◽  
Extensive Survey ◽  
North East ◽  
The North ◽  
Local Origin ◽  
East West ◽  
Made In

1. Previous investigations showed that certain Scottish soils were of glacial drift origin, that they were comparatively rich in unweathered silicates and therefore in reserves of plant-food, that they showed considerable variation in such silicates and were capable of classification accordingly. Some indication was also shown that the glacial drift, and hence the resulting soil, was sometimes of local origin, its character being determined by the underlying rock. In the present investigation a more extensive survey of Scottish soils has been made in order to discover to what extent these preliminary findings might be applicable generally.2. For this purpose soils have been collected from various localities in the north, north-east, west and south of Scotland, and have been analysed mechanically and the “fine sand” fraction examined mineralogically.

The late Wisconsinan olistostrome of the lower Coppermine River valley, Northwest Territories

1986 ◽  
Vol 23 (11) ◽  
pp. 1700-1708 ◽  
Author(s):  
Denis A. St-Onge ◽  
Jean Lajoie
Keyword(s):  
Debris Flows ◽  
Late Quaternary ◽  
Fine Sand ◽  
Coarse Sand ◽  
Coarse Fraction ◽  
River Valley ◽  
Glacial Lake ◽  
The North ◽  
Geologic Record ◽  
Coppermine River

The late Quaternary olistostrome exposed in the lower Coppermine River valley fills a paleovalley that ranges in apparent width from 150 to 400 m and was cut into Precambrian bedrock before the last glaciation. The olistostrome is here named the Sleigh Creek Formation. The coarse fraction of the formation is matrix supported; beds are massive or reversely graded and have sharp, nonerosive contacts. These characteristics suggest deposition of the coarse fraction by debris flows. The olistostrome sequence is bracketed by, and wedged into, a marine rhythmite sequence, which indicates that deposition occurred in a marine environment.About 10 500 years BP glacier ice in the Coronation Gulf lowland dammed the valley to the south, which was occupied by glacial Lake Coppermine. Sediments accumulated in this lake in a 30 m thick, coarsening upward sequence ranging from glaciolacustrine rhythmites of silt and fine sand at the base to coarse sand alluvium, and deltaic gravels at the top. As the Coronation Gulf lowlands became ice free, the Coppermine River reoccupied its former drainage course to the north. The steep south to north gradient and rapid downcutting by the river through the glacial lake sediments produced unstable slope conditions. The resulting debris flows filled a bedrock valley network below the postglacial sea level, forming the diamicton sequence.The interpretation of the Sleigh Creek Formation raises questions concerning silimar diamicton deposits usually defined as "flowtills." More generally, the results of this study indicate that care must be used when attempting paleogeographic reconstructions of "glaciogenic" deposits in marine sequences in any part of the geologic record.

scholarly journals Saharan dust infrared optical depth and altitude retrieved from AIRS: a focus over North Atlantic – comparison to MODIS and CALIPSO

2010 ◽  
Vol 10 (4) ◽  
pp. 1953-1967 ◽  
Author(s):  
S. Peyridieu ◽  
A. Chédin ◽  
D. Tanré ◽  
V. Capelle ◽  
C. Pierangelo ◽  
...  
Keyword(s):  
Optical Depth ◽  
North Atlantic ◽  
Western Indian Ocean ◽  
Saharan Dust ◽  
Orthogonal Polarization ◽  
Dust Layer ◽  
The North ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Good Agreement

Abstract. Monthly mean infrared (10 μm) dust layer aerosol optical depth (AOD) and mean altitude are simultaneously retrieved over the tropics (30° S–30° N) from almost seven years of Atmospheric Infrared Sounder (AIRS) observations covering the period January 2003 to September 2009. The method developed relies on the construction of look-up-tables computed for a large selection of atmospheric situations and follows two main steps: first, determination of the observed atmospheric thermodynamic situation and, second, determination of the dust properties. A very good agreement is found between AIRS-retrieved AODs and visible optical depths from the Moderate resolution Imaging Spectroradiometer (MODIS/Aqua) during the main (summer) dust season, in particular for three regions of the tropical North Atlantic and one region of the north-western Indian Ocean. Outside this season, differences are mostly due to the sensitivity of MODIS to aerosol species other than dust and to the more specific sensitivity of AIRS to the dust coarse mode. AIRS-retrieved dust layer mean altitudes are compared to the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP/CALIPSO) aerosol mean layer altitude for the period June 2006 to June 2009. Results for a region of the north tropical Atlantic downwind of the Sahara show a good agreement between the two products (σ≈360 m). Differences observed in the peak-to-trough seasonal amplitude, smaller from AIRS, are principally attributed to the large difference in spatial sampling of the two instruments. They also come from the intrinsic limit in sensitivity of the passive infrared sounders for low altitudes. These results demonstrate the capability of high resolution infrared sounders to measure not only dust aerosol AOD but also the mean dust layer altitude.

scholarly journals Hydrogeological characterisation of a glacially affected barrier island – the North Frisian Island of Föhr

2012 ◽  
Vol 9 (4) ◽  
pp. 5085-5119 ◽  
Author(s):  
T. Burschil ◽  
W. Scheer ◽  
R. Kirsch ◽  
H. Wiederhold
Keyword(s):  
North Sea ◽  
Underground Structure ◽  
Empirical Relation ◽  
Geophysical Methods ◽  
Strong Impact ◽  
Hydrogeological Model ◽  
Borehole Data ◽  
The North ◽  
The North Sea ◽  
D Model

Abstract. We present the application of geophysical investigations to characterise and improve the geological/hydrogeological model through the estimation of petrophysical parameters for groundwater modelling. Seismic reflection and airborne electromagnetic surveys in combination with borehole information enhance the 3-D geological model and allow a petrophysical interpretation of the subsurface. The North Sea Island of Föhr has a very complex underground structure what was already known from boreholes. The local waterworks use a freshwater body embedded in saline groundwater. Several glaciations disordered the Youngest Tertiary and Quaternary sediments by glaciotectonic thrust-faulting as well as incision and refill of glacial valleys. Both underground structures have a strong impact on the distribution of freshwater bearing aquifers. An initial hydrogeological model of Föhr was built from borehole data alone and was restricted to the southern part of the island where in the sandy areas of the Geest a large freshwater body was formed. We improved the geological/hydrogeological model by adding data from different geophysical methods, e.g. airborne electromagnetics (EM) for mapping the resistivity of the entire island, seismic reflections for detailed cross sections in the groundwater catchment area, and geophysical borehole logging for calibration of these measurements. An integrated evaluation of the results from the different geophysical methods yields reliable data. To determinate petrophysical parameter about 18 borehole logs, more than 75 m deep, and nearby airborne EM inversion models were analyzed concerning resistivity. We establish an empirical relation between measured resistivity and hydraulic conductivity for the specific area – the North Sea island of Föhr. Five boreholes concerning seismic interval velocities discriminate sand and till. The interpretation of these data was the basis for building the geological/hydrogeological 3-D model. We fitted the relevant model layers to all geophysical and geological data and created a consistent 3-D model. This model is the fundament for groundwater simulations considering forecasted changes in precipitation and sea level rise due to climate change.

Miniature mud volcanoes and other injection features in tidal flats, James Bay, Québec

1976 ◽  
Vol 13 (3) ◽  
pp. 422-428 ◽  
Author(s):  
Jean-Claude Dionne
Keyword(s):  
East Coast ◽  
Fine Sand ◽  
Tidal Flats ◽  
Mud Volcanoes ◽  
James Bay ◽  
Marine Clay ◽  
Ice Floes ◽  
Mud Deposit

Miniature injection features, including mud volcanoes, dikes forming polygonal patterns, and isolated patches of clay, occur in tidal flats along the east coast of James Bay. They are formed by localized upward ejection of a mixture of fluidized marine clay, silt, and fine sand through a surficial recent mud deposit. Liquefaction is related to the melting of ice in the clayey deposit. Upward flowing of clay, silt, and fine sand seems to result from overloading by the overlying sediments having a higher degree of density, and possibly also by pressures of ice floes or/and icefoot.

The shape and infill of the Basadingen overdeepened glacial valley from P-wave seismic reflections

2021 ◽  
Author(s):  
Anna-Catharina Brandt ◽  
David C. Tanner ◽  
Hermann Buness ◽  
Thomas Burschil ◽  
Gerald Gabriel
Keyword(s):  
P Wave ◽  
Borehole Data ◽  
North East ◽  
The North ◽  
Glacier Valley ◽  
Sedimentary System ◽  
Climatic History ◽  
The Alps ◽  
Seismic Reflections ◽  
Seismic Images

<p><span>Overdeepened valleys in the Alps allow to probe the glacial sedimentation record, which in turn can illuminate the climatic history. In particular, seismic reflections can be used to extend punctual borehole data (for instance a number of boreholes are to be drilled into Alpine glacial overdeepened valleys as part of the DOVE ICDP project) in the second dimension or even survey a region before drilling begins. Thus, we use detailed, 2-D seismic P-wave profiles to reveal the shape and infill of an overdeepened Rhine glacier valley in the area of Basadingen, near to the German/Swiss border. We acquired two profiles nearly perpendicular to the valley strike, approximately 500 m apart. The first profile was 1246 m long, and consisted of a single spread of 624 geophones. The second profile was 1120 m long and was acquired using 200 3-component geophones using a roll-along method. For both profiles we used a vibro-source with a 12 s linear sweep of 20-240 Hz at every second geophone (two metre spacing), which produced a high fold.</span></p><p><span>Both seismic images reveal that the overdeepened basin at this location is asymmetrical and circa 260 m deep, although the deepest part (220</span><span> </span><span>m wide) covers only a small portion of the broader main valley. The infill is characterised by at least three unconformities and distinct onlap and erosive boundaries between the sedimentary units. We interpret the infill to represent a highly dynamic sedimentary system. The lower part, within the deepest part of the basin is filled with chaotic sediments and slumping. Above a major unconformity, the upper part contains strongly-dipping reflectors that probably represent a prograding point-bar in a glacio-fluviatile environment that migrated toward the north-east. Beneath the deepest part of the basin we see evidence for faults in the Tertiary Molasse basement, which correlate with known faults at the surface. The faults most likely caused the valley to be sited at this location and they were probably also the cause of the ‘valley in valley’ shape.</span></p><p><span>A new DOVE research borehole will be drilled in the centre of the valley in 2021. This will bring more light on the sedimentary history and OSL-dating of the material will bracket the timing of the infill. </span></p>

scholarly journals A representative density profile of the North Greenland snowpack

2016 ◽  
Vol 10 (5) ◽  
pp. 1991-2002 ◽  
Author(s):  
Christoph Florian Schaller ◽  
Johannes Freitag ◽  
Sepp Kipfstuhl ◽  
Thomas Laepple ◽  
Hans Christian Steen-Larsen ◽  
...  
Keyword(s):  
Remote Sensing ◽  
High Resolution ◽  
Density Profile ◽  
Accumulation Rate ◽  
Sampling Technique ◽  
Data Sets ◽  
Accumulation Rates ◽  
The North ◽  
North Greenland ◽  
Good Agreement

Abstract. Along a traverse through North Greenland in May 2015 we collected snow cores up to 2 m depth and analyzed their density and water isotopic composition. A new sampling technique and an adapted algorithm for comparing data sets from different sites and aligning stratigraphic features are presented. We find good agreement of the density layering in the snowpack over hundreds of kilometers, which allows the construction of a representative density profile. The results are supported by an empirical statistical density model, which is used to generate sets of random profiles and validate the applied methods. Furthermore we are able to calculate annual accumulation rates, align melt layers and observe isotopic temperatures in the area back to 2010. Distinct relations of δ18O with both accumulation rate and density are deduced. Inter alia the depths of the 2012 melt layers and high-resolution densities are provided for applications in remote sensing.

scholarly journals Late Holocene temperature variability in Tasmania inferred from borehole temperature data

2017 ◽  
Vol 13 (6) ◽  
pp. 559-572 ◽  
Author(s):  
Asadusjjaman Suman ◽  
Fiona Dyer ◽  
Duanne White
Keyword(s):  
East Coast ◽  
Past Century ◽  
Borehole Data ◽  
Depth Profiles ◽  
The Past ◽  
North East ◽  
The North ◽  
Borehole Temperature ◽  
Temperature Depth

Abstract. Thirty-six borehole temperature–depth profiles were analysed to reconstruct the ground surface temperature history (GSTH) of eastern Tasmania for the past 5 centuries. We used the singular value decomposition method to invert borehole temperatures to produce temperature histories. The quality of borehole data was classified as high or low based on model misfit. The quality of the borehole data was not dependent on topography or land use. Analysis reveals that three to five high-quality borehole temperature–depth profiles were adequate to reconstruct robust paleotemperature records from any area. Average GSTH reconstructed from Tasmanian boreholes shows temperature increases about 1.2 ± 0.2 °C during the past 5 centuries. Reconstructed temperatures were consistent with meteorological records and other proxy records from Tasmania during their period of overlap. Temperature changes were greatest around the north-east coast and decreased towards the centre of Tasmania. The extension of the East Australian Current (EAC) further south and its strengthening around the north-east coast of Tasmania over the past century was considered a prime driver of warmer temperatures observed in north-east Tasmania.

The macrobenthos of the Beatrice Oilfield, Moray Firth, Scotland

1986 ◽  
Vol 91 ◽  
pp. 221-245
Author(s):  
J. P. Hartley ◽  
J. D. D. Bishop
Keyword(s):  
New Records ◽  
Benthic Communities ◽  
Fine Sand ◽  
Faunal Composition ◽  
Qualitative And Quantitative ◽  
The North ◽  
Moray Firth ◽  
Faunal Communities ◽  
The North Sea

SynopsisThe benthic ecology of the Beatrice Oilfield area is described from preproduction surveys carried out in 1977, 1980 and 1981. and from earlier published information. Variations in the water depth (from 33m to > 60 m) over the area were mirrored by sedimentary and faunal gradients. The sediments ranged from very fine, through fine to medium sands and were inhabited by faunal communities characterised by Thyasira flexuosa, Tellina fabula and Tellina pygmaea, respectively. Two fades of the fine sand community were noted, typified by the abundance of Thyasira flexuosa in muddier sediments and Crenella decussala in coarser deposits. Localised patches of shell gravel in which the fauna was characterised by reduced densities of Tellina fabula with elevated numbers of Scoloplos armiger and Lumbrineris gracilis occurred in medium depths. Examination of the faunal composition indicates that the Beatrice Oilfield lies at the interface between Glemarec's infralittoral and coastal étages.Comparison with earlier reports of the benthic communities of the area suggests a degree of long term persistence of the fauna in qualitative and quantitative terms. A list of all taxa found during the recent surveys is given; this includes a number of new records from the North Sea.

scholarly journals Application of seismic tomography for detecting structural faults in a Tertiary Formation

2019 ◽  
Vol 92 ◽  
pp. 18008
Author(s):  
Víctor A. Rinaldi ◽  
Horacio V. Ibarra ◽  
Ricardo F. Viguera ◽  
Juan C. Harasimiuk
Keyword(s):  
Seismic Tomography ◽  
Seismic Refraction ◽  
Soil Formation ◽  
Seismic Profile ◽  
Basic Principles ◽  
Geotechnical Parameters ◽  
Tomographic Images ◽  
The North ◽  
History Of ◽  
Good Agreement

Seismic refraction technique is an increasingly useful geophysical tool for geotechnical studies in civil engineering work including the mapping of different soil formation of subsoil and detection of the bed rock. Additionally, wave velocity is a key parameter which correlates directly with significant geotechnical parameters of soils and rocks. Today, the evolution of the measurement technique in the field and the data processing allows to obtain tomographic images which increases its potential for applications to evaluate structuration of rock mass. This work describes the basic principles of seismic tomography and a case history of an application in civil works used to detect hidden faults in the sedimentary Gatun formation at the north of Panama. The correlation between the seismic profile and geologic profile obtained from boreholes showed very good agreement. Subsequent directed boreholes performed at the site confirmed the position and nature of the faults detected.

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