Tertiary Clays Research Articles

The distribution of sodic soils in Tasmania

It is estimated that sodic soils (ESP>6) occupy at least 23% of Tasmania's land area based on the present limited soil data set. Sodic soils are mostly restricted to lower rainfall areas (<800 mm/y) of eastern Tasmania, occurring primarily in the Launceston Tertiary Basin, the Derwent, Coal, Jordan and Huon River Valleys and on Flinders Island. In Tasmania, sodic soils have formed predominantly from Triassic and Permian mudstones and sandstones, Tertiary clays and unconsolidated Quaternary deposits. However, profiles with sodic features have also developed above granite, Jurassic dolerite and Tertiary basalt. Sodic soils most commonly occur on lowland plains, river terraces and in valley floors. In Tasmania, sodic soils are characterized morphologically by: (i) abrupt separation of a sandy, bleached A2 horizon from a moderately sodic (ESP 6-15) clay subsoil; (ii) coarse prismatic, columnar and/or angular blocky pedality in the subsoil, which may exhibit vertic properties; (iii) hardsetting sandy A2 horizons in some profile classes; (iv) fine sandy crack infills and clay-organic coatings on ped faces in the upper B2 horizon; and (v) thick, sticky and greasy fine clay argillans on ped faces, and clay infills in cracks and other voids in the lower B2 horizon that contribute to reduced porosity and permeability. Sodic soils in Tasmania have traditionally been utilized for pasture production with occasional cultivation for fodder crops and pasture renewal. Under a pastoral system, few sodicity problems have been recognized as such. However, in the last 10 years there has been increased cropping, particularly for poppies and more recently potatoes. Soil structure decline and drainage problems have become key factors limiting production. Management problems are mainly due to poor internal and external drainage, with poor structure in the A2 horizons which liquefy in winter and often set hard in summer. Salinity in associated drainage depressions is a problem gaining increasing recognition.

Laboratory and field observations of the accumulation of polar organic molecules in clay mineral sealings used in waste disposal sites

The composition of the organic matter of a core taken from the clay mineral sealing of the waste disposal site of Geldern-Pont (Germany) after 8 yr of operation has been analysed using GC and GC-MS. Results show that the organic carbon content of the upper part of the sealing which was closest to the waste increased by a factor of 10 when compared with the original unaltered clay. The extractable organic matter from the upper part of the sealing is significantly enriched in long-chain n-alkanes, with a dominance of odd-numbered chain lengths. Long-chain n-alkan-2-ones with a dominance of odd-numbered homologues accumulated in the lower part of the sealing. Two tetracyclic hydrocarbons (des-A-oleanene and des-A-lupane) were present only in the upper part of the sealing close to the dump. Both compounds probably originate from reworking of organic matter in the waste by anaerobic bacteria. Additionally, four Tertiary clays have been percolated in the laboratory with leachate from an industrial landfill over periods of 9 weeks and 19 months. The organic compounds in the seepage waters were primarily phenols, aniline and pyridine derivatives as well as aromatic and alipathic acids. During percolation many of these compounds were apparently microbially degraded in the clays to C 1–C 8 fatty acids. The results indicate that physico-chemical interaction of the clay minerals with organic compounds in the leachate was accompanied by microbial activity within the clays, leading to further conversion of the primary adsorbed organic compounds.

The Hepburn landslide: an interactive slope-stability and seepage analysis

Mechanisms of active landslides are continuous processes involving the dynamics of slope failure interacting with the groundwater regime. This process is simulated in phases by combining stability calculations interactively with a seepage analysis to determine the factor of safety for a dormant landslide near Hepburn, Saskatchewan. The landslide is a multiple retrogressive failure with two parallel slip surfaces at different elevations. The slip surfaces are in originally overconsolidated Cretaceous and Tertiary clays softened by shear from glaciation. An artesian aquifer is present at the base of the slip surface, causing saline springs at the base of the valley slope. A residual effective friction angle of 6.7° with zero cohesion was found to best characterize the shear strength of the clays in the failure zone. Potential nets and head profiles from the seepage analysis illustrate the strong influence of changing topography on the groundwater flow system. The present-day factor of safety for the dormant landslide was estimated to be 1.10. Key words: multiple retrogressive landslides, dormant landslide, seepage modelling, residual strength, artesian conditions, glacial drift, Cretaceous clays.

Evolution of the Quaternary melitite-nephelinite Herchenberg volcano (East Eifel)

The Quaternary Herchenberg composite tephra cone (East Eifel, FR Germany) with an original bulk volume of 1.17·107 m3 (DRE of 8.2·106 m3) and dimensions of ca. 900·600·90 m (length·width·height) erupted in three main stages: (a) Initial eruptions along a NW-trending, 500-m-long fissure were dominantly Vulcanian in the northwest and Strombolian in the southeast. Removal of the unstable, underlying 20-m-thick Tertiary clays resulted in major collapse and repeated lateral caving of the crater. The northwestern Lower Cone 1 (LC1) was constructed by alternating Vulcanian and Strombolian eruptions. (b) Cone-building, mainly Strombolian eruptions resulted in two major scoria cones beginning initially in the northwest (Cone 1) and terminating in the southeast (Cones 2 and 3) following a period of simultaneous activity of cones 1 and 2. Lapilli deposits are subdivided by thin phreatomagmatic marker beds rich in Tertiary clays in the early stages and Devonian clasts in the later stages. Three dikes intruded radially into the flanks of cone 1. (c) The eruption and deposition of fine-grained uppermost layers (phreatomagmatic tuffs, accretionary lapilli, and Strombolian fallout lapilli) presumably from the northwestern center (cone 1) terminated the activity of Herchenberg volcano. The Herchenberg volcano is distinguished from most Strombolian scoria cones in the Eifel by (1) small volume of agglutinates in central craters, (2) scarcity of scoria bomb breccias, (3) well-bedded tephra deposits even in the proximal facies, (4) moderate fragmentation of tephra (small proportions of both ash and coarse lapilli/bomb-size fraction), (5) abundance of dense ellipsoidal juvenile lapilli, and (6) characteristic depositional cycles in the early eruptive stages beginning with laterally emplaced, fine-grained, xenolith-rich tephra and ending with fallout scoria lapilli. Herchenberg tephra is distinguished from maar deposits by (1) paucity of xenoliths, (2) higher depositional temperatures, (3) coarser grain size and thicker bedding, (4) absence of glassy quenched clasts except in the initial stages and late phreatomagmatic marker beds, and (5) predominance of Strombolian, cone-building activity. The characteristics of Herchenberg deposits are interpreted as due to a high proportion of magmatic volatiles (dominantly CO2) relative to low-viscosity magma during most of the eruptive activity.

Design of a tunnel with 9.7m diameter in tertiary clay : Proc Symposium on Computer Aided Design and Monitoring in Geotechnical Engineering, Bangkok, 3–6 December 1986 P648–660. Publ Bangkok: AIT, 1986

Design of a tunnel with 9.7m diameter in tertiary clay : Proc Symposium on Computer Aided Design and Monitoring in Geotechnical Engineering, Bangkok, 3–6 December 1986 P648–660. Publ Bangkok: AIT, 1986

Stable-isotope geochronology of the Australian regolith

Australian regolith profiles can be assigned to one of three post-Palaeozoic age groups on the basis of the oxygen-isotope composition of authigenic clay minerals developed in the profile. Systematic variations in the isotopic composition of meteoric waters, and therefore of the authigenic regolith minerals that formed in equilibrium with them, are a result of the continent's drift from high to low latitudes and changes in global climate. Residual clays (collected in situ from regolith profiles) of post-mid Tertiary age have δ 18 O values between +17.5 and +21.3%., with the exception of samples from northern Australia (north of approximately 20°S), which have anomalously low values because meteoric waters in northern Australia are largely derived from monsoonal rain. The high δ 18 O, values of post-mid Tertiary residual clays are consistent with Australia's northward drift to low (warm) latitudes during this time, compared with the much higher latitudes it occupied for most of its post-Palaeozoic history. Late Tertiary residual clays have δ 18 O values that are indistinguishable from all other post-mid Tertiary clays, indicating that further subdivision of the sample groups is not feasible on a continent-wide scale. Comparison with hypothetical “modern” clays in equilibrium with modern meteoric waters confirms that there has been very little change in the isotopic composition of meteoric waters in Australia since the mid-Tertiary. Pre-mid Tertiary clays have lower δ 18 O values, between +10.0 and +17.5%., which are consistently lower than post-mid-Tertiary clays. δ 18 O values of less than +14 to +15%. are thought to reflect weathering events during much earlier geologic periods, perhaps early or mid Mesozoic, when Australia was at high latitude and the Australian climate was humid and cool to cold. Several workers have documented the existence of very old regolith profiles and land surfaces in Australia and support for the above hypothesis comes from three analyses of clays from profiles of stratigraphically demonstrable pre-late Mesozoic age which have δ 18 O values between +10.2 and +12.3%.. Regolith profiles composed of low- 18O clays (< +15%.) are widespread in Australia, and it is possible that a much greater part of the modern landscape than previously recognized developed in the early- or mid-Mesozoic. The δ 18 O values of transported (i.e., sedimentary) kaolinites reveals that the major source for many Tertiary kaolinitic sediments was this postulated pre-late Mesozoic low- 18O regolith. The stableisotope evidence that much of the Australian regolith formed in comparatively cold conditions suggests that, contrary to some traditional interpretations, lateritization and deep weathering phenomena are not solely the result of weathering in tropical or sub-tropical climates. The hydrogen-isotope composition of the clays range from −115 to −50%.; however, it is inferred that the majority of clays have undergone some post-formational hydrogen-isotope exchange which renders their δD composition unsuitable for dating purposes.

Loading characteristics of a tertiary clay and implications for road pavement design : Smith, R B Int Assoc Engng Geol BullN37, April 1988, P137–135

Loading characteristics of a tertiary clay and implications for road pavement design : Smith, R B Int Assoc Engng Geol BullN37, April 1988, P137–135

Loading characteristics of a tertiary clay and implications for road pavement design

A Tertiary clay was subjected to California Bearing Ratio testing and repeated load testing. X-ray diffraction showed that the clay fraction was quartz-rich with minor amounts of goethite (5–10%). The clay component consisted of mainly kaolinite (55%) and a mixed layer expandable clay (45%) with a minor amount of illite. The study showed that bearing capacity of the material was very sensitive to the moulded moisture content and relative density at compaction. Similarly the repeated loading characteristics at the stress levels likely to be experienced in a road subgrade indicated that the performance under repeated loading was also extremely sensitive to the moulded moisture content and relative density. The implications for road pavement design of this material are also discussed.

A detailed gravity survey between Dartmoor and Bodmin Moor: the shape of the Cornubian granite ridge and a new Tertiary basin

A detailed gravity survey over 1800 km 2 between Dartmoor and Bodmin Moor, with an average station spacing of 3.25 kn −2 is interpreted in terms of the depth to the buried Cornubian granite. Large areas are defined where the granite surface lies within 1 km of sea level; in contrast, the NE edge of the Bodmin granite dips steeply to depths of at least 3 km. A closed minimum Bouger gravity anomaly at Lamerton, NW of Tavistock, has a residual anomaly some 2 mGal larger than the adjacent area. This can be quantitatively interpreted as either a Tertiary basin filled with argillaceous sediments or a small granite cupola extending from the roof-region of the granite at about 2 km depth. Both these solutions are novel. A shallow piston core to a depth of about 15 m together with a resistivity depth sounding supports the sedimentary interpretation of the Lamerton anomaly, and suggests a thickness of about 150 m of Tertiary clays in a fault-bounded basin, elongated to the NW.

Geochemistry of Tertiary alterite clay phases on the Iceland-Faeroe Ridge (northeast Atlantic), leg 38, site 336

The geochemistry analyses of the clay fraction (< 1 μm) of Tertiary alterites overlying tholeiitic basalt (Site 336) on the Iceland—Faeroe Ridge, revealed — close to the parent rock — the predominance of ferriferous montmorillonite (80%) over kaolinite and halloysite. Conversely, the top of alterite redbeds proved to be exclusively composed of kaolinite. A comparative study of these redbeds with the present-day ones derived from the same type of parent rock, suggested genesis under tropical climatic conditions. Compared to the basaltic parent rock, alterites are characterized by moderate desilication and partial elimination of Ca, Na, Mg, Mn, Sr, Cu and Sr and on the other hand by a concentration of some elements such as Al, Fe, Ti, K, Rb and Zr.

Aluminite and other aluminium minerals from Newhaven, Sussex: the first occurrence of Nordstrandite in Great Britain

The aluminous minerals aluminite, basaluminite, gibbsite, bayerite and nordstrandite together with poorly crystalline alumino-silicates occur in collapsed Tertiary sediments filling solution pipes in the Upper Chalk at Newhaven, Sussex. They appear to have formed by the reaction between acid groundwater and the Tertiary clays and the Chalk. Similar occurrences elsewhere on the Sussex coast are described.

Correlations between borehole logging and geotechnical properties of a stiff Tertiary clay (in French) : Dethy, B; Neerdael, B Int Assoc Engng Geol BullN26–27, Dec 1982–June 1983, P49–57 (Paper to the International Symposium on Soil and Rock Investigations by In Situ Testing, Paris, 18–20 May 1983)

Correlations between borehole logging and geotechnical properties of a stiff Tertiary clay (in French) : Dethy, B; Neerdael, B Int Assoc Engng Geol BullN26–27, Dec 1982–June 1983, P49–57 (Paper to the International Symposium on Soil and Rock Investigations by In Situ Testing, Paris, 18–20 May 1983)

BOREHOLE SEISMIC PROFILING AND TUBE WAVE APPLICATIONS IN A DAM SITE INVESTIGATION*

AbstractContinuous, single‐channel reflection profiling has been carried out in PVC‐lined boreholes, primarily with the aim of ascertaining the position of an old subsurface gas storage tunnel on a proposed dam site.Tube wave reflection patterns thus generated have been interpreted in terms of sediment rigidity and shear wave velocity, and these results could be compared with some independent data. It is interesting to note that, within the well section penetrating Tertiary clays, the velocity of the hydraulic transients apparently was not affected by the PVC casing, which might be explained by a tight coupling between casing and clay wall. In such situations, tube waves turn out a straightforward tool for the determination of shear wave velocity and the derivation of dynamic elastic moduli of unconsolidated sediments.Further applications of the study of the distribution of seismic velocities on the dam site dealt with the consolidation history of the clays. A level of abnormally low P‐wave velocities has been detected and interpreted as a gas‐charged horizon which, by its coincidence with the base level of clay diapirs, might be considered to have contributed to clay flowage in past geological times. Data about maximum past burial depth, derived from shear wave velocities, turned out to be in agreement with results from consolidation testing.

The duisburg method of metro-construction, a successful application of the gap freezing method

Between March 1977 and August 1979 contract No.4 of the Stadtbahnbau (Metro-construction) in Duisburg was executed, making successful use of gap freezing.The gap freezing was necessary because the Metro-tunnel is crossed by a groundwater stream (flow velocity up to 15 m/d) and it had to be assured that open cut construction of the tunnel was possible and that the original situation could be reinstated as far as possible after completion.The Duisburg building ground also made a special construction method necessary. Ground strata: from surface to 2–4 m, civilisation deposits; from ∼ 4 m to ∼ 25–28 m below surface, glacial sand and gravel deposits, containing stones with a diameter > 20 cm and even boulders of 1 m3 and more; from approximately 28 m below surface, layers of Tertiary clay and silt; the groundwater table is ∼ 8 m below the surface, the stream flowing within the sand and gravel deposits from SE to NW (towards the Rhine).Installing a groundwater barrier, for instance by erecting a continuous diaphragm wall enclosure, was already ruled out in early design stages as was the use of driven steelpiles.At the inception of the design in 1974, it was decided first to carry out a measuring scheme to establish the groundwater flow velocity. This was followed by a large scale (1:1) trial freezing to ascertain the feasibility of the gap-freezing method.When these experiments were scientifically valued it was established, that the risk involved was acceptable. The contract documents were prepared prescribing a combination of “cover and cut” with gap-freezing, which is tentatively called the “Duisburg method of Metro-construction”.During the construction a large scale measuring and scientific research programme was carried out.

Very High Amplitude Seismic Anomaly in Georges Bank Trough, Atlantic Continental Margin

From 1973 through 1978 the U.S. Geological Survey acquired multichannel common-depth-point (CDP) reflection seismic data along the Atlantic continental margin from southern Florida to the northern end of the Georges Bank basin for an investigation of the regional structural configuration of the basins and an assessment of petroleum potential. On one seismic line, located in blocks 974 and 975 of the Georges Bank basin at lat. 67°37^primeN and long. 41°00^primeW, a high-amplitude event approximately 9 km long is present. The top of the anomaly is at a depth of approximately 4,175 m, which roughly corresponds to the middle of the Jurassic section. This anomaly is interesting for more than its size. It apparently is a unique feature, as no similar high-amplitude ev nt has been found in the same stratigraphic interval on any other seismic line in the Georges Bank basin. The area of study lies near the middle of the Georges Bank basin, which is trough-shaped and opens to the southwest. Major structural features in the basin appear to be related to basement structure. The lithologic sequence roughly consists of (a) as much as 1 km of poorly consolidated Tertiary sands, silts, and clay; (b) as much as 3.5 km of Cretaceous clastics; (c) as much as 4 km of Jurassic dolomite, limestone, and anhydrite; and (d) a basement of lower Paleozoic crystalline rocks, similar to those underlying the coastal plain. Well logs show a layer of salt overlying the basement. Potential source rocks are expected to include organic-rich Cretaceous shale and carbonaceous Jurassic limestone. The anomaly was modeled as three possible lithologies that produce reflection amplitudes of the magnitude observed on the seismic line. Modeled lithologies included a porous carbonate containing gas, a salt lens, and an igneous intrusive rock. Analysis of the model study indicated that the porous carbonate and salt model produced a reflection amplitude that closely matched the reflection characteristics of the anomaly from the seismic data.

The distribution, variation and origins of pre-Devensian tills in eastern England

In order to define quantitatively the lithological properties of the pre-Devensian tills in eastern England, calcium carbonate contents and mechanical compositions of 501 samples from 289 sites have been measured and heavy minerals counted in 102 of them. The results show that the tills may be divided into two groups: ( a ) a North Sea Drift group consisting of the Norwich Brickearth, the Cromer Tills, the Marly Drift of Cromer type and till members of the Contorted Drift, which is characterized by high sand and low opaque heavy mineral contents; and ( b ) a Lowestoft Till group including the Lowestoft Till of East Anglia, the Chalky Boulder Clay of the east Midlands, the Calcethorpe and Wragby Tills and the Lowestoft-type Marly Drift, which is characterized by low sand and high opaque values. The qualitative similarity of the mineral suites in the two groups, however, suggests a common origin in the North Sea basin. Automated contouring (SYMAP) has been used to represent the spatial distribution of till properties. These confirm that the Lowestoft Till group can be spatially separated from the North Sea Drift group, and divided into a Calcethorpe-Marly facies high in carbonates and lying astride the Wash, and a Lowestoft-Wragby facies with moderate but variable contents of calcium carbonate and occupying the rest of the region. Trend surface analysis has been applied to the Lowestoft Till group. At the first order level there are decreasing trends across the region, from northeast to southwest, in calcium carbonate, amphibole and epidote values and increasing trends in silt and clay. These are interpreted as showing a general movement from the North Sea of sandy and chalky material which became progressively modified by assimilation of Mesozoic clays. Higher order surfaces, particularly those of sand, garnet and amphibole values, point to the Wash as the focus of this glacial activity. It is proposed that the most vigorous stream of ice entered eastern England at this point, levelling the Cretaceous scarps and excavating the Jurassic clays of the Wash-Fens basin, and then fanned out into most of the region to deposit the clay-rich Lowestoft-Wragby facies. The Calcethorpe-Marly facies is considered to represent chalky North Sea material carried by marginal, and weaker, ice streams directly onto the Chalk of Lincolnshire and north Norfolk. The North Sea Drift group is believed to be the product of another ice body, penecontemporaneous with that depositing the Lowestoft group, which entered Norfolk from a more easterly part of the North Sea, incorporating sediments from this basin, but without crossing substantial outcrops of Jurassic or Lower Cretaceous formations or Tertiary clays. The Marly Drift includes a variant showing lithological affinities with both Lowestoft and Cromer Tills and which may be the product of complex interaction between the two ice sheets. All the tills studied seem most likely to be of Anglian age.

Preliminary studies of underground facility for nuclear waste burial in a tertiary clay formation : De Beer, E; Carpentier, R; Manfroy, P Proc 1st International Symposium on Storage in Excavated Rock Caverns (Rockstore 77), Stockholm, 5–8 Sept 1977, V3, P771–780. Publ Oxford: Pergamon Press, 1978

Preliminary studies of underground facility for nuclear waste burial in a tertiary clay formation : De Beer, E; Carpentier, R; Manfroy, P Proc 1st International Symposium on Storage in Excavated Rock Caverns (Rockstore 77), Stockholm, 5–8 Sept 1977, V3, P771–780. Publ Oxford: Pergamon Press, 1978

Site investigations and calculations of the stability of slopes in the landslide area at sadowie near cracow

It is evident from extensive geological investigations completed since 1934 that the permanent landslides originate at the contact between loesses and Tertiary clays. The direct neighbourhood of subsurface watersheds and the lithological differentiation of the loesses are responsible for the lack of direct correlation between precipitation, ground water oscillations and the somewhat delayed slide movements. Site investigations, particularly by universal probe and Dutch penetrometer, provided relatively accurate results for calculating the stability of slopes by the Bishop and Nonveiller methods. The calculated results coincide very well with field observations.

COMBINED REFRACTION SEISMIC AND GRAVIMETRIC INVESTIGATIONS IN A PALEOGEOGRAPHICAL AND GEOLOGICAL RESEARCH PROGRAM*

AbstractRefraction seismic and gravity investigations were executed to solve geological and hydrographical problems in recent strata: These loose sediments necessitated a special arrangement for the energy source in the seismic measurements, By the use of a falling weight the refracted wave could be registered from a depth of more than 30 m. Quaternary fluviatile sands are characterized by lower velocities than the Tertiary sediments. Even a marked velocity difference between different Tertiary formations could be observed. Sand‐filled valleys in Tertiary clays give relatively important variations in the gravity field caused by the small differences of densities. Thus buried channels in a clay subsoil can be found by accurate gravity measurements.

Late- and Post-glacial sediments in the Randers fjord area. Geochemical, sedimentological, and geoelectric investigations

Thickness and distribution of Late- and Post-glacial sediments in an Eastern Jutland valley system have been mapped, and their sedimentogenetic and diagenetic relations have been studied. The chemical and sedimentological methods used are discussed in detail. Post-glacial marine sediments formed in a tidal fjord environment are the most important deposits in the area, and it is shown that river supplies of freshwater control the salinity of the environment and were responsible for the rather high content of allochthonous material in the sediment. The marine sediments rest on Late-glacial sand, whose surface topography indicates that the valleys were formed by subglacial erosion. Local occurrences of dead ice were present at least until the Littorina sea (Atlantic) transgression. Depth conditions for Early Post-glacial peat are used to estimate the groundwater level and the course of the river Gudenå in the Continental Period. Sedimentary facies in the Atlantic Littorina sea are discussed, including salinity, tidal activity, water depth, nutrient conditions, and exchange of stagnant bottom water from the deepest parts of the fjord area. The sequence seems to have been influenced only by minor syndiagenetic and weathering processes.With the intention of providing supplementary information to that obtained from mapping of the Post-glacial sediments of the region 161 electric soundings have been carried out in the Randers fjord area. The specific resistivity of the sediments has been determined and the principle limitations of the methods applied have been investigated. Interpretation of the electric soundings has been done using a new system of computer programs. Maps showing the thickness relationships and variations in specific resistivity in the uppermost, largely Post-glacial deposits in the area have been prepared, and a map showing the location of the surface of the Danian limestone and occurrence of Tertiary clay is also presented.