Sandy Fill Research Articles

Sedimentology, Stratigraphic Architecture, and Ichnology of Gravity-Flow Deposits Partially Ponded in a Growth-Fault-Controlled Slope Minibasin, Tres Pasos Formation (Cretaceous), Southern Chile

Abstract A recent resurgence in the study of slope deposits is strongly related to the complexity inherent with the depositional setting, and the continued prospectivity for hydrocarbons in associated units. Intraslope basins are particularly intriguing to explorationists, because they provide accommodation space for coarse-grained facies in areas often characterized by otherwise muddy deposits. An outstanding outcrop of a growth-fault-controlled slope minibasin and its sandy fill are exposed in Cretaceous strata of southern Chile. A turbiditic sandstone package (TSP) 60 m thick sharply overlies fine-grained deposits of the Cerro Toro Formation, and defines the base of the Tres Pasos Formation in the study area, 65 km north of Puerto Natales, Chile. Individual sedimentation units are rarely amalgamated, and are tabular for at least hundreds of meters, suggesting deposition in a relatively unconfined setting. Trace-fossil assemblages are grouped into the Zoophycos or Cruziana ichnofacies, and are consistent with slope deposition rather than deposition on the basin floor. Beds at the base of the TSP are truncated by a normal fault at the southern end of the outcrop, and lap out towards the north onto the tilted hanging wall. Stratal thickening and thinning across the fault, and unfaulted overlying deposits, suggest that the fault was active during sand deposition (a growth fault), and that it created accommodation space for the partially ponded TSP. This, and other growth faults in the underlying strata, suggest deposition in an intraslope minibasin setting. The TSP is overlain by ~700 m of amalgamated slump, slide, and debris-flow units, suggesting that deposition immediately preceded rapid slope progradation.

ABSTRACT: Bonga Field, Deepwater Nigeria: Comparison of Near-Surface, Well-Calibrated Submarine Channels with Reservoir Channel Sands

Comparison of near-surface channels with channel reservoirs at Bonga, offshore Nigeria (OML118, 1000 m water depth), demonstrates some important lessons in using shallow analogs for reservoir prediction. Studies of shallow hazards and pipeline routing, integrating 3D and high-resolution 2D seismic with well logs, illustrate seafloor and nearsurface features including a large mud-draped canyon, mud volcanoes, and numerous pockmarks, which indicate fluid expulsion. Both the shallow overburden (Plio-Pleistocene) and the main reservoir intervals (Miocene) are characterized by deepwater channel geometries visible in seismic profiles, on map views, and within 3D volume views. Most near-surface channel features inhabit broad, relatively straight scours 1-3 km wide and 30-300 m deep, filled by composite packages of smaller, often sinuous channels 100500 m wide and 5-50 m deep. Although many of these near-surface channels display a chaotic to low-continuity, high-amplitude seismic facies character often associated with sandy fill, well logs through the near-surface section indicate these are mainly filled with mud. Channel geometries at reservoir level show different characteristics. The smaller-scale map-view geometries are consistent in size with the near-surface channels but the larger host scours are not as prevalent or obvious, and some thin, sheet-like sands are also present. A transition from lower slope to upper slope at the end of the Miocene probably accounts for this variation. A fundamental understanding of geologic setting and rock/fluid variation is critical before extrapolating seismic facies information from shallow analogues to deeper reservoirs.

Investigation of Seismic Response of Soil Sites in Hong Kong: Part I-Preliminary Dynamic Test Results

Preliminary results of shear wave velocity measurement and dynamic tests on Hong Kong soils are presented. We measured in-situ shear wave velocities in three types of Hong Kong soil sites. Measured results suggested that an overseas correlation model relating shear wave velocity to N-values of the standard penetration test (SPT) can be possibly used for Hong Kong soils. In this paper, we also suggested a similar correlation relationship derived from our limited amount of data and this model could be our preferred model for Hong Kong alluvium deposits, marine deposits and completely decomposed rock. We took a number of soil samples and carried out resonant column tests, bender element tests and cyclic triaxial tests. According to these testing results, we propose to use a number of overseas dynamic soil models for Hong Kong soils of similar nature. We also present an example of soil amplification effects on a site with a soft soil layer (marine deposits with SPT-N value of 1 to 2) below sandy fill. It is f...

Field studies of the stress-strain state and consolidation of beds of the system of flood-protection structures in saint petersburg

Data on the soil beds of structures making up the Saint Petersburg flood-protection system and at test sites formed for field investigations of beds containing a thick layer of saturated clayey soils of highly plastic consistency are presented. Also cited are generalized results of multiyear measurements of strains, stresses, and pore-water pressure of the beds of the test sites during the installation of strip earth drains with subsequent loading by the layer-by-layer placement of sandy fills; these results are also analyzed.

Mid-Miocene progradational barrier island and back-barrier deposits, central Jylland, Denmark

This paper reports on a c. 15 m thick section of marine, coastal sand, that combine a hitherto less described fades succession transitional to the Miocene fluvio-deltaic and open marine deposits. The section is exposed in a pit located 10 km northeast of the sandy fluvio-deltaic brown coal bearing strata of the Søby-Fasterholt area, known as the Odderup Formation (Middle Miocene). The section comprises more than 6 m of trough cross-stratified, low-angle cross-stratified and parallel-laminated, sand and gravel, deposited on the foreshore and backshore of a barrier island. Locally these deposits are eroded by a steepsided washover channel with a sandy fill. The overlying back-barrier deposits are up to 9 m thick, and are initiated by a thin bituminous mud bed with a mixture of terrigeneous and marine organic matter. Above, a series of 0.2-2 m thick beds of tangential to sigmoidal cross-stratified sand, often with well preserved topsets, are deposited. These beds are interbedded with ripple-laminated and parallel-laminated sand. Burrows of Ophiomorpha, possibly Skolithos and Arenicolithes occur in the back-barrier deposits and in the top of the washover channel-fill. The succession of well-preserved coastal fades-belts indicates that the depositional area was characterized by a large sediment supply in combination with a rising sea-level. The section was probably formed fairly rapidly during a coastal progradation more or less contemporaneously with the general transgression that led to the deposition of the brackish- marine Hodde Formation and later the fully marine Gram Formation.

The application of high‐resolution sequence stratigraphy to fluvial systems: a case study from the Upper Carboniferous Breathitt Group, eastern Kentucky, USA

ABSTRACTThe Pennsylvanian Pikeville, Hyden and Four Corners formations of the Breathitt Group in eastern Kentucky, USA, contain six major facies associations along with a number of subassociations. These facies associations are offshore siltstone, rhythmically bedded mouthbar heteroliths, predominantly fine‐grained floodplain deposits, minor channel fills, major distributary channels and major, stacked fluvial bodies. The stacked fluvial bodies are incised into a variety of open marine and delta plain deposits, have widths of several kilometres and exhibit a range of sandy fill types. These fluvial complexes are interpreted as incised valley fills.Parasequences and parasequence sets are not identifiable. Nonetheless, it is possible to identify systems tracts on the basis of sequential position, facies associations and systematic changes in architectural style and sediment body geometries. The studied portion of the Breathitt Group comprises stacked 4th‐order sequences, which occur in lowstand, transgressive and highstand sequence sets related to the development of a lower frequency base level cycle.In the lowstand sequence set, incision associated with successive 4th‐order sequence boundaries has commonly removed all the HST and TST of the underlying sequences, such that succeeding 4th‐order incised valley fills are amalgamated. Within the transgressive sequence set, incision is at a minimum and incised valley fills tend to stack discretely with the maximum amount of fine‐grained TST and HST between them. The highstand sequence set is transitional between the lowstand and transgressive sequence sets in terms of the amount of transgressive and highstand deposits preserved. Incised valley fills tend to stack discretely.

Improvements on hydraulic sandy fills by compaction sand piles : Chung, Y T; Wu, W K; Chung, S T Proc Ninth Southeast Asian Geotechnical Conference, Bangkok, 7-11 December 1987V2, P8.57–8.68. Publ Bangkok: Southeast Asian Geotechnical Society, 1987

Improvements on hydraulic sandy fills by compaction sand piles : Chung, Y T; Wu, W K; Chung, S T Proc Ninth Southeast Asian Geotechnical Conference, Bangkok, 7-11 December 1987V2, P8.57–8.68. Publ Bangkok: Southeast Asian Geotechnical Society, 1987

Sandy-gravelly mass-flow deposits in an ice-marginal lake (Saalian, Leuvenumsche Beek Valley, Veluwe, the Netherlands), with emphasis on plug-flow deposits

In three pits in the Leuvenumsche Beek Valley (near Ermelo and Elspeet), massive and diffusely banded clean gravelly sands, found in association with sandy sediments showing some similarities to the Bouma sequence, were interpreted as originating from sediment gravity flows. The flows, which came to rest on a ca. 6° paleoslope, probably originated from slumping of parts of the ice-pushed ridges at either side of an ice-marginal lake. Major characteristic features in the three sand pits studied are U-shaped channel forms with a maximum depth and width of 10 × 25 rmm. The fills consist of sand and gravels, locally containing giant sand-clasts. The sediments just below the base of these channel-forms are commonly distorted and folded. Especially the massive more sandy fills are surrounded by a finer-grained diffusely bedded and inversely graded zone. These sedimentary features suggest that “rigid” sediment plugs sheared downslope, generating a finer-grained shear zone around the plug scouring a slide scar till its present semi-cylindrical form and preserving the steep sides (exceeding the angle of repose) of the channel-form by “freezing”. The U-shaped channel forms (plugged troughs) are locally overlain by shallower gently sided trough structures, with mainly diffusely banded infillings. Very shallow and often smaller troughs are found again on top of these massive and diffusely banded infillings. The sediments in these troughs consist of repetitions of two types of microsequences: (1) thickly bedded sequences of normally graded massive sands, near-horizontal stratifications, plane beds and cross-bedded sets; and (2) thinly bedded sequences of relatively thick units T A and thin units T C and T D of the Bouma sequence. The repetitions of the microsequences are interpreted as flow pulsations. Upwards thinning of the sequence, together with a finer grain size may point to waning flow conditions. Their association with plugged troughs is suggestive of retrogressive flow-slides.

Tests on Full-Sized Piles Driven in Reclaimed Land

ABSTRACT This study has been carried out systematically and over a long period to clarify practical design problems for pile foundations to be constructed on a man-made island. Forty-one test piles in total were driven at six sites of the island. Of them, fifteen piles had their lower portions enlarged. The experiments conducted from 1977 to 1981 showed the following: (1) Settlement of the ground consisted of settlements of the fill, the alluvial clay and the diluvial layers. (2) A considerable number of blows was required to drive the piles through the sandy fill, although the dynamic stress during hammering was in any case below the allowable stress of pile materials. Pull-out tests of bitumen-coated piles showed little segregation of bitumen from the piles with enlarged lower portions. (3) Consolidation settlement of the alluvial clay layer caused settlement of the fill and, consequently, negative skin friction on piles. Frictional resistance of sandy soils was large. As generally known, negative skin friction was considerably reduced by the use of a bitumen-coated pile. (4) The bearing capacity of a pile driven into the bearing soil layer was attributed to the frictional resistance on the pile. (5) In case of a pile with enlarged lower portion, its lateral resistance could be maintained to a degree similar to that of a normal straight pile by filling the gap around the pile with sand.

Efficiency of Subsurface Sewage Disposal Systems in Removal of Contaminants From Domestic Sewage

Abstract In order to determine the efficiency of subsurface disposal systems in removal of contaminants, fifteen systems located on three lakes and on the St. Lawrence River in Ontario, were under study for about two years. Tritium (3H) , radioactive phosphorus (32p) and fluorescein were used for tracing the subsurface movement of the septic tank effluent and for determining the time taken by the effluent to reach the receiving waters. It was observed that a considerable part (89 to 98%) of the phosphorus from the effluent was fixed in the soil when the soil contained more than 67% silt and clay. When clayey silt was the filtering medium the concentration of the phosphorus in the ground water dropped to a level of less than 0.2 mg/l (as P) in a distance of 17 meters from the disposal systems. A satisfactory removal of faecal coliform organisms by the same uniform undisturbed clayey silt was also observed. The removal of phosphorus and of faecal coliform organisms by disposal systems built on sandy fill was less efficient. The concentration of nitrates, free ammonia and chlorides in the ground water close to receiving waters was lower than concentrations permissible in public surface water supplies.

Tree Rings, Valley Floor Deposition, and Erosion in Chaco Canyon, New Mexico

Excavations made in 1928 at the north wall of the large pueblo of Chetro Ketl in Chaco Canyon, New Mexico, indicated that there had been fourteen feet of sandy fill in the canyon at that point since the foundations of the pueblo were laid. Sherds in the walls of the Chaco arroyo likewise pointed to considerable fill since the occupation of the large Chaco pueblos in the late 9th to early 12th centuries. This has raised the question of rate of deposition on the valley floor and of land surface levels during and since the time of prehistoric occupation. Linked with the problem of old land surfaces was that of burials, which have been notable for their scarcity in this canyon, and it seemed that an investigation of these old surfaces might yield some information on the possibility of burial grounds deep below the present surface.