Geological Society, London, Ratcliffe, K. An example of alternative correlation techniques in a low accommodation setting, non-marine hydrocarbon system: the Lower Cretaceous Mannville Basal Quartz succession of southern Alberta. Bulletin of the American Association of Petroleum Geologists, 88 , Hounslow, M. Sediment provenance determination using magnetic mineral inclusions in clastic silicates: comparison with heavy mineral analysis. Garnet compositions in Scottish and Norwegian basement terrains: a framework for interpretation of North Sea sandstone provenance. Marine and Petroleum Geology, 21 , Whitham, A.
Insights into Paleocene sediment transport paths and basin evolution in the North Atlantic from a heavy mineral study of sandstones from southern East Greenland. Petroleum Geoscience , 10 , Heavy minerals.
In: Middleton, G. Kluwer Academic Publishers, Dordrecht, Provenance patterns in a neotectonic basin: Pliocene and Quaternary sediment supply to the South Caspian. Basin Research, 15 , Geosteering of high-angle wells using heavy mineral analysis: the Clair Field, West of Shetland. In: Carr, T. Sabeen, H. The provenance of garnet: constraints provided by studies of coastal sediments from Southern India. The Millstone Grit of northern England: a response to tectonic evolution of a northern sourceland. Proceedings of the Yorkshire Geological Society , 54 , Correlation of hydrocarbon reservoirs using quantitative heavy mineral analysis.
Petroleum Geoscience , 8 , In: Jolley, D. Geological Society, London, Special Publication , McGraw-Hill, New York, Bouch, J. Authigenic apatite in a fluvial sandstone sequence: evidence for rare-earth element mobility during diagenesis and a tool for diagenetic correlation. Journal of Sedimentary Research , 72 , Hurst, A.
Generic relationships in the mineral-chemical stratigraphy of turbidite sandstones. Geosteering high-angle wells in the Ross Field, North Sea: the application of heavy mineral analysis. Offshore Magazine , April issue , Zircon age and heavy mineral constraints on provenance of North Sea Carboniferous sandstones.
Marine and Petroleum Geology , 18 , Provenance and correlation of Upper Jurassic and Lower Cretaceous reservoir sandstones in Papua New Guinea using heavy mineral analysis. In: Buchanan, P. Rimington, N. Amazon Fan sands; implications for provenance. Marine and Petroleum Geology , 17 , Jones, D. Provenance of the basin fill. In: Plant, J. Processes controlling the composition of heavy mineral assemblages in sandstones. Cretaceous depositional systems in the Norwegian Sea: heavy mineral constraints.
Bulletin of the American Association of Petroleum Geologists, 82 , Box 82 Juba, South Sudan. Author s agree to the terms that the GPH Journal will have the full right to remove the published article on any misconduct found in the published article. Skip to main content Skip to main navigation menu Skip to site footer. Abstract The current study has been conducted in seven soil profiles in clay plains of the Sudan, sites were selected in a transect from East of Rahad River, across Gezira, West of the White Nile and Malakal.
References R. Mange, and H. Padmalal, K. Ramachandran, and P. Morton, and C. Garzanti, and S. Contribution to Sedimentology, vol. Jackson, Soil Chemical analyses. Prentice Hall. However, as several different peaks are apparent, e. Within the basal part of the core 7. As for depth variations, the magnetic parameters measured in cores D4A and D4B fig. In both cases, a maximum of magnetic susceptibility values is displayed at 3. In this context, the oscillating signal is not related to the grain size distribution, since clay-rich sediments were detected throughout the profile almost exclusively.
It is also disconnected from the geological background.
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The comparison of values at low frequency clearly shows similar features in all three cores. In contrast, the underlying strata show lower values, with several infrequent susceptibility maxima. As for their origin, allochthonous contribution of sediment with higher contents of magnetic minerals aeolian input of volcanogenic particles or development of palaeosoils land use at different periods must be considered.
Moreover, it can be considered as grain-size dependent Dekkers, ; Dearing, There is little change with depth with only minor variations of trace components tab. All analysed specimens are characterised by phyllosilicates like muscovite or illite, which originate from parent limestones or mica weathering Moore and Reynolds, Contrary to the sediment samples, all limestone residuals lack kaolinite, while micas dominate.
It was identified in the XRD plots subsequent to heat treatment, which, in contrast to the behaviour of pedogenic chlorites, amplifies the Even though quartz is ubiquitous in all samples, its total amount is difficult to assess as only the corresponding 4.
Being a characteristic mineral in Mediterranean soils Moore and Reynolds, , it mostly appears in well drained locations where the parent material contains micas, illites or micaceous schists. Vermiculite also originates from destruction of primary chlorites under subtropical weathering conditions and moderate acidification Macleod, ; Scheffer and Schachtschabel, The insoluble residuals of parent rocks are predominantly composed of mica and chlorite with traces of quartz whereas kaolinite was absent. All values are expressed according to depth ordinate.
The high values in the upper horizons are in significant contrast to the lower susceptibilities in deeper profile parts. Rather, extensive areas of heavily fissured limestones suggested that dolines and poljes were open systems with a considerable loss of sediment. According to these findings, the subterraneous karst relief is buried under a thick sediment cover.
Regarding the methodological interface between geophysical and geomorphological data, their GIS-based processing and their digital visualisation, some hypotheses need to be considered because virtual 3D models are not able to display the actual buried karst relief in detail. Furthermore, such digital images cannot and should not represent a stage of landscape development at a certain point in time.
Instead, they provide an impression of the heterogeneous shape of the subrelief, allow for a synopsis of results obtained by fieldwork and represent a valuable further step of interpretation, which acknowledges the third dimension. Most notably, these models help to assess the spatial distribution of karst features as well as their sedimentary infills.
As for the enclosed depression of Zominthos, the subsurface relief appears totally different from the local surface topography with its rather smooth and slightly inclined slopes. Our results reveal an extremely heterogeneous subsurface morphology by highlighting strong variations in resistivity along with remarkable differences in the depth of the underlying bedrock, which must be considered as characteristic for karst terrains Deceuster et al. The detected subterranean declivities of the epikarst zone are occasionally very steep and form scarp-like slopes fig. Regarding the genesis of the buried doline, a significant impact of cryptokarst processes must therefore be taken into account.
Filled depressions may consequently exhibit completely distinct morphologic properties at even the smallest scales. As shown by adjacent areas where soils are eroded and washed out whereas cavities are increasingly filled with loose materials, sediment dynamics are frequently very intense. Hence, the investigated dolines must be regarded as unpredictable and highly active geomorphodynamic systems, while attention has to be paid to the fact that the sedimentary fills may be discontinuous and interrupted by hiatuses. Seen from both a geomorphological and a mesoscale viewpoint, the karst depression of Zominthos is one of the major sediment reservoirs in the northern Ida Mountains, a fact which is documented by the large amount and the impressive depth of loose infills.
Due to its specific location bordered and encompassed by the major detachment fault to the south and the east fig. As a consequence, both sites qualify for investigating the environmental history and offer promising prospects for further studies. Grain-size analyses provide evidence for the dominating heterogeneous strata with poorly sorted material from top to bottom.
This fact is supported by their heterogeneous components of autochthonous and allochthonous provenance e. Corresponding strata predominate in the basal part of Z1, particularly in depths below 4. In contrast, occasional interbedded fine-grained materials clearly indicate semi-fluvial dynamics, which are shown by lamination textures resulting from fining-upward sequences in consequence of sedimentation in a stagnant water body.
They mainly occur in the central part of Z1, where they alternate with coarse horizons while being less frequent in greater depths. One of its origins can be traced back to strata-bound springs near the uvala of Zominthos Agia Marina. The graded layers must have been accumulated during periods of geomorphologic stability with reduced erosion intensity and slow surface discharge velocities wetter conditions, lower periodicity of annual precipitation, closed vegetation cover.
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Such opposed geomorphodynamic phases, which show alternating regimes rather than just a singular change during the mid- and late-Holocene, occurred episodically in the Ida Mountains Siart et al. However, ponding of water within karst depressions is also a recent phenomenon that commonly occurs during wintertime due to local precipitation maxima. The results from D4A and D4B highlight the predominance of extremely fine-grained materials that are only occasionally mixed with coarser detritus black nodules from local breccia outcrops. After chemical dissolution of the carbonated breccia cement, the residual nodules are transported into the lower part of the doline subsequent to stronger precipitation or torrential events and finally buried by the red clay sediments.
These distinctions between the two study sites are related to different geomorphodynamic processes and petrographic factors, proving that Zominthos experienced rather stronger colluvial events or phases, a fact that might be supported by the existence of its larger catchment area approx. Residual clays, which represent typical remains of non-carbonate impurities from limestones, and associated terra rossa soils constitute the major proportion of the corresponding sediment fills.
Even though both investigated sites have their origin in limestone dissolution and massive karstification, they must be considered as different types of landforms e. This finding indicates a widespread distribution along with a massive contribution of ultrafine grains to the total ferromagnetic assemblage Oldfield, ; Dearing et al. Increased values in the near surface must be considered as a result of recent land use and current soil formation, which generally manifests itself in pronounced susceptibilities due to the genesis of ferromagnetic minerals Hanesch and Scholger, Further maxima Z Both the geophysical prospection of the subsurface in Zominthos fig.
On the other hand, the presence of volcanogenic sediments with higher contents of magnetic minerals might produce peaks in susceptibility, since the method is very sensitive to the Fe-rich properties of tephra. As stated by C. Siart et al. Despite the scarcity of datable material in the cores Z1, D4A, and D4B - a fact that may complicate the reconstruction of the environmental history to a certain degree -, such mineralogical results serve as alternative time markers. As ERT-results from Zominthos prove a very heterogeneous morphology of the bedrock, which has to be seen in conjunction with a potential discontinuity of sediment archives, geochronological methods are indispensable for palaeoenvironmental investigations.
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Since the fallout of tephra from Thera predominantly occurred in eastern Crete as well as in coastal-proximate regions at lower altitudes Boekschoten, ; Hempel, ; Bruins et al. However, the igneous minerals found in the loose sediments of Zominthos are dispersed through the entire sediment column of the depression and do not occur in one single ash layer Siart et al.
This fact must be considered as a further proof for the massive colluvial activity in Mount Ida subsequent to the Minoan eruption during the late Bronz Age. In this context, the peaks in the magnetic susceptibility measurements of several strata from Z1, D4A and D4B are most likely the result of the colluvial enrichment of volcanogenic minerals in comparison to over- and underlying horizons.
Mica, chlorite and quartz occurring in both the parent material and the loose sediments suggest an authigenic provenance. Kaolinite minerals that occur in the colluvial fills but are absent in limestone residuals must either be derived from neoformation or deposited by wind as they are absent in parent limestones Durn et al.
Since several studies verified the polygenetic attributes of terra rossa type sediments, the formation of kaolinite could also be of Neogene age Bronger and Bruhn-Lobin, ; Jahn, However, given the fact that it occurs in remarkable amounts while it is dispersed all over the sediment column, an exclusive in-situ genesis is not plausible.
Considerable quantities must derive from windblown dust comp. Vermiculite and interstratified minerals were not found in D4A, D4B or local rock samples. The distinctive peak for chlorite indicates the presence of mainly primary types. All in all, the clay mineral spectra only show slight variations. In the case of in-situ soil formation, a stronger diversification between horizons should be observable Delgado et al. ERT and SRT profiles from Zominthos prove that the dolines and uvalas in Mount Ida are filled with remarkable amounts of loose materials several decametres thick.
Contrary to the hitherto established opinion, these hollows are not just open systems but also serve as storage basins for colluvial sediments and preserve them from further transport. Hence, they are important palaeoenvironmental archives. The measured tomographies also reveal an unpredictable buried karst morphology, which requires certain precautions and a versatile methodologic strategy in order to investigate. Moreover, the combined mineralogical and sedimentological investigations underline the heterogeneous characteristics of sediment fills in Cretan karst depressions. Our findings demonstrate that petrographical conditions and the local relief determine the genesis and also the type of resulting landform in terms of size, catchment area, type of sedimentary infill and local geomorphodynamic processes.
The sediments in micro-scale dolines and meso-scale uvalas may consequently differ with regard to grain-size, magnetic susceptibility and mineralogical composition. The reason for the multi-provenance character of these colluvials lies in climatic changes, tectonic activity, heterogenic petrographical units, anthropogenic land use and deforestation Durn et al. In addition, investigating the magnetic parameters of the sediments produces information on the contribution of very fine grain-sizes to the total of the ferromagnetic assemblage. The corresponding dolines and uvalas obviously represent the most favourable locations fur human purposes because they are uniquely qualified regarding hydrology water capture of springs for drainage and irrigation , geomorphology plane bottom suitable for agriculture, ubiquitous clay deposits for pottery manufacturing , ecology sufficient amounts of soil for arable farming and topography protective location.
This fact becomes even more important, as large parts of Mediterranean karst regions are generally unsuitable for land use due to massive lack of soils, extensive bedrock outcrops, severe land degradation and scarcity of surface waters Siart et al. In order to validate and confirm our findings, to gain more precise information about the environmental history and to develop a chronostratigraphical record, datings are required in addition to further mineralogical, geomorphological and geochemical analyses.
However, the geophysical and sedimentological results obtained thus far offer promising prospects for future geoarchaeological research in karstic regions by proving the suitability of dolines and uvalas as important sediment reservoirs.
Bartels G. Erdkunde 45, Boekschoten G. In Strid A. Opera Botanica 30, Bronger A. Catena 28, Bruins H. Journal of Archeaological Science 35, Bruxelles L. Karstologia , , Karstologi a, 47, Karstologia , 49, Buurman P. Soil Science , Creutzburg N.