Sand Belt Research Articles

NATURAL AND ANTROPOGENIC DIFFERENTIATIONS IN LANDSCAPEMORPHOLOGICAL STRUCTURE OF THE SOUTHERN PART OF ANAPA BAY BAR: CARTOGRAPHIC ESTIMATION

In terms of detail landscape-morphological mapping, a series of observing maps of Anapa sand bar was compiled, including maps of morphometric characteristics of sand bar (wideness of beach, dune belt and hillock sands, height of dunes), wind exposition of shore, aeolian processes, anthropogenic impact. The maps show essential differences in morphological structure of sand bar caused by natural and anthropogenic factors. At the northern edge of sand bar, where wind exposition is 90°, builder areas are disposed at some distance from sand bar beach reach 100–130 m. Beach, dune belt and hillock sands are wide, dunes height is 10 m at long extend, and so sand bar has reached some dynamic equilibrium. At more southern region, where wind exposition is 80°, builder areas of Vityazevo and Northern Jemete settlements have come just to sand bar. Strong anthropogenic impact, walking on dune’s surface caused degradation of vegetation and intensification of aeolian processes, forming of sand trains. Height of dunes grows to 12–13 m due to implantation of trees at hillock sands. At central part of region buildings of Jemete settlement have come into coastal zone. Beach and dune belt decreased to 30–50 m everyone, dunes transformed to bush fixed hillocks, divided by bare sands. Some remains of dunes are very high (18 m). At the south of Jemete, recreation area of Northern Anapa has come to dune belt. Under reducing of wind exposition to 60° and decreasing of beach to 50–70 m, dune belt is widen to 100–130 m and series of 2–3 ramparts of 7–8 m in high are formed instead of one. Buildings rapidly move into dune belt, destroying ramparts, and hollows with hillock sands are used for waste storing. At the edge of southern part of region, near Anapa, wind exposition reduces to 40–50°; dune belt decreases to 50 m and has one rampart of 3–4 m in high, and with reducing of wind exposition to 30° disappearing at whole. These differences in morphological structure and statement of sand bar must be taken into account in land use planning and in decision-making for sand bar conservation and defense.

Landscape vision and zonal orientation in the Equatorial sandhopper Talorchestia martensii

We investigate the role of the landscape in the zonal recovery of the Equatorial sandhopper Talorchestia martensii Weber. It is known that this species uses the sun and the magnetic compasses to return to the belt of damp sand of the beach following the shortest route (the sea-land axis). However, the sun is not always easy to use at Equatorial latitudes because of astronomical reasons (its zenithal culmination and its hourly azimuthal speed) at least during the central time of the day (around noon) and close to the equinox. Our experiments were performed in Kenya, during the equinoctial period. We tested adult individuals, belonging to Malindi (Kenya) population, in a confined environment with and without the vision of the landscape of their home beach and with the vision of the prominent landscape of a different-orientated shore (Temple Point). Releases were carried out with either natural or zeroed magnetic field. Results clearly show the importance of the landscape as an orienting factor mainly during the central hours of the day when it seems to assume a greater importance than magnetic cues.

History and mechanisms for the expansion of the Badain Jaran Desert, northern China, since 20 ka: Geological and luminescence chronological evidence

Desert landscapes are widely distributed in the arid northern China. The Badain Jaran Desert (BJD) is located north-west of the Tengger Desert (TD) and Ulan Buh Desert (UBD), with the Yabrai and Bayan Ulan Mountains separating the BJD from the TD and UBD. Many sand belts with an orientation of NW-SE, which is similar to that of the prevailing sand-transporting winds, connect the BJD with the TD and UBD, forming the sand transportation routes from the BJD to the TD and UBD. Thus, these sand belts are sensitive to the expansion or shrinkage of the BJD, whose chronologies could be critical for understanding the evolution of the BJD. However, age data are still very limited. In this study, field investigation and optically stimulated luminescence (OSL) dating have been conducted in 14 profiles, and 24 OSL ages are obtained. The OSL ages range from approximately 15 ka to modern. Our results and previous chronological data revealed that the BJD’s expansion initiated at 20 ka, and the present-day landscape formed within the latest 2 ka with periodic expansions at 19–15, 11–9, 7.3 and 6–5 ka. We propose that these expansions of the BJD before ~5 ka and during the 0.9–0.8 ka interval were responses to regionally low effective moisture conditions in north-western China, while the expansions at ~2 ka and within the latest 200 years were likely triggered by intensified human activity.

Palaeohydrological reconstruction (1500–2000 AD) of a drift sand landscape using pedogeomorphological and historical data (Campine area, NE Belgium)

In order to build confidence in describing the hydrological cycle under future global change, hydrological models not only need to be calibrated and validated with recent data, but should also be tested against different boundary conditions from the past. This requires building a dataset of hydrological state variables against which the modelling output can be tested. We use pedogeomorphological and historical data to monitor hydraulic heads at specific time slices during the last 500years for a sandy interfluve in the Nete catchment, NE Belgium. The nature of the archive is temporally and spatially highly discontinuous but allows to observe a systematic drop in phreatic groundwater levels during the second half of the 19th century. It is concluded that the approach yields promising results and that it might be of use elsewhere in drift sand landscapes across the European sand belt.

The Whole Story. Bridging the Gap between Landscape-archaeological Data from Drylands and Wetlands

Detailed historical reconstructions require high-quality data. In the traditionally densely settled higher and drier Pleistocene sandy areas (‘drylands’) of the North European Plain (the European aeolian sand belt) and comparable regions elsewhere evidence-based reconstructions are hampered by poor preservation of archaeological remains and archaeologically relevant deposits. This problem can be partially solved by combining, on a microregional level, dryland data with data from nearby wetland pockets (‘wetlands’),in particular stream valleys. This asks for an integrated and systematic inventory of all available data. For this purpose an instrument was developed: the Landscape-Land use Diagram (LLAND). Because data from dry and wet contexts are to some degree supplementary, integrated analysis is essential for obtaining information on the full range of economic and ritual practices. This is demonstrated by research carried out in the valley of the small river Regge (the Netherlands), the results of which are being treated as a stratified landscape-archaeological sample. This paper does not focus on cultural interpretation but on methodology, specifically the potential of data and the benefits of an integrated approach.

Useful plants from the site Lutomiersk–Koziówki near Łódź (central Poland) with special reference to the earliest find of Xanthium strumarium L. seeds in Europe

Archaeological features at the multi-culture site of Lutomiersk–Koziówki 3a-c in central Poland contained preserved charred plant macro-remains. The site is located within the “Central European sand belt” characterised by sandy terraces and dunes, nowadays covered mainly by podzols and anthropogenically changed soils. The samples come from pits dated to the Middle Bronze Age (MBA, ca. 18th–14th centuries BC), the Late Bronze Age (LBA, ca. 10th–8th centuries BC), and the Roman Iron Age (RIA). The most intensive occupation was connected with the development of the LBA settlement of Lusatian culture. During that time mostly peas (Pisum sativum) and millet (Panicum miliaceum) were cultivated while remains of large-grained crops like einkorn (Triticum monococcum), emmer (Triticum dicoccum), spelt (Triticum spelta), and barley (Hordeum vulgare) were not common. In that time goosefoot (Chenopodium album) and wild buckwheat (Fallopia convolvulus) were probably used as a source of food. In the Roman Iron Age, the presence of those plants decreased and rye (Secale cereale) appeared, becoming the most common cultivated plant besides barley. The unique find of cocklebur (Xanthium strumarium) seeds in the LBA samples was possibly connected with their useful properties, primarily as medicinal plants and secondarily as a source of oil. The cocklebur remains were probably processed, but no by-products and no whole fruits were noted. The context of these finds is exceptional compared with the other samples from the site, possibly reflecting medicinal activities of the people. Taking into account the history and migration of the cocklebur in Europe during the Holocene, it must be emphasized that the charred seeds from Lutomiersk–Koziówki are currently the oldest radiocarbon-dated finds in Europe (2745±30 BP, ca. 975–818cal. BC) and can reflect distant contacts of the settlers mostly with south-eastern Europe although eastern routes cannot be excluded as well.

Reconstruction of sediment provenance and transport processes from the surface textures of quartz grains from Late Pleistocene sandurs and an ice-marginal valley in NW Poland

Abstract During the Pomeranian phase of the Weichselian glaciation (~17-16 ka), the Toruń-Eberswalde ice-marginal valley (NW Poland and easternmost Germany) drained water from the Pomeranian ice sheet, while intensive aeolian processes took place across Europe in the foreland of the Scandinavian ice sheet (‘European Sand Belt’). The micromorphology of the quartz grains in the Toruń-Eberswalde ice-marginal valley shows no traces of these aeolian processes, or only vague signs of aeolian abrasion. This is unique among the aeolian sediments in other Pleistocene ice-marginal valleys in this part of Europe. The study of the surfaces of the quartz grains shows that the supply of grains by streams from the south was minimal, which must be ascribed to the climate deterioration during the Last Glacial Maximum, which resulted in a decrease of the discharge of these extraglacial rivers to the ice-marginal valley.

Climate evolution during the Pleniglacial and Late Glacial as recorded in quartz grain morphoscopy of fluvial to aeolian successions of the European Sand Belt

Abstract We present results of research into fluvial to aeolian successions at four sites in the foreland of the Last Glacial Maximum, i.e., the central part of the “European Sand Belt”. These sites include dune fields on higher-lying river terraces and alluvial fans. Sediments were subjected to detailed lithofacies analyses and sampling for morphoscopic assessment of quartz grains. Based on these results, three units were identified in the sedimentary succession: fluvial, fluvio-aeolian and aeolian. Material with traces of aeolian origin predominate in these sediments and this enabled conclusions on the activity of aeolian processes during the Pleniglacial and Late Glacial, and the source of sediment supply to be drawn. Aeolian processes played a major role in the deposition of the lower portions of the fluvial and fluvio-aeolian units. Aeolian material in the fluvial unit stems from aeolian accumulation of fluvial sediments within the valley as well as particles transported by wind from beyond the valley. The fluvio-aeolian unit is composed mainly of fluvial sediments that were subject to multiple redeposition, and long-term, intensive processing in an aeolian environment. In spite of the asynchronous onset of deposition of the fluvio-aeolian unit, it is characterised by the greatest homogeneity of structural and textural characteristics. Although the aeolian unit was laid down simultaneously, it is typified by the widest range of variation in quartz morphoscopic traits. It reflects local factors, mainly the origin of the source material, rather than climate. The duration of dune-formation processes was too short to be reflected in the morphoscopy of quartz grains.

Age and sedimentary record of inland eolian sediments in Lithuania, NE European Sand Belt

We present a study based on four inland eolian locations in Eastern, Central and Southeastern Lithuania belonging to the northeastern part of the ‘European Sand Belt’ (ESB). Although there have been several previous studies of the ESB, this north-eastern extension has not been investigated before in any detail. The sedimentary structural–textural features are investigated and a chronology was derived using optically stimulated luminescence on both quartz and feldspar. The sedimentary structures and the rounding and surface characteristics of the quartz grains argue for a predominance of eolian transport. Additionally, some structural alternations and a significant contribution of non-eolian grains are interpreted as inherited local glacial/glaciofluvial-bearing lithologies.Three main (glaciolacustrine–) eolian phases are distinguished based on the position in the landscape and the luminescence ages: (1) An older eolian series around 15 to 16ka, possibly correlated with the cold GS-2a event according to the GRIP stratigraphy, and (2) a younger eolian series around 14.0ka, possibly representing the GI-1d and 1c events. The older eolian series is underlain by (3) a glaciolacustrine–eolian series for which the period of deposition remains uncertain due to the significant discrepancy between the ages based on quartz and feldspar.

Study on sanding force and sanding optimal parameters of Manchurian ash

The effects of grit size (40–120), feeding speed (2.5–5.14 m min−1), sanding speed (5.35–10.74 m s−1) and sanding thickness (0.1–0.5 mm) on sanding force and normal force as well as surface roughness during abrasive belt sanding of Manchurian ash were investigated using orthogonal experiments. The major influencing factors on sanding force and normal force and surface roughness were identified using visual analysis and variance analysis. The sanding force and sanding quality were synthetically evaluated and optimally selected using fuzzy synthetic evaluation. The results showed that sanding force and normal force were significantly affected by all the four factors during sanding of Manchurian ash, especially sanding thickness and feeding speed had greater effect on sanding force and normal force. The optimal parameters for sanding of Manchurian ash were: 40 and 60 mesh of grit size, 2.5 m min−1 of feeding speed, 10.74 m s−1 of sanding speed and 0.1 mm of sanding thickness.

Bathymetric zonation of modern shelf benthic foraminifera in the Levantine Basin, eastern Mediterranean Sea

Siliciclastic carbonate-poor sediments are common in southern and central parts of the inner Israeli shelf, part of the Nile littoral cell and in deeper water along the entire coast, while carbonate rich sediments occur in northern Israel and in submerged rocky environments. The distribution of benthic foraminifera, common components of these environments, was studied in surface sediment samples in order to identify their bathymetric zonation using multivariate statistical analyses. The dead foraminiferal assemblages exhibit a clear bathymetric zonation directly related to substrate type. A distinct faunal change has been found at approximately 40m water depth coinciding with the shift from the shallow-water sand belt, distributed parallel to the Israeli coast up to Haifa Bay, to a silty–clayey belt relatively rich with organic matter extending westward along the entire SE Mediterranean shelf. Ammonia parkinsoniana, Ammonia sp. 1, Buccella granulata, Nubeculina divaricata and Adelosina sp. 1 predominating the shallow-water depths are positively related to sand content and negatively related to water depth. Other species, such as Asterigerinata mamilla, Hanzawaia rhodiensis, Reussella spinulosa, Triloculina marioni and Valvulineria bradyana, occurring between 40 and 100m, exhibit a positive relationship with total organic carbon content and water depth. Beyond the Nile littoral cell and partly in its distal part Amphistegina lessonii, Peneroplis pertusus, Pseudoschlumbergerina ovata, Pseudoschlumbergerina sp. 1 and Quinqueloculina ungeriana dominate the rocky and coarse sand substrate, exhibiting a more positive relationship with higher carbonate content values. The distinct bathymetric zonation established in this study may prove to be useful in fossil records for accurate paleo-bathymetry reconstruction of Quaternary records in this dynamic system prone to frequent sea level fluctuations.

The depositional conditions of the fluvio-aeolian succession during the last climate minimum based on the examples from Poland and NW Ukraine

The object of the study was the fluvio-aeolian sedimentary succession in eight sites located in the central part of the European Sand Belt, in Poland and NW Ukraine. Based on the lithofacies, pedological and morphoscopic analyses, the analyses of frost structures and grain size as well as the TL, IR-OSL and 14C dating, three lithofacies complexes deposited at the turn of the Weichselian and Holocene were documented. The fluvial complex was deposited in the Pleniglacial within a sandbed braided river, which in the final stage of deposition of the complex was transformed into an anastomosing river. These rivers functioned in continuous permafrost coverage.The fluvio-aeolian complex was the result of aeolian deposition and fluvial redeposition, resulting from the degradation of continuous permafrost at the turn of the Pleni- and Late Glacial. These processes operated in the areas abandoned by regular flow. The aeolian complex was accumulated following the development of aeolian sand forms – sandy and silt covers as well as parabolic and longitudinal dunes, after the complete degradation of permafrost at the end of the Late Glacial and Holocene. Improving climatic conditions were expressed by the presence of fossil levels of initial gley soil in the roof of the fluvio-aeolian complex as well as poorly developed podzolic and colluvial soils in the aeolian complex.

The geomorphology and evolution of aeolian landforms within a river valley in a semi-humid environment: A case study from Mainling Valley, Qinghai–Tibet Plateau

This paper systematically analyzes a valley's aeolian landforms in a semi-humid region and presents a model of its contemporary evolution. Mainling Valley of the Yarlung Zangbo River on the Qinghai–Tibet Plateau was chosen as the case study for the analysis of morphometric characteristics and the evolution sequence of aeolian landforms via field data and remote sensing images. The aeolian landforms were primarily composed of aeolian sand belts on river terraces and dunes (sheets) on hillside slopes. Three types of aeolian sand belts were identified based on their dune types. In type I belts, an erosive air stream combined with relatively high vegetation cover (10%) produced sparsely distributed parabolic dunes with a high variability of dune heights; in type II belts, the continual reworking by the erosive air stream in combination with low vegetation cover (3%) formed more densely distributed barchans and transitional dunes with a moderate variability of dune heights; and in type III belts, the gradual evolution from an erosive sand-laden air stream to a saturated sand-laden air stream in combination with low vegetation cover (2%) produced the densest crescentic dunefields but with the least variability in dune heights. Dune sizes increase, dune shapes become uniform, and dune distribution becomes close from type I to III belts. Lateral linking and merging of the dunes were also observed within the belts. Together this evidence indicates that an evolution sequence may exist. Aeolian dunefields in the belt appear to evolve from embryonic parabolic dunefields to adolescent barchan dunefields and, subsequently, to mature compound crescentic dunefields. As the aeolian sand belt evolves into the mature stage, sand accumulations at the foot of the mountain valley can be steps for sand accumulation on valley-side slopes.

Late Quaternary (15 ka to present) development of a sandy landscape in the Mol area, Campine region, north‐east Belgium

ABSTRACTThe geomorphological analysis of two sections cut into a sandy landscape in north‐east Belgium enabled the establishment of a chronology for a sequence of events during the last 15 ka that illustrate the polycyclical nature of the evolution of such landscapes. Field descriptions, analytical sediment and soil characterization, and pollen analysis are combined with the optically stimulated luminescence dating method to unravel the recent geomorphological history of the investigated site. The principal results include apparently discontinuous sand deposition between ∼15 and 12 ka, landscape stabilization and Podzol formation between ∼12 and 1 ka, the development of a drift sand landscape between ∼650 and 200 a, and renewed stabilization over the last two centuries. The results are discussed in the light of climate, land‐use and vegetation changes and compared with findings at similar sites in the European Sand Belt.

A reassessment of the Lower Namoi Catchment aquifer architecture and hydraulic connectivity with reference to climate drivers

We demonstrate the need for better representations of aquifer architecture to understand hydraulic connectivity and manage groundwater allocations for the ∼140 m-thick alluvial sequences in the Lower Namoi Catchment, Australia. In the 1980s, an analysis of palynological and groundwater hydrograph data resulted in a simple three-layer stratigraphic/hydrostratigraphic representation for the aquifer system, consisting of an unconfined aquifer overlying two semi-confined aquifers. We present an analysis of 278 borehole lithological logs within the catchment and show that the stratigraphy is far more complex. The architectural features and the net-to-gross line-plot of the valley-filling sequence are best represented by a distributive fluvial system, where the avulsion frequency increases at a slower rate than the aggradation rate.We also show that an improved understanding of past climates contextualises the architectural features observable in the valley-filling sequence, and that the lithofacies distribution captures information about the impact of climate change during the Neogene and Quaternary. We demonstrate the correlation between climate and the vertical lithological succession by correlating the sediment net-to-gross ratio line-plot with the marine benthic oxygen isotope line-plot – a climate change proxy. Pollens indicate that there was a transition from a relatively wet climate in the mid–late Miocene to a drier climate in the Pleistocene, with a continuing drying trend until present. Groundwater is currently extracted from the sand and gravel belts associated with the high-energy wetter climate. However, some of these channel belts are disconnected from the modern river and flood zone. We show that the cutoff between the hydraulically well- and poorly connected portions of the valley-filling sequence matches the connectivity threshold expected from a fluvial system.

Optic flow and sea-land orientation in the sandhopper Talitrus saltator.

The problem sandhoppers face when they find themselves on the dry sand is to reach as quickly as possible the belt of moist sand near the water. In the present study, I ask whether, alongside many other orienting factors, sandhoppers use the optic flow they experience to maintain their bearing relative to the sea-land axis. Adult individuals of Talitrus saltator were released in a transparent Plexiglas bowl, horizontally placed between four walls with a pattern of vertical black and white stripes. The orientation of one pair of opposite walls was south-north, orthogonal to the sea-land axis of the home beach, whilst the second pair of walls was oriented east-west. The black and white striped pattern of opposite walls could be moved in pairs and in the same direction (speed=4.8 cm s(-1)). The results demonstrate that the optic flow sandhoppers experience when moving on the sea-land axis of their home beach influences their direction of travel and could help sandhoppers in maintaining a straight path to reach favourable ground by the shortest route.

Control of anticline crest zone on depositional system and its geological significance for petroleum in Changshaling, Yinger sag, eastern Jiuquan Basin

Yinger (营尔) sag is the main petroleum generative sag in eastern Jiuquan (酒泉) Basin, and only the Changshaling (长沙岭) oil resource has been found after 60 years prospecting. Changshaling anticline crest zone was formed above the regional uplift, and was slightly affected by over thrust during Tertiary Period. The anticline crest was identified as a structural transposition zone. Based on analysis of seismic facies, logging facies and seismic inversion technique, it has been demonstrated that anticline crest zone conducts drainage entering basin and dominates sedimentary detritus further dispersing, and the anticline crest zone controls the distribution of sand bodies and the development of sedimentary system consequently. The sequence stratigraphic patterns of multi-step fault belt in Member 3 of Xiagou (下沟) Formation in Lower Cretaceous in the anticline crest zone is composed of the development of sedimentary facies in plan and distribution of multi-step fault belt sand bodies in spatial. This research investigates the sand-control models and sequence patterns, and finally a model of reservoirs in anticline crest zone is identified.

Periglacial structures within fluvio‐aeolian successions of the end of the Last Glaciation – examples from SE Poland and NW Ukraine

The nature of permafrost and related environmental conditions in the Weichselian Late Pleniglacial and Lateglacial are reconstructed based on the assessment of frost structures that are best documented in the Loess Belt and in plateau areas composed of glacial till. Investigations were conducted in the central‐eastern part of the European Sand Belt (SE Poland and NW Ukraine) on a fluvio‐aeolian sedimentary succession and took into account its chronological context given by luminescence dating. Various generations of periglacial structures found in these deposits indicate not only the development of permafrost (ice‐wedge pseudomorphs) and decreased humidity (composite wedge casts) but also the degradation of permafrost (large‐scale involutions) and, finally, the establishment of deep seasonal frost (frost cracks). The diversity of structures in the study region appears to result from local conditions rather than increasing continentality of climate towards the east.

Reconstructing Quaternary Rhine–Meuse dynamics in the southern North Sea: architecture, seismo‐lithofacies associations and malacological biozonation

ABSTRACTMapping the Middle to Upper Pleistocene Rhine–Meuse sequence in the southern North Sea based on new core and seismic data has allowed a detailed palaeoenvironmental re‐assessment. An integrated seismo‐lithostratigraphic and malacological biostratigraphic framework is correlated with the optically stimulated luminescence‐dated Rhine–Meuse sequence onshore. The data point to a dynamic interplay of fluvial and marine systems in the southern part of the North Sea driven by longer‐term (>100 ka) tectonic and epeirogenic processes and shorter‐term (<10 ka) climatic processes. The final permanent breaching of the Cretaceous chalk at the Strait of Dover during the Saalian (Marine Isotope Stage 6, MIS 6) ice age led to the formation of the ‘Eurogeul’ belt, a gravelly sand belt that represents the largest concentration of gravelly fluvial sediments in the southern North Sea. The formation and preservation of the Rhine–Meuse sequence is related to long‐term (>100 ka) uplift of the Wealden–Artois synclinorium and compaction‐driven subsidence of Tertiary shales within the Voorne Trough. The dominant erosive sedimentary signatures within the Rhine–Meuse sequence resulted through shorter‐term (<10 ka) interplay of Pleistocene transgressions, glaciations and the permanent breaching of the Cretaceous chalk at the Strait of Dover by the Palaeo‐Channel river during the Saalian (MIS 6).

Key variables for the identification of soil management classes in the aeolian landscapes of north–west Europe

At present, spatially very detailed data sets can be obtained about soil, landscape and crop variability. However, there is a need to select independent key properties to identify management classes needed for precise land management. In a previous study performed in the European loess belt, topsoil pH, apparent electrical conductivity (ECa) and elevation were identified as key properties. In this study we enlarged the number of soil properties by including gamma ray measurements and employed a similar methodology to a field in the sand belt of northern Europe. Based on a principal component analysis we identified the same three variables as key properties. This was surprising given the big differences in landscape topology and pedogenesis between the loess and sand areas. These three key variables were used to delineate management classes using a fuzzy k-means with extragrade classification procedure. This classification was evaluated by mapping the wheat grain yield in the year 2006. A multiple regression model could be constructed that predicted yield from ECa and elevation well (Radj2=0.88). To analyse the influence of ECa on crop yield in depth a boundary line analysis was conducted. The boundary line could be modelled with an excellent Radj2 of 0.98. It was concluded that ECa, elevation and pH are generic key variables for the delineation of management classes of the aeolian landscapes of north–west Europe. Given its integral nature and strong relationship with crop performances, the authors plea to upgrade ECa from a “secondary” (proxy) source of information to a “primary” variable which can be used directly as a basis for detailed soil mapping of the bulk soil.