Heavy-mineral Concentrates Research Articles

放射光X線分析による北海道地方の法科学土砂データベースの構築

The purpose of the present study is to construct a nation-wide forensic soil database, which allows for the identification of soil evidence based on heavy element and heavy mineral signatures determined by two synchrotron radiation (SR) X-ray techniques, i.e., a high-energy synchrotron radiation X-ray fluorescence analysis and a synchrotron-radiation X-ray powder diffraction analysis, respectively. The heavy element and heavy mineral compositions of the stream sediments collected at 3024 points located all over Japan were measured by the two SR X-ray techniques. The present paper focuses on a regional characterization of the sediments collected from the Hokkaido areas. The concentrations of heavy elements and heavy minerals in the Hokkaido areas were visualized as maps that enable us to compare the heavy element and heavy mineral compositions with the geological context of the samples. Based on a hierarchical cluster analysis using the semi-quantitative compositions of the heavy minerals, we could successfully classify the sediments into six groups corresponding to their background geologies. A Bonferroni multiple comparison demonstrated that these six groups also have significant differences in the heavy element composition. From these examinations, we could demonstrate that detailed regional identification of unknown samples is possible by analyzing both heavy element and heavy mineral compositions of each sample.

Technogenic Transformations of Sea Coasts on the Example of the Baltic Sea

Natural and technogenic factors of violation of natural development of the Liepaja sandy rerash in Southeast Baltic are considered. Along coast for many years there has been a stream of substance and energy, unidirectional to the North. At the beginning of the 20th century after the reconstruction of the Russian port of Libava and lengthening of piers for more than 2 km, a stop of sea deposits along the coast appeared. It caused catastrophic local washout of the coast and bottom. In result, territorial losses, beach titanium-zirconium rerash, different types of pollution appeared. By a research it was established: 1. Rate of abrasion (20th century the coast receded to 200 m); 2. Formation and dynamics of the centers of concentration of heavy minerals, is defined amount of the useful ore minerals in a productive size of beach sands (0,2-0,25 mm, an ilmenite, a magnetite, zircon, rutile, a monocyte, leucoxene; 74% or 1523 kg/m3); 3. Major factors of change of a condition of coast and bottom of the sea. Also an assessment of consequences is given to events of World War II and on the Chernobyl NPP. Illustrations of the article show localization of concentrates of heavy minerals in a ledge of washout of the coast and on the beach, and also structure of mean annual coastal streams of substance and wave energy in technogenic morpholytho-dynamic anomaly at the port of Liepaja.

Reconstructing the formation of a costal aquifer in Nampula province, Mozambique, from ERT and IP methods for water prospection

In continental margin basins, the hydrogeological setting is complex due to transgression/regression events that removed old sediments in the basin and formed new geologic units. Due to the geological complexity, the use of vertical electrical sounding has proven to be insufficient for groundwater explorations. The lack of understanding the geological underground has resulted in many boreholes with low yield or poor water quality. By performing electrical resistivity tomography (ERT) and induced polarization (IP) measurements in 11 villages in Mongicual district, three different layers covering the basement were identified: a weathered autochthon layer, a weathered allochthon layer (paleo-coastal dune) and eolian white sand layer. The drilling at successful boreholes penetrates formations where the resistivity value is between 220 and 770 Ωm, whereas at unsuccessful boreholes the lower parts of the drilled range have resistivity values higher than 770 Ωm. Also, the thickness ratio of the weathered and semi-weathered layer in the unsuccessful boreholes is less than 1/3, whereas in all successful boreholes the ration is higher than 1/2. The difference between autochthon and allochthon layers was detected by heavy minerals content in the red eolian sand layer (Tupuito formation) that increased the chargeability value. The groundwater with a conductivity higher than 2000 µS/cm is linked to the white eolian sand. The surface extension of white eolian sand layer is small to be mapped; therefore, by mapping the eolian white sand formation and the use of ERT and enhanced with IP method would lower the failure rate.

Rare earth elements pilot studies of the baltic marine sands enriched in heavy minerals

Abstract The carried out pilot work on the concentration of rare earth elements (REE) in the Baltic marine sands from the Odra and Słupsk Banks showed that in some places their accumulations are quite interesting in terms of the placer deposits and may be the subject of an interesting prospecting project. The results of ICP-MS and electron microprobe (CAMECA SX-100) investigation confirm the close relationship of REE concentration to heavy minerals content in the sediments of marine sands. It is indicated, in addition to monazite, as a primary mineral carrier of rare earth elements. The vast preponderance of light REE is noted in the samples of heavy mineral concentrates from the Odra and Słupsk Banks as well as in the beach sand sample from the Hel Peninsula. The highest concentrations are achieved mainly by cerium and almost two times less by lanthanum. The total REE in the most interesting considered samples range from c.a. 0.14% (trench on the beach) to 0.9% (heavy minerals concentrate from the Odra Bank). The high contents of REE are accompanied by a high concentration of Th (900-150 ppm). Neodymium (0.1-0.17% Nd), whose presence is associated with the presence of pyrochlore and Nb-rutile also appears in the heavy minerals concentrate samples. It is necessary to systematically identify heavy minerals resources in the Baltic sands. More detailed research should cover the prospective areas situated to the North-East from the documented placer fields of the Odra Bank, as well as tentatively identified areas of the Słupsk Bank and submarine paleo-slope of the Hel Peninsula.

Hair Mineral Levels in Dogs with Atopic Dermatitis

Atopic dermatitis is a genetic allergic skin disease that can be triggered by various environmental factors. This research aimed to study the possible correlation between heavy metal and mineral concentration and presence of atopic dermatitis. Hair samples from dogs suffering from atopic dermatitis were analyzed and compared to samples from the control group via ICP-OES method. Cu was the only element significantly decreased (p = 0.01) in the study group. No statistical significance was found for heavy metals.

Error sources in single-clinopyroxene thermobarometry and a mantle geotherm for the Novinka kimberlite, Yakutia

A new suite of 173 clinopyroxene grains from heavy-mineral concentrates of the diamondiferous Novinka kimberlite (Upper Muna field, Yakutia) has been analyzed for major and minor elements with an electron microprobe to perform a thermobarometric study and model the thermal structure of the Archean Upper Muna lithospheric mantle. Scrupulous evaluation of propagation of analytical uncertainties on pressure estimates revealed that (1) the single-clinopyroxene geobarometer can be very sensitive to analytical uncertainties for particular clinopyroxene compositions, and that (2) most clinopyroxenes from Novinka have compositions that are sensitive to analytical uncertainties, notwithstanding their apparent compositional suitability for single-clinopyroxene thermobarometry based on previously proposed application limits. A test on various mantle clinopyroxenes containing different proportions of the sensitive elements Cr, Na, and Al allowed us to identify clinopyroxene compositions that produce unacceptably high propagated errors and to define appropriate analytical conditions (i.e., higher beam currents and longer counting times for specific elements) that allow precise P-T estimates to be obtained for sensitive compositions. Based on the results of our analytical test, and taking into account the intrinsic limitations of the single-clinopyroxene thermobarometer, we have designed a new protocol for optimum thermobarometry, which uses partly revised compositional filters. The new protocol permits precise computation of the conductive paleogeotherm at Novinka with the single-clinopyroxene thermobarometer of Nimis and Taylor (2000). Thermal modeling of the resulting P-T estimates indicates a ~34 mW/m 2 surface heat flow, a thermal lithosphere thickness of ~225 km, and an over 100 km thick “diamond window” beneath Novinka in the middle Paleozoic (344–361 Ma). We estimate that appropriate analytical conditions may extend the applicability of single-clinopyroxene thermobarometry to over 90% of clinopyroxene-bearing garnet peridotites and pyroxenites and to ~70% of chromian-diopside inclusions in diamonds. In all cases, application to clinopyroxenes with Cr/(Cr+Al) mol P > 4.5 GPa.

Origin of placer gold and other heavy minerals from fluvial Cenozoic sediments in close proximity to Rote Fäule-related Au mineralisation in the North Sudetic Trough, SW Poland

Detailed morphological and geochemical studies of placer gold grains and other heavy minerals from Cenozoic fluvial clastic sediments in the area of the Zimnik Creek drainage basin (North Sudetic Trough, Lower Silesia) allowed the description of their specific features: shape and morphology, flatness index, internal textural features and chemical composition of the gold grains. It enables an estimation of the distance from the source area and determination of the source of the ore mineralisation, along with establishing the feeder areas for placer mineralisation including Rote Faule-related gold hosted by Rotliegend-Zechstein transitional sediments. The comparison of the heavy mineral contents of placer grains from the Zimnik Creek drainage basin makes it possible to identify the area of origin for the gold particles. The crystalline Au-Ag-Pd-Hg (polymetallic) alloy grains of fluvial gold are assumed to come from the transitional sediments between the Rotliegend and the Zechstein in the North Sudetic Basin. The morphological and geochemical features of the polymetallic grains strongly suggest that the grains from the upper course of the Zimnik Creek valley sediments represent what has eroded from the local gold mineralisation and this mineralisation is probably in the vicinity of the upstream sampling site. The bimodal chemical composition of the Au-Ag-Pd-Hg alloy grains with electrum and medium-Ag grains (<15 wt.% Ag) found in the study area is typical of the Rote Faule and Kupferschiefer-related gold mineralisation on the southern side of the North Sudetic Trough and the Sieroszowice-Polkowice copper mining district of the Fore-Sudetic Monocline. The study of the Ag contents of placer grains from the Zimnik Creek drainage basin highlights the contrast between the placer gold grains derived from Paleozoic orogenic gold mineralisation in the Sudetes (typically simple Au-Ag alloys containing between 5 and 20 wt.% of Ag) and the one formed by the oxidizing chloride hydrothermal systems. The grains identified in this manner as originating from the oxidizing hydrothermal system of the transitional zone can be distinguished from the placer gold derived from other styles of mineralisation, which are not Rote Faule-related. It is particularly important considering the ongoing reconnaissance exploration in the North Sudetic Trough (SW Poland), which employs gold grain analyses as a prospecting tool for the detection of potentially economic primary gold mineralisation.

La Géomorphologie De La Plage De Haouzia (Littoral Atlantique Marocain) : Origine Et Mise En Place De Ses Sédiments Actuels

Geomorphological study of the range of Haouzia shows that the latter is more or less homogeneous but influenced by the mouth of the Oued Oum Rbia to the No. Spatio-temporal variation and the heterogeneity and beach profiles are related to the morphology of the beach and the coastal dynamics. Its sediments enrich carbonate because they feed Cretaceous land upstream of the mouth and the Quaternary calcarenites outcropping in the submerged area of the beach. Heavy minerals come from land metamorphic (Boulaouane) and magmatic (Sidi Saïd Maachou) through the Oued Oum Rbia and then taken over by the littoral drift. The weight content of heavy minerals is a good indicator of the direction of the transfer (no SW) of these minerals and sediment. The relative heterogeneity of sediments is favoured by the mouth of the Oued Oum Rbia allowing mixing of continental and marine sediments. It is all the more pronounced to the SW (breaking the waves) and winter (storms). Sediment (coarse and fine) are generally ranked especially in part SW (quiet environment despite the onslaught of the waves) and dune (sorting by the wind). Haouzia beach is under anthropogenic pressure to order, essentially, tourist who is behind the deforestation of the forest of Hameed and therefore the destabilization of the environment (including the beach). Urgent action is needed to protect this beach playing an important socio-economic role in the region.

Spatial patterns in heavy-mineral concentrations along the Curonian Spit coast, southeastern Baltic Sea

The 98-km-long Curonian Spit is fronted by beaches mainly composed of quartz sand with minor high-density fractions. In this study heavy-mineral concentration (HMC) trends and grain-size statistical parameters were used to assess their role as indicators of natural processes, human activities, and patterns of longshore transport. A total of 92 surface sand samples were collected at 1 km intervals from the middle of the beach along the Baltic Sea shoreline of the spit between Klaipėda strait in Lithuania and Zelenogradsk in Russia. HMC contribution was assessed in the laboratory using bulk low-field magnetic susceptibility (MS) as a proxy for ferrimagnetic and paramagnetic mineral content. Quartz-dominated (background) sand is generally characterized by low MS values of κ < 50 μSI, whereas higher values κ > 150 μSI are typical for heavy-mineral-rich sand. The greatest MS values along the middle of the beach occur in the southern part of the spit and are 40 times higher than in the northern sector. This pattern suggests the existence of a longshore particle flux with HMC distribution having the potential as a useful tracer of longshore sediment transport. Local anomalously high MS excursions are associated with contribution of iron-rich materials from adjacent man-made structures. Therefore, temporally constrained HMC distribution along the middle of the beach reflects the cumulative effect of antecedent geologic framework, longshore sediment transfer, erosional and accretionary processes, wave and wind climate, and local coastal protective structures.

Geological and Exploration Models of Beach Placer Deposits, Integrated from Case-Studies of Southern Australia

The processes leading to the formation of beach placer deposits generally begin inland and terminate at the coast, including source rocks being weathered, eroded and then transported by streams and rivers to the coast, where the sediments are deposited in a variety of coastal environments. The coastal sediments are reworked by the action of waves, tides, longshore currents and wind, which are effective processes for sorting the mineral grains based on differences in their size and density, resulting in laminated or lens-shaped packages of sediments up to tens of meters thick that are rich in heavy minerals. Detailed studies of sedimentary basins, as well as peripheral (paleo-)valleys that drained sediment source areas, are important tools in the exploration for heavy mineral resources. Knowledge of the (paleo-)basin, associated valley architecture and the source of heavy minerals concentrated in the shorelines and valleys are useful guides to the potential for, and location of, economic deposits.Evidence from sedimentology can be combined with that from other geological and geophysical characteristics to arrive at a general reconstruction of basin and paleovalley architecture and depositional environments. Complex paleogeography of the shorelines can influence or determine the sites of heavy mineral concentration. Heavy mineral sands tend to concentrate in certain shoreline settings during storm activity. Repeated storm erosion and reworking over centuries (e.g., the southeastern coast of Australia) or millennia (e.g., the Eucla and Murray Basins of Australia) can progressively enrich heavy mineral sand deposits. Preservation of these deposits over a geological timeframe of millions of years can ensue through subsidence of coastal sediments, and during sea-level change that results in either shorelines migrating inland (marine transgression) or seaward (marine regression), potentially burying or stranding earlier deposits or reworking them to form younger deposits. Refinements in remote sensing and geophysical techniques, data processing, sedimentology and computer-aided interpretations provide effective, economic and efficient methods for modeling coastal reconstructions and for exploring provinces and terrains prospective for heavy mineral sand deposits. Landscape topography analysis, combined with geophysical methods that can resolve physical property contrasts between the shoreline sediments and underlying sequences, are increasingly used in mineral exploration to locate and to reconstruct paleoshorelines and paleovalleys.Australia has modern and ancient beach-placer deposits, both of which show many similar geologic features. The formation of these heavy mineral deposits provides one of the best examples of applying knowledge of modern systems (e.g., the west and east coasts of Australia) as an analogue to interpret and understand the geology and form of ancient deposits (e.g., the Eucla and Murray Basins of southern Australia). This study provides descriptive and exploration models of Australia’s heavy mineral sand deposits formed in coastal environments, which can be applied to similar settings worldwide.

Geology of the PQ deposit, Sri Lanka

The PQ heavy mineral sand deposit is located on the west coast of Sri Lanka, approximately 30 km north of the town of Puttalam within the North Western Province. The PQ heavy mineral deposit was previously defined and explored between 1994 and 2002. Since 2010 further evaluation work has been completed. The ilmenite dominated deposit is hosted in a Quaternary to Recent age sedimentary sequence overlying the Miocene Vanathavillu limestone. It is a relatively homogenous red-brown palaeo-dunal deposit that extends for more than 5 km in length, is up to 3-km wide and contains 46.4 Mt of heavy mineral. Mineralisation commences from surface to a depth of over 50 m and grades range between 1.0 and 50.4% total heavy minerals. The PQ deposit shares many similar attributes with the teri sand (red sands) environments in southern India in terms of size, increased heavy mineral concentration, depositional environment and age.

WIM150 mineral sand deposit, Murray Basin, Australia: geology and mineral resources

The first significant heavy mineral sands discovery within the Murray Basin, Australia, was made in 1982 at the WIM150 deposit near Horsham, Victoria. This fine-grained (20–75 µm) deposit formed in an offshore environment (WIM-style deposit). The heavy minerals (HM) are within the Loxton Sand, which is prospective throughout the Murray Basin for HM in both strandlines and WIM-style deposits. At WIM150, HM are concentrated in a horizon that extends for 10 km north–south and 12 km east–west and has a thickness that ranges from 2 to 22 m with an average of 11.2 m. Measured, Indicated and Inferred Mineral Resources totalling 1650 million tonnes at 3.7% total HM were estimated in 2013. Test work has demonstrated that the resource can be processed to +20 µm and that the 20–38 µm size fraction contains significant concentrations of HM (14.8% of the HM within the 20–75 µm size fraction). Test work also demonstrated that the HM from the 20 to 38 µm size fraction contain more than 40% ZrO2 and CeO2 (assumed to be contained in zircon and monazite, respectively). The project is estimated to have an Ore Reserve mine life of 55 years and is the most advanced, in terms of development, of the Murray Basin WIM-style deposits. A definitive feasibility study for the WIM150 deposit was completed in mid-2013.

Heavy mineral concentrations in the sandstones of Amij Formation with particular emphasis on the mineral chemistry and petrographic characteristics of monazite, western desert of Iraq

The heavy minerals in the clastic unit of the Lower Jurassic Amij Formation exposed in the western desert of Iraq were studied. The uppermost part of the clastic unit contains thin, placer-like black sandstone horizons that are radioactive and abnormally rich in heavy minerals (0.6–56%), dominated by opaque (65%) and transparent (35%) heavy minerals. The minerals, in the order of decreasing abundance are pseudorutile, goethite, zircon, hematite, magnetite, monazite, rutile, leucoxene, tourmaline, ilmenite, chromite, and few others. Electron probe microanalysis (EPMA), microscopic and autoradiographic observations and analysis showed that the monazite is monazite-(Ce) type with an average composition of (Ce0.39Nd0.16La0.19Pr0.04Sm0.02Gd0.02Eu0.01Y0·04Th0·06U0·01Ca0·05Fe0.01)(P0·98Si0.03)O4.Monazite consists predominantly of REE-oxides (57.93%) and P2O5 (29.31%), with minor amounts of ThO2 (6.60%), Y2O3 (1.92%), UO2 (0.76%), CaO (1.14%), SiO2 (0.69%), and FeOt (0.17%). The dominant compositional substitution operating between REE and P were a mixture of the complex cheralite type substitution ([REE]−2 [Th][Ca]) and the coupled huttonite type substitution ([REE]−1 [P]−1 [Th][Si]). The chondrite-normalized REE distribution patterns of monazite show enrichment in LREE with positive Eu- and Pr-anomalies of 1.46 and 9.13, respectively. The median values of (La/Sm)CN and (La/Nd)CN ratios are 4.35 and 1.97, respectively. Zircon which is the dominant transparent mineral is Hf-rich that is composed of 30.61% SiO2, 57.58% ZrO2, 7.03% HfO2, 2.04% Y2O3, 0.56% ThO2, 0.19% UO2, and 0.19% Al2O3 corresponding to a formula (Zr0.909Hf0.065Th0·004U0·001Y0.031)Σ1.011(Si3·966Al0.028)Σ0.999O4. Rutile and tourmaline form 7% and 4% of the heavy minerals. Ilmenite which is one of the predominant heavy minerals forms 2.5% of the opaques because it is pervasively altered to Ti-Fe oxides. In addition of zircon and monazite, the chemical compositions of most of the other heavy minerals are also given in this study. The expected dominant source of heavy minerals and their host sandstones are most probably the felsic igneous and metamorphic complexes of the Arabian Shield, currently located ∼600 kms to the south of the studied area. The heavy minerals were carried from the source area by northward moving rivers and sorted out by ocean waves as black sand concentrations at the delta mouth along the southern beaches of the Neo-Tethys Ocean under passive margin tectonic setting. This border was apparently bordering the current western part of Iraq during Upper Jurassic period.

Erosion and heavy mineral depletion of a placer mining beach along the south-west coast of India: Part I— Nearshore sediment transport regime

The Chavara coast of southwest India is well known for its rich beach placer deposits which are being commercially exploited by the industries. Replenishment of these resources, which consist of heavy minerals of varying densities, by the hydrodynamic processes is essential for maintaining the stability of the coast as well as sustenance of mining. Rich concentrations of heavy minerals were reported consistently in the beach sediments of this coast in the past, but a systematic reduction in the concentration of the heavies has been reported during the past one-and-a-half decades. This paper, the first in a series of three, emanates from a programme of study launched to understand the mechanisms that manifest the reported changes in the morphology and mineralogy along this coast. In this study the longshore and cross-shore sediment transport rates along this coast have been estimated adopting numerical model studies. The validated LITDRIFT and LITPROF modules of the LITPACK modelling system have been used for computing the longshore and cross-shore sediment fluxes in the surf zone and innershelf region. The net annual longshore sediment transport is northerly in the surf zone where as it is southerly in the innershelf. Detailed analysis of the computed results shows domination of onshore transport over offshore transport. The beach volume change estimated from the measured beach profile on the other hand shows a reduction in the annual replenishment. The domination of the onshore flux as seen in the computations is actually not reflected in the field observations, and this can be attributed to the influence of excessive sand mining by the industries.

Erosion and heavy mineral depletion of a placer mining beach along the south-west coast of India: Part II—Sedimentological and mineralogical changes

Mining of beach placers or heavy minerals (HM) has been going on along the Neendakara–Kayamkulam coastal sector of the SW India for the past several decades by two public sector undertakings. Rich concentrations of HM were reported consistently in the beach sediments of this coast in the past, but a systematic reduction in the concentration of the heavies has been reported during the past one and a half decades. This paper emanates from a programme of study launched to understand the mechanisms that manifest the reported changes in the morphology and mineralogy along this coast. A detailed study of the sedimentology and mineralogy of the beach and innershelf has been carried out based on surficial sediment sampling from the beach and innershelf and core sampling from the innershelf. The study confirmed the depletion in the HM concentration in the beaches of the Chavara coast after 2000. One of the factors that led to the depletion in HM concentration along this coast was the 2004 tsunami which brought down the concentration to as low as 2 % in the innershelf. In addition to the tsunami, the other factors responsible for the observed depletion of beach placers along the coast are excessive beach sand mining and construction of coastal structures.

Erosion and heavy mineral depletion of a placer mining beach along the south-west coast of India: part III—short- and long-term morphological changes

The Chavara coast of south-west India is well known for its rich beach placer deposits which are being commercially mined by two public sector firms. The erosion of the beach and innershelf and the depletion of heavy mineral content of this coast have attracted a lot of attention of late, and an investigation of the mechanisms that drive these changes was taken up recently. The results of the investigation are presented in three parts. This paper, which is the last in the series, presents a study of the morphological changes of the beach and innershelf and integrates the results from the other two papers with an analysis of multi-dated shoreline and bathymetry data. The analysis of the multi-dated data showed an overall retreat of the shoreline and a relative deepening of the innershelf. The shoreline retreat has been quite alarming at the mining sites with one of the mining sites showing a retreat of nearly 400 m. The sediment deposition adjacent to the breakwater (built during 2000–2007) at the northern inlet has defused to some extent the high erosion observed earlier in the northernmost sector, and the presence of well-maintained seawalls has nearly maintained the shoreline south of the mining site. The erosion of the beach is accompanied by a deepening of the innershelf which is more pronounced in the shallower portions up to 10 m depth. The observed changes in the beach–innershelf morphology are analysed with respect to the nearshore sediment transport regime and heavy mineral distribution of the coast. It is observed that the combined intake of sediments by the two firms during the past one and a half decade is much above the sustainable mining level. Another contributing factor is the 2004 tsunami which drained off a sizable quantity of innershelf sediments rich in heavy minerals to the hinterland regions. The breakwaters at the two inlets bordering this coast have virtually compartmentalized this coast from the rest of the south-west coast making it a sediment sub-cell. In addition, the breakwaters act as groins causing imbalances in the erosion/accretion pattern. The recent spate in construction of shore protection structures like groins and seawalls is another contributing factor to the morphological changes. The study points to the urgent need for regulating the mining volumes to the sustainable levels as well as controlling the introduction of hard structures without proper impact analysis.

Risk assessment of mineral and heavy metal content of selected tea products from the Ghanaian market.

Food consumption is the most likely route of human exposure to metals. Tea (Camellia sinensis L.) is among the most widely consumed non-alcoholic beverages. Concentrations of heavy metals and minerals in tea from 15 different brands in Kumasi, Ghana were measured to assess the health risk associated with their consumption. The mineral and metal contents (Fe, Cu, Zn, Pb, As, Cd) were analyzed using atomic absorption spectrophotometer (Z-8100 polarized Zeeman). The results revealed that the mean concentrations were in the order: Ca > Fe > As > Cd > Zn > Pb. The average contents of Ca, Fe, Zn, Pb, Cd, and As in the samples were 94.08, 6.15, 0.20, 0.16, 0.36, and 1.66mg/kg, respectively. All the minerals and heavy metals were below the maximum permissible limits stipulated by the World Health Organization (WHO) and US Pharmacopeia (USP). Metal-to-metal correlation indicated strong correlations between As/Zn, Cd/Zn, Cd/As, and Pb/As pairs. Factor analysis demonstrated a clear separation between minerals, grouped on one side, and heavy metals, clustered on another side. Both the target hazard quotient (THQ) and hazard index (HI) levels in green tea were far below 1, suggesting that consumption of green tea should pose no potential risk to human health. However, carcinogenic risk levels for arsenic were high; R > 10(-6). The results showed that residents in Kumasi consume tea could be at risk from exposure to these heavy metals and minerals.

Origin of Jurassic-Cretaceous neptunian dikes from the Cracow-Częstochowa Upland in southern Poland

Neptunian dikes, representing deposit-filling fractures in older rocks, have long attracted the attention of paleontologists because they may provide unique insights into ancient cryptic submarine cave ecosystems. In the epicratonic Poland, fossil-bearing neptunian dikes are especially well known in Upper Jurassic (mainly Oxfordian) strata. However, the age, origin and faunal composition of these dikes remain the subject of debates. To address these issues, we integrated new paleontological and petrographic data from the Janina Quarry in southern Poland, where neptunian dikes are particularly well exposed. On the basis of sedimentary facies and faunal content occurring as infill of the analyzed dikes, we recognized three distinct stages of Neptunian dike development. Initially, these dikes represented fissures in the sea bottom resulting from the intense Oxfordian and/or Kimmeridgian synsedimentary processes related to Meso- and Neocimmerian tectonic movements. These initial voids were colonized by small crinoids (cyrtocrinids) and brachiopods (lacunosselids), which resulted in the formation of bioclastic limestones. This is the first Mesozoic record of cryptic cyrtocrinids, which implies that migration of this echinoderm group to cryptic habitats has already occurred in the Late Jurassic, consistent with the so-called Mesozoic Marine Revolution. After the initial opening and subsequent rapid sedimentary filling of voids, rejuvenation of these dikes occurred in the Aptian-Cenomanian that was likely induced by the Austrian tectonic phase. Reopened fissures were subsequently filled by rare allochthonous echinoderms and sandstones containing unusually high (5% vol.) content of heavy minerals implying the Bohemian Massif as the most probable source area. The neptunian dikes were finally reopened during the Turonian-Santonian that was probably related to the subhercynnian tectonic phase. They were presumably inhabited by annelids and ultimately filled by a micritic sediment subsequently bioturbated by infaunal echinoids.

River response to climate and sea level changes during the Late Saalian/Early Eemian in northern Poland – a case study of meandering river deposits in the Chłapowo cliff section

Abstract Fluvial sediments in the Chłapowo cliff section were studied in order to reconstruct their palaeoflow conditions and stratigraphical position. Lithofacies, textural and palaeohydraulic analyses as well as luminescence dating were performed so as to achieve the aim of study. Sedimentary successions were identified as a record of point bar cycles. The fluvial environment probably functioned during the latest Saalian, shortly after the retreat of the Scandinavian Ice Sheet. Discharge outflow was directed to the northwest. The river used the older fluvioglacial valley and probably was directly connected to the Eem Sea. Good preservation and strong aggradation of point-bar cycles were related to a rapid relative base level rise. The meandering river sediments recognised showed responses to climate and sea level changes as illustrated by stratigraphical, morphological and sedimentological features of the strata described. The present study also revealed several insights into proper interpretation of meandering fluvial successions, in which the most important were: specific lithofacies assemblage of GSt (St, Sp) → Sl → SFrc → Fm (SFr) and related architectural elements: channel/sandy bedforms CH/SB → lateral accretion deposits LA → floodplain fines with crevasse splays FF (CS); upward-fining grain size and decreasing content of denser heavy minerals; estimated low-energy flow regime with a mean depth of 1.6–3.3 m, a Froude number of 0.2–0.4 and a sinuosity of 1.5.

Heavy mineral analysis to identify sediment provenance in the Dan River drainage, China

Identifying the provenance of sediments carried by modern rivers can provide information on earth surface processes and help us to interpret geological history more clearly. The types and distribution patterns of surface sediments deposited in river systems are determined mainly by the fluvial flux and weathering of the proximal source rocks. In this paper, analysis of the heavy mineral content of 99 surface sediment samples was used to identify the source of the sediments carried by the Dan River in China. The objectives of this study are to: (1) determine the characteristics and distribution of the sediments, and (2) identify and classify the various depositional areas according to their differing source areas. The Dan River is divided into the lower, middle, and upper reaches to investigate the spatial distribution of heavy minerals. The main minerals detected were amphiboles, pyroxene, epidote, garnet, tourmaline, zircon, apatite, rutile, sphene, anatase, pyrite, and ilmenite. Generally, ilmenite (0.7% to 69.1%), amphibole (0% to 93.6%), epidote (0% to 53.3%), garnet (0% to 36.7%) and pyroxene (0% to 42.0%) were the most frequent detrital heavy minerals in the studied river sections. The Dan River and its tributaries are characterized with respect to their heavy mineral assemblages and heavy mineral indexes. Six depositional areas are distinguished and classified as Depositional area A (the Laoguan, Qi, and Xian rivers), Depositional area B (the Qingyou and Wuguan rivers), Depositional area C (the Laojun River), Depositional area D (the upper reaches of the Dan River), Depositional area E (the Yinhua River), and Depositional area F (the Tao River). The provenance study indicated that the sediments were derived mainly from the proximal exposed rocks. Sediments in the middle reaches of the Dan River were derived from Depositional areas B, C, and E, whereas sediments in the lower reaches were derived mainly from the local rocks along the river. Similar heavy mineral assemblages were obtained from Danjiangkou Reservoir and Depositional area A, especially for the Laoguan River, indicating the significant influence of Depositional area A on the reservoir.