ZTR Index Research Articles

A Regional Paleoclimate Record of the Tropical Aeolian Sands during the Last Deglaciation in Hainan, China

The KLD segment of the Kenweiyuan section in Wenchang, Hainan, China is a set of aeolian sand deposits of the Last Deglaciation. The chemical element and heavy mineral analysis performed in this study reveals the chemical index of alteration (CIA) in the segment to be as high as 93–95, with all the heavy minerals identified as stable and extremely stable making up 38–45% of the total. Furthermore, the zircon, tourmaline, and rutile content (ZTR index) of the segment is determined to range between 48–71. The (Al2O3 + TOFE)/SiO2 ratios display obvious fluctuations from old to new strata in the segment, with the low values corresponding to Heinrich event (H1), Dansgaard-Oeschager (D-O), and Younger Dryas (YD) and the high values corresponding to Bølling and Allerød. Our study suggests that these fluctuations are attributed to the alternation of the East Asian winter and summer monsoons. Hainan Island is also impacted by the surface ocean climate of the South China Sea, and characteristics of the KLD segment may be connected to the climate changes in the North Atlantic related to the winter monsoon season or westerlies. Furthermore, the segment presents a clear response to millennium-scale climate changes during the Last Deglaciation on Hainan Island. Based on the high CIA values in the KLD segment, and particularly due to the observed stable detrital minerals, the ratios can be linked to the overall tropical climate, indicating a relatively warm tropical climate environment in the Last Deglaciation in Hainan. The high CIA values also reveal the cause of aeolian sand formation under the tropical environmental conditions in the low latitude region of China in the Late Quaternary.

Sedimentary provenance and U-PB detrital zircon in the mesozoic record of the Parecis Basin, Rôndonia and Juruena sub-basin

Sediment provenance analysis is a tool increasingly used in the study of basins. This technique allows identifying the mineralogical and lithological composition of source areas, inferring paleogeography, climate and relief, determining the main sand distribution routes, and estimating the distance and transport time. The Mesozoic volcanic-sedimentary packages of the Parecis Basin mark a significant part of the South American Platform evolution, regarding tectonism, subsidence, sedimentation, basic and alkaline magmatism, uplift and erosion. Also, these packages registers the initial stages of Andean Orogeny subduction. Different authors have established opposite stratigraphic proposals for Parecis Basin regional correlations, and also for its tectonics evolution. Given this context, there are controversies regarding the chronostratigraphic positioning and relationships between the intervals, especially the units called Salto das Nuvens and Utiariti formations. This article presents the faciological framework and facies association, heavy mineral assemblage, ZTR index and sediment sources, and U-Pb detrital zircon ages to both sub-basins. Detrital Zircon data reveal minimum ages of 124 Ma for the Rondônia sub-basin and 245 Ma for the Juruena sub-basin for sedimentary deposition attributed to the base of the Cretaceous units. The detrital age of zircons points to a varied contribution, between elements from different provinces and ages of the Amazon Craton, the Paraguay Fold Belt and records of alkaline magmatism of ages Permo-Triassic and Cretaceous in the different kimberlithic fields of Rondônia and Mato Grosso.

Size Distribution And Heavy Mineral Pattern In Some E Gbe Streams, Southwestern Nigeria

The Egbe-Isanlu schist belt has received scholarly attention from several researchers but there is no documented report on types and the distribution of heavy minerals in streams of the area. This study is intended to reveal the types of heavy minerals, the distribution and possible source rocks to guide prospectors in gems. The study area lies within latitude 08o 03' and 08o 16 ' and longitude 05o 31' and 05o 43’ of the Southwestern Basement Complex terrain in Nigeria. Fifteen stream sediment samples were collected at appropriate points along river channels, air dried at room temperature, sieved and subjected to heavy mineral separation process using bromoform. Graphic mean, sorting, skewness and kurtosis were determined and heavy minerals identified under microscope. The graphic mean ranges between 0.67 (coarse sand) to 2.49 (fine sand), skewness between 0.75 and -0.10 and Kurtosis between 0.87 and 1.88. The calculated ZTR index ranges between 6.86% and 3.35.0%. The identified heavy minerals in the study area included tourmaline, epidote, rutile, zircon, kyanite, staurolite, garnet and zeolite. These minerals are modernly distributed across the sampled area and in some locations, they are relatively high in abundance. Some of the heavy minerals are angular to sub-angular in shape suggesting a short distance of travel from source. The graphic mean gives values that suggests a moderately to poorly sorted sediment and skewness indicated a platykurtic and leptokurtic nature for the sediments. Calculated ZTR index classified the sediments as immature to sub-mature indicating a short distance of travel suggesting that the sediments could have been derived within the catchment area. The presence of zircon, tourmaline and rutile suggests that the sediments might probably have its source from acid intrusive rocks and pegmatites.
 
 

Mineral Composition and Provenance of Al-Chabbab Stream Sediments, Wasit, Southeastern Iraq

A mineralogical study was carried out on the sediments of Al-Chabbab stream, one of the seasonal tributaries of the Tigris River, southeast of Wasit, Iraq. This study includes the sediments of the Tigris River sited before and after the mouth of the Al-Chabbab stream. Light and heavy minerals are determined by using polarized microscope and X-Ray Diffraction technique. The light minerals are composed of quartz, rock fragments, and feldspar, which are the prevailing compositions in all samples. The quantity of monocrystalline quartz in the Tigris River was more than Al- Chabbab stream, which refered to the supplied of felsic sours rocks sediments to the Tigris River more than the sediments of Al-Chabbab stream. The average value of minerological maturity index and ZTR index of Al-Chabbab stream, Tigris and Al-Chabbab inflow samples indicates that clasts generally are sub-mature. The Tigris River clasts have high mineralogical maturity index, which refers to the long transportation. Heavy mineral accumulation of the recent sediments from Al-Chabbab inflow and the Tigris River is composed of opaque and transparent minerals including epidotes; pyroxenes; amphiboles (hornblende and glaucophane); zircon; garnet; tourmaline; rutile; kyanite; staurolite; flaky minerals (muscovite; biotite and chlorite) and celestite (glaucophane and celestite are absent in the sediment of Tigris River). Based on the mineralogical signatures, the light and heavy minerals reflect metamorphic, mafic and felsic igneous rocks, of the active margin of the unstable shelf, in addition to the carbonate, evaporite and mud rocks that could be sourced from the Euphrates, Fatha and Injana formations.

Provenance Studies of Alluvial Tin Deposits in Parts of Ropp Younger Granite Complex, Northcentral Nigeria

The study area in this research is within the Ropp Complex, part of the Nigerian Mesozoic Younger Granite province. The study aims to interpret the depositional environment and establish the provenance of the alluvial cassiterite deposits in the study area. Boreholes/mining pits were logged for this study, and stanniferous sandstone samples were collected, which were used for textural and mineralogical studies. The mineral assemblages documented in the samples include ilmenite (3% to 27%). Cassiterite (2 to 14%), Zircon (2 to 16%), magnetite (0 to 17%), tourmaline (5 to 11%), rutile (2 to 8%) and monazite (2 to 7%).The ZTR Index calculated from the result of heavy minerals analysis for the selected pieces is 59%. Mineralogical studies revealed that quartz is the most dominant detrital mineral averaging about 93-99%, indicating that the stanniferous sandstones are compositionally matured and have experienced a high degree of chemical weathering. The quartz grains have grain sizes ranging from coarse to very coarse. They are poorly sorted, sub-angular to sub-rounded, with low sphericity. This also indicates a closeness to the source and textural immaturity. The occurrence of relatively very few feldspar grains suggests a slow sedimentation rate, very high rate of chemical weathering and composition maturity. The bivariate plots, univariate grain size parameters and probability plots, and the absence of fossils and trace fossils suggest deposition in a fluvial environment. The results of the granulometric analysis indicate that the study area's stanniferous sandstone was deposited in a fluvial environment by a low-energy fluvial (river) depositional system and the deposition in proximal (close to the source). This study suggests that the Basement complex and Younger Granite are the sources of the stanniferous placer deposits.

Provenance, Tectonic Setting and Paleoclimate of the Bhuban Formation Exposed in Jampui Hills, Tripura Fold Belt, Tripura, India: Insights from Petrography and Clay Mineralogy

Abstract The sandstones of the Bhuban Formation (Miocene) exposed in the Jampui hills of Tripura Fold Belt, India has been studied for provenance, tectonic setting and paleoclimate using the petrography, heavy mineral assemblage and clay mineral studies. The detrital mode of the sandstones indicate that the sediments consists predominantly of detrital quartz (avg. 92.19%), with subordinate proportions of feldspar (avg. 4.55%) and rock fragments (avg. 3.25%). The provenance discrimination diagrams depict the derivation of the detritus from both plutonic and metamorphic source rocks having affinity to continental block provenance. The plots of QFR and semi quantitative weathering index of the clastics support a moderate degree of paleoweathering in the source area under humid climatic condition. The presence of zircon, tourmaline, rutile, kyanite, epidote, sillimanite and garnet in the Bhuban sandstones is ascribed to the provenance of plutonic and metamorphic rocks. Dominance of zircon in the heavy mineral assemblage and the ZTR index values (75.13% avg.) indicate towards moderate degree of maturity with long distance of transport. The study of the shale samples by XRD and SEM analyses shows the dominance of illite over kaolinite and montmorillonite. The presence of minor amount of montmorillonite may suggest the addition of tuff and volcanic ash in the sediments under alkaline environment.

Sedimentological and palynological assessment of three wells in eastern Dahomey Embayment, southwestern Nigeria, West Africa

Integrated studies were carried out on one hundred and eleven (111) ditch samples retrieved from three wells drilled in Lagos area within the Dahomey Embayment, coastal southwestern Nigeria. The purpose of this study is to determine the provenance, heavy mineral assemblage(s), establish the lowstand - highstand episodes, Quaternary palaeoenvironment and date the encountered lithofacies which constitute sandstones, siltstones with thin beds of lignite. The textural parameters show that the sandstones are medium to fine grained with the lignite consisting of plant fragment remains. Petrographic analyses showed abundant detrital minerals with average modal composition of quartz (Q = 90%), feldspar (F = 2%) and rock fragments (RF = 4%). The QFR ternary plots revealed that the sandstones are quartz arenites of continental block provenance origin deposited under humid climatic setting. This lithofacies has undergone medium distance range of transportation and have been subjected to mechanical and chemical weathering prior deposition. The heavy mineral assemblages and the ratios of Zircon-Tourmaline (ZTR index) in the wells suggest matured sediments. The Apatite: Tourmaline (ATi) ratios showed variations within the studied wells indicating differences in rate of weathering. It is evident that the periods of residence on the floodplain despite similar provenances and fluctuations in ratios, suggest sea level changes. The fluctuations in apatite: tourmaline ratios with respect to weathering are attributed to rapid changes in climatic conditions during the floodplain residence. The high ATi values in sandstone were deposited during relative sea level highstand (transgression), while sandstones with low ATi were deposited during lowstand (regression) in Nigeria and along the West African region. The abundance species of Rhizophora sp., Avicennia africana, Acrostichu mauruem, Laevigatosporite sp., Combretaceae sp., Mitrogynaciliata, Sapotaceae sp., Disopyros sp., Elaeis guineensis and Alchronea spp. indicated depositional transition from mangrove to fresh water swamp due to the episodic highstand and lowstand regimes. The abundance of Podocarpus milianjanus and Retitricolporites hians and the absence of Miocene diagnostic forms suggest late Pleistocene (Tarantian = 0.012–0.126 Ma) deposition.

Mineralogical and geochemical signatures of surface stream sediments from Dibamba River basin, SW Cameroon: Implications for provenance, weathering, and tectonic setting

The Dibamba River (DR) basin is one of the major fluvial basins of the Cameroon coastal area. The current work presents the very first systematic study of elemental geochemical characteristics, including REE, of surface sediments collected from the river bed at different parts of the river courses to determine the intensity of weathering, provenance, and tectonic settings, and evaluate the features that most faithfully mirror the nature of the source terrane. The sediments are dominantly fine and coarse sands. The framework components mainly consist of quartz. The clay minerals comprise kaolinite and illite. Opaque minerals, associated with kyanite, zircon, sillimanite, garnet, and hypersthene, are present as common accessory minerals. The DR sediments are classified geochemically as Fe-shale and Fe-sand. The CIA (72.04 ± 7.1), PIA (66.1–89.2), CIW, and the A–CN–K and (A-K)-C-N plots indicate moderate to high intensity of chemical weathering in the source areas. The SiO2/Al2O3, Al2O3/Na2O, K2O/Na2O ratios, and ICV indicate that the samples were predominantly texturally and compositionally mature. The ZTR index and the ternary Al2O3–TiO2–Zr and binary Th/Sc versus Zr/Sc diagrams suggest recycling and sorting of almost all the sediments. The REE patterns and the size of Eu, and various ternary and bivariate plots such as Zr versus TiO2, Th/Co versus La/Sc, and Cr/V versus Y/Ni indicate the contribution of sediments from intermediate and felsic source rocks. The tectonic discriminant-function-based diagrams revealed a rift or a passive margin setting for the source region. This is consistent with the tectonic history of the Pan-African domain and the Douala Cretaceous sub-basin, which are the probable source terranes of the studied stream sediments.

Provenance evolution of the English Lower Cretaceous Weald Basin and implications for palaeogeography of the northwest European massifs: constraints from heavy mineral assemblages

The first comprehensive provenance studies of the English Lower Cretaceous facies based on detailed analyses of heavy minerals is presented from 11 locations across the Weald, southeast England. These samples were subjected to QEMSCAN® analysis which provided detailed comprehensive datasets on the heavy minerals within the sediments. Four heavy mineral assemblages were identified in the Hastings Beds: rutile, olivine, tourmaline and apatite dominated assemblages in decreasing order. The Weald Clay Formation is also dominated by four heavy mineral assemblages: apatite, rutile, tourmaline and pyroxene-garnet-epidote dominated assemblages in decreasing order. The high concentrations of rutile, tourmaline and zircon in these samples show that bulk of the sediments were recycled from older sediments within the provenance and show a high degree of reworking of sediments into the basin. These provenances appeared to be primarily granitic with metamorphic interruptions at different times in the basin. Heavy minerals indicate little or no secondary modifications to the sediments. Drastic changes in the values of ZTR index suggested repeated retreat and advance of these provenances. Pearson correlation coefficients revealed that four distinct provenances (Londinia, Armorica, Cornubia and Boreal) supplied varying quantities of sediments into the basin at different times. The evolution of these four provenances revealed the complex nature of the palaeogeography of these massifs which had significant implications on other north-western European basins. The wider implication of this study shows that QEMSCAN® method can be successfully and effectively used for analysing heavy minerals for provenance studies when traditional petrographic/heavy mineral methods are not available or unreliable.

Provenance, clastic composition and their impact on diagenesis: A case study of the Oligocene sandstone in the Xihu sag, East China Sea Basin

Sandstone composition, heavy mineral analysis, and bulk rock geochemistry analyses were used to investigate the provenance lithotypes and sediment transport pathways of the third, fourth, and fifth (E3h3, E3h4 and E3h5) members of the E3h Formation at the gas–reservoir scale in the Xihu sag, East China Sea Basin. In addition, the diagenetic features and porosity of the metamorphic-sourced and volcanic-sourced sandstones were investigated. The provenance lithotypes of the E3h3, E3h4, and E3h5 were mainly medium–low grade metamorphic rocks and felsic to intermediate volcanic rocks. The sediment transport pathways were from northeast to southwest and from east to west, indicating that the E3h3, E3h4 and E3h5 members had two sediment provenance, namely, the metamorphic rocks of the northern Hupijiao Rise and the volcanic rocks of the eastern Diaoyudao Rise. Then the sedimentary microfacies distribution of the E3h3, E3h4, and E3h5 members and its relationship with the dual provenance sedimentary system were determined by using the heavy mineral assemblages, ZTR index, grain sizes, lithic fragments and quartz content. The initial porosity values of the metamorphic-sourced medium-grained and fine-grained sandstones were 35.35% and 35.22%, respectively; while the initial porosity values of the volcanic-sourced medium-grained and fine-grained sandstones were 34.09% and 34.97%, respectively. The average porosity compaction loss percentages were mainly 80.2% and 86.91% for the metamorphic-sourced medium–grained and fine–grained sandstones, and 86.95% and 87.23% for the volcanic-sourced medium–grained and fine–grained sandstones. The contact types of mineral grains in the metamorphic-sourced sandstones were mainly punctual, linear and concave-convex contacts; while the contact types of mineral grains in the volcanic-sourced sandstones were mainly linear, concave-convex, and sutured contacts. The metamorphic-sourced sandstone mainly developed chlorite coats; while the volcanic-sourced sandstones mainly contained pore-filling chlorite. The average quartz cement contents were 0.83% and 0.61% for the metamorphic-sourced medium–grained and fine–grained sandstones, and 0.67% and 0.43% for the volcanic-sourced medium–grained and fine–grained sandstones. The illite, mixed-layer illite/smectite and calcite cement reduced the sandstone porosity by filling pores. The metamorphic–sourced sandstones mainly developed primary intergranular pores and intergranular dissolved pores; while the volcanic–sourced sandstones mainly developed intergranular dissolved pores, intragranular dissolved pores, and moldic pores. The metamorphic-sourced sandstones had a higher porosity than the volcanic-sourced sandstones with the same grain size, which the difference in their porosities reached 1–3%.

Grain Size and Heavy Minerals Analysis of Maastrichtian Sandstone, Anambra Basin, Nigeria: Implication for Aquifer Properties

The Maastrichtian sediments of Anambra Basin, south western Nigeria was studied for grain characteristics and maturity of the sediments, so that by combining sedimentological characteristics, maturity and its paleoenvironment of deposition of the Ajali sandstone, in order to ascertain the aquifer properties of the groundwater within the study area and by extension the availability of drinking water for both the urban and rural settlers. Grain size analysis (51 samples) and heavy mineral analysis (15 samples each) were analyzed. The textural parameters show that the Sandstone are medium sand, poorly to moderately sorted, coarse to strongly coarse skewed with mesokurtic to leptokurtic grains. The heavy minerals present in lithologic sand and sandstone units of Ajali Formation are mainly zircon, rutile, tourmaline, apatite, staurolite, and opaque minerals (Goethite, hematite, ilmenite), these heavy minerals found in the sandstone are associated with igneous and metamorphic source which indicates that these maastritchian sediments are from basement complex rock The ZTR index of 67.96% and the values of the kurtosis indicates a sub-mature sandstone to mature sandstone, which gives an excellent aquifer properties. Also, the paleoenvironment of deposition of the Maastrichtian sediments is Fluvial. The sand and sandstone bodies deposited in a fluvial system have sheet-like geometries and due to the differences in the extent of aquifer compartmentalization, Sandstone deposited in fluvial environment normally has better hydraulic conductivity which again reveals a good aquifer property. The sedimentological characteristics for the Sandstone exposed at Fugar and environs, is a coarsening upward sequence (increasing grain sizes) with a progressive increase in sorting. since hydraulic conductivity increases with increasing grain sizes and sorting, hence, excellent aquifer characteristics for the groundwater within the study area. The foregoing revealed that the aquifer geometry and properties of the study areas is favourable for the availability of drinking water for both the Urban and rural dwellers within these communities.
 Keywords: Aquifer geometry, groundwater, hydraulic conductivity, Anambra Basin

Assessment of heavy metals contamination of the water resources in the vicinity of Barapukuria Coal Mine, Phulbari, Dinajpur, NW Bangladesh

The present research work shows that the concentrations of heavy metals can be expressed as Fe>Mn>Zn>Ni>Cr>Pb>Co>As in the groundwater of Phulbari area, Dinajpur, Bangladesh on the basis of their abundance. The Plio-Pleistocene Dupi Tila aquifer sediment is principally composed of quartz, feldspar and lithic grains and is characterized by low ZTR index. Seventeen groundwater samples have higher iron concentrations than the permissible limit of WHO, 2004. The chemical weathering of pyrite release iron in the natural water of the study area. The manganese content of two groundwater samples is higher than the acceptable limit. The high abundance of potassium in 11.11% water samples is indicative of the influence of agricultural activity in the investigated area. The factor analysis reveals the dominance of four factors that comprise 77.276% of the groundwater sample. The contamination index (Cd) for the heavy metals were performed and 88.89% of the groundwater samples have low contamination index. The calcium of the groundwater is resulted from the dissolution of carbonate rocks. The low arsenic concentrations indicate the fast flowing nature of the groundwater and/or low arsenic content of the aquifer sediments. The low cobalt content of the groundwater reflects the low cobalt concentration of the aquifer sediments. The heavy metal chemistry of the groundwater of the study area reveals that the quality of the water is influenced by the geogenic sources as well as the anthropogenic activities like coal mining and agricultural activities. Â

Sedimentology and maturity of Ajali formation, Benin flank Anambra basin, Nigeria

The Ajali Sandstone, western flank, Anambra Basin, was studied for textural characteristics and maturity of the sediments. Grain size analysis (51 samples), thin section and heavy mineral analysis (15 samples each) and XRF fusion for metallic oxides (15 samples) were analyzed. The textural parameters show that the Ajali Sandstone are medium sand, poorly to moderately sorted, coarse to strongly coarse skewed with mesokurtic to leptokurtic grains. The thin section analysis reveals grains that are sub-angular to sub-rounded (this typifies grains that have travelled fairly long distance to the deposition site), of moderate to well sorted grains, with both monocrystalline and polycrystalline quarts-grains type, with a modal composition of Q F and L . A mineralogical maturity 90.4, 2.3 2.9 index (MMI) of 17.04, SiO /Al O ratio of 180.24, and a ZTR index of 67.96% were obtained. The values for the 2 2 3 MMI and SiO /Al O indicates mineralogical matured sediments, the ZTR index shows a chemically immature 2 2 3 to sub-mature sandstone, and the modal composition values are consistent with a texturally and compositionally matured sands. The mineralogical maturity is indicative of high degree of chemical weathering of source area. Furthermore, the high quartz and silica content make the sandstone prospective for glass and glassware production.
 Key words: Anambra Basin, Maturity, Mineralogical maturity index, Textural characteristics, Glass

Fluvial facies and petrography of Late Pleistocene Baneta sediments, Central Narmada Basin, Madhya Pradesh, India

Baneta Formation, comprising of fining upward sequences of pebbly conglomerate, sandstone and siltstone, exhibits development of five distinct lithofacies, viz., massive pebbly conglomerate, large scale tabular cross bedded sandstone, horizontal parallel bedded coarse-grained sandstone, parallel laminated fine-grained yellowish sandstone and siltstone; representing channel lag, point bar and overbank flood plain deposits of mixed load meandering river. In these sediments, development of nodular, buckled bedded calcrete, rhizoliths and tepee is noticed. Granulometric studies of these sediments revealed presence of wide range of grain size classes, polymodal grain size distribution, moderate to very poor sorting, positive skewness and leptokurtic nature, supporting fluvial environment of deposition. Lithic arenitic nature, heavy mineral assemblage with dominance of augite and low ZTR index of these sediments indicate mineralogical immaturity and presence of illite, kaolinite and montmorllionite together with geochemical composition indicate their derivation from mixed provenance of Precambrian granite, metapelites, Vindhyan Supergroup, Gondwana Supergroup, Deccan trap basalt, and laterite. The thin sections studies reveal signatures of meteoric phreatic and vadose zone diagenesis related with semi-arid climate and subaerial exposure. The δ13C and δ18O content of calcretes indicate their pedogenic and/or shallow groundwater origin under semi-arid climatic conditions, and C3–C4 mixed vegetation with dominance of C4 vegetation. OSL and 14C dates of the samples from Baneta Formation suggest deposition of these sediments in Late Pleistocene.

Reconstructing provenance interaction of multiple sediment sources in continental down-warped lacustrine basins: An example from the Bodong area, Bohai Bay Basin, China

Abstract The Neogene Guantao Formation has been proven to be one of the most important reservoirs in the Bohai Bay Basin (BBB), but its sediment provenance, sediment routing and dispersal have remained controversial. In this study, we perform an integrated of detrital zircon geochronology, heavy mineral assemblages and seismic-based analyses of the Guantao Formation to investigate the sediment provenance and reconstruct provenance interaction of multiple sediment sources. Our results show that the detrital zircon (DZ) age spectrums of Guantao Formation display significant spatial differences corresponding to the changing sources. DZ ages from the northern part of the Bodong area display a relatively complex age spectrum and are characterized by a multimodal distribution, indicating sediment contribution from Liaodong uplift (LDU). In contrast to the sediments from LDU, the southern part of the Bodong area was characterized by Yanshanian-dominated unimodal age spectra together with the absence of 170–180 Ma and Triassic age populations suggesting sediments sourced from the Jiaodong uplift (JDU). However, in the central part of the Bodong area, DZ ages exhibit Yanshanian-dominated unimodal age spectra but present 170–180 Ma and Triassic age populations. Combined with seismic-based provenance analysis and heavy mineral ZTR index study demonstrate that both the LDU and JDU have made important provenance contributions to the central part of the Bodong area. Consequently, the provenance intersection area can be trapped by samples sharing similar age signature in the three members (from base to top: NgL, NgM, and NgU) of the Guantao Formation. These results shed light on the spatial and temporal provenance heterogeneity in such dynamic sediment-routing systems. Our findings may serve as a useful reference for reconstructing provenance interaction of multiple sediment sources in other types of petroliferous basins.

Petrography and tectonic provenance of the Miocene Surma Group in parts of the Naga-Manipur hills, in and around Nungba, Northeast India

The Miocene molassic Surma sandstones in parts of the Naga-Manipur hills, in and around Nungba, Northeast India have been studied for their tectonic provenance using petrography and heavy mineral contents. The poorly-to-moderately-sorted sub-litharenite to lithic-arkose type Surma sandstones display predominance of monocrystalline quartz (av. 61%) and include undulose and non-undulose varieties and almost equal amounts of feldspars (av. 22%) and rock fragments (av. 17%). The heavy mineral suite of Surma sandstones is dominated by transparent varieties (96%) that include garnet, zircon, tourmaline, rutile, staurolite, scapolite, phlogopite, chondrodite, humite, wollastonite, hedenbergite. sphene, chlorite, sillimanite, glauconite, glaucophane, and chloritoid. These heavy minerals characterize the granitic and silicic metamorphic complexes (GM) as well as the basic metamorphic rocks (MT) like greenstones, green schist, and amphibolites relating to passive continental margin set-up. The opaque grains constitute nearly 4% of the total heavy minerals. The presence of euhedral, as well as abraded heavy mineral grains, further supports a mixed provenance having substantial contribution from sedimentary and metamorphic rocks. A ZTR index of approximately 45% indicates mineralogically sub-mature nature of Surma sandstones. Based on the light and heavy mineral suites coupled with the type of terrain available in the vicinity of the study area, it may be visualized that the sediment supply was largely made by the Himalaya, the IMR, the Shillong plateau, and the Mikir Hills under the influence of semi-arid to semi-humid climatic conditions. An overall supply from a recycled orogen provenance has been envisaged.

Mineralogical Studies of Kerur Formation Badami Group, Kaladgi Basin, Karnataka

Abstract Heavy and clay mineral analysis is a significant tool to interpret the provenance and paleoclimate of sandstone in proterozoic intracratonic Kaladgi-Badami basin, southern India. The distributions of heavy minerals are more in lower conglomerate; at the depth of 162.35m, zircon is 9.01%, magnetite is 74.18% and ilmenite is 24.61%. The ZTR index is 97.02%. The lower part of the upper unit of core quartz arenite, at the depth of 70.55m shows the following distribution of heavy minerals; zircon 2.94%, magnetite 50.84% and ilmenite 35.71%. The ZTR index of the quartz arenite is 65.52%; moderately abundant heavy minerals are tourmaline, rutile, and garnet; less abundant mineral is zircon in the core. The clay deposits in the basal arenite unit starts from 187 to 171.45m. The X-ray diffraction patterns shows 75% of Illite at the depth of 187m and 181.4m, 40% of chlorite at the depth of 181.7m, 36.36% of monmorillonite and 25% of kaolinite at the depth of 183m but 36.36% at the depth of 177.1m. kaolinite peaks are identified only in two samples. The study reveals that intense weathering in humid climate was responsible for alteration of granitic source rocks in the formation of kaolinitic clays in an acidic environment. The ZTR index reflects that the Badami sediments have attained moderate to high mineralogical maturity. The inference made out of the assemblage of heavy minerals point out that the Badami sediments have been sourced mainly from granitic and metamorphic terrain with a broad drainage basin. In most sandstone and conglomerate, the average ZTR index is moderate but varies widely among samples; apparently local lithologic source area variations largely control these relatively unmodified heavy mineral assemblages.

Grain size and mineralogical characteristics of the stream sediments, east of Abu Zeneima area, southwestern Sinai, Egypt

Grain size and mineralogical characteristics of the stream sediments east of Abu Zeneima, southwestern Sinai, were examined using collaborative techniques. Thirty-two samples were collected from four main Wadis, namely, Nasieb, El Seih, Baba, and El Sahu. Wet and dry sieving as well as pipette method were used for grain size analysis. Heavy liquid separation, microscopic investigation, X-ray diffraction, and scanning electron microscope equipped with energy dispersive X-ray spectroscopy were used to examine the mineralogical composition. The clay minerals are present mostly as kaolinite and illite. The heavy minerals are dominated by opaques, pyroxenes, amphiboles, zircon, tourmaline, rutile, epidote, kyanite, sillimanite, monazite, staurolite, barite, xenotime, and apatite. Autunite and goyazite are reported for the first time in these sediments. Autunite forms encrustation on colloidal iron oxide grains whereas goyazite is found as prismatic grains. The two minerals show considerable contents of rare earth elements, mainly Ce, La, Pr, Sm, and Nd. Texturally, the unimodal grain size distribution, the subangular to subrounded grains, and the poorly sorting class signify short transportation distance from one source area. Mineralogically, the low ZTR index indicates a mineralogical immature to sub-mature sediments. The prismatic ultrastable zircon, tourmaline, and rutile and the dominance of unaltered amphibole and pyroxene grains as well as absence of chlorite indicate that the source rocks are mainly the nearby exposed basement units. The presence of uranyl minerals and rare earth bearing phosphate minerals in these sediments reflect a contribution from the Paleozoic sedimentary successions.

New insights into multiple provenances evolution of the Jurassic from heavy minerals characteristics in southern Junggar Basin, NW China

Abstract The method of random forest was used to classify the heavy mineral assemblages of 2 418 Jurassic samples in the southern Junggar Basin, and determine the distribution of the heavy mineral assemblages from the same provenance systems. Based on the analysis of heavy minerals assemblages, ZTR index, sedimentary characteristics, U-Pb zircon ages, whole-rock geochemical and paleocurrent direction analysis, the study reveals that five important provenances were providing sediments to the southern Junggar Basin in the Jurassic period: The North Tianshan (NTS), Central Tianshan (CTS), Bogda Mountains, Zhayier Mountains and Kalamaili Mountains. During the Early Jurassic, NTS-CTS, Kalamaili Mountains and Zhayier Mountains are primary provenances, Bogda Mountains started to uplift and supply clastic materials in the Middle Jurassic. There are three sedimentary area in the Jurassic of southern Junggar Basin: the western part, the central part and the eastern part. In the western part, the clastic materials of the Early Jurassic was mainly from NTS blocks and Zhayier Mountains, and the sediments were dominantly derived from the Zhayier Mountains during the Middle–Late Jurassic. In the central part, the main provenance of the Early Jurassic switched from NTS to CTS. In the Xishanyao Formation, the main source went back to NTS again. The NTS was the primary provenance during the sedimentary periods of Toutunhe Formation and Qigu Formation. In the eastern part, the contribution of CTS and Kalamaili Mountains were considered as major provenances in the Early Jurassic−Xishanyao Formation, small proportion of sediments were from NTS. The Bogda mountains uplifted and started to provide sediments to the Junggar Basin in the sedimentary period of Xishanyao Formation, and became the major source during the Toutunhe Formation period, with small amount of sediments from CTS. The provenance from CTS was hindered during the sedimentary period of Qigu Formation owing to the uplifting of the Bogda mountains, and the sediments were mainly from the Bogda mountains and NTS.

Provenance of the Gondwana sediments, Palar Basin, Southern India

Palar Basin is considered as one of the pericratonic rift basins of East Coast of India. An integrated petrography, clay mineralogy, and heavy mineral studies of sandstone and shale from the Palar Basin South India, Tamil Nadu, have been carried out to decipher their provenance, palaeoclimate, and tectonic setting. The mineralogical make-up of the clastic rocks is largely composed of quartz followed by feldspar, rock fragments with minor amounts of chlorite, glauconite, zircon, garnet, and opaque. Palar sandstones are coarse to medium-grained and mineralogically immature (poorly sorted and few are moderately sorted). The detrital quartz grains consist of well rounded and rounded quartz, monocrystalline quartz with uniform or straight extinction, and polycrystalline grains with five crystals of straight to slightly curved intercrystalline boundaries. Few of the monocrystalline quartz contain inclusions of sillimanite, rutile, and zircon needles and low content of plagioclase and k-feldspar. These petrographic analyses of the sandstone suggest derivation from metamorphic, igneous, and reworked sediments of different grades which infer that the recycling and the clasts were subjected to both long and short transport distances. The recycled orogen provenance suggests that the sandstone has been derived predominantly from low-lying granite and gneissic sources. The framework petrography exhibits (a) higher percentage of quartz, (b) predominance of monocrystalline grains, (c) feldspar affinity, and (d) paucity of rock fragments, and low F/R ratio suggests that the sediments deposited were in a passive continental margin tectonic setting. The presence of euhedral, angular, and subrounded grains of zircon, rutile with reddish and dark boundaries, the high and moderate ZTR Index (zircon-tourmaline-rutile) and the ratio of RuZi (rutile/zircon) and GZi (garnet/zircon) low values reveal that the Palar Basin sediments were sourced from the combination of metamorphic and igneous (granite and gneisses) rock types. The presence of high amount of rock derived clay (illite, chlorite) is predominant than soil derived (kaolinite, smectite) clay minerals. The high content of illite indicates the source of the clay minerals from pre-existing rocks of granite and gneisses, subjected to physical weathering over chemical weathering in a temperate climate (hot/humid) with moderate hydrolysis.