Petrological Analyses Research Articles

Petrological characterization for material provenance of haniwa earthenware from mounded tombs in the Kibi region, Japan

To determine the provenance of the materials used in the production of haniwa earthenware unearthed from mounded tombs (kofun) in the Kibi region (modern Okayama Prefecture) during the Kofun period (late 3rd – 6th century CE) of Japan, we carried out petrological analyses of haniwa sherds, including optical microscopy, X-ray diffractometry, X-ray fluorescence spectroscopy, and electron-probe analysis. The 25 haniwa sherds analyzed from 12 representative mounded tombs are composed of mineral and rock inclusions with variable grain size set in a clay matrix. The dominant inclusions are quartz, K-feldspar, and plagioclase, associated with minor amounts of amphibole, volcanic glass, and granitic rocks in all the haniwa sherds, and small amounts of hornfels, quartz rock, and accessory minerals, including mica, ilmenite, and chromite, in some of the sherds. Amphibole and plagioclase have compositional variations indicative of the mixing of tephra and granitic components. The compositions of volcanic glass inclusions are similar to those of the Aira-Tanzawa and Kikai-Akahoya tephras widely distributed in southwestern Japan. Bulk chemical compositions show magmatic differentiation trends, which are variable between individual tombs. From these results, it is concluded that the paste materials of haniwa in the Kibi region were commonly derived from weathered granitic rocks mixed with minor amounts of three widespread tephras. The variations of chemical and mineralogical compositions are probably the reflection of local geologic settings, suggesting the presence of specific mining sites of paste materials around each tomb. The mining sites could be located at the bases of hills of granitic rocks covered by widespread tephras and in some cases, near the flood plain of big river systems.

Disentangling causes of the limestone-marl bedding couplets in the Bridge Creek Limestone Member of the Greenhorn Formation through an integrated sedimentological and organic petrology analysis

Disentangling causes of the limestone-marl bedding couplets in the Bridge Creek Limestone Member of the Greenhorn Formation through an integrated sedimentological and organic petrology analysis

High-precision digital rock construction and electrical property upscaling in tight sandstone

The lithology and rock physical properties of tight sandstone reservoirs become increasingly complex, resulting in a more challenging reservoir evaluation process. Conventional rock physics experiments are too restrictive to adequately investigate formation properties. The emerging digital rock physics (DRP) technology in recent years effectively overcomes these constraints. Nevertheless, the current DRP faces two major challenges: the integration of multiple-resolution images and the upscaling of rock physics properties (electricity). In this paper, we propose an innovative method for assigning electrical characteristics to voxel units, enabling the integration of multi-resolution images, as well as a novel approach for establishing a new saturation model to achieve electrical property upscaling. Initially, core samples are selected and drilled based on logging data and lithology analysis, followed by multi-resolution scanning experiments, including X-ray CT, QEMSCAN, and MAPS. After that, mineral components are segmented, and multi-component digital rocks are constructed. Considering mineral voxel as the analytical units, pore characteristics within each mineral, which are extracted from MAPS, are used to generate 3-D pores by QSGS method. These generated 3-D pores are then merged with their respective mineral voxel. Subsequently, the electrical properties of the merged models are simulated and assigned to multi-component digital rock. This process enables the integration of multi-resolution images, leading to the construction of high-precision digital rocks. Additionally, high-precision digital rock-based electrical modeling is conducted, and a new saturation model is then established by combining digital rock physics, experiment rock physics, and theoretical rock physics. Finally, the new saturation model is applied to calculate saturation, accomplishing electrical property upscaling. Application results show the new saturation model improves the accuracy of saturation evaluation, demonstrating the feasibility of the upscaling method for electrical properties.

Spatiotemporal Variation in Mature Source Rocks Linked to the Generation of Various Hydrocarbons in the Fuxin Basin, Northeast China

The assessment of highly mature source rocks linked to hydrocarbon generation remains a challenge in oil and gas exploration. However, substantial terrigenous influences and thermal variations have complicated the formation and evolution of source rocks. This study presents an integrated assessment of highly mature source rocks in the Fuxin Basin, based on sedimentological, geochemical, and organic petrological analyses. Two types of oil- and coal-bearing source rocks were deposited in the semi-deep lake and shore–shallow lake facies during the Jiufotang and Shahai periods. The development of source rocks migrated eastward alongside the lacustrine depocenter, influenced by basin evolution related to extensional detachment tectonism. Furthermore, a gradual increase in thermal records was detected from the western to eastern basins. Consequently, thermal decomposition of source rocks in the Jiufotang formation reduced the organic matter (OM) abundance in the central and eastern basins. Meanwhile, OM types of source rocks range from kerogen type-II1/-I to type-II2/-III, with intense hydrogen generation observed from the western to eastern basins. Consequently, the quality and hydrocarbon accumulation of source rocks are influenced by sedimentation and thermal maturity variation. The spatiotemporal variation in mature source rocks enhances the potential for exploring conventional petroleum, coalbed methane, and shale gas across different strata and locations. Our findings illustrate the significance of the sedimentary and thermal effects in characterizing the evolution of highly mature source rocks, which is relevant to determine oil and gas exploration in similar geological settings.

Lake sediments on the Adamawa Plateau (Central Cameroon) as archives of climate change and the Bantu impact during the last 4000 years BP

AbstractThis study investigates Late Holocene environmental changes in Central Cameroon induced by the combined effects of climate and human impact. For this purpose, sediments from lakes Dang, Massote, Fonjak and Ngaoundaba were studied through lithologic analysis including mineralogical composition and organic geochemistry combined with radiocarbon dates. From these analyses, the sediments at the base of lakes Massote and Dang cores are respectively dated to 4680–3530 and 4220–3580 cal yr BP, whereas the sediments of lakes Fonjak and Ngaoundaba seem to be younger, respectively dated to 3210–3000 and 1870–1740 cal yr BP. Lake sedimentation is dominated by organic matter (OM) poor deposits (OM < 3%) in the lower sections and OM-rich deposits (OM: 5–54%) in the upper sections. This shift from OM-poor to OM-rich sedimentation induced by climate variations occurred at $$\sim $$ ∼ 2800–2400 cal yr BP. The mineral assemblage is predominantly composed of kaolinite with minor contributions from chlorite, smectite, chlorite/smectite, illite/smectite, quartz, K-feldspar, gibbsite, plagioclase, siderite, hematite and goethite. These sediments are clastic, except for Lake Fonjak core sediments which correspond to peat intercalated with carbonate clay and clastic deposits. Age-depth models suggest that the sedimentation rate was 0.2 mm yr-1 for lakes Dang and Massote before $$\sim $$ ∼ 690–560 cal yr BP and $$\sim $$ ∼ 660–470 cal yr BP, respectively. Thereafter, it increased to 0.8 mm yr-1 in Lake Dang and 0.7 mm yr-1 in Lake Massote. Finally, Late Holocene environment changes in Central Cameroon consisted of the shift of open water lakes to marshy fringes with abundant vegetation induced by human activities and facilitated by increasing seasonality.

Chronology and geofluids characteristics of calcite cement in the Upper Triassic Xujiahe Formation tight sandstone reservoir, Western Sichuan Basin, SW China

Geological fluid activities significantly influence diagenesis and hydrocarbon accumulations in reservoir rocks. However, it remains challenging to precisely determine the timing of these activities. This study aims to investigate the chronology and geofluids characteristics of calcite cement that leads to reservoir tightness in the Upper Triassic Xujiahe Formation in the Western Sichuan Foreland Basin, which is a critical exploration target for hydrocarbon resources. We examine calcite cement as a marker of fluid activities, employing petrological analyses, U-Pb dating, and in-situ carbon-oxygen isotope analysis. These methods are integrated with simulations of regional burial and thermal histories to assess pore evolution and hydrocarbon accumulation mechanisms in these tight sandstone reservoirs. Results reveal two main calcite cementation stages within the second member of the Xujiahe Formation (Xu-2 Member): early cements from the Middle Jurassic around 175 ± 11 Ma and late cements from the Late Jurassic between 161 and 156 Ma. Initially, basin-derived alkaline fluids and near-surface atmospheric freshwater supplied the calcium and carbon for early cements during ongoing basin subsidence. Calcium and carbon for the late calcite cements came from the dissolution of carbonate rock fragments by organic acids. The heavier δ13C is primarily associated with in-situ generation and consumption of carbon within the system, while the δ18Ofluid, which is close to modern seawater values, is mainly related to active water-rock reactions induced by processes such as the dissolution of carbonate rock fragments by organic acids. The closed diagenetic system due to calcite cementation in the Late Jurassic led to reservoir tightening. Therefore, basin-scale chronological constraints on calcite cement are of great significance for quantitatively studying sandstone reservoir densification and exploring the mechanism and control factors of hydrocarbon accumulation.

First Late Cambrian Paleomagnetic Results From the Oulongbuluke Terrane, Northern Tibetan Plateau: Implications for the Paleogeography of the Proto‐Tethys Ocean

AbstractThe Early Paleozoic paleolatitudinal position of the terranes in the northern Tibetan Plateau is the key to unraveling the evolution of the Proto‐Tethys Ocean. We present the first Late Cambrian paleomagnetic results from the Oulongbuluke terrane (OT), in the northern Tibetan Plateau. The mean paleomagnetic direction for 16 sites is Ds = 196.2°, Is = −36.9° with κs = 31.5, α95 = 6.7°, corresponding to a paleopole at 68.2°S/51.9°E with dp/dm = 4.6°/7.8°. Rock magnetic and petrologic analyses demonstrate the primary origin of the magnetic mineralogy. This paleomagnetic result defines the Late Cambrian paleolatitude of the OT as 20.6 ± 4.6°S (reference point: 37.2°N/96.6°E). Combined paleomagnetic and geological evidence suggests that the terranes in the northern Tibetan Plateau were located to the northwest of the Indian plate of Gondwana during the Late Cambrian.

Difference of Sedimentary Characteristics and Main Controlling Factors Between Platform Margin Shoal and Ramp Shoal in M Formation of A Oilfield in The Middle East

Abstract The bioclastic limestone reservoirs of M Formation in A Oilfield mainly develop in the ramp shoal and platform margin shoal, but the sedimentary characteristics, spatial distribution and main controlling factors of the two types of shoals are significantly different. Based on the data of seismic, well logging, core, casting thin sections and analytical tests, the comparative analyses of lithology, petrophysics and spatial distribution of the two types of shoals are carried out, and the control mechanism of relative sea level rise and fall and paleogeomorphology on their development is clarified. It is showed that the two types of shoals can be subdivided according to hydrodynamic conditions and bioclastic types. The platform margin shoals are dominated by grainstone and gravel limestone, and the bioclastics are mainly rudist and echinoderms. The logging curve is funnel-shaped, and the seismic is patchy distribution. In the vertical direction, the grain size of shoals becomes coarser, and the sedimentary sequence of medium energy shoal—medium-high energy shoal—high energy shoal is developed. In the horizontal direction, the facies belts of different shoals are narrow, and they are distributed quasi-layered semi-continuously around high energy shoals. The ramp shoals are dominated by packstone and grainstone, and the bioclastics are mainly non-fixed bivalves and algae. The logging curve is micro-tooth box-shaped, and the seismic is sheet distribution. In the vertical direction, the grain size change of shoals is not significant, and the sedimentary sequence of medium energy shoal—medium-high energy shoal is developed. In the horizontal direction, the facies belts of different shoals are wide, and they are distributed layered continuously around medium-high energy shoals. Relative sea level change controls the energy of sedimentary environment and the type of shoal facies, and the high position of paleogeomorphology controls the formation and distribution of high energy shoals. When the relative sea level is high and the paleogeomorphology is gentle, the ramp shoal is developed. As the relative sea level drops, the hydrodynamic condition increases, and the difference in the accumulation speed of different shoals enhances the fluctuation of the paleogeomorphology, the ramp shoal gradually transitions to the platform margin shoal. The above research can provide reference for the exploration and development of such reservoirs.

Deformation and melt–rock interaction in the upper mantle: Insights from the layered structure of the Horoman peridotite, Japan

To obtain a better understanding of melt–rock interactions in the upper mantle, microstructural and petrological analyses were conducted on deformed mantle peridotites from the Horoman peridotite complex, Hokkaido, Japan. The Horoman peridotite complex is lithologically heterogeneous and contains various kinds of ultramafic and mafic rocks. We studied an outcrop of 3 × 70 m in size that contains layered spinel harzburgite, plagioclase lherzolite, and mafic rocks. The results indicate that reactive melts migrated preferentially along the foliation in the already deformed peridotite, and that these melt-rich zones became especially prone to further deformation. This inference is supported by (1) the parallelism of the boundaries of rock layers and foliation in the deformed peridotite, and the shape and crystallographic preferred orientations (SPOs and CPOs) of olivine in the peridotites; (2) the diffusive trends of magnesium and modal compositions of pargasite grains near the boundaries between peridotite and mafic layers; (3) variations in the NiO content of olivine crystals; (4) variations in olivine CPOs with orthorhombic (010)[100] slip system patterns and weak fiber-[010] patterns; and (5) the strong pargasite SPOs, the cuspate shapes of the pargasites, and the absence of intercrystallite deformation. The results, combined with previously reported P–T conditions for the Horoman peridotite complex, indicate that the deformed peridotites and mafic rocks with a layered structure represent temperatures of 1050–1150 °C and pressures of 0.7–1.5 GPa. Our results suggest that a decrease in pressure led to the transition from a melt-free to a melt-bearing system with a consequent change in the deformation mechanism, from dislocation creep in the melt-free system to diffusion creep in the melt-bearing system, with strain localization in the fine-grained melt-rich layers. The change in deformation mechanism is likely to have occurred in the uppermost mantle beneath a mid-ocean ridge, where strong rheological contrasts are controlled by spatial variations in the melt fraction.

The southeasternmost area of the long barrow cemeteries of the Funnel Beaker culture in the 4th millennium BC. The case of two newly investigated structures in Pawłosiów forest (Subcarpathian loess region, Poland) in the context of the settlement network

Abstract The eastern part of the Subcarpathian loess region (the Rzeszów Foothills and the Lower San Valley) may now be referred to as the southeasternmost zone of the occurrence of the long barrow cemeteries of the Funnel Beaker culture. In recent times, new intriguing mounds have been discovered in Pawłosiów forest through the utilisation of LiDAR data sources. In order to investigate whether these structures are long barrows built by “beakers” communities, we have carried out preliminary geophysic research, geological drillings, and lithological analysis. As a result, we confirmed the anthropogenic origin of both structures. The main feature registered during the fieldwork was the lithological and stratigraphical difference between the mounds and their direct geological context. Moreover, a presence of an archaeological feature was identified within the frontal part of one of the mounds. These facts, together with key information regarding the location of both earthen structures in the field and their spatial relationship to the nearby FBC settlement at site 52 in Pawłosiów, suggest that they may be relics of the FBC long barrows. In this study, we also discussed these mounds in the context of their spatial-chronological position in the settlement network(s). It is plausible that the inhabitants of Pawłosiów 52 settlement were responsible for the construction of both long barrows in the period ca. 3650–3400 BC. Additionally, we do not exclude the possible alternative (non-funeral) functions and meanings of the cemetery.

Multimodal analysis of renal stones to explore new biomarkers of urolithiasis

Despite advances in minimally invasive surgery, urolithiasis still recurs within the first five years after the first episode in more than 50% of patients. Researchers continue to search for new crystallisation inhibitors, metaphylaxis strategies and laser sources for stone destruction. Therefore, to achieve these goals, it is necessary to study kidney stones not only as the result of an isolated process of pathological biomineralisation in the human body, but also as a biogenic mineral or rock that obeys universal patterns and has certain properties. Consequently, kidney stones need to be studied using methods that are widely used in the geological sciences for the study of minerals, such as computed microtomography and petrological analysis. In this review, the properties of kidney stones studied using various research methods used in geosciences are discussed. These properties are also considered as new biomarkers of urolithiasis. This review discusses how new data from multimodal stone analysis can be used to develop personalised metaphylaxis and treatment strategies for all types of urolithiasis, including the most common idiopathic calcium-oxalate urolithiasis.

Mouth bars’ development along the West Pearl River main course

River mouth bars’ formation is a key process of the delta development and river bifurcation, but details of the long-term developmental history of mouth bars and their role in the delta evolution are substantially less well documented. To characterize deltaic mouth bars’ development, this study investigated the Sixianjiao, Jun’an, Da’aosha and Denglongsha mouth bars formed successively along the main course of the West Pearl River. The detailed lithological analyses of sediment cores indicate that the mouth bar sediment is characterized by its sandy nature with mud laminations or lenses and poorly preserved foraminifera. The onset of mouth bar sedimentation is affected by water depth. The Sixianjiao and Jun’an mouth bars initiated at shallower water depth (8.0 m and 11.0 m, respectively) due to the restrictions of higher basement landforms. In an area where water is deeper, the mouth bar development would begin only with the site being elevated up to about 16.0 m water depth, such as a case in Da’aosha. The duration between their onset and end of vertical growth varies between 2000 and 2800 years, which is inversely related to their sedimentation rates between 2.7 and 5.7 mm/a, indicating the importance of sediment supply. In addition, the locations of the four mouth bars were to some extent determined by the antecedent landscapes. Finally, the ages of these four mouth bars show a chronological order from land to sea, reflecting seaward delta progradation, contrary to previous morpho-dynamical numerical model’s predictions. Our reconstruction of the West Pearl River mouth bars’ developmental history provides a new insight into the geomorphological evolution of the Pearl River delta, a special delta developed within a complex estuarine bay.

Petrophysical characterization of the Late-Cretaceous Logbaba Formation in the Kribi/Campo sub-basin, Cameroon: Implication on deep-water hydrocarbon exploration

Deep-water hydrocarbon exploration in the Kribi/Campo sub-basin offshore Cameroon is targeting the promising Campanian-Maastrichtian turbidite reservoirs. However, a detailed understanding of the petrophysical properties of these Upper Cretaceous reservoirs is not well documented. In this study, well logs from two boreholes W1 and W2 located in the southern part of the sub-basin provide a unique opportunity to assess the reservoir quality of the Upper Cretaceous Logbaba Formation. Four potential reservoir intervals with thickness ranging between 27 and 105.7 m were delineated in W1, compared with two intervals in W2 with thickness ranging between 72.2 and 93.6 m. Lithological analysis of these reservoir intervals indicates a heterogeneous reservoir matrix consisting of sand, limestone, and dolomite. These reservoir intervals are interpreted as turbidite sand deposits with a clay content ranging from 6.3 to 19.8%, porosity ranging from 15.5 to 21.3%, permeability ranging between 5.65 and 75.09 mD and a water saturation of 34.5–74.2%. Fluid free index, reservoir quality index, and flow zone indicator are insignificant and suggest reservoirs with poor transmissibility. These analyses reflects good petrophysical characteristics for the sandstones of Logbaba Formation. However, both wells were water-bearing with non-mobile hydrocarbon residuals and did not contain commercial quantities of hydrocarbons. There is no evidence of hydrocarbon migration in either reservoir, suggesting that the source rock and the hydrocarbon migration pathways are the main risk factors and reason for the failure of the wells. The findings from this study extend the understanding of the reservoir characteristics of the Upper Cretaceous Logbaba Formation, which will further enhance hydrocarbon prospectivity offshore Cameroon. Since these reservoirs are water-laden, they may serve as potential offshore saline aquifers for geological storage of CO2 offshore Cameroon.

Petrographic and geochemical analysis of lunar meteorite NWA 11788: Parallels with Luna 20 and the Apollo magnesian granulites

AbstractThe first in‐depth geochemical and petrological analyses of new lunar meteorite Northwest Africa (NWA) 11788 were conducted with the aim of better understanding the diversity of lunar rock types. Petrography, microcomputed tomography, electron probe microanalysis, and laser ablation inductively coupled plasma mass spectrometry were employed to analyze mineralogic/elemental makeup, petrologic profile, melt history, and inferred composition of the lunar mantle from which the crystals in this sample originated from. Geochemical maps of the lunar surface were generated to constrain potential lunar launch locations for NWA 11788. Potential launch locations are concentrated in the outer rims of impact basins on the lunar Eastern nearside limb (e.g., Crisium, Fecunditatis, Marginis, Smythii) and around the South Pole–Aitken Basin. Similarities in the major, minor, and trace element chemistry of NWA 11788 along with its potential launch locations suggest a petrogenetic relationship with regolith samples returned from the Luna 20 mission and the Apollo 16 and 17 magnesian granulites. Additionally, the results of this study add to the growing body of evidence that KREEP (potassium, rare earth elements, phosphorous)‐poor, Mg‐suite‐“like” lithologies are common in non‐Apollo‐type locales, that KREEP may not be required to generate lithologies like the Mg‐suite, and that KREEP is not globally distributed at present.

Petrology and Provenance Study of Stone Artifacts from the Mesolithic Cave of Kouvaras in Attica: A Preliminary Report

ABSTRACT This paper focuses on the lithology and raw material provenance of stone artifacts discovered in the prehistoric cave of Kouvaras in Eastern Attica, dating back to the 10th-9th millennia B.C. The study aims to determine whether these prehistoric artifacts were made on local or non-local raw materials. The research consists of two main components: a field study to detect the geological features of the region and collect raw material samples, and a laboratory investigation using XRD, SEM and p-XRF techniques to conduct a petrological analysis. The results suggest that relying solely on chert chemistry to effectively determine the sources of chert artifacts is not a reliable method. By combining several analytical methods and taking a holistic approach, researchers can gain valuable insights into prehistoric human interactions with the local geological environment and the use of available natural resources to make artifacts in prehistoric times.

The color systematics of volcanic ashfall samples in estimating eruption sequences: a case study of the 2017–2018 eruption at Shinmoe-dake, Kirishima volcano, Southwest Japan

The color of pyroclasts is fundamental, because it reflects various magma properties and eruption processes, including particle morphology, chemistry, and petrological characteristics. However, deriving the componentry ratio (CR) of pyroclasts for ongoing eruption monitoring remains challenging due to the lack of a robust quantitative standard. The derivation of the CR, as well as other petrological analyses, is too laborious and time-consuming to introduce as a sustainable monitoring method. To address this, we employed spectroscopic colorimetry to rapidly and quantitatively describe eruptive product colors, enabling CR derivation based on clear, objective standards for ash particle classification. Through color spectroscopy of bulk and sieved ash samples, we analyzed the major size fraction for time-series samples during the waxing stage of the 2017–2018 Shinmoe-dake eruption in Kirishima volcano, Southwest Japan. Our findings reveal that the color changes in bulk ash systematically changed with the evolution of componentry. This temporal color change was due to an increase in the amount of vesicular particles with clear glass against dark angular lava particles, as well as a grain size change, which we interpret as an indication of a transition from phreatic/phreatomagmatic to magmatic eruption. Subsequently, the color of the ash changed when the amount of different lava particles increased gradually, coinciding with a shift toward a more dominant effusion of lava. As the lava effusion continued, a slight reddening of the ash, indiscernible to the naked eye, was clearly detected by the spectrometer before the onset of intermittent Vulcanian eruptions. We interpreted this reddening as oxidation resulting from decreased ascent speed and caprock formation, which accumulates overpressure for Vulcanian explosions. These results highlight the potential of rapid, objective color value and componentry derivation for sustainable quasi-real-time monitoring of ongoing eruption materials.Graphical

When an explosion of life leads to death – hypoxic zones in the Menilite Shales from the Silesian Unit (Polish Outer Carpathians)

Oligocene siliciclastics belonging to the Silesian Unit in the Outer Carpathians were sampled from five locations (Iwonicz Zdrój, Krosno, Równe, Rymanów Zdrój, Zmysłówka) with the first four locations connected to Menilite Shales. The sample from Zmysłówka is an example of the lowermost part of the Krosno Beds. Preliminary geochemical results obtained from the Rock-Eval analysis suggested the presence of immature mixed II/III Type kerogen. Detailed geochemical (GC-MS) and petrological analyses show evidence of extensive phytoplankton blooms, causing the occurrence of episodic ferruginous hypoxic zones. Hypoxic zones were present in the photic zone, where molecular evidence of green and/or brown pigmented sulfur reducing bacteria were marked. The size and character of the blooms were controlled by the palaeoenvironmental conditions. In cases of intense nutrient-rich freshwater loading by a palaeoestuary and/or rainfall, extensive algal blooms were reported. With the increasing aridity and/or decrease of the palaeoestuary impact, the phytoplankton blooms gradually acquired a mostly bacterial character and were reduced in size. The most hypoxic conditions were noted in causes linked with the most intense algal blooms. In most of the cases, algal blooms were dominated by diatoms, suggested by the extensive presence of C25 Highly Branched Isoprenoid, a specific biomarker linked with these organisms. The dinoflagellates only recorded a dominant role in blooms in the Krosno location. A comparison of diterpenoids and triterpenoids revealed that terrestrial organic matter was mostly dominated by gymnosperms like conifers from the Cupressaceae, Pinaceae and Podocarpaceae families. Beside these, the molecular evidence of the angiosperms, bryophytes, and fungi was marked. Both geochemical and petrological analyses confirm the minor role of palaeo-wildfires in the land areas near the deposition place of the analysed samples.

An Analysis of Coal Seam Lithology using The Well-logging Method for Correlation of Location X, Musi Banyuasin Coalfields, South Sumatra

An Analysis of Coal Seam Lithology using The Well-logging Method for Correlation of Location X, Musi Banyuasin Coalfields, South Sumatra

Petrological Characteristics of Lateritic Bauxite Deposits of India and Their Significance in Mineral Processing

India is endowed with 3896 million tons of bauxite resources and ranking it fifth globally. The bauxite comprises various minerals such as gibbsite, boehmite, diaspore, hematite, goethite, kaolinite, quartz, anatase and rutile. India possesses abundant lateritic bauxite resources originating from parent rocks like Khondalite, Deccan trap basalt, Granite Gneiss, Sandstone, etc., each exhibiting its specific characteristics. The geotechnological evaluation of India's lateritic bauxite deposits, conducted by Jawaharlal Nehru Aluminium Research Development and Design Centre (JNARDDC), revealed the presence of two types of deposits: high-level and low-level (coastal). In this study, bauxite and laterite samples were collected from different regions in India and subjected to comprehensive technological evaluation. Mineral processing techniques are optimized based on the mineralogical and petrological characteristics of the bauxite deposits. The mineral liberation, association, and alteration information obtained through petrological analysis guide the selection and optimization of various methods. The understanding of the mineralogy and petrological characteristics also assists in predicting the behaviour of bauxite during the processing stages, facilitating process control and minimizing losses. This paper aims to highlight the petrological, chemico-mineralogical characteristics of Indian lateritic bauxite deposits and emphasize the significance of petrology and mineralogy in their evaluation and mineral processing. Microscopic examination plays a vital role in mineral characterization and the beneficiation process by enabling mineral identification, texture analysis, grain size, mineral liberation, association, alteration, and process optimization. Such comprehensive analysis contributes to maximizing the economic value of mineral resources, aiding informed decision-making in exploration, mining, and mineral processing industries. Keywords: Bauxite, Lateritic Deposits, Petrological Characteristics, Mineralogy, Mineral Processing

Late Quaternary tectonic uplift and Yellow River evolution create high arsenic aquifers in the Hetao Basin, China

High arsenic (As) groundwater is a global problem primarily originating from As-enriched sediments. The provenance (source) and release mechanisms (sinks) of high As sediment have been identified, but the source-sink transfer is poorly understood, especially the influence of geological and surface processes. In this study, we explore the roles of tectonic movement and Yellow River evolution in provenance formation processes and evaluate the combined effects of provenance and sediment age on the As content of aquifer sediments in the northern Hetao Basin of Inner Mongolia. Based on optically stimulated luminescence (OSL) and 14C dating and detrital zircon U-Pb, As content, and lithological analyses of a 400 m core, we reconstructed As changes over the last 160 ka. Our results show clay deposited in a paleo-lake during the Gonghe movement period in the late Pleistocene (∼100 ka B.P.) is enriched in As (31.8 μg/g) due to significant provenance contributions of the As-bearing Langshan Group under tectonic uplift and mountain erosion. In contrast, clay deposited in the middle Pleistocene (∼160 ka B.P.) has lower As content (7.3 μg/g) due to the Yellow River as the primary provenance. Accordingly, the provenance of basin As forced by tectonic uplift and Yellow River evolution determines the background As of aquifer sediments. After deposition, sediment As content decays over time, with higher decay rates in coarse-grained sands than fine-grained. Overall, both provenance formation and sediment age, representing initial and dynamic states of solid phase As, jointly determine the As content of aquifer sediments. More solid phase As provided by younger sediments from the proximal orogenic provenance and reducing conditions due to frequent river–lake transitions, jointly lead to higher As concentrations in shallow groundwater. The study highlights the potential for using a combined analysis of the tectonic movement-surface processes-environment system to improve understanding of geogenic high As groundwater over global large sedimentary basins in the proximity of young orogenic belts.