Provenance Of Sandstones Research Articles

Provenance of Mesozoic sandstones from the northwestern Gulf of Suez, Egypt: new evidence from petrography and whole-rock geochemistry

New investigations of petrographic and geochemical characteristics of Mesozoic sandstones from the northwestern Gulf of Suez in Egypt have been undertaken, documenting dominance of quartzose sandstones containing on average ~ 5% of mostly sedimentary and subordinately metamorphic lithic fragments (siltstone, sandy siltstone, and, more rarely slate, metasiltstone, limestone, dolostone, quartz-muscovite schist, and gneiss). These sandstones are depleted in many chemical elements and display low Al2O3/SiO2 and K2O/Na2O ratios. Mineralogical and geochemical parameters point at extensive recycling from older (i.e., Paleozoic) siliciclastic strata. Relatively constant composition throughout the Mesozoic contrasts with successive palaeogeographic changes associated to the major events of rifting and dispersal, which may be explained by the widespread distribution of Paleozoic clastic wedges all across northern Gondwana.

Provenance study of potential Oligocene reservoirs in Nile Delta and offshore Mediterranean

This study aims to investigate the provenance of the Oligocene sandstones exposed at Gebel Qatrani Formation at the Fayum Province and analogues subsurface Oligocene sandstone intervals cored from 2.7 to 5.12 km at the Nile Delta. The analysis and quantification of heavy mineral assemblages revealed that the two sites maintain similar heavy mineral suites but with variable concentrations and different patterns. The provenance reliable heavy mineral indices indicate that the exposed Oligocene sandstones at Gebel Qatrani Formation are much more mature than those of the Oligocene sandstone intervals at the Nile Delta. The lower and the upper members of Qatrani Formation display heavy mineral contents indicating more maturation than the middle member which reflects an influx of less mature sandstone. The middle member may reflect a tectonic reconfiguration of the hinterland during its deposition. The reliable heavy mineral indicators of the Oligocene sandstones at the Nile delta maintain their higher values at different depths along the entire wells indicating a significant rejuvenation of the source area and hence sand supply from a source(s) that was not far distant. In contrast, Habbar-1 well sand samples (cored from 3.8 to 4.5 km) display the highest pyroxene values along with considerable contents of amphibole, mica, sillimanite, and kyanite indicating transport from a shorter distant source including a metamorphic one. Thirty seismic cross sections are interpreted and used to construct isopach maps which revealed the diagenetic effect of the heavy mineral suits with depth. That will subsequently affect the reserving characteristics of Oligocene sand intervals. Moreover, according to the estimated petrophysical parameters, the Oligocene intervals in Habbar-1 and Port Fouad Marine Deep-1 wells are very promising.

Significance of sandstone provenance in tracking potential uranium reservoirs: A case study of the Middle Jurassic Zhiluo Formation, western Ordos Basin, northern China

The Middle Jurassic Zhiluo Formation is the main uranium-bearing sequence in the western Ordos Basin, northern China. Provenance studies of clastic rocks in the Zhiluo Formation are important to provide guidelines for uranium exploration. In this paper, we describe the sandstones from the Zhiluo Formation and report their bulk rock elemental compositions by using samples that were collected from the Lingwu area, western Ordos Basin. Our main objective is to provide constraints on the provenance of the sandstones and thus new insights into uranium exploration. The results show that the sources of the Zhiluo Formation sandstones have TTG (trondhjemite-tonalite-granodiorite) attributes and mainly consist of magmatic arc orogenic belts that were mixed with continental blocks and recycled orogenic belt materials. The paleocurrent measurements that average 144° suggest that the provenance supply direction of the sandstones is from northwest to southeast. Combined with the regional tectonic settings, it can be inferred that the sandstone provenance was mainly provided by the Xingmeng Orogenic Belt, while the Alxa Block and Helan Mountain complex rocks also contributed. Our research might provide a crucial reference for predicting the locations of potential uranium reservoirs, i.e., the search for uranium mineralization should target the northwest of the Ordos Basin, especially near regions where intermediate-acid rocks are present. This information is integrated into a predictive model in which tracking along the provenance supply directions of clastic sediments is an efficient method for conducting uranium exploration in a sedimentary basin.

Multi-proxy provenance of the lower Pennsylvanian Pottsville sandstone of the northern Appalachian basin in Pennsylvania, U.S.A: Paleodrainage, sources, and detrital history

ABSTRACT The lower Pennsylvanian Pottsville Formation, in the Appalachian foreland basin, constitutes a late Paleozoic clastic wedge formed close to the Appalachian orogenic belt. In this study, we analyzed Pottsville sandstone from the western bituminous and eastern anthracite fields in Pennsylvania to evaluate the detrital history of the sediments. Petrographic modal analyses show that sandstone in the western bituminous field ranges from quartzarenite to sublitharenite, with mean composition of Qt84F1L15; sampled sandstone from the eastern anthracite field is dominated by sublitharenite to litharenite with mean composition of Qt70F2L29. Heavy-mineral assemblages from both fields are dominated by ultrastable minerals (zircon, rutile, and tourmaline), apatite, sphene, spinel, siderite, and abundant opaques. Almost all the studied sandstone samples are garnet-depleted except one from the eastern anthracite field. The chemical composition of chromium- and zinc-rich spinel in samples from both fields might suggest exhumation of an arc terrane and ophiolitic belt with ultramafic igneous rocks. Particularly, the ternary plot of Fe3+–Cr3+–Al3+ end members for the chrome spinels possibly suggest a derivation from an alpine-type peridotite complex. Laser 40Ar/39Ar analyses of detrital muscovite from eastern anthracite fields and western bituminous fields record separate ages, with the former characterized by prominent Middle to Late Ordovician Taconic and Middle Devonian Acadian ages with two discrete modes at 463 and 369 Ma, and the latter dominated by Late Ordovician Taconic, Middle Devonian Acadian, and Late Devonian Neoacadian ages with discrete modes at 445, 397, 360, and 351 Ma. The new data suggest that early Pennsylvanian sedimentation in the Appalachian foreland basin was controlled by southward, southwestward, and westward drainage systems that originated in the Appalachian orogenic belt to the east and northeast.

Establishing a Provenance Framework for Sandstones in the Greenland–Norway Rift from the Composition of Moraine/Outwash Sediments

The crystalline basement and Caledonian orogenic belt of East Greenland between 70 and 78° N are divided into five source regions on the basis of heavy mineral assemblages, mineral geochemistry, and isotopic age data from 42 modern moraine/outwash samples. The sand types generated by the five source regions can be recognized in the Mesozoic sedimentary rocks of Mid-Norway, and are named, from south to north, MN7 (Gåseland), MN4i (Milne Land–Renland), MN2ii (Hinks Land–Suess Land), MN2iii (Payer Land–Dronning Louise Land), and MN6 (Germania Land). These provide a framework for interpreting the provenance of Greenland–Norway rift sedimentary deposits. The provenance characteristics of Liverpool Land have also been defined, but whether this relatively small region merits a separate provenance status is unclear. Provenance links can be made by comparing the source region sand types with the composition of onshore and offshore sediments from previous studies. Triassic sandstones of the Nordland Ridge and the far south of the Møre Basin, along with Jurassic sandstones of the Heidrun Field in the Haltenbanken area, were derived from the MN4i source region. The provenance of Cretaceous sandstones in East Greenland can be linked to the MN2ii source region. The source of Turonian sandstones on Traill Ø can be pinpointed by zircon U–Pb ages to the Neoproterozoic Lyell Land Group of the Franz Josef Allochthon. Cretaceous sandstones in the Vøring and Møre basins were derived from the MN2iii and MN4i source regions. In addition, some of the Cenomanian–Campanian sedimentary rocks of East Greenland and Mid-Norway contain Permian–Cretaceous-aged zircon grains that are absent from the moraine/outwash samples. The most likely source of these zircon grains is the circum-Arctic region, implying the existence of a long-lived axial drainage system that entered the Greenland–Norway rift from the north.

Provenance of sandstones in the Hastings Block, southern New England Orogen: implications for tectonic setting

The Devonian–Carboniferous sandstones in the Hastings Block, southern New England Orogen have a predominantly arc-like provenance based on ternary QFL or QmFLt ternary diagrams and have a lower quartz content than Permian sandstones. Stratigraphically correlated formations show similar QFL components but not the same patterns of sandstone compositional variability for formations that outcrop over a wide area such as the Mingaletta and Pappinbarra formations. It is possible to correlate most of the petrological intervals in the Tamworth Belt with the Hastings Block. The trend of petrofacies from Devonian to Permian for the southern Tamworth Belt, Tamworth Belt overall and Hastings Block, is towards sandstone with more monocrystalline quartz and less feldspar and lithics. The areal pattern of sandstone compositions within individual formations shows similarities in the percentage of quartz, feldspar or lithics. This suggests areal continuity of sandstone compositions within a formation during deposition and that the faulting did not substantially change the formations continuity at the time of deposition. The arc-like provenance of Devonian to Permian sandstones within the Hastings Block indicates that the block was likely an along-strike continuation of the Tamworth Belt. KEY POINTS The Devonian–Carboniferous sandstones have predominantly arc-like provenance on QFL or QmFLt ternary plots with a higher quartz content in younger formations. The Hastings Block and Tamworth Belt sandstones of comparable age are similar but not the same on ternary QFL and QmFLt plots. The areal pattern of the composition of sandstones within formations suggests that faulting was not active during deposition.

Provenance and maximum depositional ages of Upper Triassic and Jurassic sandstone, north‐eastern Mexico

AbstractUpper Triassic to lowest Upper Jurassic strata in north‐eastern Mexico record surface processes during the early rifting that led to the opening of the Gulf of Mexico. Exposed near Ciudad Victoria, Tamaulipas and northwest to Galeana, Nuevo Leon, these continental deposits are called the Huizachal Group. Several key questions about these strata hamper their integration into a regional understanding of Late Triassic and Jurassic sediment routing and deposition. First, the depositional age of the stratigraphically lowest unit, the El Alamar Formation, is less well established than the depositional ages of the stratigraphically higher parts of the succession, leading to questions about the timinig of the onset of tectonic context, and regional correlation of these strata. Second, better knowledge of provenance and sediment routing, including fluvial transport distance, can help determine whether and when the depositional basin was split into subbasins versus connected by a throughgoing river system. This study uses sandstone detrital zircon U‐Pb isotopic ages and clast compositions to constrain depositional ages and reconstruct tectonic setting and provenance. Detrital zircon U‐Pb ages yielded a maximum depositional age of 210 Ma for the part of the El Alamar Formation exposed near Galeana, younger than previously determined. Although long‐distance (>100 km) sediment transport cannot be ruled out, the sources for Huizachal Group sandstone framework grains and detrital zircon could have been entirely local, within about 100 km. Alluvial deposits and pyroclastic and lava flows likewise indicate transport of no more than 100 km. We therefore infer deposition in partitioned rift basins receiving sediment from local sources. These data and interpretations contribute to understanding surface processes during the initial rifting that eventually led to opening of the Gulf of Mexico.

Sandstone Provenance Study in Wonosegoro, Boyolali Regency, Central Java

Wonosegoro is part of western Kendeng Zone, the depocenter of North East Java Basin that is mainly filled with thick pelagic and volcaniclastic sediments. Sandstones lithofacies is presence within the research area and may act as a useful tool to reach the aim of this research, which is to determine the provenance. The research has conducted field observation, petrographic analysis on seven thin sections of sandstones from the field, and bathymetry interpretation from benthic foraminifera. Overall, the sandstones are predominantly composed of lithic components (72.73%-88.05%) and significant matrix (25%-50%), thus classified as lithic greywacke. The combination of quartz-feldspar-lithic (QFL) and the heavy minerals composition suggest that the sandstone provenance in research area is a product of Oligo-Miocene volcanic of southern mountain range.

The provenance of coarse-grained turbidite sandstones in the Kırkgeçit Formation(western part of the Elazığ Basin-east Turkey)

Modal analysis of sandstones for conglomerate rich marine basins is useful for investigating the provenance types surrounded by plate tectonics. Different kinds of siliciclastic rocks are important indicators for defining the paleogeography and geotectonic conditions of the sedimentary basin by provenance analysis. This paper, which focuses on the petrography and provenance of conglomerate rich turbidite systems, is one of the rarest studies on the sedimentary characteristics in the scientific literature. In this context, the study was carried out in the western part of the Elazığ Basin. The Middle Eocene?Oligocene basin infill called the Kırkgeçit Formation is characterised by the conglomerate rich submarine channel deposits and coarse-grained turbidite sandstones. Petrographically, the coarse-grained sandstones of the Kırkgeçit Formation are composed of litharenite and rarely feldspathic litharenite, lithic arkose and rock fragments. Mostly the components are derived from volcanic and plutonic rocks of the Elazığ Magmatites. Fossils and fossil fragments are transported from the shallow part of the western Elazığ Basin. The components transported from metamorphic rock fragments, which are rarely observed in the sandstone samples, are composed of recrystallized limestones and derived from Keban Metamorphites in the northern part of the basin. The provenance studies and petrographic analyses indicated that the conglomerate rich channels and coarse-grained sediments of turbidite sandstones in the Kırkgeçit Formation were plotted mostly to the recycled orogenic and undissected arc type source rocks. Therefore, this type of source rocks has been reflected as a back-arc basin deposit during Middle- Upper Eocene. The geotectonic evolution of the western Elazığ Basin has also supported this remark.

Sedimentary Petrography as the Basis for Understanding Provenance and Diagenesis of Sandstones and Surrounding Tectonic and Paleogeographic Context: The Upper Miocene Reservoirs from the North Croatian Basin (Pannonian Basin System)

Sedimentary Petrography as the Basis for Understanding Provenance and Diagenesis of Sandstones and Surrounding Tectonic and Paleogeographic Context: The Upper Miocene Reservoirs from the North Croatian Basin (Pannonian Basin System)

Dinoflagellate biostratigraphy of Eastern Indonesia stratigraphy: key of petroleum exploration success

Several major discoveries in the eastern part of Indonesia (e.g. Tangguh and Abadi) have increased more petroleum exploration interest in the area. These sizeable discoveries encountered gas in the Jurassic sandstone, which is a key reservoir target in the Northwest Shelf of Australia. The Mesozoic sandstone provenance is located in the Australian Continental Plate or also known as the Sahul Shelf. Thousands of wells were drilled in the Sahul Shelf and the stratigraphy in this area is well understood. The extension of the Mesozoic sandstone towards Indonesian territory, with much less well information, is one of the keys of success for petroleum exploration. Refinement of the stratigraphy of the eastern part of Indonesia is crucial to understand the extension.To refine the stratigraphy of Eastern Indonesia, especially for the Mesozoic interval, dinoflagellates play a significant role. Several types of this marine biota have been used by Australian stratigraphers as markers. In the case where stratigraphic tie to Northwest Shelf Australia discoveries, key wells or standard chronostratigraphy, dinoflagellate understanding is critical.Dinoflagellate markers are used to mark several subdivisions of Plover Sandstone. Norvick (2001) used W. indotata and D. caddaensis Maximum Flooding Surfaces to subdivide the reservoir target into upper, middle and lower Plover Formation. These surfaces are named after dinoflagellates. More markers were identified to mark the source rock and seal in the petroleum system. To have a detail correlation from Indonesia to the NW Shelf, understanding of dinoflagellates is crucial.

Early Carboniferous (Mississippian) intertwining sediment dispersal network across the Laurentian cratonic interior

Early Carboniferous (Mississippian) strata across the Laurentian cratonic interior record the transition from a stable carbonate platform, supporting a broad epicontinental sea, to a series of widespread, mixed carbonate-siliciclastic successions. As the southern terminal sink, the Mississippian succession preserved on the southern Midcontinent provides evidence and constraints for sediment dispersal patterns. This paper presents the first comprehensive U–Pb detrital-zircon geochronological record of all known Mississippian sandstones from the southern Ozark Dome of southern Missouri and northwestern Arkansas. This study identifies the provenance of these Mississippian sandstones and establishes their sediment dispersal networks across the cratonic interior. Results show that a major provenance shift occurred between Lower and Upper Mississippian strata. The Lower Mississippian Bachelor Sandstone was sourced from the Laurentian craton, while Upper Mississippian and basal Pennsylvanian sandstones were sourced through recycling of upper Proterozoic and lower Paleozoic sandstones within the Laurentian craton to the north, the unroofing of the Appalachian orogenic belt from the east-northeast, and potentially some direct contribution from uplifted Precambrian basement along the Transcontinental Arch to the northwest. By combining previously published detrital zircon data from Laurentia, we propose that the Mississippian sedimentation reflects an intertwining dispersal system associated with multiple sources. Sediments derived from all three potential sources were merged and transported southward across Laurentia.

Studi Provenance Batupasir Karbonatan Formasi Kerek Dengan Metode Point Counting Di Daerah Kandangan Kabupaten Semarang

Carbonate sandstone in the study area was found around rivers and hills in the study area. Provenance of sandstones in the research area of interest to be examined, because not known provenance the sandstone rock formations karbonatan Kerek especially in the research area. The purpose of this study was to determine the provenance of Kerek carbonated sandstones in the study area using themethod point counting. The methodology used for the analysis of Provenance in the study area is using petrographic incisions. The results of the analysis of provenance on the five samples of carbonated sandstones of the Kerek Formation in the study area obtained data in the form of: rock types including lithic arenite (Pettijohn, 1975), the climate of the source area is semiarid (Nelson, 2007), the source rock type is plutonic rock (Tartosa, et al, 1991). ) and its tectonic setting is in the magmatic arc transitional arc sub-zone (Dickinson and Suczek, 1979).

Provenance and Tectonic Setting of Lower Cretaceous Huanhe Formation Sandstones, Northwest Ordos Basin, North-Central China

In adjustment to fulfill the requirements of the investigation regarding the lower Cretaceous sandstone uranium deposit in the Naogaodai area within the northwest of Ordos Basin, twenty-seven sandstone samples obtained from the Lower Cretaceous Huanhe Formation were analyzed for major, trace and rare earth elements (REE). The source of clastic and tectonic background was additionally analyzed. The results show that Huanhe sandstone is feldspar rich sandstone, and also the mineral composition is principally quartz, albite and plagioclase; the ratio of light to heavy rare earth elements (LREE/HREE) is 9.25–10.83, with an average value of 10.00; (La/Yb)CN is 10.20–12.53, with an average value of 11.24, demonstrating that LREE is enriched and fractionated compared with HREE. REE distribution patterns are similar, which additionally reveals that Huanhe sandstone has a homogenous source; the Index of Compositional Variability (ICV) value is 1.17–1.73, with an average value of 1.35, both greater than 1, showing an immature property, which may be first-order cycle deposition. The average value of the Chemical Index of Alteration (CIA) is 50.29, suggesting that the source rock has encountered weak chemical weathering; sandstones are near-source first-cycle provenance, which is not significantly influenced by sedimentary sorting and recycling. The geochemical qualities further indicate that Huanhe sandstone was deposited in a passive margin and experienced moderate weathering.

Depositional mode and Provenance of Kopili sandstones from parts of Dima Hasao District, Assam, NE India: Evidence from Grain size distribution and Heavy mineral assemblage

This study presents a record of the depositional mode and provenance of the Kopili sandstones outcropped in and around Umrangso, the Dima Hasao district of Assam, India using proxies such as grain size and heavy mineral study. The Grain size study reveals that the sandstones of the Kopili formation consist predominantly of fine-grained sands mixed with medium sands. The grain size statistical parameters divulge that the sandstones are characterized mostly by moderately sorted sands, coarse skewed to near symmetrical, leptokurtic to extremely leptokurtic nature. The frequency distribution curves reflect mostly bimodal as well as polymodal distribution of sediments. The Linear Discriminant Function analysis indicates shallow marine beach sub environment in agitated water depositional condition for the Kopili sediments. The CM pattern discloses that saltation and suspension are the dominant transporting modes. The Heavy mineral analysis discerns that opaques dominate over transparent heavies. Transparent heavies in decreasing order of abundance are zircon, tourmaline, rutile, clinopyroxene, staurolite, hornblende, garnet, chlorite and epidote. The zircontourmaline- rutile (ZTR) maturity index (average 53.15%) discloses sub-mature to mature nature of the Kopili sandstones. The heavy mineral assemblage corroborates their mixed provenance (silicic igneous and metamorphic) for the Kopili sandstones.

Constraining the timing of Arabia-Eurasia collision in the Zagros orogen by sandstone provenance (Neyriz, Iran)

AbstractThe Zagros orogen, formed by the collision of the Arabian and Eurasian continental margins, represents one of the largest and richest oil and gas provinces in the world. The Zagros fold-thrust belt records collision and convergence along the Neotethys suture zone. By coupling field observations, sandstone modal analysis, U-Pb zircon dating, and Hf isotopic data from the Upper Cretaceous to Pliocene sedimentary succession of the Neyriz region, this paper documents several major provenance changes that allow us to propose a refined scenario for the Zagros orogeny. An ophiolitic complex dated by detrital-zircon U-Pb geochronology as ca. 95 Ma provided detritus to Upper Cretaceous-Paleocene strata deposited along the northeastern margin of the Arabian lower plate (ophiolite provenance). Yet, on the southwestern margin of the Eurasian upper plate, upper Paleocene-lower Eocene strata indicate provenance from Mesozoic magmatic rocks yielding zircons dated as ca. 240 Ma and 170 Ma as well as the recycling of clastic rocks. Since the early Miocene, the sedimentary basin located on the Arabian plate received both ophiolitic detritus and magmatic-arc, recycled clastic, and axial-belt metamorphic detritus from Eurasia. U-Pb ages of detrital zircons reflect polyphase magmatism at 170 Ma, 95 Ma, and 40 Ma on the Eurasian active margin. Our results indicate that progressive accretion, uplift, and exhumation of the Zagros orogen was well under way by the beginning of the Miocene in the Neyriz region. Literature data from adjacent regions suggest that the Arabia/Eurasia collision may have occurred diachronously and later in the Kermanshah and Lurestan areas to the north.

Provenance, tectonic setting, and source area palaeoweathering of the Lower Cretaceous Nubian sandstones at Gebel Duwi, Eastern Desert, Egypt: inferences from mineralogy and whole-rock geochemistry

Provenance, tectonic setting, and source area palaeoweathering of the Lower Cretaceous Nubian sandstones at Gebel Duwi, Eastern Desert, Egypt: inferences from mineralogy and whole-rock geochemistry

U–Pb ages and sandstone provenance of the Permian volcano-sedimentary sequence of the Hida Gaien belt, Southwest Japan: Implications for Permian sedimentation and tectonics in Northeast Asia

The Permian volcano-sedimentary strata of the Hida Gaien belt of SW Japan are characterized by Lower Permian felsic tuffs and tuffaceous clastic rocks, Middle Permian andesites and sandstones rich in volcanic detritus, and upper Middle to Upper Permian feldspathic sandstones and mudstones. A combination of petrographic and geochemical analyses together with zircon U–Pb dating for the sandstones reveals a provenance change from an immature undissected arc with active felsic and intermediate volcanism during the Early–Middle Permian to a mature arc with basement uplift during the Late Permian. The Upper Permian sandstone yields syn-depositional zircons with 500–400 Ma zircons. This age distribution suggests that sediment was derived from the Permian arc and early Paleozoic basement. Similar characteristics to Permian strata in the Hida Gaien belt are recognized in the eastern Central Asian Orogenic Belt in terms of detrital zircon ages and the change in dominant lithology from volcanic to clastic rocks. In particular, Permian strata of the Jilin area (NE China) are lithostratigraphically similar to those of the Hida Gaien belt and have similar detrital zircon U–Pb ages. As such, Permian strata in both areas would have been deposited proximal to each other in the same tectonic setting along a single subduction zone in the western Paleo-Pacific Ocean.

Geochemical Characteristics, Palaeoenvironment and Provenance of Uranium-Bearing Sandstone in the Sifangtai Formation, Northern Songliao Basin, Northeast China

During the Cretaceous period of the northern Songliao Basin (northeast of China), a 100 m thick layer of fluvial-phase sandstone (Sifangtai Formation) with uranium potential was widely deposited, but its geochemical characteristics, paleoenvironment, and provenance remain unknown. This research proposes a new set of relevant geochemical data for sandstones to investigate their paleoenvironment, provenance and tectonic setting. The results revealed that: (1) The sandstone of the Sifangtai Formation was dominated by feldspar lithic sandstone. Geochemical signatures demonstrate that these sandstones have a high silicon content (SiO2 = 68.30~83.60 wt%) and total alkali content, but are poor in magnesium and calcium. They are also enriched in Rb, Th, U, K and LREE, and depleted HFSE (e.g., Nb, Ta), with crustal magmatic source. (2) The paleoclimate discriminant indicated that the rocks of the Sifangtai Formation might that the climate of Sifangtai Formation is semi-arid, and the chemical weathering of the source rocks is weak under the semi-arid climate environment. (3) The combination of element Sr/Ba, 100 MgO/Al2O3 and the combination of v/v + Ni, V/Cr, Ni/Co, and Sr/Cu indicated that the paleo-water medium was deposited in an oxygen-rich freshwater environment when the Sifangtai Formation was deposited. (4) The discriminate diagrams showed that almost all the sandstones of the Sifangtai Formation fell in the range of the active continental margin, indicating that the source area of the sandstones of Sifangtai Formations is an active continental margin tectonic environment, and the source is a felsic rock developed in the Xiaoxing’an Ridge and Zhangguangcailing area.

Depositional mode and Provenance of Kopili sandstones from parts of Dima Hasao District, Assam, NE India: Evidence from Grain size distribution and Heavy mineral assemblage

Depositional mode and Provenance of Kopili sandstones from parts of Dima Hasao District, Assam, NE India: Evidence from Grain size distribution and Heavy mineral assemblage