Mineral chemistry, P-T pseudosection and in-situ U-Th-Pbtotal monazite geochronology of Banded Iron Formation from Bundelkhand craton North-Central India, and its geodynamic significance

2021 ◽  
Author(s):  
Mohd Baqar Raza ◽  
Pritam Nasipuri ◽  
Hifzurrahman
Keyword(s):  
Central India ◽  
Mineral Chemistry ◽  
Iron Formation ◽  
Age Group ◽  
Banded Iron Formation ◽  
Tectonic Zone ◽  
Third Age ◽  
The Third ◽  
Hydrothermal Activities

<p>The Banded Iron Formation (BIF) in Bundelkhand craton (BuC) occurred as supracrustals associated with TTG’s, amphibolites, calcsilicate rocks, and quartzite within the east-west trending Bundelkhand tectonic zone (BTZ). The BIFs near Mauranipur do not show any prominent iron-rich and silica-rich layer band and are composed of garnet, amphibole, quartz, and magnetite. The volumetrically dominant monoclinic-amphiboles are grunerite in composition. X<sub>Mg</sub> of grunerite varies between 0.39-0.37. The garnets are Mn-rich, the X<sub>Spss</sub> of garnet ranges from 0.26-0.20, X<sub>Pyp</sub> and X<sub>Grs </sub>vary between 0.10-0.06 and 0.07-0.05, respectively. P-T pseudosection analysis indicates that by destabilizing iron-silicate hydroxide phases through a series of dehydration and decarbonation reactions, amphibole and garnet stabilized in BIF at temperature 400-450°C and pressure 0.1-0.2 GPa.</p><p>Massive type BIFs have monazite grains that vary from 10 to 50 µm in size, yield three distinct U-Th-Pb<sub>total</sub> age clusters. 10-20 µm sized monazite grains yield the oldest age, 3098±95 Ma. 2478±37 Ma average age is obtained from the second group, which is relatively larger and volumetrically predominant. The third age group of Monaiztes gives an age of 2088±110 Ma. ~3100 Ma monazite suggests the older supracrustal rocks of Bundelkhand craton, similar to those obtained from Singhbhum and the Dharwar craton. The 2478±37 Ma age is constrained as the timing of metamorphism and stabilization of BuC. The third age group, 2088±110 Ma probably associated with renewed hydrothermal activities, leading to rifting and emplacement of mafic dykes in BuC.</p>

Phase relations and in-situ U-Th-Pbtotal monazite geochronology of Banded Iron Formation, Bundelkhand Craton, North-Central India, and their geodynamic implications

2021 ◽  
Author(s):  
Mohd Baqar Raza ◽  
Hifzurrahman ◽  
Pritam Nasipuri ◽  
Lopamudra Saha ◽  
Jayanta Kumar Pati ◽  
...  
Keyword(s):  
Central India ◽  
Phase Relations ◽  
Iron Formation ◽  
Banded Iron Formation ◽  
North Central

scholarly journals Dental status in adults of the municipality of Foca

2011 ◽  
Vol 58 (4) ◽  
pp. 202-208 ◽  
Author(s):  
Aleksandra Zuza ◽  
Igor Radovic ◽  
Jelena Krunic ◽  
Nikola Stojanovic
Keyword(s):  
Dental Care ◽  
Dental Treatment ◽  
Dental Status ◽  
World Health ◽  
Age Group ◽  
Care Providers ◽  
Oral Diseases ◽  
Third Age ◽  
The Third ◽  
Dmft Index

Introduction. Dental caries has been one of the oldest but still one of the most common oral diseases in humans. Even though it has been almost eradicated in developed countries due to increased fluoride use, adoption of proper oral hygiene habits and systematic implementation of preventive programs, caries remained one of leading oral diseases in developing countries. Epidemiological data about the prevalence of caries is very important for prediction of need for dental care, number of dental care providers as well as financial aspect. The aim of this study was to determine dental status and indicate dental treatment need in adults of the municipality of Foca, Republika Srpska (Bosnia and Herzegovina). Material and Methods. The study included 244 randomly selected residents (131 males and 113 females) from the municipality of Foca which were divided into three age groups: 20-29, 30-39 and 40-49 years. Dental status and need for dental treatment were determined in accordance to the criteria and methodology of the World Health Organization. Results. Mean value of DMFT index was 12.7 for the first age group, 16.4 for the second and 20.5 for the third age group of respondents. Dominant components in the first group were restored and carious teeth while in the third age group number of extracted teeth dominated. Also, in the third age group of respondents need for one and two or more surfaces fillings was significantly lower (p<0.01), but need for removable dentures was significantly higher (p<0.01) as compared to other two groups. Conclusion. These results indicated high value of DMFT index in adult population of the municipality of Foca.

Archean and Proterozoic tectono-magmatic activity along the southern margin of the Superior Province in northwestern Iowa, United States

1993 ◽  
Vol 30 (6) ◽  
pp. 1275-1285 ◽  
Author(s):  
Kenneth E. Windom ◽  
W. Randall Van Schmus ◽  
Karl E. Seifert ◽  
E. Timothy Wallin ◽  
Raymond R. Anderson
Keyword(s):  
United States ◽  
Iron Formation ◽  
Superior Province ◽  
Banded Iron Formation ◽  
Tectonic Zone ◽  
Minnesota River ◽  
Rock Types ◽  
Tectonic Environment ◽  
Juvenile Crust ◽  
Archean Greenstone Belt

A Precambrian igneous body of ultramafic and mafic rocks, named the Otter Creek layered igneous complex, occurs within the basement of northwestern Iowa, United States. It is marked by a circular magnetic anomaly, one of several that lie north and west of an inferred suture between the Archean Superior Province and Early Proterozoic juvenile crust. Sm–Nd whole-rock analyses for several rock types from the Otter Creek complex yield an isochron age of 2890 ± 90 Ma, with an εNd(t) of −0.9 ± 2.4. A block of older banded iron formation, itself intruded by lamprophyre dikes, is contained within the layered sequence. The iron formation – lamprophyre block has undergone high-temperature metamorphism followed by a retrograde event. A quartz monzodiorite gneiss, with a U–Pb age of 2523 ± 5 Ma, occurs near the layered complex, but the contact relations are not known. The layered series is overlain by Proterozoic keratophyre with a U–Pb age of 1782 ± 10 Ma. These felsic pyroclastic rocks are extremely depleted in K, Rb, Ba, and Cs. Our data are consistent with Archean greenstone-belt formation, including chemical sedimentation followed by mafic–ultramafic magmatism at approximately 2.9 Ga, followed by two later episodes of magmatism, one at approximately 2.5 Ga and the other at approximately 1.78 Ga. The Otter Creek complex is the first Archean greenstone reported south of the Great Lakes Tectonic Zone (GLTZ); its 2.9 Ga age is older than those reported for the granite–greenstone rocks north of the GLTZ. The southern portion of the Superior Province thus appears to have formed later, and in a different tectonic environment, than the high-grade gneisses of the Minnesota River Valley, but before the bulk of the granite–greenstone rocks exposed in northern Minnesota, Ontario, and eastern Manitoba.

Persistence of rare species depends on rare events: demography, fire response and phenology of two plant species endemic to a semiarid Banded Iron Formation range

2019 ◽  
Vol 67 (3) ◽  
pp. 268 ◽  
Author(s):  
Ben P. Miller ◽  
David R. Symons ◽  
Matthew D. Barrett
Keyword(s):  
Plant Species ◽  
Rare Events ◽  
Arid Zone ◽  
Iron Formation ◽  
Western Boundary ◽  
Banded Iron Formation ◽  
High Rainfall ◽  
Slow Growing ◽  
Structure Patterns

The association of rare plant species and Banded Iron Formation (BIF) ranges in semiarid Western Australia is a noted phenomenon. These ranges are also a focus of iron ore exploration and mining. Decisions and planning required for development, conservation and management resulting from this interest, often consider translocation of these threatened species. Nonetheless, little is known about the ecology of BIF-endemic species to support any such decisions. We assessed population structure, patterns of growth, mortality, recruitment, reproduction and in situ seedbank persistence for two declared rare flora species. The shrub Darwinia masonii, and sedge Lepidosperma gibsonii are endemic to an area &lt;40 km2 on the south-western boundary of the Australian arid zone. Both species were found to be long lived and slow growing, with evidence for reliance on rare events such as fire, and high rainfall years, including, for some processes, consecutive high rainfall years for growth, reproduction and recruitment. Retrieval and germination of seed batches shows that both species’ seedbanks are long-lived, with seasonal dormancy cycling. This, together with the ability of mature plants to survive through years not supporting growth, and, for L. gibsonii, to resprout after fire, are key mechanism for persistence in this unpredictable and low rainfall environment.

scholarly journals Magnetic Survey for Iron-Oxide-Copper-Gold (IOCG) and Alkali Calcic Alteration Signatures in Gadarwara, M.P, India: Implications on Copper Metallogeny

Minerals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 671
Author(s):  
P.V. Sunder Raju ◽  
K. Satish Kumar
Keyword(s):  
Iron Oxide ◽  
Magnetic Anomaly ◽  
Central India ◽  
Iron Formation ◽  
Magnetic Survey ◽  
Banded Iron Formation ◽  
Model Studies ◽  
Copper Mineralization ◽  
Copper Gold ◽  
Magnetic Signatures

A government airborne geophysical survey flown in the late 1970s detected a large Magnetic anomaly at Gadarwara, Madhya Pradesh, in north-central India. Deep drilling indicates that the oval-shaped Magnetic anomaly is caused by underlying Magnetite-bearing banded iron formation belonging to the Mahakoshal Formation of Archean to Early Proterozoic age. The anomaly is hosted in a tectonic rift zone (Narmada-Son Lineament). After drilling alluvium up to 312 m thick, rocks intersected to depths of 612 m provided core samples for research. Broadly speaking, the samples contain banded hematite jaspilite (BHJ) and banded Magnetite (BM) iron formation with pervasive carbonate alterations. Three vertical diamond drill holes were drilled along a 1.4 km long N-S transect across the center of the geophysical anomaly. DDH-1, near the northern edge of the anomaly, went through 309 m of alluvium before intersecting bedrock and then cored 303 m of bedrock for a total depth of 612 m. Copper mineralization with appreciable amounts of cobalt, zinc, molybdenum, silver, rare earth elements, uranium and other elements was intersected. The litho-units are highly oxidised and intensely brecciated with hydrothermal overprinting of Na-K metasomatism alteration mineralogy. The second borehole, DDH-2 failed as the core drilling bit stuck in the alluvium and further drilling was abandoned, whereas the third borehole DDH-3 didnot intersect a Magnetite-hematite association and cored only siltstone. Two-dimensional model studies suggest that the signature of high Magnetic anomaly is at a depth of 0.4 km from the surface, with a width of 3.5 km, dipping at 45∘ in a northerly direction. The causative body has a Magnetic susceptibility of 0.0052 C.G.S. units, suggestive of a hematite with quartz veinlets lithology. Based on predictive Magnetic exploration models for Iron-Oxide-Copper-Gold (IOCG), such deposits can be inferred from geological observations combined with petrophysical data and forward modelling of the observed Magnetic signatures. This paper reports a prospective IOCG-like mineralization style hosted in a rift (Narmada-Son) type of tectonic environment.

Music and the Third Age

2003 ◽  
Vol 31 (4) ◽  
pp. 415-423 ◽  
Author(s):  
Vernon Pickles
Keyword(s):  
Hearing Aids ◽  
Contemporary Music ◽  
Music Appreciation ◽  
Age Group ◽  
Third Age ◽  
Group Activities ◽  
The Third ◽  
Music Making ◽  
General Preference ◽  
The Many

Questionnaires were sent to members of some UK University of the Third Age (U3A) music groups and to other people of similar ages, enquiring into their present and past musical tastes and practices, and inviting free comment. This information was intended to identify factors either improving or impairing the enjoyment of music, and to indicate the value of music at that time of life. The first stage of the survey was directed to members of Sheffield U3A music groups, and this was followed by a further selective survey of U3A members throughout England and Wales. In all, 119 responses were received. Where the details were clearly stated, women respondents outnumbered men by about 2 to 1. The range of ages as stated by 38 respondents in the first stage of the survey was 58-86 (mean 68) years. Most groups contacted were devoted to music appreciation and concert-going, and two others to practical music-making. A general preference for music of the baroque, classical, romantic and late-romantic periods had remained unchanged over the recollected years, but many respondents expressed their appreciation of being introduced to more recent works. However, some contemporary music remained impenetrable. Questions of hearing aids and other kinds of instrumentation are considered, as are the benefits of group activities, especially under an expert leader. Further individual comments were received from members of the Incorporated Society of Musicians (ISM). The many individual free statements from all sources spoke of the great value of music, especially in helping to overcome the personal difficulties of that stage of life. A plea is made for better understanding of the musical needs and opportunities of this age group.

scholarly journals The distance of the main and auxiliary openings from the top of medial and distal root of the first lower permanent molar

2005 ◽  
Vol 52 (3) ◽  
pp. 143-151
Author(s):  
Milica Jovanovic-Medojevic ◽  
Slavoljub Zivkovic
Keyword(s):  
Average Distance ◽  
Age Groups ◽  
Morphological Characteristics ◽  
Maximum Distance ◽  
Age Group ◽  
Third Age ◽  
The Third ◽  
Permanent Molar ◽  
Permanent Molars ◽  
The One

The main prerequisite for a successful treatment of pulp disease in apex periodontium is knowledge of morphological characteristics of root canal system, especially one third of his apex. The aim of this work was to define the exact distance of the main and auxiliary openings from the top of medial and distal roots of the first lower permanent molars. Methods: as a research material it was used a hundred extracted first lower molars of the patients of both gender, divided into three age groups. The analysis of the one third of apex was done with the help of binocular magnifying glass and digital roentgenography analysis half of the samples, which were filed with capillary contrast. Results: The results obtained showed that the longest average distance of the main opening from the top of medial root was 0.84mm, and the shortest was 0.61mm; while for the distal root the longest average distance was 0.89mm, and the shortest was 0.62mm. Maximum distance of the auxiliary openings from the top of medial root in the first group was 3.5mm, and the maximum distance of the auxiliary openings from the top of distal root was 2, 5 mm. The results obtained with digital rentgenography showed that the longest average distance of the main opening from the top of medial root was the one noticed in the second age group (0.91mm) then the one from the first group (0,83), and the shortest one in the third age group (0,71mm); as for the distal root: the longest average distance of the main opening from the top of the root was noticed in the third age group (0,95mm) then in the first (0,90mm) and than shortest in the second age group (0,89mm). Conclusion: The distance of the main and auxiliary openings from the top of medial and distal root of the first lower molar varies in the range from 0 to 3,5mm and it depends on the tooth age. .

Using In Situ Monazite and Xenotime U-Pb Geochronology to Resolve the Fate of the “Missing” Banded Iron Formation-Hosted High-Grade Hematite Ores of the North China Craton

2020 ◽  
Vol 115 (1) ◽  
pp. 189-204
Author(s):  
Li-Xing Li ◽  
Jian-Wei Zi ◽  
Jie Meng ◽  
Hou-Min Li ◽  
Birger Rasmussen ◽  
...  
Keyword(s):  
North China Craton ◽  
North China ◽  
Greenschist Facies ◽  
Iron Formation ◽  
High Grade ◽  
Banded Iron Formations ◽  
Banded Iron Formation ◽  
The North ◽  
Proposed Model

Abstract High-grade hematite mineralization is widely developed in banded iron formations (BIFs) worldwide. However, in the North China craton where Neoarchean-Paleoproterozoic BIFs are abundant, economic high-grade hematite ores are scarce. High-grade hematite ores hosted in the Paleoproterozoic Yuanjiacun BIFs represent the largest occurrence of this type of ore in the North China craton. The orebodies are fault controlled and show sharp contacts with lower greenschist facies metamorphic BIFs. In situ U-Pb geochronology of monazite and xenotime intergrown with microplaty hematite and martite in high-grade ore established two episodes of metamorphic-hydrothermal monazite/xenotime growth after deposition of the BIFs. The earlier episode at ca. 1.94 Ga is interpreted as the timing of lower greenschist-facies metamorphism, and the later episode at 1.41 to 1.34 Ga represents the timing of high-grade hematite mineralization. Petrography and microthermometry of primary fluid inclusion assemblages indicate that the high-grade hematite ore formed from hot (313°–370°C), CO2-rich, and highly saline (~20 wt % NaCl equiv) hydrothermal fluids. These fluids channeled along faults, which concentrated iron through interaction with the BIFs—a process similar to typical hematite mineralization elsewhere. The deposition of hematite was probably related to tectonic extension in the North China craton related to the breakup of the Columbia/Nuna supercontinent. Our results challenge a previously proposed model ascribing the scarcity of high-grade hematite ores in the North China craton to the lack of prolonged weathering conditions. Rather, we argue that the high-grade ore formed in lower metamorphic-grade BIFs at shallower depths than magnetite mineralization and was largely eroded during later exhumation and uplift of the craton.

scholarly journals Tourism Activity in the Third Age Group: its Characteristics on Selected Examples

2016 ◽  
Vol 36 ◽  
pp. 141-151
Author(s):  
Piotr Oleśniewicz ◽  
Julita Markiewicz-Patkowska ◽  
Krzysztof Widawski
Keyword(s):  
Age Group ◽  
Third Age ◽  
The Third ◽  
Tourism Activity

scholarly journals Hydrologic Alteration and Enhanced Microbial Reductive Dissolution of Fe(III) (hydr)oxides Under Flow Conditions in Fe(III)-Rich Rocks: Contribution to Cave-Forming Processes

2021 ◽  
Vol 12 ◽  
Author(s):  
Kayla A. Calapa ◽  
Melissa K. Mulford ◽  
Tyler D. Rieman ◽  
John M. Senko ◽  
Augusto S. Auler ◽  
...  
Keyword(s):  
Groundwater Flow ◽  
Void Formation ◽  
Iron Formation ◽  
Flow Conditions ◽  
Hydrologic Alteration ◽  
Banded Iron Formation ◽  
Batch Cultures ◽  
Flow Through ◽  
Microbial Community Profile

Previous work demonstrated that microbial Fe(III)-reduction contributes to void formation, and potentially cave formation within Fe(III)-rich rocks, such as banded iron formation (BIF), iron ore and canga (a surficial duricrust), based on field observations and static batch cultures. Microbiological Fe(III) reduction is often limited when biogenic Fe(II) passivates further Fe(III) reduction, although subsurface groundwater flow and the export of biogenic Fe(II) could alleviate this passivation process, and thus accelerate cave formation. Given that static batch cultures are unlikely to reflect the dynamics of groundwater flow conditions in situ, we carried out comparative batch and column experiments to extend our understanding of the mass transport of iron and other solutes under flow conditions, and its effect on community structure dynamics and Fe(III)-reduction. A solution with chemistry approximating cave-associated porewater was amended with 5.0 mM lactate as a carbon source and added to columns packed with canga and inoculated with an assemblage of microorganisms associated with the interior of cave walls. Under anaerobic conditions, microbial Fe(III) reduction was enhanced in flow-through column incubations, compared to static batch incubations. During incubation, the microbial community profile in both batch culture and columns shifted from a Proteobacterial dominance to the Firmicutes, including Clostridiaceae, Peptococcaceae, and Veillonellaceae, the latter of which has not previously been shown to reduce Fe(III). The bacterial Fe(III) reduction altered the advective properties of canga-packed columns and enhanced permeability. Our results demonstrate that removing inhibitory Fe(II) via mimicking hydrologic flow of groundwater increases reduction rates and overall Fe-oxide dissolution, which in turn alters the hydrology of the Fe(III)-rich rocks. Our results also suggest that reductive weathering of Fe(III)-rich rocks such as canga, BIF, and iron ores may be more substantial than previously understood.

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