scholarly journals Unraveling Sources and Climate Conditions Prevailing during the Deposition of Neoproterozoic Evaporites Using Coupled Chemistry and Boron Isotope Compositions (δ11B): The Example of the Salt Range, Punjab, Pakistan

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 161
Author(s):  
Syed Asim Hussain ◽  
Feng-Qing Han ◽  
Zhe Ma ◽  
Amjad Hussain ◽  
Muhammad Saleem Mughal ◽  
...  
Keyword(s):  
Boron Content ◽  
Boron Isotope ◽  
Multiple Sources ◽  
Climate Conditions ◽  
Molar Ratios ◽  
Salt Range ◽  
Late Neoproterozoic ◽  
Meteoric Precipitation ◽  
End Members ◽  
Marine Basins

In this study, the ion concentrations (K+, Na+, Ca2+, Mg2+, Cl−, SO42−, Br−, NO3−, and B3+) and boron isotope compositions (δ11B) of 34 halite and brines samples from the Neoproterozoic Salt Range Formation, Punjab, Pakistan were studied. Relation among B3+ vs. Mg2+, B3+ vs. SO42−, δ11B vs. B3+, and δ11B vs K+ were observed, they indicated that these elements originate from multiple sources and the end members were identified as seawater, B desorption from clays, and meteoric precipitation. Halite samples of the area under study displayed a Na-HCO3-type to Ca-Cl type sedimentary basin of deposition, on δ11B vs. 1/B plot. Molar ratios of B/Cl vs. δ11B revealed the addition of B in some of the studied samples from desorption of clay minerals. This type of diagenetic desorption of B from clays is the consequence of a stress driven mechanism, generated in the proximity of a decollement zone. Results confirm that the number of B stable isotopes that fractionate between the brine and the halite is low. The halite δ11B from the Salt Range Formation vary from +2.1 to +24.4‰, compared to +17.3 to +26.1‰ in the salt pool brines, and suggest that boron isotope compositions are controlled by the δ11B of the B sources. The positive relationship between the boron content and the corresponding δ11B indicates a higher salinity and drier paleoclimate conditions during the formation process, associated with a high evaporation rate in the Late Neoproterozoic time. Presence of elevated δ11B in the present study, demonstrate compatibility with other marine basins of the world, arising the need for further investigations to better characterize the 11B-enriching processes.

Chlorine isotopes unravel conditions of formation of the Neoproterozoic rock salts from the Salt Range Formation, Pakistan

2020 ◽  
Vol 57 (6) ◽  
pp. 698-708
Author(s):  
Syed Asim Hussain ◽  
Feng-Qing Han ◽  
Jibin Han ◽  
Hawas Khan ◽  
David Widory
Keyword(s):  
Isotope Geochemistry ◽  
Local Scale ◽  
Climate Conditions ◽  
Chlorine Isotopes ◽  
Marine Strata ◽  
Salt Deposition ◽  
Salt Range ◽  
Salt Deposits ◽  
Late Neoproterozoic ◽  
Gypsum Dehydration

During the late Neoproterozoic, the Salt Range in Pakistan was one of the regions where the Tethys truncated and marine strata developed. The numerous transgressions and regressions that occurred during that period provided enough initial material for the development of marine evaporites. The geology of the Salt Range is characterized by the presence of dense salt layers and the existence of four regional and local scale unconformities. These thick salt deposits geologically favor potash formation. Here we coupled chloride isotope geochemistry and classical chemistry of local halite samples to assess the extent of brine evaporation that ultimately formed the salt deposits. Our results indicate that evaporites in the Salt Range area are Br-rich and precipitated from seawater under arid climate conditions. The corresponding δ37Cl values vary from –1.04‰ to 1.07‰, with an average of –0.25‰ ± 0.52‰, consistent with the isotope range values reported for other evaporites worldwide. The positive δ37Cl values we obtained indicate the addition of nonmarine Cl, possibly from reworking of older evaporites, the influx of dilute seawater, the mixing of meteoric and seawater, and the influence of gypsum-dehydration water. The negative Cl isotope compositions (δ37Cl < –1‰) indicate that brines reached the last stages of salt deposition during the late Neoproterozoic. We conclude that the Salt Range Formation could be promising for K-Mg salts.

scholarly journals Multispecies integrated population model reveals bottom-up dynamics in a seabird predator-prey system

2020 ◽  
Author(s):  
Maud Quéroué ◽  
Christophe Barbraud ◽  
Frédéric Barraquand ◽  
Daniel Turek ◽  
Karine Delord ◽  
...  
Keyword(s):  
Breeding Success ◽  
Species Interactions ◽  
Interspecific Interactions ◽  
Demographic Parameters ◽  
Multiple Sources ◽  
Bottom Up ◽  
Climate Conditions ◽  
Predator Prey ◽  
Relative Contribution ◽  
Prey System

AbstractAssessing the effects of climate and interspecific relationships on communities is challenging because of the complex interplay between species population dynamics, their interactions, and the need to integrate information across several biological levels (individuals – populations – communities). Usually used to quantify species interactions, integrated population models (IPMs) have recently been extended to communities. These models allow fitting multispecies matrix models to data from multiple sources while simultaneously accounting for various sources of uncertainty in each data source. We used multispecies IPMs accommodating climate conditions to quantify the relative contribution of climate vs. interspecific interactions on demographic parameters, such as survival and breeding success, in the dynamics of a predator-prey system. We considered a stage-structured predator–prey system combining 22 years of capture–recapture data and population counts of two seabirds, the Brown Skua (Catharacta lönnbergi) and its main prey the Blue Petrel (Halobaena caerulea) both breeding on the Kerguelen Islands in the Southern Ocean. Our results showed that climate and predator-prey interactions drive the demography of skuas and petrels in different ways. The breeding success of skuas appeared to be largely driven by the number of petrels and to a lesser extent by intraspecific density-dependence. In contrast, there was no evidence of predation effects on the demographic parameters of petrels, which were affected by oceanographic factors (chlorophyll a and sea surface temperature anomalies). We conclude that bottom-up mechanisms are the main drivers of this skua-petrel system. We discuss the mechanisms by which climate variability and predator-prey relationships may affect the demographic parameters of these seabirds. Taking into account both species interactions and environmental covariates in the same analysis improved our understanding of species dynamics.

scholarly journals Optimization of multi variant process parameters to reduce emissions of high sulfur coal during combustion in fluidized bed facility

2021 ◽  
Vol 13 (9) ◽  
pp. 168781402110446
Author(s):  
Bhutta Muhammad Mahmood Aslam ◽  
Shafiq ur Rehman ◽  
Asad Naeem Shah ◽  
Muhammad Sajid Kamran ◽  
Ahmad Naveed ◽  
...  
Keyword(s):  
Particle Size ◽  
Energy Demand ◽  
Gaseous Emissions ◽  
Considerable Decrease ◽  
Molar Ratios ◽  
Bed Temperature ◽  
Salt Range ◽  
Reduce Emissions ◽  
Sulfur Emissions

Pakistan has 185 billion tonnes reserves of coal but unfortunately the quality of 80% of this coal is not good. As the country has a shortage of energy so it is necessary to refine the coal before it can be used to produce electricity. In this sense, this research is very important as it enables indigenous coal to meet the increasing energy demand. This study is focused on the control of sulfur emissions during the combustion of high sulfur Pakistani coal from the Trans Indus Range and the Salt Range. Parameters like Ca/S molar ratios (MRs), limestone particle size, bed temperature, and different percentages of biomass in co-firing with coal have been studied. It is showed that desulfurization of coal was maximum with the fine-sized particles of limestone. Co-firing of moderate quantity biomass exhibited a considerable decrease in SO2 emissions. Results achieved are presented in the form of tables and plots. This study for control of the gaseous emissions from combustion in FBC facility has great potential for new coal based power projects, especially in Pakistan.

Geochemical attributes of late Neoproterozoic Salt Range Formation, Pakistan: constraints on provenance, paleoclimate, depositional and tectonic settings

2018 ◽  
Vol 23 (2) ◽  
pp. 201-218 ◽  
Author(s):  
Muhammad Ahmed Farooqui ◽  
Muhammad Umar ◽  
Muhammad Amjad Sabir ◽  
Rashid Pervez ◽  
Tarib Jalees
Keyword(s):  
Salt Range ◽  
Tectonic Settings ◽  
Late Neoproterozoic

Nano-scale investigation of co-precipitated subglacial calcite and opal, antarctica 

2021 ◽  
Author(s):  
Silvia Frisia ◽  
Péter Németh ◽  
Andrea Borsato ◽  
John C. Hellstrom ◽  
Attila Demény ◽  
...  
Keyword(s):  
Ice Sheet ◽  
Chemical Species ◽  
Multiple Sources ◽  
Calcite Precipitation ◽  
Subglacial Environment ◽  
Transmission Electron ◽  
Microscope Images ◽  
History Of ◽  
Co Precipitation ◽  
End Members

&lt;p&gt;Calcite crusts from the Elephant Hill Moraine (EHM) (76&amp;#176;17'35&quot; S &amp;#160;157&amp;#176;20'05&quot; E) collected during 1983-84 &amp;#160;were interpreted as formed in subglacial environments influenced by hydrothermalism (Faure et al., 1988). More recently, &lt;sup&gt;234&lt;/sup&gt;U enrichment in these crusts was used to suggest that during the warm MIS 11 interglacial (ca. 400 ka), the ice sheet margin at the Wilkes Basin retreated about 700 km inland (Blackburn et al., 2020). Their &lt;sup&gt;234&lt;/sup&gt;U data from separate analyses of pure calcite and pure opal crusts suggested that &amp;#8220;connate seawater would impart marine signatures to subglacial waters&amp;#8221; (Blackburn et al., 2020), with the former associated with massive melting during MIS 11. &amp;#160;However, robust U-series dating by Blackburn et al (2020) was only possible on pure end members of opal and calcite, whilst other EHM crusts did not yield reliable ages and were discarded. The inferred MIS11 ice-loss was then based on a model of &lt;sup&gt;234&lt;/sup&gt;U accumulation and on those carbonate ages that fit their hypothesis that connate seawater influenced the subglacial environment.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Here, we investigated the nanostructure of EMH samples that yielded unreliable U-Th ages, which were too old to fit into the &lt;sup&gt;234&lt;/sup&gt;U-based model of MIS11 connate seawater influencing subglacial waters. High-resolution transmission electron microscope images showed a complex history of precipitation, dissolution, re-precipitation, including the co-precipitation of nanocrystalline calcite and opal. Co-precipitation was documented by the inclusion of micrometre-scale opal spherules within calcite crystals whose lattice orientation does not change across the spherules and can be explained by the fluid being extremely enriched in silica. The calcite immediately surrounding the opal spherules was characterized by twins and likely a response to sub-ice sheet stress during their precipitation. The calcite-opal mixture partially replaced pre-existing calcite crystals, which appear broken, corroded and pre-date a final, pure calcite void-filling cement. Clearly, these EHM samples document several stages of crystallization, which imply repeated mobilization of chemical species. Preliminary Fluid Inclusion analyses of the crusts yielded a temperature of about 85&lt;sup&gt;o&lt;/sup&gt;C, which inferred that at one stage calcite precipitation may have been influenced by hydrothermalism associated with volcanism.&amp;#160; Our identification of complex crystallization histories for the Elephant Moraine subglacial carbonates opens up alternative formation hypotheses to that proposed by Blackburn et al. (2020) such as the existence of multiple sources of aqueous solutions. Consequently, it is fraught to infer that all the EMH formed from connate marine waters generated 400 ka without dating of multiple phases of calcite precipitation from each sample.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;References: Blackburn, T. et al. 2020, Nature, 583 (7817), pp.554-559. Faure, G.&amp;#160; et al, 1988, Nature, 332(6162), pp.352-354.&lt;/p&gt;

Mechanical properties and oxidation resistivity of carbon fiber/ceramic composites prepared from borosiloxane

1996 ◽  
Vol 11 (10) ◽  
pp. 2536-2540 ◽  
Author(s):  
Shinsuke Hoshii ◽  
Akira Kojima ◽  
Sugio Otani
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Ceramic Composite ◽  
Boron Content ◽  
Infrared Absorption Spectrum ◽  
Ceramic Composites ◽  
Molecular Weights ◽  
Molar Ratios ◽  
High Boron ◽  
Si Content

Diphenylborosiloxane (PBS), an organometallic compound with Si–O–B bonds, was compounded with carbon fiber (CF) to form CF/ceramic composite. Three types of PBS with different molar ratios (Si/B) in the materials were used. On the PBS obtained, specific gravity, Si content, molecular weight, melting point, and infrared absorption spectrum were measured. On the basis of these results, structures of PBS were examined, which clarified that the PBS thus synthesized consisted of several components with different molecular weights. Mechanical properties and oxidation resistivity of the CF/ceramic composites obtained differed with the Si/B ratios of PBS. Mechanical strength of the CF/ceramic composites increased with increase of Si content of PBS. It was also found that, when PBS with high boron content was used, compact vitreous film consisting mainly of B2O3 was formed over the composite. Due to the formation of this film, oxidation resistivity of the composite was improved.

The role of metamorphic fluids in the development of the Cornubian orefield: fluid inclusion evidence from south Cornwall

1990 ◽  
Vol 54 (375) ◽  
pp. 219-230 ◽  
Author(s):  
J. J. Wilkinson
Keyword(s):  
Vapour Phase ◽  
Ore Deposits ◽  
Contact Metamorphism ◽  
Contact Aureole ◽  
Cation Composition ◽  
Molar Ratios ◽  
Low Salinity ◽  
Granite Emplacement ◽  
Granite Batholith ◽  
End Members

AbstractVeins developed during contact metamorphism associated with the emplacement of the Cornubian granite batholith contain both H2O-rich and CO2-rich fluid inclusions. Microthermometric data indicate that unmixing of a low-CO2, low-salinity fluid occurred at 400–200°C and 1000–500 bars to produce low-density CO2-rich vapour and saline aqueous fluids (8–42 wt. % NaCl equivalent). Decrepitation-linked ICP analyses show that the cation composition of the brines is dominated by Na, K and Ca, but that significant amounts of Li, Sr, Ba, Fe, Mn, Zn and B are also present. Bulk volatile analyses confirm the dominance of CO2 over N2 and CH4 in the vapour phase, with CO2/N2 molar ratios of 15.3–28.7 and CO2/CH4 molar ratios of 66.9–292. The relative abundance of nitrogen suggests an aureole-derived ‘organic’ component is present.The source of the fluids is ambiguous as they are intermediate in composition between ideal ‘magmatic’ and ‘metamorphic’ end-members. It is proposed that this is due to mixing of the two types of fluid in the contact aureole during granite intrusion. A model is suggested in which magmatic-metamorphic circulation occurred synchronously with granite emplacement and subsequently evolved to a meteoric-dominated system with the bulk of the ore deposits forming in response to the influx of meteoric fluids.

Efficient separation of boron using solid-phase extraction for boron isotope analysis by MC-ICP-MS

2015 ◽  
Vol 7 (24) ◽  
pp. 10322-10327 ◽  
Author(s):  
Maoyong He ◽  
Zhangdong Jin ◽  
Hai Lu ◽  
Tongxiang Ren
Keyword(s):  
Solid Phase Extraction ◽  
Boron Content ◽  
Solid Phase ◽  
Isotope Analysis ◽  
Boron Isotope ◽  
Phase Extraction ◽  
Efficient Separation ◽  
Icp Ms ◽  
Experimental Apparatus ◽  
Pump Pressure

An experimental apparatus for ion exchange solid-phase extraction (SPE) was designed to separate boron for boron isotope analysis by MC-ICP-MS. Using the SPE under a pump pressure of up to 0.04 MPa, boron can be efficiently separated from >10 mL water samples with a low boron content.

Clay minerals from rock salt of Salt Range Formation (Late Neoproterozoic–Early Cambrian, Pakistan)

2016 ◽  
Vol 32 (1) ◽  
pp. 63-74 ◽  
Author(s):  
Iaroslava Iaremchuk ◽  
Mohammad Tariq ◽  
Sophiya Hryniv ◽  
Serhiy Vovnyuk ◽  
Fanwei Meng
Keyword(s):  
Clay Minerals ◽  
Rock Salt ◽  
Early Cambrian ◽  
Salt Range ◽  
Late Neoproterozoic
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