Discrimination between extrusive and intrusive Archean ultramafic rocks in the Shaw Dome area using selected major and trace elements

The ultramafic rocks in the Shaw Dome area, southeast of Timmins, Ontario, are divided on the basis of held criteria into two groups for the purpose of comparing their chemical compositions: (1) extrusive ultramafic rocks consisting of peridotitic komatiites and (2) intrusive ultramafic rocks, consisting of dunites and lherzolites.The two groups can be distinguished on a chemical basis by graphical and statistical methods which provide accuracies of extrusive–intrusive classification of about 92 and 96% respectively. Both methods provide qualitative and quantitative aspects of discrimination.The discriminating parameters were developed using samples which show all types and degrees of alteration that are common in ultramafic rocks. Preliminary studies indicate that the genera! procedure for chemical discrimination between extrusive and intrusive ultramafic rocks may be applicable to similar Archean rocks from other areas.In addition, the separation provides an aid to exploration for minerals such as nickel sulphides, asbestos, magnesite, and gold which may be largely restricted to either extrusive or intrusive ultramafic rocks.

Download Full-text

Petrogenetic insights from chromite in ultramafic cumulates of the Xiarihamu intrusion, northern Tibet Plateau, China

American Mineralogist ◽

10.2138/am-2020-7222 ◽

2020 ◽

Vol 105 (4) ◽

pp. 479-497 ◽

Cited By ~ 1

Author(s):

Xie-Yan Song ◽

Kai-Yuan Wang ◽

Stephen J. Barnes ◽

Jun-Nian Yi ◽

Lie-Meng Chen ◽

...

Keyword(s):

Trace Elements ◽

Major And Trace Elements ◽

Tibet Plateau ◽

Ultramafic Rocks ◽

Sulfide Deposit ◽

Northern Tibet ◽

Mid Ocean Ridge ◽

Ultramafic Cumulates ◽

Positive Correlations ◽

Ocean Ridge

Abstract Chromite is one of the earliest crystallized minerals from mafic melts and has been used as an important “petrogenetic indicator.” Its composition may be modified by interaction with intercumulate melt and adjacent minerals. Thus, chromite in mafic-ultramafic rocks contains clues to the geochemical affinity, evolution, and mantle source of its parent magmas. The Devonian Xiarihamu intrusion, located in the East Kunlun Orogenic Belt in the northern Tibet Plateau, China, hosts a very large disseminated Ni-Co sulfide deposit. This study focuses on geochemistry of the chromite enclosed in olivine of ultramafic rocks of the intrusion. Enrichments in Mg and Al in the rim of the chromite indicate only minor effects of alteration on the compositions of the chromite. The chromites enclosed in the olivines with forsterite percentage (Fo) lower than 87 are characterized by large variations in major and trace elements, such as large ranges of Cr·100/(Cr+Al) (Cr# = 15–47), Mg·100/(Mg+Fe2+) (Mg# = 41–65), and Al2O3 (= 26–53 wt%) as well as 380–3100 ppm V, 70–380 ppm Ga, and 1100–16300 ppm Zn. The chromites display positive correlations between Cr/(Cr+Al) and Ti, Mn, V, Ga, and Sc, inconsistent with fractional crystallization but indicative of an interaction between the chromites, intercumulate melts and hosting minerals. In contrast, chromites hosted in olivine with Fo > 87 in harzburgite have small variations in Cr# (ranging from 37 to 41), Mg# (48 to 51), and Al2O3 (30 to 35 wt%) as well as restricted variation in trace elements, indicating relatively weak interaction with trapped liquid and adjacent phases; these compositions are close to those of the most primitive, earliest crystallized chromites. The most primitive chromite has similarities with chromite in mid-ocean ridge basalt (MORB) in TiO2 and Al2O3 contents (0.19–0.32 and 27.9–36.3 wt%, respectively) and depletion of Sc and enrichment of Ga and Zn relative to MORB chromite. The geochemistry of the chromite indicates a partial melting of the asthenospheric mantle that was modified by melts derived from the subduction slab at garnet-stable pressures.

Download Full-text

Geochemical controls on the distribution of radio-trace elements in groundwater resources of Shir-Kuh granitoid aquifer, central Iran

Hydrology Research ◽

10.2166/nh.2019.129 ◽

2019 ◽

Vol 50 (3) ◽

pp. 974-989 ◽

Cited By ~ 2

Author(s):

Bahareh Yazdizadeh ◽

Hadi Jafari ◽

Rahim Bagheri

Keyword(s):

Trace Elements ◽

Arid Regions ◽

Major Ions ◽

Groundwater Resources ◽

Principal Component ◽

Major And Trace Elements ◽

Mineral Weathering ◽

Central Iran ◽

Chemical Compositions ◽

Calcite Dissolution

Abstract Granitic groundwaters are important resources in arid regions. However, they are not always pure due to having appreciable amounts of trace elements. The present study was conducted to investigate chemical compositions for finding controls on distribution of heavy metals and natural radioelements (U and Th) in groundwater resources of Shir-Kuh granitoid aquifer (SGA), central Iran. Thirty water samples were collected and analyzed for major and trace elements. The average values of electrical conductivity (EC) and pH are 624 μs/cm and 7.5, respectively. The dominant groundwater type is Ca-HCO3, as a result of the calcite dissolution and biotite weathering. Principal component analysis in support of mass balance studies recognizes dissolution of fracture-filling sediments and rock mineral weathering as the main factors enhancing major ions in SGA. These processes also release trace elements in decreasing order of Sr > Ba > Sn > W > Cu > U > Zn > Th. Weathering of biotite enclosing accessory minerals of monazite and zircon is introduced as the main source of radio-trace elements in SGA. Health concerns are currently related to U in drinking groundwater, as the maximum concentration (13.6 μg/L) approaches the Iranian drinking standard of 15 μg/L, in response to the oxidizing nature of the groundwater, calcite dissolution-related mobilization, and the degree of the water–rock interactions.

Download Full-text

Geochemical classification of groundwater using multivariate statistical analysis in Latvia

Hydrology Research ◽

10.2166/nh.2016.020 ◽

2016 ◽

Vol 47 (4) ◽

pp. 799-813 ◽

Cited By ~ 7

Author(s):

Inga Retike ◽

Andis Kalvans ◽

Konrads Popovs ◽

Janis Bikse ◽

Alise Babre ◽

...

Keyword(s):

Trace Elements ◽

Statistical Methods ◽

Principal Component ◽

Hierarchical Cluster ◽

Ion Chemistry ◽

Multivariate Statistical Methods ◽

Multivariate Statistical ◽

Gypsum Dissolution ◽

Major Ion

Multivariate statistical methods – principal component analysis (PCA) and hierarchical cluster analysis (HCA) – are applied to identify geochemically distinct groundwater groups in the territory of Latvia. The main processes observed to be responsible for groundwater chemical composition are carbonate and gypsum dissolution, fresh and saltwater mixing and ion exchange. On the basis of major ion concentrations, eight clusters (C1–C8) are identified. C6 is interpreted as recharge water not in equilibrium with most sediment forming minerals. Water table aquifers affected by diffuse agricultural influences are found in C3. Groundwater in C4 reflects brine or seawater admixture and gypsum dissolution in C5. C7 and C2 belong to typical bicarbonate groundwater resulting from calcite and dolomite weathering. Extremely low Cl− and SO42− are observed in C8 and described as pre-industrial groundwater or a solely carbonate weathering result. Finally, C1 seems to be a poorly defined subgroup resulting from mixing between other groups. This research demonstrates the validity of applying multivariate statistical methods (PCA and HCA) on major ion chemistry to distribute characteristic trace elements in each cluster even when incomplete records of trace elements are present.

Download Full-text

The Early Neolithic Pottery of Ifri Oudadane, NE Morocco – Qualitative and Quantitative Evidence

Journal of African Archaeology ◽

10.3213/2191-5784-10242 ◽

2013 ◽

Vol 11 (2) ◽

pp. 155-196 ◽

Cited By ~ 13

Author(s):

Jörg Linstädter ◽

Gregor Wagner

Keyword(s):

Statistical Methods ◽

Animal Species ◽

Early Neolithic ◽

Late Neolithic ◽

Quantitative Evidence ◽

Qualitative And Quantitative ◽

Northwest Africa ◽

First Occurrence ◽

Neolithic Pottery

This paper presents the Early and Late Neolithic pottery of Ifri Oudadane, a littoral shelter in Northeast Morocco containing both Epipalaeolithic as well as Neolithic deposits. The transition is indicated by the appearance of domesticated plant and animal species, pottery and diverse changes in lithic technology. A domesticated lentil dated to 7.6 ka cal BP may mark the onset of this transitional process. With the help of 22 14C-ages the Early Neolithic deposit can be subdivided in three phases (ENA, ENB, ENC). In addition, the ENC phase contained the remains of a sporadic Late Neolithic occupation. Pottery decoration of the initial ENA phase (7.6–7.3 ka cal BP) is dominated by single Cardium impressions forming horizontal and vertical bands of impressions arranged vertical, horizontal or oblique. The successive ENB phase represents the main occupation phase between 7.1 and 6.6 ka cal BP. By means of statistical methods its assemblage, which consists of 243 vessel units, could be further subdivided (ENB1, ENB2). While ENB1 (7.1–6.9 ka cal BP) is still characterised by single Cardium impressions, the transition to ENB2 is marked by the appearance of Cardium and, later, comb impressions made using rocker stamp technique as well as a few impressions of points and spatulas, striations and modelled applications. Thus the pottery assemblage of Ifri Oudadane offers insights into the first occurrence of pottery in Mediterranean Northwest Africa and opens up the possibility for an internal classification of the Early Neolithic.

Download Full-text

Geochemistry of the Île Cadieux monticellite alnöite, Quebec, Canada

Canadian Journal of Earth Sciences ◽

10.1139/e91-095 ◽

1991 ◽

Vol 28 (7) ◽

pp. 1050-1057 ◽

Cited By ~ 2

Author(s):

Luc Harnois ◽

Raymond Mineau

Keyword(s):

Trace Elements ◽

Rare Earth ◽

Rare Earth Elements ◽

Mineral Chemistry ◽

Major And Trace Elements ◽

Major Elements ◽

Chemical Compositions ◽

Nickel Sulphide ◽

Physicochemical Conditions ◽

Iron Nickel

The Île Cadieux alnöite, a small Cretaceous intrusion, is a member of the Monteregian Hills Petrographic Province. Mineral chemistry was determined for olivine, spinel, clinopyroxene, melilite, and a potassium–iron–nickel sulphide akin to djerfisherite. Whole rocks were analysed for major elements and 24 trace elements (including rare-earth elements). The Île Cadieux alnöitic rocks have greater MgO/Al2O3 ratios than most alnöites but are otherwise similar to typical alnöites with respect to major and trace elements. Comparison of spinel and whole-rock chemical compositions from the Île Cadieux and Île Bizard (located 15 km to the northeast) alnöitic intrusions suggests that these magmas were generated under different physicochemical conditions of melting, or alternatively that they are fractions of a single magma which crystallized under different conditions.

Download Full-text

Phosphorus minerals in tonstein; coal seam 405 at Sośnica-Makoszowy coal mine, Upper Silesia, southern Poland

Acta Geologica Polonica ◽

10.2478/agp-2013-0012 ◽

2013 ◽

Vol 63 (2) ◽

pp. 271-281 ◽

Cited By ~ 5

Author(s):

Magdalena Kokowska-Pawłowska ◽

Jacek Nowak

Keyword(s):

Trace Elements ◽

Coal Seam ◽

Mineral Composition ◽

Coal Mine ◽

Chemical Compositions ◽

Coal Basin ◽

Upper Silesia ◽

Southern Poland ◽

Basin Area

Abstract Kokowska-Pawłowska, M. and Nowak, J. 2013. Phosphorus minerals in tonstein; coal seam 405 at Sośnica- Makoszowy coal mine, Upper Silesia, southern Poland. Acta Geologica Polonica, 63 (2), 271-281. Warszawa. The paper presents results of research on tonstein, which constitutes an interburden in coal seam 405 at the Sośnica- Makoszowy coal mine, Makoszowy field (mining level 600 m), Upper Silesia, southern Poland. The mineral and chemical compositions of the tonstein differ from the typical compositions described earlier for tonsteins from Upper Silesia Coal Basin area. Additionally, minerals present in the tonsteins include kaolinite, quartz, kaolinitised biotite and feldspars. The presence of the phosphatic minerals apatite and goyazite has been recognized. The presence of gorceixite and crandallite is also possible. The contents of CaO (5.66 wt%) and P2O5 (6.2 wt%) are remarkably high. Analysis of selected trace elements demonstrated high contents of Sr (4937 ppm) and Ba (4300 ppm), related to the phosphatic minerals. On the basis of mineral composition the tonstein has been identified as a crystalline tonstein, transitional to a multiplied one.

Download Full-text

Major and Trace Elements in the Humic Acid

10.26434/chemrxiv.7122413.v1 ◽

2018 ◽

Author(s):

Zoltán Kis ◽

Katalin Gméling ◽

Tímea Kocsis ◽

János Osán ◽

Mihály András Pocsai ◽

...

Keyword(s):

Trace Elements ◽

Humic Acid ◽

Activation Analysis ◽

Analytical Techniques ◽

Major And Trace Elements ◽

Prompt Gamma Activation Analysis ◽

Prompt Gamma ◽

Gamma Activation ◽

X Ray ◽

Precise Analysis

We present precise analysis of major and trace elements of the humic acid. We used three different element analytical techniques in our investigations as prompt-gamma activation analysis (PGAA), neutron activation analysis (NAA) and X-ray fluorescence (XRF) analysis was carried out. We identified 42 elements in our sample.

Download Full-text