scholarly journals Phosphate minerals in granitic pegmatites from the Mount Wills District, north-eastern Victoria

2015 ◽  
Vol 127 (2) ◽  
pp. 55
Author(s):  
Ryan M. Eagle ◽  
William D. Birch ◽  
Stafford McKnight
Keyword(s):  
Hydrothermal Alteration ◽  
Spatial Relationship ◽  
Radiometric Dating ◽  
Metasomatic Alteration ◽  
Rare Element ◽  
Peraluminous Granite ◽  
Granitic Pegmatites ◽  
North Eastern ◽  
Close Spatial Relationship

Tin- and tantalum-bearing LCT-type granitic pegmatites occur in a 45 km long belt between Eskdale and Mount Wills in north-eastern Victoria. Near Mount Wills, several compositionally zoned rare-element pegmatites contain complex assemblages of primary and secondary phosphate minerals, many of which are rare and previously unrecorded in Victoria. The phosphate assemblages can be divided into Al-rich and Fe–Mn-rich suites, in addition to ubiquitous fluorapatite. The Al-rich phosphate suite includes montebrasite, scorzalite, bertossaite and brazilianite. The Fe‒Mn phosphate suite includes heterosite, phosphoferrite, wolfeite, alluaudite (sp.), arrojadite (sp.) and jahnsite (sp.), derived from the metasomatic alteration of primary triplite. Further hydrothermal alteration of this assemblage has resulted in a secondary suite of strengite, rockbridgeite, phosphosiderite, whiteite, jahnsite and whitmoreite forming in etch cavities and fractures. A Late Silurian age of 420±4 Ma was obtained from one of the dykes via CHIME radiometric dating of monazite, suggesting a similar age for the adjacent Mount Wills Granite, which has not been reliably dated. This highly fractionated, peraluminous granite is presumed to be the source of the rare-element pegmatites based on their close spatial relationship.

scholarly journals Corrigendum to: Phosphate minerals in granitic pegmatites from the Mount Wills District, north-eastern Victoria

2017 ◽  
Vol 129 (1) ◽  
pp. 53
Author(s):  
Ryan M. Eagle ◽  
William D. Birch ◽  
Stafford McKnight
Keyword(s):  
Hydrothermal Alteration ◽  
Spatial Relationship ◽  
Radiometric Dating ◽  
Metasomatic Alteration ◽  
Rare Element ◽  
Peraluminous Granite ◽  
Granitic Pegmatites ◽  
North Eastern ◽  
Close Spatial Relationship

Tin- and tantalum-bearing LCT-type granitic pegmatites occur in a 45 km long belt between Eskdale and Mount Wills in north-eastern Victoria. Near Mount Wills, several compositionally zoned rare-element pegmatites contain complex assemblages of primary and secondary phosphate minerals, many of which are rare and previously unrecorded in Victoria. The phosphate assemblages can be divided into Al-rich and Fe–Mn-rich suites, in addition to ubiquitous fluorapatite. The Al-rich phosphate suite includes montebrasite, scorzalite, bertossaite and brazilianite. The Fe‒Mn phosphate suite includes heterosite, phosphoferrite, wolfeite, alluaudite (sp.), arrojadite (sp.) and jahnsite (sp.), derived from the metasomatic alteration of primary triplite. Further hydrothermal alteration of this assemblage has resulted in a secondary suite of strengite, rockbridgeite, phosphosiderite, whiteite, jahnsite and whitmoreite forming in etch cavities and fractures. A Late Silurian age of 420±4 Ma was obtained from one of the dykes via CHIME radiometric dating of monazite, suggesting a similar age for the adjacent Mount Wills Granite, which has not been reliably dated. This highly fractionated, peraluminous granite is presumed to be the source of the rare-element pegmatites based on their close spatial relationship.

Ultrastructural evidence for mast cell-macrophage interrelationships in the dura mater of the rat: Infrequent mast cell-nerve associations

1990 ◽  
Vol 48 (3) ◽  
pp. 352-353
Author(s):  
Ruth V.W. Dimlich
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Dura Mater ◽  
Spatial Relationship ◽  
Potassium Phosphate ◽  
Plasma Extravasation ◽  
Close Spatial Relationship ◽  
Male Wistar Rats ◽  
Headache Pain ◽  
Relationship Of

Mast cells in the dura mater of the rat may play a role in cerebral pathologies including neurogenic inflammation (vasodilation; plasma extravasation) and headache pain . As has been suggested for other tissues, dural mast cells may exhibit a close spatial relationship to nerves. There has been no detailed ultrastructural description of mast cells in this tissue; therefore, the goals of this study were to provide this analysis and to determine the spatial relationship of mast cells to nerves and other components of the dura mater in the rat.Four adult anesthetized male Wistar rats (290-400 g) were fixed by perfusion through the heart with 2% glutaraldehyde and 2.8% paraformaldehyde in a potassium phosphate buffer (pH 7.4) for 30 min. The head of each rat was removed and stored in fixative for a minimum of 24 h at which time the dural coverings were removed and dissected into samples that included the middle meningeal vasculature. Samples were routinely processed and flat embedded in LX 112. Thick (1 um) sections from a minimum of 3 blocks per rat were stained with toluidine blue (0.5% aqueous).

LA-ICP-MS U Pb columbite ages and trace-element signature from rare-element granitic pegmatites of the Pampean Pegmatite Province, Argentina

Lithos ◽  
2021 ◽  
Vol 386-387 ◽  
pp. 106001
Author(s):  
Miguel Ángel Galliski ◽  
Albrecht von Quadt ◽  
María Florencia Márquez-Zavalía
Keyword(s):  
Trace Element ◽  
Rare Element ◽  
Granitic Pegmatites ◽  
Icp Ms ◽  
Trace Element Signature

Quantifying mass changes during hydrothermal alteration in listwaenite-type mercury mineralization, Tavreh area, northwestern Iran

2020 ◽  
Vol 20 (4) ◽  
pp. 425-439
Author(s):  
Ali Imamalipour ◽  
Samaneh Barak ◽  
Farzaneh Mami Khalifani
Keyword(s):  
Comparative Analysis ◽  
Hydrothermal Alteration ◽  
Wall Rock ◽  
Mineral Deposits ◽  
Altered Rock ◽  
Loss On Ignition ◽  
Rare Element ◽  
Mass Balance Method ◽  
Northwestern Iran ◽  
Silica Phases

The Tavreh mercury prospect, a listwaenite-type alteration/mineralization system, is located c. 90 km west of Khoy in northwestern Iran. Tavreh is hosted within the Khoy ophiolite zone. Three types of listwaenites have been recognized in the Khoy ophiolite: silica, silica-carbonate and carbonate. Of these three, Hg mineralization at Tavreh is spatially and genetically associated with the silica-type listwaenite, also known as berberite. Alteration and mineralization at Tavreh are restricted to a faulted contact between shale and serpentinite. The Tavreh listwaenite is inferred to form from the hydrothermal alteration of brecciated serpentinite. Major mineralogical changes resulting from this alteration include the decomposition of serpentine-group minerals and the formation of silica phases. In this study, the mass changes of 18 listwaenites from Tavreh were assessed relative to the least altered serpentinites. To illustrate these changes quantitatively a comparative analysis of three different methods of calculating mass change was undertaken using Grant's isocon analysis, MacLean's equation and Gresens’ equation. Results from the three methods are similar. Listwaenite alteration was associated with a large increase in SiO2 (44.4, 36.2, 63.9%, respectively). MgO and loss on ignition were depleted (−34.8, −36.9, −36.6; −8.5, −9.3, −8.3%, respectively) and Al2O3 was relatively unchanged (0.7, 0.6, 0.9%). Mercury is the most enriched rare element in altered rock (375.1, 346.8, 474.6 ppm). Arsenic, Pb, Au and Sb were also enriched. The intensity of mass changes of the various alteration components increases significantly from the serpentinite wall rock towards the listwaenite alteration and the ore-bearing zone. Therefore, the mass balance method can probably be used to locate mineral deposits from a few hundred metres and to explore for blind mineral deposits.

scholarly journals An unusual sponge – microbe – synsedimentary cement framework in a Late Ordovician reef, Southampton Island (Nunavut, Canada)

2016 ◽  
Vol 53 (8) ◽  
pp. 815-822 ◽  
Author(s):  
Ariane Castagner ◽  
André Desrochers ◽  
Denis Lavoie
Keyword(s):  
Spatial Relationship ◽  
Late Ordovician ◽  
Calcareous Algae ◽  
Upper Ordovician ◽  
Shallow Marine ◽  
Early Ordovician ◽  
Subaerial Exposure ◽  
Close Spatial Relationship ◽  
Diverse Community ◽  
Calcite Cement

A large, resistant buildup at the top of the Upper Ordovician (Hirnantian?) Red Head Rapids Formation on Southampton Island (Nunavut, Arctic Canada) is dominated by massive boundstone and cementstone facies. These massive facies have more in common with the sponge–microbial reefs that dominated worldwide in the Early Ordovician, including the following primary components: early calcified sponge material, microbial elements, and synsedimentary cement. A close spatial relationship between sponge and microbial framework elements suggests that a poorly preserved decaying sponge framework provided substrates for the attachment and development of microbes and that the microbes played essential roles as reef consolidators. Centimetre-scale colonial metazoans are present and locally intergrown with the sponge and microbial components. Other mound-dwelling invertebrates or calcareous algae are rare. Although altered now to calcite, cement fabrics suggest that aragonite was ubiquitous as seafloor precipitate. Prior to its subaerial exposure in the latest Ordovician, the Red Head Rapids Formation buildup developed on the margin of a shallow-marine evaporative epicratonic basin where a diverse community of reef-building metazoans was unable to flourish.

Three-dimensional spiral CT angiography in the detection of cerebral aneurysm

1998 ◽  
Vol 39 (3) ◽  
pp. 233-238 ◽  
Author(s):  
M. Strayle-Batra ◽  
M. Skalej ◽  
A. K. Wakhloo ◽  
U. Ernemann ◽  
R. Klier ◽  
...  
Keyword(s):  
3D Reconstruction ◽  
Ct Angiography ◽  
Internal Carotid ◽  
Three Dimensional ◽  
Spatial Relationship ◽  
Spiral Ct ◽  
Posterior Communicating Artery ◽  
Close Spatial Relationship ◽  
Spiral Ct Angiography ◽  
Acute Subarachnoid Hemorrhage

Purpose: The value of CT angiography in the detection and evaluation of aneurysms was compared to digital subtraction angiography (DSA) Material and Methods: Seventeen patients with acute subarachnoid hemorrhage (SAH) or with known or suspected aneurysm were investigated by means of spiral CT angiography, which included 3D reconstruction. These findings were compared with those at DSA Results: In 16 patients, 20 aneurysms were found; the remaining patient had an ectatic vessel that simulated an aneurysm. Seventeen of the angiographically proved aneurysms were detected at CT angiography (sensitivity 85%). One further aneurysm was identified retrospectively as the result of greater experience in the method. All the aneurysms that escaped detection at CT were 3 mm in size. All the vessels of the circle of Willis, except for the posterior communicating artery, were properly evaluated at CT angiography. Difficulties were encountered in assessing the posterior communicating artery and the extradural segment of the internal carotid artery owing to their close spatial relationship to the bony structures of the skull base and the cavernous sinus Conclusion: CT angiography is a low-risk technique with a low level of invasiveness that is useful in following up known aneurysms. The 3D reconstruction yields further topographic information that helps in the planning of endovascular or surgical intervention. The facility for rotating the reconstructed vessels and displaying them from different angles is of particular value in cases difficult to assess at angiography

Behaviour of spruce grouse broods in the field

1985 ◽  
Vol 63 (11) ◽  
pp. 2494-2500 ◽  
Author(s):  
Michael A. Schroeder ◽  
David A. Boag
Keyword(s):  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Spatial Relationship ◽  
Close Spatial Relationship ◽  
Behavioural Repertoire

Behaviour of juvenile spruce grouse (Dendragapus canadensis), from hatching to brood breakup, was observed in 30 radio-tracked broods inhabiting lodgepole pine (Pinus contorta) forests of southwestern Alberta. The immediate posthatch period (first 20 days) was characterized by a close spatial relationship between the chicks and hen, with brooding being the dominant behaviour. Hens with broods appeared to respond immediately, both vocally and through movement toward their chicks, whenever the latter uttered the following calls: sreep, sury, seer, and purring. Brooding sessions decreased in frequency but not duration (median of 11 min) until they disappeared from the behavioural repertoire of the chicks at about 50 days of age. Hen–chick and intersibling distances increased as the chicks grew older. The breakup of broods appeared to result when the cohesiveness of the brood decreased to a point at which calls of the chicks no longer elicited a response from the brood hen. There was no evidence that agonism contributed to this decline in brood cohesion.

scholarly journals Rhenium - rich molybdenites in Thracian porphyry Mo±Cu occurrences, NE - Greece

2001 ◽  
Vol 34 (3) ◽  
pp. 1015 ◽  
Author(s):  
Β. ΜΕΛΦΟΣ ◽  
Π. ΒΟΥΔΟΥΡΗΣ ◽  
Κ. ΑΡΙΚΑΣ ◽  
Μ. ΒΑΒΕΛΙΔΗΣ
Keyword(s):  
Chemical Composition ◽  
Hydrothermal Alteration ◽  
Fluid Inclusions ◽  
Mineral Chemistry ◽  
Rare Element ◽  
Alteration Zones ◽  
Porphyry Cu ◽  
Mineral Assemblages ◽  
Host Rocks

The present study correlates both the mineralogy of the hydrothermal alteration and the mineral chemistry of molybdenites from three porphyry Mo ± Cu occurrences in Thrace: Melitena, Pagoni Rachi/Kirki and Ktismata/ Maronia. The mineralisations are genetically related to calcalkaline, subvolcanic bodies of Tertiary age. According to their mineralogical and chemical composition the host rocks are characterized as dacite (Melitena), dacitic andésite (Pagoni Rachi) and porphyry microgranite (Ktismata/Maronia). The molybdenites occur in disseminated form, as fracture fillings, as well within quartz stockworks crosscuting the central alteration zones of the intrusives. They are accompanied by the following mineral assemblages: quartz, sericite, pyrophyllite, diaspore, Ca-Ba-rich alunite, pyrite (Melitena); quartz, albite/K-feldspar, biotite, actinolite, magnetite (Pagoni Rachi); and sericite, kaolinite, pyrophyllite, chlorite (Ktismata). Preliminary microthermometric results showed homogenisation temperatures from 352° to 390 °C for Pagoni Rachi area and from 295° to 363 °C for Melitena area. The salinities range between 4.5 and 6.1 wt% eq. NaCl and between 2.7 and 3.4 wt% eq. NaCl, respectively. Detailed study on over 400 fluid inclusions from the porphyry Cu-Mo deposit in Maronia area revealed formation temperatures from 300° to 420 °C, whereas salinities are distincted in two different groups from 6 to 16 wt% eq. NaCl and from 28 to 55 wt% eq. NaCl. The chemical composition of the molybdenites from the three porphyry Mo±Cu deposits in Thrace was studied with 155 microprobe analyses. The results revealed unusual high and variable Re concentrations in the studied molybdenites. Re content in molybdenite from Melitena area vary from 0.21 to 1.74 wt%, 0.79 wt% on average. The highest values were measured in samples from Pagoni Rachi (0.45-4.21 wt%, 1.98 wt% on average). Finally, microprobe analyses from molybdenite in Ktismata/Maronia showed Re content between 0.12 and 2.88 wt% (0.76 wt% on average). Rhenium is a very rare element with many definite uses, and is mainly associated with molybdenite in porphyry type deposits. According to the data published so far the Re content in molybdenite reaches up to 0.42 wt%. It is obvious therefore that such high Re concentrations (0.12 to 4.22 wt%) from the studied molybdenites in Thrace, are very ineresting for a possible future exploitation.

scholarly journals The visible dead: dolmens and the landscape in Early Bronze Age Jordan

2017 ◽  
Vol 1 ◽  
Author(s):  
James Fraser
Keyword(s):  
Bronze Age ◽  
Spatial Relationship ◽  
Early Bronze Age ◽  
Limited Area ◽  
Jordan Valley ◽  
Large Stone ◽  
Close Spatial Relationship ◽  
Rectangular Chamber ◽  
Over The Top

Overview:Dolmens are usually described as part of a regional megalithic phenomenon that spanned the 5th-2nd millennia BC. However, this presentation assumes that most ‘dolmens’ are mis-identified. When strictly defined, dolmens better reflect a local funerary tradition of the 4th millennium BC.Definitions:The term dolmen includes a variety of features whose only similarity is their use of large stone slabs. This presentation defines a dolmen as a freestanding,rectangular chamber formed by two upright orthostats along each long side, and a single roof slab over the top. Dolmens have often been conflated with cairns. This presentation defines a cairn as a large pile of small stones. Such features may have contained a low, cist burial chamber; others may simply be piles of field clearance.Distribution:Dolmens, as defined above, concentrate within a limited area of the east rift escarpment of the Jordan Valley, consistent with a local funerary tradition.Chronology: Recent dolmen excavations have yielded assemblages that date exclusively to the EB I (c.3700-3000 BC). This talk examines the close spatial relationship between dolmens and EB I settlement sites in a discrete geographical zone.

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