Results 81 to 90 of about 141 (134)
The origin of lamproites revisited: Mediterranean perspective
International Kimberlite Conference Extended Abstracts: 2008, 2019 openaire +2 more sources
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Petrology of Lamproites from the Nuapada Lamproite Field, Bastar Craton, India
2013This work presents the first mineralogical, geochemical and 40Ar/39Ar geochronological data on hypabyssal facies lamproites near Kalmidadar and Darlimunda in the Nuapada Lamproite Field of the Bastar Craton. The Kalmidadar lamproite is a diamondiferous intrusion with surface dimension of ~320 m × 160 m, whereas the Darlimunda lamproite is a dyke swarm ...
N. Sahu +6 more
exaly +2 more sources
1991
The mineralogy of the lamproite clan is perhaps one of the most exotic of all alkaline rocks. The perpotassic and peralkaline traits of the magmas lead to a distinctive mineral assemblage that is virtually unparalleled. The paragenesis and composition of the minerals comprising lamproites are detailed in this chapter.
Roger H. Mitchell, Steven C. Bergman
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The mineralogy of the lamproite clan is perhaps one of the most exotic of all alkaline rocks. The perpotassic and peralkaline traits of the magmas lead to a distinctive mineral assemblage that is virtually unparalleled. The paragenesis and composition of the minerals comprising lamproites are detailed in this chapter.
Roger H. Mitchell, Steven C. Bergman
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1991
The development of realistic hypotheses for the petrogenesis of potassic rocks has been hindered, until recently, by the tendency of petrologists to consider all leucite-bearing K-rich rocks as being related. Sufficient geological, geochemical, and mineralogical evidence (see Chapter 2) has now accumulated to show that this assumption is not correct ...
Roger H. Mitchell, Steven C. Bergman
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The development of realistic hypotheses for the petrogenesis of potassic rocks has been hindered, until recently, by the tendency of petrologists to consider all leucite-bearing K-rich rocks as being related. Sufficient geological, geochemical, and mineralogical evidence (see Chapter 2) has now accumulated to show that this assumption is not correct ...
Roger H. Mitchell, Steven C. Bergman
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LAMPROITES OF NORTHERN ALGERIA
International Geology Review, 1993The mineralogy and chemistry of lamproitic rocks from two bodies in northern Algeria, near the city of Constantine, have been studied in detail. On the basis of the ultra-alkaline, highly potassic and highly mag-nesian composition and the presence of magnesian olivine, low-alumina and low-soda diopside and other minerals, these rocks are classified as ...
F. V. Kaminskiy +3 more
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1991
Igneous rock classifications have never been graced with the elegance and simplicity of terminology employed in other branches of science. Consequently rock names present us with a bewildering plethora of unrelated, noninformative, and commonly unpronounceable terms.
Roger H. Mitchell, Steven C. Bergman
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Igneous rock classifications have never been graced with the elegance and simplicity of terminology employed in other branches of science. Consequently rock names present us with a bewildering plethora of unrelated, noninformative, and commonly unpronounceable terms.
Roger H. Mitchell, Steven C. Bergman
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The Geochemistry of Lamproites
1991Relative to other mafic alkaline rocks lamproites are distinguished by their high K2O, TiO2, P2O5, and MgO contents, K2O/Na2O ratios and low Al2O3 and CaO contents. The general characteristics of the lamproite clan have been outlined in Section 2.6. In this section the compositional averages and ranges of lamproites are compared with those of other ...
Roger H. Mitchell, Steven C. Bergman
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Description of Lamproite Occurrences
1991Lamproites have been recognized in over 25 occurrences (provinces or fields) on all continents (Figure 3.1). In common with kimberlites, they are restricted to continental environments. As noted in Chapter 4, the formation of both kimberlite and lamproite magmas has occurred from the Precambrian to the Cenozoic, although the Mesozoic Era was the time ...
Roger H. Mitchell, Steven C. Bergman
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Fluorine-bearing phases in lamproites
Mineralogy and Petrology, 1991The distribution of F between phlogopite, amphibole, apatite, and glass has been determined for 261amproites from Leucite Hills, Wyoming; West Kimberley, Western Australia; Smoky Butte, Montana; Prairie Creek, Arkansas; and Gaussberg, Antarctica. The F contents of these phases are inconsistent in different lamproite localities, with distinct variations,
A. D. Edgar, H. E. Charbonneau
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