III.—On the Classification and Nomenclature of Rocks

1875 ◽  
Vol 2 (12) ◽  
pp. 583-587
Author(s):  
S. Allport
Keyword(s):  
Igneous Rocks ◽  
The Other ◽  
Granitic Rocks ◽  
Acidic Group

In the September Number of the Geol. Mag. pp. 425, 426, there are some remarks by Mr. G. H. Kinahan on the nomenclature of certain igneous rocks, on which I should like to offer a few observations. The rocks referred to belong to the acidic group, and are mentioned under the various names of granite, nevadite, granitic rhyolite, liparite, trachyte, elvanite, siliceous elvanite, felstone, bottleite, trachalite; the two last being synonymous, for it appears that bottleite is the local name for a vitrioid rock pronounced to be trachalite; but several of the other names are also synonymous or useless, for we are told that nevadite—a proposed new addition to our granitic rocks—is characterized by a more or less crystalline felsitic matrix inclosing crystals of quartz, one or two felspars with mica or amphibole.

IV.—Allotropic Forms of Silica and their Significance as Constituents of Igneous Rocks

1906 ◽  
Vol 3 (3) ◽  
pp. 118-120
Author(s):  
Cosmo Johns
Keyword(s):  
Rock Mass ◽  
Igneous Rocks ◽  
The Other ◽  
Free Silica

That silica appears as a constituent mineral of igneous rocks in two distinct phases, viz. quartz and tridymite, has been known for some time. The writer is not aware that any explanation has been offered which would indicate the conditions determining the appearance of one or the other in a cooling fused rock-mass. He now proposes to describe certain experiments made with a view to explain why it is that though the free silica generally appears as quartz, yet occasionally, as in certain trachytes, it crystallizes out as tridymite.

The distribution of gold and silver in the crystalline rocks of the Malvern Hills

1936 ◽  
Vol 24 (152) ◽  
pp. 260-264 ◽  
Author(s):  
A. Brammall ◽  
D. L. Dowie
Keyword(s):  
Spectroscopic Data ◽  
Senior Author ◽  
Crystalline Rocks ◽  
Igneous Rocks ◽  
Granitic Rocks ◽  
Image Position

In re-examining the crystalline rocks of the Malvern Hills, the senior author has had occasion to apply quantitative spectroscopic data for the rarer constituents of hornblendes and micas. The recognition of silver in the spectrograms of biotite led to tentative fire-assays of granitic rocks in bulk-a procedure which revealed the presence also of gold.The assay results for this preliminary suite of granitic types are given below; values less than 5 grains per ton are returned as 'traces':The higher values appear to be related to the reddening of the felspars, which is a widespread 'late' pneumatolytic effect; it is conspicuous in the major granite masses and related pegmatites, but somewhat local and 'arterial' in its distribution over rocks of pre granite age. Among the igneous rocks of post-granite age, the intrusive granophyric quartz-diabase ('Ivy Scar' type) shows only feeble reddening; the newer dolerites are unaffected.

The decomposition of some organophosphorus insecticides and related compounds in plants

1955 ◽  
Vol 239 (663) ◽  
pp. 191-214 ◽  
Keyword(s):  
Hydrogen Peroxide ◽  
Organophosphorus Compounds ◽  
Degradation Products ◽  
Parent Compound ◽  
The Other ◽  
Acidic Group ◽  
Water Partition Coefficient ◽  
Unknown Structure ◽  
One Step ◽  
High Yields

To discover the reactions undergone in plants by organophosphorus compounds of the type used as insecticides the non-ionizable metabolites of several compounds were studied. Octamethylpyrophosphoramide (schradan) is degraded in four species of plants. Low yields of heptamethylpyrophosphoramide and a powerful anticholinesterase are obtained besides ionizable compounds. Oxidation of schradan with hydrogen peroxide and with oxygenated liver slices gives the same products in similar proportions. Thus plants probably degrade schradan by oxidation, producing mainly compounds unstable in water, which are hydrolyzed to substituted phosphoric acids. The powerful anticholinesterase is believed to be hydroxymethyl-heptamethylpyrophosphoramide from its chloroform/water partition coefficient and its yield in plants. It may, however, be octamethylpyrophosphoramidic oxide. Turnip plants also degrade the dimethylamide, monomethylamide, n -butylamide, iso propylamide and ethyl ester of tetramethylphosphorodiamidic acid. As these compounds contain no acidic group which can be removed by hydrolysis after oxidation, high yields of compounds extractable from water by chloroform are obtained. None of the parent compounds are hydrolyzed, nor are butyl or wopropyl groups removed in one step. Probably the dimethylamide is demethylated to the monomethylamide in a way similar to schradan. The physical properties of the degradation products of the other compounds indicate that only the dimethylamido groups are attacked, the other groups being inert. OO -diethyl O -ethylthioethyl phosphorothionate is converted in plants to at least three compounds extractable by chloroform. Their structures are unknown. OO -diethyl S -ethylthioethyl phosphorothiolate is oxidized rapidly in plants to OO -diethyl S -ethylsulphinylethyl phosphorothiolate and another compound of unknown structure, both of which are more stable in plants than the parent compound. The same products are formed by the action of hydrogen peroxide on the parent compound. Thus a number of organophosphorus compounds are degraded by oxidation in plants. There is no evidence that their hydrolysis is catalyzed.

Isotopic age determinations on clay minerals from lavas and tuffs of the Derbyshire orefield

1972 ◽  
Vol 109 (6) ◽  
pp. 501-512 ◽  
Author(s):  
P. R. Ineson ◽  
J. G. Mitchell
Keyword(s):  
Clay Minerals ◽  
Hydrothermal Alteration ◽  
Igneous Rocks ◽  
The Other ◽  
Mineral Deposits ◽  
Isotopic Age ◽  
Hydrothermal Mineralization ◽  
Pumice Tuff ◽  
Southern Section ◽  
Age Determinations

SummaryEpisodic hydrothermal mineralization has previously been recognized in the northern section of the Pennine orefield. Igneous rocks from the southern section (the Derbyshire orefield) have yielded isotopic ages, some of which are thought to represent ages of hydrothermal metasomatism (deuteric or subsequent). In order to ascertain whether epicyclic hydrothermal events gave rise to the Derbyshire mineral deposits, samples of highly altered doleritic lava and pumice tuff were collected adjacent to areas of mineralization. Clay-mineral concentrates from 34 samples were dated by the potassium–argon method. The conclusions drawn from these analyses support a hypothesis of repeated hydrothermal alteration of the clay minerals, reflecting at least two episodes of mineralization, one about 270 m.y., the other about 235 m.y. The geo-chronological significance of these and other results is considered.

Ferrodiorite from the Isle of Skye

1962 ◽  
Vol 33 (256) ◽  
pp. 26-36 ◽  
Author(s):  
L. R. Wager ◽  
E. A. Vincent
Keyword(s):  
Igneous Rocks ◽  
The Other ◽  
Hybrid Origin ◽  
Skaergaard Intrusion ◽  
The One ◽  
Isle Of Skye

Summary As a preliminary to an account of the marscoite suite of the Western Redhills Tertiary igneous centre of Skye, a description is given here of one unit, the ferrodiorite. While accepting Harker's hypothesis of the hybrid origin of marscoite (1904, pp. 175–196) we consider that the ferrodiorite, with which marscoite on Marsco is associated, is not itself a hybrid, but one of the parents from which the hybrids were formed. Among Thulean igneous rocks the ferrodiorite has mineralogical and chemical affinities with Hebridean mugearites, on the one hand, and with the ferrogabbros of the Skaergaard intrusion on the other, but is probably significantly different from both.

VI.—The Petrology of Arran

1913 ◽  
Vol 10 (7) ◽  
pp. 305-309 ◽  
Author(s):  
G. W. Tyrrell
Keyword(s):  
Great Britain ◽  
Igneous Rocks ◽  
The Other ◽  
Red Sandstone ◽  
Neighbouring Area

The Riebeckite-Orthophyre of the Holy Isle.—Four Occuxrences of acid and sub-acid igneous rocks containing the rare soda-amphibole riebeckite have been recognized in Great Britain, of which that of Ailsa Craig is the best known. The occurrences of Ailsa Craig and Mynydd Mawr, Carnarvonshire, are riebeckite-microgranites or paisanites. They contain ragged moss-like areas of riebeckite, together with microphenocrysts of quartz and alkalifelspar, in a microcrystalline groundmass of quartz and felspar. Riebeckite was also found by Dr. Teall in the granophyre of Meall Dearg and the neighbouring area of Druim an Eidhne, Skye. Harker described the riebeckite in these rocks as occurring in two forms, one having the usual ragged, sponge-like appearance, and the other being idiomorphic, the faces in the prism zone being well-defined, but with irregular terminations. The fourth occurrence differs somewhat from the others. This rock occurs as an intrusion into the Upper Old Red Sandstone, or Calciferous Sandstone of Easter Eildon Hill, Melrose, and was described by Barron as riebeckite-trachyte or phonolite. It consists principally of sanidine, occurring both as microphenocrysts and in the groundmass, with interstitial patches of riebeckite, and a little nepheline. Harker describes the rock as an orthophyre.

scholarly journals Rock Types Classification and Distribution on Anabanua Village, Barru Regency, South Sulawesi

2020 ◽  
Vol 8 (1) ◽  
pp. 1-8
Author(s):  
Muhammad Resky Ariansyah ◽  
Muhammad Fawzy Ismullah Massinai ◽  
Muhammad Altin Massinai
Keyword(s):  
Sedimentary Rocks ◽  
Research Area ◽  
Igneous Rocks ◽  
The Other ◽  
Metamorphic Rocks ◽  
Geological Process ◽  
Rock Types ◽  
South Sulawesi ◽  
Geological Conditions ◽  
Limestone Sand

Anabanua Village, Barru Regency is one of the areas in South Sulawesi that has quite unique geological conditions. This condition inseparably comes from the complicated geological process that took place during the formation of the island, Sulawesi. In Anabanua Village, there are many types of rocks such as sedimentary rocks, metamorphic rocks and igneous rocks. This paper aims to map and classify the types of rock by taking samples on different places in the research area. Then we observe the samples physical properties. The results showed, from taking 10 rock samples in different places, they have various characteristics. 8 of them were sedimentary rocks, they are Limestone Quartz, Limestone Sand, Shale, Sandstone, Coal, Limestone Bioturbation, Breccia, and Chert Stone. The other 2 samples were metamorphic rocks, they are Greenschist and Quartzite.

scholarly journals The ammonium content in the Malayer igneous and metamorphic rocks (Sanandaj-Sirjan Zone, Western Iran)

2011 ◽  
Vol 62 (2) ◽  
pp. 171-180 ◽  
Author(s):  
Vahid Ahadnejad ◽  
Ann Hirt ◽  
Mohammad-Vali Valizadeh ◽  
Saeed Bokani
Keyword(s):  
Colorimetric Method ◽  
Igneous Rocks ◽  
Granitic Rocks ◽  
Metamorphic Rocks ◽  
Low Grade ◽  
High Concentration ◽  
Western Iran ◽  
Metasedimentary Rocks ◽  
Sanandaj Sirjan Zone ◽  
External Sources

The ammonium content in the Malayer igneous and metamorphic rocks (Sanandaj-Sirjan Zone, Western Iran)The ammonium (NH4+) contents of the Malayer area (Western Iran) have been determined by using the colorimetric method on 26 samples from igneous and metamorphic rocks. This is the first analysis of the ammonium contents of Iranian metamorphic and igneous rocks. The average ammonium content of metamorphic rocks decreases from low-grade to high-grade metamorphic rocks (in ppm): slate 580, phyllite 515, andalusite schist 242. In the case of igneous rocks, it decreases from felsic to mafic igneous types (in ppm): granites 39, monzonite 20, diorite 17, gabbro 10. Altered granitic rocks show enrichment in NH4+(mean 61 ppm). The high concentration of ammonium in Malayer granites may indicate metasedimentary rocks as protoliths rather than meta-igneous rocks. These granitic rocks (S-types) have high K-bearing rock-forming minerals such as biotite, muscovite and K-feldspar which their potassium could substitute with ammonium. In addition, the high ammonium content of metasediments is probably due to inheritance of nitrogen from organic matter in the original sediments. The hydrothermally altered samples of granitic rocks show highly enrichment of ammonium suggesting external sources which intruded additional content by either interaction with metasedimentary country rocks or meteoritic solutions.

The origin of a Pre-Cambrian diorite-granite plutonic series from Pembrokeshire (Wales)

1970 ◽  
Vol 107 (6) ◽  
pp. 491-499 ◽  
Author(s):  
R. S. Thorpe
Keyword(s):  
Parent Magma ◽  
Igneous Rocks ◽  
Granitic Rocks ◽  
Chemical Analyses ◽  
Magmatic Differentiation ◽  
Similar Composition

SummaryA series of dioritic, granodioritic and granitic igneous rocks, of Pre-Cambrian age, is exposed near Johnston in south Pembrokeshire. Chemical analyses of representative rocks show the suite to be of calcalkaline type. An origin is suggested involving magmatic differentiation of a diorite parent magma, and the granitic rocks are compared with a granophyre of similar composition in north Pembrokeshire.

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