The Elements of economic geology

Bibliographic data

Monograph

Identifikator:: 1773832379

URN:: urn:nbn:de:zbw-retromon-172798

Document type:: Monograph

Author:: Gregory, John W. http://d-nb.info/gnd/11683014X

Title:: The Elements of economic geology

Place of publication:: London

Publisher:: Methuen

Year of publication:: 1928

Scope:: XIV, 312 S.; graph. Darst.

Digitisation:: 2021

Collection:: Economics Books

Usage license:: Get license information via the feedback formular.

Chapter

Document type:: Monograph

Structure type:: Chapter

Title:: Part II. Ore deposits

Collection:: Economics Books

ORES OF IRON 137 The ores are mainly in a coral limestone, which is from 150-300 feet thick. Its age corresponds to the Lower Greensand. It is overlain by shales and sandstones, some of which contain pyrites and abundant nodules of clay ironstone which beside the Abandanado Mine have been altered into iron oxide. The main ore is brown hematite, and its banded botryoidal stalactitic structure shows that it ls of secondary formation. It rests on a massive carbonate of iron which passes into the oxide and often includes lumps of limestone. As these ores are secondary limonite, as they narrow below and rest on hummocks and pinnacles of limestone, it is natural to explain them by the replacement of limestone, NW. - Sh. Fie. 41.—THE BILBAO ANTICLINE. Section across the Bilbao anticline; the iron mine at H, between faults FF. The beds consist of Cretaceous shales containing, CLL, clay Ironstones ; Sh,, shale: L. limestone: the lowest bed is sandstone. and to a smaller extent of sandstone and shale, by solutions that obtained their iron from the once extensive overlying beds. The view was therefore adopted (as by F. D. Adams, Fourn. Canad. Min. Inst, 1901, iv, p. 202; Lindgren, Mineral Deposits, 1913, p. 310) that the spathic ore results from the descent of an iron solution which altered the lime- stone into siderite. According to an alternative view (e.g. Beyschlag, Vogt, and Krusch, Ore Deposits, 1916, ii, p. 833; R. W. van der Veen, Econ. Geol., xvii, 1922, p. 602; R. M. de Rotaeche, Minas de Bilbao, 1926, p. 157), the iron is of hydrothermal origin, came up along the faults, and was deposited as siderite by the alteration of the limestone and the replace- ment of sandstone and shale; and this primary carbonate Ore was altered to oxide by descending water. Siderite

Access restriction

Copyright

fullscreen: The Elements of economic geology

Monograph

Chapter

Table of contents

Download

Monograph

Chapter

This page

Image fragment

Citation links

Citation recommendation