Full text: The Elements of economic geology

ORES OF IRON 
133 
clude lumps of garnet and amphibole, that can be removed 
by hand sorting. In some places (e.g. Kennedy Lake, 
Vancouver Island), the igneous rock is granite, and the iron 
must have been brought up the contact plane and not 
derived from the igneous rock. (For this type of ore in 
Canada, cf. Lindeman and Bolton, Iron Ores, Canada, Dept. 
Mines, 1917.) 
PRIMARY LODES—CZECHO-SLOVAKIA AND WESTPHALIA 
Owing to the abundance of iron within the earth, and its 
ready solubility, it has naturally been often carried upward 
in solution and deposited in primary lodes. They are as a 
tule commercially unimportant as other iron ores are more 
cheaply mined. 
Some lodes of specular hematite with sulphides of copper, 
lead, and zinc are associated with igneous rocks, and have 
been regarded as contact ores ; but when neither of the rocks 
in contact contains much iron, the lodes must have been 
supplied along the contact plane. In some Tuscan localities 
these ores occur between igneous and sedimentary rocks; 
but in Elba similar ores, in large masses, lenticles and veins, 
replace limestones some distance from any igneous rock. 
The hematite is associated with garnet, pyroxene, epidote, 
and a hydrous iron-calcium silicate, ilvaite. The ores in 
Elba were formed after the Eocene in connection with 
'gneous activity and earth-movements. 
In Czecho-Slovakia (near 49° N., 21° E.), about 220 miles 
S. of Warsaw, between the towns of Wallendorf and Ein- 
stedel, a mountain range of Devonian and Carboniferous 
slates and sandstones contains many fissure lodes of siderite 
near intrusive greenstones and granite. The lodes are of 
Paleozoic age and consist of siderite and quartz with tourma- 
line and barite. The ores are probably primary and were 
formed in connection with the granite intrusions. The area 
1810 the Carpathian Mountains, and during their uplift in 
the Middle Kainozoic, the field was intensely disturbed, and 
"he lodes received additional constituents including mercury. 
The primary iron lodes hitherto of most value are those 
of the carbonate, siderite, as in the Siegerland in West- 
phalia. an aren, of Devonim: slates and sanittonct batide the
	        
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