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49
following: — in Tösse Parish, Dalsland, a quartzite displaying
ripple-marks and discordant stratification; at ATästanå in north-east Skåne a
quartzite conglomerate; at Los in Hälsingland a slate formation; and in
Västerbotten (principalis’ in the district round Skellefteå) and Norrbotten,
several areas’ of slate, conglomerate and quartzite sandstone.
Ores. Most Swedish ore-deposits occur connected with porphyries and leptites.
The majority and by far the most important are the iron ores, distributed
mainly in two regions, one in central Sweden and the other in north
Lapp-land. In the first-named region the deposits occur grouped together in large
numbers — most abundantly in the so-termed "Bergslagen", embracing west
and north Västmanland and the adjacent parts of east Värmland and south
Dalarne. The Grängesberg mining-field., situated in the last-named province,
may be regarded as the most important of all. There are besides several
iron mines in north Uppland (Dannemora, etc.), in Södermanland (Kantorp),
and in Östergötland. The ores occur as layer — like bodies, usually
intercalated in rocks of the leptite group. — The Lappland deposits are remarkable
for their unusual size. In addition to Gällivare. Luossavara, Tuollavara and
Svappavara, there is the enormous iron mountain Kirunavara. The ores,
preponderatingly magnetite with intermixed apatite, occur as lenticular masses.
At Kirunavara the ore body has a length of about 5 kilometers and a thickness
of nearly 150 m.; it lies enclosed between beds of porphyry; at Gällivare
leptites and gneisses constitute the border rocks. A distinctly different type of ore
forms the greater part of the huge mountain Taberg, situated in Småland some
six miles south of Jönköping; the ore, a low-grade mixture of titaniferous
magnetite and olivine, is merely a facies of a greenstone intrusion (byperite). —
Copper Ore, chalcopyrite, is at present only mined to any extent in the Falun
Mine. This deposit, the largest copper-ore deposit in Sweden and one of the
largest deposits of chalcopyrite in the world, has been worked for nearly seven
centuries. Other copper deposits are found at Garpenberg in south Dalarne, at
Tunaberg in Södermanland, at Bersbo in Östergötland, at Areskutan in Jämtland,
etc. — Argentiferous galena is found at Nya Kopparberg, Guldsmedshyttan, and
Kallmora Silver Mine in Västmanland, and also at a few other places in
"Bergslagen"; it is however of comparatively small importance. At the Sala Mine, the
rich silver ore, formerly so renowned and productive, is to a large extent
exhausted. — An important zinc-blende deposit is worked in the Åmmeberg Zinc
Mines, near Askersund. Zinc ore is also obtained at Ryllshyttan, Saxberget and
Stollberget in Dalarne, and at the Dannemora Mines. — Manganese ore
(pyro-lusite) is found at Bölet, north of Karlsborg, and at Spexeryd and Hohult, south
of Jönköping.
Granites extend through a very considerable part of the Swedish Archæan.
The largest granite districts are found in south-eastern Sweden (Småland) and in
the central parts of Norrland. Geologically most of the granites appear as
distinct intrusions in the surrounding rocks of the gneiss, leptite and porphyry
groups, but their eruption clearly belongs to several different epochs.
Petro-graphically a wide series of types are represented, differing in composition,
structure and colour. The Swedish granites furnish an excellent material for paving
and building stone as well as for various monumental purposes; they constitute
the basis of a flourishing industry that has its centres principally in the southern
coast regions (Bohuslän, Blekinge, Småland) and at Stockholm. — Pegmatite is
of very general occurrence in the Archæan rocks in the shape of dikes, veins
and lenticular masses; it constitutes the mother röck of several valuable deposits
of felspar und quartz.
4—133179. Sweden. /.
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