Full resolution (JPEG) - On this page / på denna sida - First part - I. Physical Geography - 3. Geology. By E. Erdmann, Ph. D., State geologist, Stockholm
<< prev. page << föreg. sida << >> nästa sida >> next page >>
Below is the raw OCR text
from the above scanned image.
Do you see an error? Proofread the page now!
Här nedan syns maskintolkade texten från faksimilbilden ovan.
Ser du något fel? Korrekturläs sidan nu!
This page has never been proofread. / Denna sida har aldrig korrekturlästs.
46
I. PHYSICAL GEOGRAPHY OF SWEDEN.
varies between O s and 1 meter; and they ordinarily rest on layers of
fire-clay or shales, that are quarried with the coals and furnish the
material for a considerable manufacture of fire-proof bricks, sewerage
pipes, tiles, etc.
In a few places the sandstone is quarried for the purpose of making
grind-stones and mill-stones out of it.
The clay-slates and shales of the coal-bearing formation contain in
many places well preserved fossil remains of the vegetation dominant
at the time of their accumulation. In the upper parts, which
principally consist of sandstones, are found marine fossils, chiefly molluscs.
The Cretaceous system extends over a large area of south-western
Skåne and over a considerable district around Kristianstad, Åhus, and
other places in the north-eastern part of the province. The deposits
found in the first-named district consist partly of white chalk
containing layers and nodules of flint, partly of limestones (Saltholm-limestone
and Faxe-limestone), occupying the largest area, partly also of a
calcareous sandstone (Köpinge-sandstone), in the neighbourhood of Ystad,
and of a kind of marl at Eriksdal and Kullemölla close to the
boundary of the Rhæto-Liassic district north of Ystad. The north-eastern
Cretaceous district is occupied partly by a limestone consisting chiefly
of crumbled shells and stalks of bryozoæ (Ignaberga-limestone), partly
by a soft, almost earthy limestone, and partly by quartz-sandstone.
The thickness of the Cretaceous system has not been ascertained; a
borehole that was sunk north of Ystad to the depth of 450 meters did
not reach its bottom. The limestones of this system are of great
economical importance, and several technical industries are established to
utilize them. White chalk is quarried and made ready for use at
several places. Saltholm-limestone is quarried on a large scale,
constituting, together with clay, the raw material to the manufacture of
Portland Cement at Lomma. The Ignaberga-limestone and the soft,
earthy variety are used for the burning of lime; they are also ground
and used as manure, for which purpose these limestones seem to be very
suitable as they contain a notable percentage of phosphoric acid. At
many places in north-eastern Skåne the Cretaceous limestones overlie
a bed of kaolin, under which is found the Archæan röck, more or less
decomposed.
From the period following the Cretaceous, or the Tertiary, no
sedimentary deposits are known in Sweden; but during this period great
disturbances took place in the rock-basement of Skåne. Great
dislocations in the form of faulting set in, following fracture-lines going in
the direction of north-west to south-east, while certain districts,
especially some Cretaceous areas, were sunk one thousand meters and more
beneath the adjoining territories. Volcanic eruptions also occurred, and
remnants of their lava-beds and ash coverings are met with in the
form of basalts and basalt-tuffs north of lake Ringsjön in the central
<< prev. page << föreg. sida << >> nästa sida >> next page >>
