Full resolution (JPEG) - On this page / på denna sida - Sidor ...
<< 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.
65
Jernoxydul og Jernoxyd er bestemt ligesom ved de
foregaaende Slamarter.
Det vil fremgaa af Tabellen, at Biloculinlerets
Kalk-gehalt differerer meget paa de forskjellige Punkter af
Havbunden. Vetl paa Kartet at opstille Tallene for
Kalk-mængden vil man imidlertid finde, at en tydelig
Lovmæssighed er raadende med Hensyn til Kalkens Fordeling i
Biloculinleret. idet visse Partier af dette skarpt adskiller sig
fra hinanden i denne Retning.
Vestenfor den Kurve, der paa Kartet er betegnet
med 15°/o CaCÖ3, finder vi saaledes et meget kalkfattigt
Ler.
Her fandtes i 7 Bundprøver fra 5.7 pCt. til 12.2 pCt.
kulsur Kalk og som Middeltal 8.8 pCt. I det store Parti
af Biloculinleret söndenfor og østenfor Kurven 15 °/0
CaC03 finder vi en langt høiere Kalkgehalt. Denne
fandtes her ved 22 Bestemmelser at ligge imellem 21 og 40
pCt.; Middeltallet var 30 pCt.
Kurven 45°/,, CaC03 betegner den mest kalkrige Del
af Biloculinleret. Kalkgehalten i 4 Bundprøver var her
fra 45.8 pCt. til 56.2 pCt.. Middel 52.4 pCt.
Den mærkelig ringe Kalkgehalt i Biloculinleret
vestenfor Kurven 15°/0 CaCO.t synes at staa i Samklang med de
zoologiske Observationer. At dømme efter det forholdsvis
ringe Udbytte, der blev indvundet ved Skraaningerne paa
denne Del af Havbunden, skulde man tro. at Dyrelivet her
stod tilbage i kvantitativ Udvikling. Derimod syntes
Slammet her at indeholde mange Stene, der vanskeliggjorde
Skrabningerne og paa et Sted (Ståt. 350) rimeligvis var
Aarsag i. at Trawlen gik tabt.
Denne Afleiring af Stene maa skyldes den drivende
Is, hvis Virkninger vistnok i særlig Grad er fremtrædende
i dette udprægede polare Parti af Havet. Maaske kan
denne Tilførsel af grovere Materiale være Grunden til. at
de ovenomtalte Bundprøver fra Ståt. 301, 302 og 306 ikke
befinder sig i den samme finkornige Tilstand som de øvrige
fra den sydligere Del af Biloculinleret.
De Tal, der udtrykker det brune Lers
Oxydations-grad. ligger paa faa Undtagelser nær imellem 3 og 4 (Middel
af samtlige Bestemmelser: 3.0). Til yderligere
Karakteristik af det eiendommelige kalkfattige Parti af Biloculinleret
fortjener det imidlertid at nævnes, at Bundprøverne herfra
gjennemsnitlig syntes at være noget høiere oxyderet end de
øvrige. I de 8 Bundprøver vestenfor Kurven 15°/o CaC03
fandtes nemlig som Middeltal for Lerets Oxydationsgrad :
3.4; i den øvrige Del af det brune Ler: 2.7.
From this Table, the amount of lime present in
Biloculina clay appears to vary considerably in different parts
of the ocean-bed. If we set down on the map the figures
denoting the proportion of lime, a manifest regularity will,
however, be found to characterize the distribution of that
constituent in Biloculina clay, with regard to which certain
surface-layers of the deposit differ widely from one another.
Thus, for instance, west of the curve 15°/0 CaC03
we meet with a clay in which the proportion of lime is
exceedingly small.
In 7 samples of the bottom brought up here, I
determined from 5.7 per cent to 12.2 per cent of carbonate
of lime, the average amount being 8.8 per cent. The
extensive surface-layer of Biloculina clay stretching south and
east of the curve 15°/0CaCO3 was found to contain a much
larger proportion of lime. The amount of this constituent, as
shown by 22 determinations, ranged from 21 per cent to
40 per cent, averaging 30 per cent.
The curve 45 °/0 CaCÖ3 indicates the section of the
seabed within which the greatest quantity of lime has been found
in Biloculina clay. The proportion in 4 samples varied
between 45.8 per cent and 56.2 per cent, the average amount
being 52.4 per cent.
The remarkably low amount of lime, present in
Biloculina clay west of the curve 15% CaC03, may in part,
it would seem, be explained by the results of the zoological
observations. To judge from the comparatively meagre
yield of dredgings in this part of the ocean-basin, the
quantitative development of animal life would not
appear to be large. Meanwhile, numbers of large stones —
a serious impediment to successful dredging — were, on
the other hand, apparently imbedded in the deposit, and
the loss of the trawl — at Station 350 — must in all
probability be ascribed to their presence there.
This distribution of stones is obviously to a great
extent the work of drift-ice in this peculiarly Polar tract of
the ocean. Maybe, this addition of coarser material will serve
to account for the deposit brought up at Stations 301, 302, and
306 having been much less finely granulated than were the
samples of Biloculina clay from more southerly localities.
The figures expressing the oxidation of the brown
clay lie, with very few exceptions, between 3 and 4 (the
mean for all such determinations was 3.0). As a further
characteristic of that deposit west of the curve 15°/u CaC03,
where it contains so small an amount of lime. I may mention
that, as a rule, the samples would appear to have been
more highly oxidized than was the case with those from
any other part of the sea-bed. For the 8 samples of brown
clay brought up west of the curve 15°/0CaCO3, I found the
mean degree of oxidation to be 3.4; elsewhere it was 2.7.
Den norske Nordhavsexpedition. Schmelck: Chemi.
<< prev. page << föreg. sida << >> nästa sida >> next page >>
