THE COLLIERY GUARDIAN

AND

JOURNAL OF THE COAL AND IRON TRADES.

Vol. CXI.	FRIDAY, MARCH 10, 1916.	No. 2880.

■ ■ ' ' A

The Campine Coal Field.

Its Relation to the other Coal Fields of Belgium and North=western Europe.

P. KRUSCH, “Gluckauf.”
(Continued from page 408.)

Marine Horizons of the Campine.

The importance of the marine horizons in identifying
the seams necessitates an examination of. the observa-
tions collected up to the present.

The same marine horizon was discovered in the
following borings :—

No. 51 (near Mechlin).—Numerous schist horizons,
rich in Anthracomya Williamsoni, which characterise the
strata overlying the “ poudingue houillier ” (coal-bear-
ing conglomerate) at Liege. Small seams were also
found immediately above a white sandstone or quartzite.
At 252 m., a 15 cm. bed was found containing Lingula
mytiloides and mussel remains. The overlying schists
also contained fragments of mussels and fish scales.

No. 49 (at Opgrimby).—Numerous impressions of
Goniatites were found in a black schist at 474 metres,
together with a 10 cm. bed of limestone filled with
Goniatites. This level, also, lies at the base of schists,
with Anthracomya, directly upon a bank of brown
quartzite. A second Goniatite horizon is found between
519 and 525 metres.

No. 61 (at Sutendael). —■ Goniatites and Posidoniella
found at 624 m. Here also the over- and underlying
schist horizons are extremely rich in mussels, such as
Carbonicola, Naiadites, and Anthracomya.

No. 75 (near Eysden).—The coal measures extended
from 439-20 to 1,402-70 m., a thickness of nearly 1,000 m.
One marine and several fresh water horizons were,
found. Marine fossils occurred at the base of a 3-20 m.
layer of schist at 1,162’40 meters, amove a 20 cm. seam..
The horizon contained Lingula. Immediately above this
was a schist rich in Anthracoinya Williamsoni (a petri-
faction occurring in many horizons). This boring also
traversed several limestone horizons, especially two
directly above and below the marine horizon. At
1,310’90 to 1,336 m., i.e., about 150 m. below the marine
horizon, a noteworthy sandstone was discovered, which
Schmitz and Stainier are inclined to class with the
“ poudingue houillier,” and therefore, in all probability,
the marine horizon is about 150 m. above the pudding-
stone.

According to the experience in other districts, the
divergence of the fossils found in the borings is no
hindrance to regarding the horizons tas of equal age.

The following horizons are on a much higher level :—•

Boring No, 66 (near Asch railway station).—A schist
occurring at 596*5 to 604’5 metres, between two seams
(591’94 and 605’5 metres respectively), contains a large
Lingula and a small Discina. The boring traversed an
extremely large number of calcareous schists and lime-
stone beds, a pale grey, very pure limestone, with
conchoidal fracture, occurring not far above the marine
horizon.

Remarkably enough, the marine horizon was not found
in 'adjacent boring (67) which traverses the same
horizons, a fact which proves the individual poverty of
the marine horizon in No. 66.

No. 79 (Voort).—A 50 cm. layer of coarse-grained
schist, beginning at 1,116’5 metres, and greatly resemb-
ling cannel coal in appearance, exhibits small
impressions of Lingula mytiloides. Above this horizon
follows grey. schists with fish scales, and above this
again, at 1,111’5 metres, a fresh-water horizon with
Naiadites. The Lingula stratum is precisely the same
as that found in the Haine-Sambre-Meuse trough,
though, the; grain is coarser.

The horizon in No. 66 is the highest, and is probably
about 620 metres higher than that in No. 79, which, in
turn , is about‘413 metres higher than that mentioned
in connection with No, 51. .

Hence, up to the present, three marine horizons have
been identified in the Campine, viz., from above down-
ward :—

(1)	That in the boring No. 66, about 1,180 metres
above the pudding stone horizon;

(2)	That in No. 79, about 560 metres above the
pudding stone horizon ;

(3)	That in Nos. 76, 51, 49 and 61, about 147 metres
above the pudding stone horizon.

They are all situated in the poor or barren zones of the
Campine, the uppermost one (boring 66) being in the
top 100 metres of Schmitz and Stanier‘s zone C (the
so-called upper barren beds), about 180 metres above the
base and about 1,180 metres above the pudding stone
horizon. The second horizon (boring .79) is 40 metres
below the upper edge of the zone'E, and about. 560
metres above the pudding stone horizon; whilst the third
(borings 76, 51, 49 and 67) occurs 147 metres above the
pudding stone horizon.

From the situation of the topmost horizon with rela-
tion to the pudding stone, it may be concluded that it
corresponds to that of the Ste. Barbe de Florifioux seam
in the Charleroi basin, and to that of the Chenou seam
in the Liege basin. Up to the present, the’two higher
horizons cannot be identified with similar ones in the
Haine-Sambre-Meuse trough.

In comparison with the Lower Rhenish-Westphalian
carboniferous, the lowest horizon probably corresponds
to that of Finefrau-Nebenbank. Whether the second is
identical with that of Katharina, and therefore to that
discovered by van Waterschoot and Klein in two
borings in Dutch Limburg, cannot yet be decided. In
the case of the uppermost horizon, too, the available
material is insufficient for any comparison.

Fluctuation of Gas Content According to Strike and Dip.

A point of special difficulty in the identification of the
seams is the behaviour of the gas-flaming and gas coal
stage with over 30 per cent, of gas, since here the known
law of diminishing gas content with increasing depth is
not manifested. . In the seams with less than 30 per
cent, of gas, the diminution with the depth follows the
law. It must also be borne in mind that the gas content
of one and the same seam is not a constant quantity.

Owing to the increased gas content in the westerly
direction, the various kinds of coal cannot be construed
as of constant level from east to west, the line of con-
stant gas content intersecting the seams uniformly at
an acute angle towards the west. This is in strong
contrast to the conditions found in the Westphalian coal
field, where the gas content in one and the same seam
diminishes towards the west.

The changes in gas content from east to west are
shown in the following table :—

Cam pine, district west of the Rhine Valley graben.	Rhine Valley graben and vicinity.	Westphalia, district east of the Rhine Valley graben.
Decrease in the same seam from west to east, and throughout,in lower division as depth increases.	Irregular fluctuations. Gas content often ex- tremely low.	Regular decrease in the same seam from east to west and throughout as depth increases.

No regularity exists in the Rhine Valley graben dis-
trict ; and many of the seams are extremely low in gas.

Noteworthy irregularities in the gas content of closely
adjacent seams can, if they occur in the same manner
in several borings in different localities, be called in aid
in identifying the seams.

Fixing the Horizons of the Seams.

In the instances reproduced in fig. 5, it has been
found possible to allocate each borehole section in one or
other of the five stages. Nevertheless the identification
is, of course, only approximately reliable. In each of
the five stages datum levels have been selected, which
lie on the same plane, and exhibit concordant
characteristics in a large number of boreholes. Denoel
does not go so far as to allege that the seams thus iden-
tified really represent the same. He believes, how-
ever, that he has established an approximate level.

For stages 1 and 2, the datum levels are approxi-
mately in the middle; for stage 2, in the upper third;
and for stages 4 and 5 they are formed by the top and
bottom boundary seams of the barren zone. The former
extends right through the province of Limburg, whilst
the latter is found in many places in the province of
Antwerp. Whilst no workable seam is known in the
barren measures, a new datum level for stage 5 has
been found at the base of the small barren zone.

From this it undoubtedly follows that the decrease
in the direction of the Rhine Valley graben is due to
the originating disturbances thereof, and therefore to
tectonic causes.

Certain of the horizons in the Campine are easily
correlated to the corresponding horizons in the Lower
Rhenish-Westphalian district. Thus, the pudding stone
horizon forms the boundary between the barren measures
and the lean coal.

Similarly, the barren sandstone measures, which play
an Important part in Westphalia, can also be discovered
under the Sonhenschein. They belong to Renier’s
stage 2, and zone E of Schmitz and Stainier; and they
also correspond to the small lower barren measures in
Denoel’^ 1904 classification. The Sonnenschein seam,
which lies on the boundary of the Charleroi and Chatelet
series in the Haine-Sambre-Meuse trough, therefore
shuts off from above the lower barren measures.-'’

In the Inde district the Gedau conglomerate corre-
sponds to the pudding stone horizon, and, the boundary
between the Breitgang horizon and the Bi.nnenwerken
is identical with the level of the Sonnenschein seam.

Stratigraphical Conditions of the Coal Measures.

In general, the rocks of the productive coal measures
form , fairly regular strata, dipping gently toward the
north, the usual angle being less than 10 degs. Excep-
tions are afforded by the boring at Zittaert (No. 34),
where the dip is 60 degs., and that at Stockheim (No. 52)
with a dip of 45 degs., as well as a few others, from
which the existence of faults or the influence.of disturb-
ances may be deduced. Nevertheless, up to the present,
extensive folding has been demonstrated in only a single
core.

As a rule the dip of the strata diminishes from east to
west, and this also is evident by the broadening out .of
Renier’s zones 1 to 5 in a westerly direction.

Palaeontologically, the first member of the carboniferous
system encountered in the north to south section (fig. 2)
is Renier’s zone 1, with few plant remains, problematical
remains of Sphenopteris Hoeninghausi, etc.; and it is
only further northward that we find Neuropteris tenui-
folia, then Dictyopteris, and so on.

In all probability the basin is intersected by numerous
disturbances (borings, Nos. 28, 34, 56 and 53); and,
according to the experience gained in neighbouring dis-
tricts,'the disturbances run along two main lines, one
to the north-west and the other toward the north-east.
They accumulate in the vicinity of the Meuse valley,, as
was demonstrated by Forir, where two. characteristic
circumstances occur, viz., an increase in the angle of
dip,.and an irregularity in the lines of equal thickness of
cover rock, both of which point to the influence . of
extensive faults.

The general line of strike of the strata in the basin
may be taken as west-north-west.

Denoel considers that the Campine contains several
very faint troughs running south-west; and, bearing in