The results of paleostress analyses in the

Vìstník Èeskéhogeologickéhoústa!::u75, l, 2000
The results of paleostressanalysesin the easternparts
of the Nízký Jeseníkand the Drahany Uplands
JOSEFHA vIØ
Ostavfyziky Zemì, PøFMU Brno, Tvrdého 12,602 00 Brno, e-mail: [email protected]
A b str a c t. The orientation of the principal paleostress axes were studied in the Culmian sediments ín the eastem partsof the Nízký Jeseník area
(the Moravice and the Hradec-Kyjovice Formations) and ofthe Drahany Uplands (the Myslejovice Formation). The paleostress analyses were based
on the fault geometry investigation. Several different Variscan paIeostress fields were computed. In the case of compressional stress fields with subvertical oríentation of the maximum extension, the axis of maximum compression (JI were orientated from E- W to NW -SE, in south-eastem part of
the Drahany Uplands up to NNW-SSE. In some cases, both the maximum compression axis and the maximum extension axis are orientated sub-horizontally. The axis of (JI was orientated NE-SW or E- W, axis of (JJwas orientated NW -SE or N-S. But at one síle (the site 26) in the eastem part of
the Nízký Jeseník area the inverse orientation of the (JI axis and the (JJaxis were aIso computed. The extensional paleostress fields were computed only in the Nízký Jeseník area. The maximum extension axes were orientated approximately E- W (in wide range of orientations from NW -SE up to NESW). The orientations of the tensile fractures and the quartz veins measured in the eastem part of the Nízký Jeseník area do not agree to this result.
The facts discussed in the article indicate the generally Variscan age of the found compressional stress fields. The younger extensional stress fields
are probably late- Variscan and they can reflect the gravitational collapse of the Variscan orogene.
A b str ak t. V kulmských sedimentech východní èásti Nízkého Jeseníku (moravické a hradecko-kyjovické souvrství) a Drahanské vrchoviny
(myslejovické souvrství) byla studována orientace hlavních os paleonapìtí. Paleonapì•ová analýza byla založena na studiu geometrie zlomù se striacemi. Bylo zjištìno nìkolik rùzných paleonapì•ových polí. V pøípadì kompresních napì•ových polí se subvertikální orientací maximální extenze byla osa maximální komprese orientována ve smìru V-Z až SZ-JV, v jižní èásti Drahanské vrchoviny až ve smìru SSZ-JJV. V nìkterých pøípadechbyly jak smìry maximální komprese, tak i smìry maximální extenze orientovány subhorizontálnì. Osa 0"\ byla orientována ve smìru SV -JZ nebo až VZ, osa 0"3pak ve smìru SZ-JV nebo S-J. Na jedné z lokalit ve východní èásti Nízkého Jeseníku (lokalita 26) však bylo spoèítáno také paleonapì•ové
pole s obrácenými orientacemi os 0"1a 0"3.Extenzní paleonapì•ová pole byla zjištìna pouze v Nízkém Jeseníku. Smìr maximální extenze byl pøibližnì V.-z. (s širokým rozptylem orientací od smìru SZ-JV po smìr SV-JZ). S tímto výsledkem nesouhlasí orientace tahových puklin a køemenných žil,
které byly mìøeny v regionu Nízkého Jeseníku. Skuteènosti diskutované v tomto èlánku ukazují obecnì variské stáøí zjištìných kompresních napì•ových polí. Mladší extenzní paleonapì•ová pole jsou pravdìpodobnì pozdnì variská a mohou být odrazem gravitaèního kolapsu variského orogenu.
Ke y word s: brittle deformation, faults with striations, paleostress analyses, Nízký Jeseník area, Drahany Uplands, Variscides
lntroduction
The Lower Carboniferous Culmian sediments depositeï at the eastem boundary of the Bohemian Massif (in the
Moravian-Silesian region) belong to the extemal domain
of the Variscan orogene. They have been proposed to be a
part of the Rhenohercynian zane (for instance Behr et aj.
1984). There are two main outcrops of the Culmian sediments (shales,graywackes and conglomerates) on the eastem margin of the Bohemian Massif: the Nízký Jeseník
and the Drahany Upland areas.These sediments represent
a flysh and Jateran early molasse of the Variscan orogeThe age and deformation of the Culmian sediments
decreasegenerally from west to eastor from north-west to
south-east in the Moravian-Silesian units (Dvoøák 1973,
1993, 1994; Hrouda 1979; Kumpera 1972). In Dvoøák's
(1993) opinion, the Culmian sedimentation started in the
Andìlská Hora Formation (the western part of the Nízký
Jeseník Uplands) already during the Famennian. The age
of sediments decreaseseastwards through the Tournaisian
and Viséan up to Namurian in the eastern part of the
Nízký Jeseník Uplands.
The Culmian sediments were folded during Variscan
deformation, the fold axes and strike of the cleavage planes are predominantly orientated approximately NNESSW in the Moravian-Silesian region (Dvoøák 1973,
1993; Kumpera 1983). Cháb (1986) supposes the nappe
fabric of the Culmian units. Some evidence of the nappe
fabric was shown by some other authors (for instance
Èížek, Tomek 1991; Melichar, Buèek 1994).
Stress analyses based on the fau1t geometry investigation were carried aut in the eastern part of the Nízký
JeseníkUpland by Grygar (1991). Both the axes ofmaximum compression (0"1)and extension (0"3)computed by
his analyses were subhorizontal. The axis 0"1was orientateï in WNW-ESE direction, 0"3was orientated in NNESSW direction in the Jakubèovice quarry. Hanžl (1997)
distinguished several different stressfield analyses at sites
in the Brno pluton. Only some from the distinguished
stress field are considered to be Variscan age. Hanžl supposes the post-Variscan age of the NE-SW extension, the
E-W compression also could be post-Variscan. New results of the paleostress ana}yses based on the fault geometry investigation, carried aut in the easternparts of the
Nízký Jeseník area (the Moravice and the HradecKyjovice Formations) and of the Drahany Uplands (the
Myslejovice Formation), are discussed in this article.
27
~
r..I,
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Bulletin ofthe CzechGeologicaJSurvey 75, 1,2000
O"
N
H
~
N
ple
t
of
Km
o
10
Angelier-Mechler's
graphical
Mechler
20
30
c-
I!::>
40
analysis
1977).
'>-
aut
:
in
the
Nízký
eastern
Jeseník
Sub-region
in the
part
area
valley
Bystøicí,
cr,\\.
.";
;~~
~:
~<:,,~
~~,~
.,
'~"""
~
"
of
'.'
'. .
,,:;:: ~~;jj;'
~t
~
~
~::~::Jlli~
~
0",
~
!\\
N
'?~
western
rocks
base
Formation
Sub-region
sites
south-eastwards
the
most
~
~:
Us TRIA
West Car pathians
Bohemian Massif
:g
~
OuterFlyschBelt
of
Neogenesedi~entsol
Formation).
Vienna
Basln
E3
Tertlary.Quaternary~
volcanicrocks
Permlan
E1
Cretaceous
eastern
part
n.
river
in the nort-
of
this
Uplands,
Front01Principal
named
aut in the western
of Vítkov.
~
Only
sub-region
aut.
On ly at some sites it was possible to carry
Moldah.ubian.
analysis.
Varlscan
one
E was single
..
granrtolds
aut a separate
results
were
program
S
erner
et
al.
com p uted
INVERS
(1993)
and
the
~
Cadomlanlgneous gram
BRUTE3
Hardcastle
and
made
by
Hllls
(1991),
which
simple stress analyses (see text).
les of
(Angelier
et al.
principal
data
ratio
matic
indicators
of the
analyses
Nízký
measurements
planes
were based mainly
with
striations
in the Culmian
Jeseník
rocks
and of the
of the quartz
dikes
on the in-
and other kine-
in the eastern parts
Drahany
Uplands.
and extensional
les were used less often.
Planes
of micro-faults
number
of sites,
Jeseník
area. But the number
insufficient
at a single
28
striations
in the eastern
were
found
ofmeasured
analysed
at a
part of the Nízký
data were often
sites. That is why the data from
tes near each other were
But the
together
using
si-
the sim-
(defined
accuracy
was too low.
of the principal
stress
Thus
tensor
the orientations
of the
of the stress
by Angelier
of the
1975)
calculation
only the computed
stress field
1989).
variab-
we-
of the
orienta-
axes are discussed
in this
article.
The kinematic
ten
show
indicators
strongly
Somewhere,
with
mainly
tions
the reduced
It means,
0=(0"2-0"3).(0"1-0"3)-1
stress ratio
The
fractu-
1982).
are based on the inversion
axes (0"1, 0"2 and 0"3) and the value
re computed.
of fault
by
pro-
-..p
andvolcanicrocks
method
(Angelier
1984;
Both programs
computed
The paleostress
usmg
made
simple graphicaI Angelier-Mechler's method of the paleostress analysis (Lambert projection, lower
hemisphere, 0"1-horizontal hatching, 0"3-vertical hatching). A-E are sub-regions single aut for common
vestigation
stress
At these sites the nume-
rocks.
ofthe
In the
part of the Drahany
Lugianand
Moravo-Slleslan
crystaillneurnts.the
sedlmentary
ana1yses
near
sub-region
Fig. I. Schematic geologicaI map of the eastern margin of the Bohemian Massif and the results of the
Paleostress
area.
in the
area,
Moravicí,
single
PrincipalFaults
crystalllne urnts
..ncal
-
-Devonian-Carbonilerous
and
theCarpathian
Faredeep
sub-
aut in the val-
C is situated
Hradec
Nappes
~cr3
Jurassic
Neogene
of the
Two
hern part of the investigated
southeastern
~
~
part
0"3
~
~
the
Vítkov
Formation
upper
part, northwards
111111111 '
..
the
B contains
were single
D was
I
("
of
Tise on sur-
face.
ley of Moravice
~
of
of
the
Sub-region
tP
-.
part
tes
Moravice
'lili,. )
river,
Domašov n.
area. At these si-
and
~3
by sites
Bystøice
in the
regions
the
1).
(the Hradec-Kyjovice
"
\t?
D
the
the investigated
Moravice
11111110,-'1
of
(see fig.
A is created
southwards of
,4
(Angelier,
Four sub-regions
for common stress analysesof
the measureddata were single
~'"
~I~
method
the reversed
slips, which
at same site.
different
stress fields
Jeseník
represent
character
and
cannot be created
re found
Nízký
on the micro-fault
various
the
After
normal
faults
planes
separation
were found
of-
movement.
and
in the same stress field,
area and Drahany
Variscan
of
strike
we-
of data sets, more
in the eastern parts ofthe
Uplands.
compression,
other
Some
of them
stres s fields
;.
~
'?~::~,.;
!;,'-f:
"K;
~
'*:
Vìstnik ÈeskéboKeoloKickébo ústavu 75. 1.2000
show probably late-V ariscan or
post-V ariscanextension.
Compressionalpaleostress
fields
o
10
20
30
t
~.~~~;
Km
40
+"\~
o((f
Compressionalpaleostressfields with subvertical
orientation
of the axis of maximum extension
No.
a,
Drahany
~
i?
Uplands. The orientation of maximum compression 0"\ computed in
N
separated sub-regions
various
from E-W to NW-SE (fig.l). The
orientation E-W or WNW-ESE
were found in the sub-regions C (ji"
+
,No. ofsite: 21
-'J(
.
(0"3) were found both in the Nízký
Jeseník area and
N
I:.J
'\\
a,
NO.ofsite:~~
})
a,
a,
No.ofsite:192.-:::::
and D in the north-easternern part
N
of the Nízký Jeseník area. Result
of stress analysis in the sub-region
B (south-eastern part ofthe Nízký
Jeseník area) shows orientation of
0"1 rather in direction NW-SE.
..~'+
..
++,
++.'
"
~
part of the Drahany Uplands gave
two different results of compressi-
~
:
>ht
maximum extension 0"3. First resuIt shows orientation of 0"\ approximately in direction from WNWESE to NW -SE, second result
shows trus orientation rather in di.Fig.
rectlon NNW -SSE.
Other paleostress fields connected with the Variscan compression show sub-horizontal ori-
":;;~~~~~~~~
Principal axesofpaleostress field:
A U STR
IA
~
No. ofsite: 108
.a,
Á a,
.a,
maximumofcompression
intennediateaxis
maximum of extension
2. Schematicgeologicalmapof the easternmarginof the BohemianMassif (legendis sameasin fig.
I) and the orientationsof principal paleostressaxes(arrowsrepresentorientationof principal horizontal
stresses)-compressionalpaleostressfields (Lambertprojection,lower hemisphere,great circles -fault
planes).
the eastern part of the Nízký Jeseník. The axis of maximum compression 0"1 is orientated in direction NE-SW,
axis of maxim extension 0"3is orientated in direction NWSE. Same orientations of principal axes of paleostress field were found also in the south-eastern part of the
Drahany Uplands. But in this sub-region E also another
stress field with orientation of 0"1 in direction W-E and
with orientation of 0"3 in direction N-S was singled aut
(fig. I).
Results of the common analyses in separated sub-regions agree to some results of numerical analyses carried aut
at single sites in the eastern part of the Nízký Jeseník area
(fig. 2). Subvertical orientation of 0"3and axis of 0"1orientated in direction E-W and NW-SE follows from analyses carried aut at sites I and 21. Paleostress field with axis of 0"\ orientated in direction NE-SW and axis of 0"3orientated in direction NW-SE was found at site 25 north-eastwards of
This field
1
]No. ofsite: 120
)
entation both axis 0"1and axis 0"3.
This paleostress field were found in the sub-region C in
Vítkov.
~r::+~~)
\
onal paleostress fields with subvertical orientation of the axis of
,
~
"
I+
Common stress analysis of the
fault striations in the south-eastern
;""
No.ofsite:
agrees to result from
sub-region D.
Notwithstanding, the strongly different result, with opposite
orientations of {J] and {J3,follows from kinematic indicators
found at some micro-fault planes at site 26, southwards of
Domašov n. Bystøicí (the sub-region A). Unfortunately,
small numberof measurementsand existence another strikeslip faults with opposite characterof movements at site 26
bring some uncertainty into result of analysis at this site.
Numerical paleostress analyses were carried aut also
at three single sites in the south-eastern part of the
Drahany Uplands (sites 102, 108 and 120). At the site
102, the principal axes orientations are similar to orientations at the site 25. The axis of maximum compression {Jj
is orientated in direction NE-SW, axis of maximum extension {J3is orientated in direction NW-SE (fig. 2).
Another result was computed at the site 108. The axis of
maximum compression {J] is orientated in direction E- W
or ENE- WSW and the axis of maximum extension {J3is
orientated in direction N-S or NNW -SSE. The subvertical
orientation of {J3and axis of {J] orientated approximately
in direction NW-SE were found at the site 120. These re29
~
íÍ~
~;
~~
1~
~
~
30
-::::k::;
Bulletin ofthe Czech GeolopJcal S!![vey75. 1.2000
N
Km
o
10 20 30 .40
~
~C1,r
N
x
-'~No.
or site: 32
No. ofsite: 24"
..1;::3
~,
~
~
q
~;;,,~
N
N ty and their orientationvery well
t retlects the orientationof maximum extension. But the planes
are often pre-existing and their
polescould differ from the orientation of principal extensional
stressaxis. The rangeof the orientationdifferencesof the quartz
...,,"!
mineralfibres onthe fractureplanesandthepole of this planesvisible at somesitesis up to value
~]i1J
200 in the eastern part of the
Nízký Jeseníkarea.
The ma:ximumof densitydistributionof the fracturepolesis
~
'
",
orientated
in direction
to NNE-SSW
r
from N-S
(fig. 4). AIso poles
of quartzveins are predominantly south-dipping(fig. 4). It can
"
indicate rather N-S extension,
while resultsof normalfault geo-~
metry analysesshow ratherE-W
extension.
No.ofsite:5
~?J>
:~c
No.ofsite:
Ages of found paleostress
Principalaxesof pa1eostress
field: fields
.(J,
maximumof compression
Á (J, inte~ediate axis .Important
question is age of
(J, maxlmumofextenslon
found stress fields. Some infor-Fig.
AUSTRIA
3. Schematicgeologicalmapof the easternmarginof the BohemianMassif (legendis sameasin fig.
I) and the orientationsof principal paleostressaxes(arrowsrepresentorientationof principal horizontal
stresses)-extensional paleostressfields (Lambertprojection,lower hemisphere,greatcircles -fault planes).
mation about relative ages of the
stress fields can be obtained from
the study of relationships of different products of brittle defor-
sults agree to mentioned
mation. At a few sites it was ra-
results obtained from common
simple graphical analyses in this slib-region E.
rely possible to see two different generations of striations
on same fault planes. The striation showing oblique re-
Extensional
versed movement along the fault plane is covered younger
paleostress fields
Micro-fault planes with striations proving the existence of the extensional stress fields with subvertical orientation of axis of maximum compression (JI were found auly
in the Nízký Jeseník area. The orientations of axes ofmaximum extension (J3 strongly differ from place to place.
rather strike-slip striation at site I in the southeastem part
of the Nízký Jeseník area, south-eastwards of Vítkov.
Similarly, the younger striation showing normal movement covers the older strike-slip striation on the fault plane at site 32 northwards of Vítkov. AIso the quartz mineral fibres indicating the younger tensile movement on the
Significant
some predominantly
differences
are visible
mainly from results of
separated numerical analyses at some single sites. The
axis of (J3is orientated approximately in direction E- W at
sites I and 24, at site 5 the NW-SE
extension was found
E-W orientated fault planes with ki-
nematic indicators of the older sinistral strike-slip movement is important for study of relative age of stress fields.
The crossing of different planes (faults, fractures and
and at site 32 the NE-SW extension follows from analysis
(fig. 3).
Also extensional fractures with quartz mineralization
and quartz veins gel evidence about extension in the eastem part of the Nízký Jeseník area. But it is necessary to
veins) can give another important information about relative age of the stress fields. For example the crossing of
tensile fractures and reversed fault planes was found at site 21 in the valley of Moravice river in the eastem part of
the Nízký Jeseník area. Absence of any offset of parts of
draw attention to the fact lhal the orientation of maximum
extension is parallel to the orientation of the miner~l fib-
tensile fractures crossing the reversed fault plane proves
the younger age of tensile fractures. At the same site the
res on the fracture plane rather lhali to the pole of thlS pla-
crossing quartz vein and a few normal and reversed faults
ne. The mineral fibres grew during the stress field activi-
was observed. The quartz vein is shifted along the normal
Vìstnik Ceského J!eo1oJ!ickéhoústavu 75. 1.2000
Equal Area
(Schmidt)
Conclusion
Fig. 4. Diagram of the poles of fractureswith quartz mineralization
(circles)and the polesofthe quartzveins (squares)-the eastempart of
the Nízký Jeseníkarea(Lambertprojection,lower hemisphere).
fault planes, blit no movement along the reversed fault
planes was found.
The relationships of different products of brittle deformation show the generally oldest age of compressional
stress fields obtained from analyses of reversed faults,
younger age of the stress fields with subhorizontal orientations of maximum compression axis (JI and of maximum
extension axis (J3represented by the strike-slip faults and
youngest age or extensional stress fields connected with
normal faults. The tensile fractures are probably generally younger than strike-slip faults and older than normal
faults. This distinguishing of relative ages, based on the
observation of relationships of different products of brittle deformation, is only schematic, the existence more different generation of fault planes with similar orientation
and sense of movements could be possible.
The Culmian sediments were folded during Variscan
deformation in the eastern part of the Nízký Jeseníkarea.
Variscan folding involved also fault geometries at some
sites. For example fault planes found in arm of large fold
at site 17 near Hradec n. Moravicí were rotated together
with the sedimentary layers during folding. Before the rotation the fault geometries had character of sinistral strikeslip and reversed faults. This relationship proves Variscan
age of found rotated faults indicating compressional stress
fields. Similarly the close orientations of maximum compression (JI, cleavage poles and the minimum axis offinal
fabric ellipsoid of deformed Culmian conglomerates at site 21 can indicate Variscan age of compressional stressfield obtained from analysis of reversed micro-faults found
at this site.
The discussed facts indicate the generally Variscan
-,
"'"
--~
R
31
age of the found compressional stress fields. The younger
extensional stress fields connected with tensile fractures
and normal faults are probably late- Variscan and they can
reflect the gravitational collapse of the Variscan orogene.
But the post-Variscan (saxonian) age ofyounger stress fields cannot be excluded on base of discussed results.
The results of stress analysis in the easternparts of the
Nízký Jeseník area and Drahany Uplands show the existence of some different stress field. There is evidence of
the Variscan age of the compressional stress fields. The
axis of maximum compression (J\ of stressfields with subvertical axis of maximum extension (J3were orientated in
direction from E-W to NW-SE, in south-eastern part of
the Drahany Uplands up to NNW-SSE. Other compressional stress fields connected with the Variscan compression show sub-horizontal orientation both axis (JI and axis
(J3.The axis of (JI was orientated in direction NE-SW, axis
of (J3was orientated in direction NW -SE. In addition, in
the southeastern part of the Drahany Uplands another
stress field with orientation of (JI in direction W-E and
with orientation of (J3in direction N-S was found.
The stress analyses of younger predominantly normal
micro-fault geometry show rather E-W orientation of the
axis of maximum extension (in wide range from NW-SE
up to NE-SW). The orientation of tensile fracture poles
and quartz veins do not agree to this result. The maximum
of density distribution of the fracture poles is orientated in
direction from N-S to NNE-SSW. The younger extensional stress fields connected with tensile fractures and normal faults are probably late- V ariscan and they can reflect
the gravitational collapse of the Variscan orogene. But the
post- V ariscan (saxonian) age of some younger stress fields cannot be excluded.
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-(1984): Tectonic analysis of fault slip data sets. -J. geophys. Res., 89,
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-(1989): From orientation to magnitudes in paleostress determinations
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Grygar, R. (1991): Strukturnì-kinematická analýza sv. okraje Èeského
masivu. -Záv. zpráva HS 105/90. -MS archív VSB. Ostrava.
Hantl, P. (1997): Structural profile through the Brno Massif. -Exploration
Geophysics, Remote Sensing and Environment, IV, 1,29-38.
Hardcast1e, K.C. -Hil1s,
L.S. (1991): BRUTE3 and SELECT:
Quickbasic 4 programs for determination of stress tensor configurations and separation of heterogeneous populations of fault-slip data.
-Computers & Geosciences, 17, 1,23-43.
RECENZE
Hrouda, F. (1979): The strain interpretation of magnetic anisotropy in
rocks ofthe Nízký Jeseník Mountains (Czechoslovakia). -Sbor. ge01. Vìd, užitá Geofyz., 16,27-62. Praha.
Cháb, J. (1986): Stavba moravsko-slezské vìtve evropského mladopaleozoického orogenu. -Vìst. Ústø. Úst. geol., 61, 113-120. Praha.
Kumpera, O. (1972): Problém vzniku druhotné tektonické stavby na pøechodu mezi nemetamorfovanými a dynamometamorfovanými sériemi (na pøíkladu sérií západojesenického synklinoria). -Èas. Slez.
Muz., Sér. A, 21, 23-34. Opava.
Kumpera, O. (1983): Geologie spodního karbanu jesenického bloku. Knih. Ústø. Úst. geol., 59, 5-172. Praha.
Melichar, R. -Huèek, Z. (1994): Tektonikajižní èásti šternbersko-hornobenešovského pruhu v Nízkém Jeseníku. -Geol. výzk. Mor. Slez.
v Roce 1993, 45-46. Brno.
Sperner, H. -Ratschbacher, L. -Ott, R. (1993): Fault-striae analysis: a
Turbo Pascal program package for graphical presentation and reduced stress tensor calculation. -Computers & Geosciences, 19, 9,
1361-1388.
Karnských Alp a Barrandienu. Èeský pøíspìvek obsahuje i seznam 127
geologù a pøírodovìdcù,kteøí do roku 1918 mìli úzké vztahy jak
H
Lobitzer
-P.
Grecula (editoøi, 1999): Geologie ohne
Gtenzen. Festschrift 150 Jahre Geo/ogischeBundesansta/t.Abhandlungen,56, 1,460 str., GeologischeBundesanstalt,
Wien.
Na jiném místì jsme ve Vìstníku Èeského geologického ústavu informovali o 150. výroèí založení Rakouské geologické služby a o oslavách tohoto neobyèejnì významného jubilea. Souèástí tìchto oslav bylo
i vydání sborníku prací v kmenovém periodiku vídeòského geologického ústavu. Sborník byl pøipravován již v polovinì roku 1998 a rozvržen
tak, aby obsahoval jednak èást historickou, jednak odborné èlánky s tématy vìdecké spolupráce Rakouska s okolními zemìmi. Rukopisù se postupnì nahromadilo tolik, že tento sborník musil být rozdìlen do dvou
èástí. První vyšla vèas a byla k dispozici úèastníkùm oslav v listopadu
1999. Rakouští pøátelé, pouèeni tím, že podobné títuly jako "Sborník
k výroèí spolupráce" jsou komerèním propadákem, tentokráte nazvali
svazek chytøe "Geologie bez hranic". To mùže naopak zájem pøípadných
konzumentù pøilákat.
Editoøi rozdìlili první svazek na nìkolik sekcí: Po úvodním slovì øeditele ústavu následuje blok s pøíspìvky zástupcù okolních zemí o dìjinách geologické spolupráce s Rakouskem. Druhý blok se soustøedil na
nìkterá speciální témata z historie geologických výzkumù. Následuje
èást zahrnující geologické pøíspìvky, popisující výsledky mezinárodních
výzkumù rakouského krystalinika a staršího paleozoika. Poslední èástí
jsou "varia", smìs tematicky rùznorodých geologických statí. Na následujících øádcích postupnì probereme charakter jednotlivých sekcí.
Pøedešlemejen, že sborník je dvojjazyèný, èástje publikována nìmecky,
èást anglicky. Všechny èlánky pak mají nìmecký a anglický abstrakt.
Èlánky do historické èásti byly pøímo objednány oslavencem,
Rakouskou geologickou službou. Editoøi pøitom ponechali na vùli autorù, jak tyto pøíspìvky pojmou. Švýcaøi pojednali o pøíkrovové stavbì
Alp a o úloze rakouských geologù pøi tektonických studiích. Zástupce
Bavorska psal sice též o Alpách, soustøedil se však spíše na biostratigrafické studie v druhé polovinì minulého století. Nezùstal jen pøi historii,
nýbrž vìnoval se i moderním koncepcím deskové tektoniky. Èeský pøíspìvek je ponìkud odlišný. Jde spíše o esej, nebo• si vybral nìkolik zajímavých témat rakousko-èeských vztahù: osobu Franze Eduarda Suesse
a jeho pøedstavu moldanubického nasunutí pøes moravikum, osudy
bloku ortocerového vápence z Kosova, práci rakouských a èeských geologù na Blízkém východì, vztahy mezi hornickými akademiemi
v Leobenu a Pøíbrami a nápadnou faunistickou pøíbuznost mezi silurem
32
k Rakousku, tak k Èeským zemím. Slovenský pøíspìvek je velmi struèný a bohužel ho nenapsal zamìstnanec spøátelené geologické služby.
Maïaøi a Slovinci se vìnovali historii spoleèných geologických výzkumù a svá pojednání vyzdobili portréty, ukázky rukopisù a starých map.
Podobnì je koncipován i italský pøíspìvek. Z Bosny a Hercegoviny došel rukopis, který je vlastnì biografií rakouských geologù, geografù
a montanistù, pracujících v této balkánské zemi, patøící kdysi k monarchii.
Druhá èást sborníku je historicko-biografickou všehochutí. Obsahuje
krátké èlánky o nìkterých osobnostech nebo událostech. Nìkteré z nich
popisují vyloženì "vnitøní záležitosti" Rakouska, jako tøeba vztahy mezi Geologickou službou a univerzitou ve Štýrském Hradci. Bylo sem zaøazeno i pojednání o Joachimu Barrandovi, jehož úzké vztahy k Vídni
byly obšírnì popsány v jiných pub)ikacích.
Do tøetí sekce sborníku jsou zaøazeny spoleèné práce, týkající se
krystalinika a staršího paleozoika. Pomohli ji naplnit i naši autoøi. Jeden
z nich popisuje silurské a spodnodevonské mlže Kamských Alp, druhý
spolupracoval na výzkumu silurských èerných bøidlic téhož regionu
a tøetí studoval dvojsIídné žuly jihoèeského plutonu. Ostatní pøíspìvky
se týkají krystalických vápencù Štýrska, metamorfovaných bazaltù
Solné Komory a silurských nautiloidù Karnských Alp.
Do poslední sekce byly zaøazenyrukopisy, které byly v termínu redakènì zpracovány. I zde má Ceský geologický ústav své zastoupení,
a to v èláncích o miocenním vulkanismu. Jinak jde o skuteènou smìs
petrografických a paleontologických prací z Rakouska i zahranièí.
Z této struèné recenze vyplývá, že spoleèným jmenovatelem vydaného sborníku je starší i souèasná mezinárodní spolupráce v geologických
vìdách. Zámìrem vydavatele bylo dodržet koncepci a pøitom pøíliš neomezovat autory a netrvat na dodržování osnovy. Takový pøístup má samozøejmì své výhody i nevýhody. Již se objevily názory, že nìkteré rozsáhlejší paleontologické práce pøíliš neodpovídají pùvodnímu zámìru.
Odvážíme se též kritizovat, že nìkteré historické poznámky mají až pøíliš místní význam. Vìtšina prací však ètenáøepotìší. Pamìtníkù ubývá,
dokumenty ze starého Rakouska-Uherskajsou vzácnìjší a vzácnìjší. Dík
patøí našim rakouským pøátelùm nejen za vydání sborníku, ale i za peèlivé archivování a zpracovávání historických materiálù, ve kterých najdeme mnoho údajù o zemích koruny Ceské i o pøírodovìdcích, kteøí mìli zásluhu na jejich geologickém prozkoumání.
Zdenìk Kukal