Mesozoic and Early Tertiary evolution of the Alpine foreland in upper Austria and Salzburg, Austria

Mesozoic and Early Tertiary evolution of the Alpine foreland in upper Austria and Salzburg, Austria

Tectonophysics, Elsevier 61 137 (1987) 61-76 Science Publishers B.V., Amsterdam - Printed in The Netherlands Mesozoic and Early Tertiary evolut...

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Tectonophysics, Elsevier

61

137 (1987) 61-76

Science Publishers

B.V., Amsterdam

- Printed

in The Netherlands

Mesozoic and Early Tertiary evolution of the Alpine foreland in Upper Austria and Salzburg, Austria W. NACHTMANN Rohd-Aufsuchungs

G.m.b.H.,

(Received

and L. WAGNER

Schwaeenbergplatr

January

31.1986;

16. A-1015

accepted

Vienna (Austria)

July 30,1986)

Abstract Nachtmarm,

W. and Wagner,

and Salzburg,

Austria.

Tectonophysics, The Cenozoic extends

Basin of Upper

basement

for a considerable

The area occupied Jurassic

Massif

increased

by Upper

craton

Following the Alpine

Austria

Europe,

carbonate

Deformations

were accompanied

partial

in Upper

Austria

in the Alpine

Foreland.

Its substratum

is formed

cover. This autochthonous

complex

erogenic

phase during

nappes.

to subside Early

during

the Middle

Jurassic,

and by Late

Cretaceous

wrench

deformations,

related

by a major erosional

At the transition

basin inversion.

sedimentary

the Alpine

platform.

phase. During

in the area, whereby from the Cretaceous

This deformation

the Late Cretaceous.

to 750

the elastic influx from the Bohemian to the Tertiary,

phase may be related

dextral

to the collision

transpres-

of the North

system. the Palaeocene

and Early Eocene the area subsided

again and became

part of

foredeep.

Introduction The

of the Alpine foreland

Intra-Plate

is part of the Alpine foredeep.

started

shales and elastics accumulated

with the Alpine

an erosional

beneath

and Salzburg

the Late Senonian.

induced

and Salzburg

distance

by an extensive

marine

during

sional deformation European

evolution

Compressional

Massif and its Mesozoic

but unquantifiable

in northwestern

to 1000 m of shallow

Austria

of the Bohemian

time it was covered

rifting activity

and Early Tertiary

(Editor),

137: 61-76. Molasse

by the crystalline

L., 1987. Mesozoic

In: P.A. Ziegler

“ Molasse

margin is formed by the outcropping basement of the Bohemian Massif while its southern margin corresponds to the Alpine thrust front. In this

Zone”

Salzburg

forms

part

Cenozoic

foredeep,

of Upper Austria and of the Alpine-Carpathian

the Molasse

Basin,

which ex-

basin

the thickness

of the Cenozoic

from

a few meters

along

its northern

series ranges margin

to

tends from France through Switzerland, Germany and Austria to Czechoslovakia. In Upper Austria and Salzburg, this basin contains Late Eocene to

over 3000 m along the Alpine deformation front. During the Oligocene and Early Miocene phases of the Alpine orogeny, the southern parts of the

Quaternary

Molasse Basin were overridden and partly scooped out by the advancing Alpine nappe systems.

sediments

conformably

on

which

Mesozoic

were deposited series

overlaying

unthe

crystalline basement of the southern extension of the Bohemian Massif (Kollmann, 1977; Kollmann and Malzer, 1980).

Seismic reflection and well data indicate that the autochthonous foreland basement with its Mesozoic and partial Cenozoic cover extends for a considerable distance under the Alpine nappes (Wessely, 1987). This paper deals mainly with the Mesozoic and

The Cenozoic Basin of Upper Austria and Salzburg has the geometry of an asymmetrical, southdipping, 30-55 km wide trough. Its northern 0040.1951/87/$03.50

cl 1987 Elsevier

Science Publishers

B.V.

A

SEISMIC SECTION

e

FA

GEOLOGICAL CROSS SECTION

....... ........ PALINSPASTIC PROFILE

1130 __B__

-

-

,”

Fig. 1. Situation

^

.-

^

,

,.

map of discussed

-_i?!L__

-

,

j__

wells and sections

. . ...

/

1!

63

Early Tertiary Molasse the

evolution

Basin and its southward

frontal

acquired

Alpine by

nappes.

its

Austria

and Salzburg.

by RAG,

search

for

entirely

hydrocarbons

and Early This

study

on subsurface

data,

of the

possible

under

was repeatedly

on data

GmbH

(RAG)

in

In the concession

Mesozoic

outcropping.

extension

It is based

Rohol-Aufsuchungs

during

not

of the substratum

Upper

Early

appear

to control

Carboniferous Bohemian

is therefore

based

the results

Austria

seismic

into

(Schroder.

Late Palaeozoic setting The Variscan Bohemian Massif

basement complex of dips southward under

the the

but as Alpine

While a number of wells drilled in Upper have reached the top of the crystalline

basement,

only

two

of them

have

encountered

230 m of grey to greenish silts and was terminated Only

and red claystones

major

reaching

indeterminable,

of

the base of this series.

strongly

corroded

the

faulting

The

earliest

Permo-Carboniferous

(Ziegler.

spores

view.

1982). However, by the

series

encountered

by

Austria are fluvial to shalcontaining occasional thin

their thickness

ranges

from zero to 60

These

dark

brown

erous series occurring along the western margin of the Bohemian Massif (Schroder, 1987) and overly-

and sponge

ing the Bohemian

chert nodules

(Vasi-

elastics

have

yielded

Bathonian

to

Bajocian spores (W. Klaus. pers. commun.. 1978) and they are conformably overlain by Callovian glauconitic

in Lower Austria

Mesozoic

wells drilled in Upper low-marine sandstones,

were obtained from these sediments, and these are lithologically comparable to the Permo-Carbonif-

Massif

fracture

series of Upper

m, and their occurrence is restricted to the southern and southeastern part of the area under re-

and

at a final total depth

the

Jurassic basin evolution

coal seams:

continental Late Palaeozoic sediments. The Perwang 1 well (Per 1, Fig. 1) penetrated

3531.50 m without

Other

this hypothesis cannot be substantiated available subsurface data.

Molasse Basin and extends a considerable yet indeterminate distance under the nappes. Austria

within

1987) and along its

may, in fact. also have come

during

phase of wrench

zones

of the Permo-

the Mesozoic

and Salzburg

a Later

fracture

series

1987).

which

Mesozoic

with

Similar

continental

evidence

the

the distribution

zones which transect

from some 300 wells and a dense grid of reflection lines.

zone.

Massif (Malkovsky,

margins

feature,

during

is associated

fracture

series are

structural

reactivated

Tertiary,

Hercynian

areas held

Tertiary

including

and

that this major

micrites and

arenaceous.

tain lumachelles, stromal

which,

carbonates

upward

abundant

and, in the eastern

base,

micrites

belemnites,

and grade with

their

These

ammonites,

spicules

at

are con-

echinoids into bio-

sponges

and

parts of the area.

cek, 1977; Matura, 1980). Over 400 m of probably Late Palaeozoic dark grey, fluvial sandstones, silts

also coral reefs (Fig. 3).

and clays were penetrated (Hohg 1. Fig. 1) near

Jurassic corresponds approximately to a glauconitic limestone bed which is a few metres thick,

border. These Carboniferous

yielded spores

in the Hochburg area the Austrian-Bavarian

an association of Permo(Stephanian-Lower Per-

mian; I. Draxler, pers.commun., 1981). It is, however, uncertain whether these spores are in-situ or were reworked. The area1 distribution

and

thickness

of these

Late Palaeozoic sediments is difficult to determine on the basis of the available well and seismic data. They appear to be limited to the southwestern margin of the Central Swell Zone which forms the southeastern extension of the Landshut-Neuoetting High of Bavaria (Fig. 2). In view of this, it is

The boundary

and correlates

between

the Middle

with a similar

horizon

and

known

Late

from

outcrops on the Franconian Platform of Bavaria (Meyer and Schmidt-Kaler. 1984). The late Jurassic series forms an extensive

carbonate

During the Callovian and Late Bajocian-Bathonian basin margins

platform. Jurassic, the became pro-

gressively overstepped. In the northern and northwestern parts of the area. the Late Jurassic platform carbonates transgress directly over the crystalline basement. In the west, Oxfordian and Kimmeridgian algal and sponge banks, some 200 m thick. are capped

64

65

TIDAL WT,,

FLAT+ LAGOON BRECCIA HORIZONS

CORAL

REEF

OOLITES-GRAINSTONES

SPONGE

ALGAL-

Fig. 3. Distribution

of Jurassic

facies types in the subcrop

by coral reefs. To the east these grade into oolitic grainstone which are interspersed with sponge biostromes

and

coral

reefs,

and

occasionally

lime

collapse lagoonal

muds,

structures and

channelled

limestones

and gravitational

tidal-flat

deposits

Austria

in Upper

and to establish

Late Jurassic

SIOHERM

and Salzburg

the configuration

of this

basin.

Early Cretaceous erosional phase During

breccias,

cement. occur

northeast

SPONGE

by

lagoonal, semi-restricted banks (Fig. 3). The latter are characterised by “bird’s eye” and “black pebble”

of the Molasse

BIOSTROME

These

at strati-

Austria and

the Early Cretaceous

became

uplifted

karstification.

the area of Upper

and subjected

This

was

to erosion

accompanied

by

graphically deeper levels in the east than in the west, indicating a progressive westward shallowing

tectonic activity along NW-SE striking fault systems to the southwest of the Bohemian Massif and

of the basin.

the Central Swell Zone. Subsurface data indicate

that

blocks

uplifted

Purbeckian

(Early Berriasian)

close this depositional ded fine crystalline breccias

and

carbonates,

cycle, consist dolomites,

stromatolites.

of thin-bed-

cherty The

which

limestones,

occurrence

became

differentially

individual

fault

(Figs. 4 and

7). of

For example,

uplift

of the Central

Characea indicates that fresh water conditions were repeatedly established on these extensive tidal

was probably

flats.

Over the crest of this NW-SE

Late Jurassic carbonates are frequently dolomitised and characterised by secondary porosity. Moreover, in most wells, there is evidence for deep

Jurassic series became deeply truncated during the Early Cretaceous. This is evident from the unconformable relationship between Jurassic carbonates and the overlaying Late Cretaceous strata, particu-

karstification and fracturing. The top of the Jurassic and Purbeckian series corresponds to a regional unconformity. Prior to their regional truncation, Jurassic sediments probably attained a maximum thickness of some 750 m in the western parts of the area. Because of their complete erosion towards the Bohemian Massif, it is difficult to assess their depositional limit to the

pre-existing

accompanied

Swell Zone

by the reactivation

(Permo-Carboniferous?)

of

fault systems. trending

structure,

larly along the northern flank of the Central Swell Zone near the Austrian-Bavarian border where the thickness of these carbonates varies between 35 m in Munderfing 1 (Mu I ) and 398 m in Maria Schmolln 1 (MS 1). To judge by the thickness of Jurassic series preserved in areas adjacent to the Central Swell Zone, its Early Cretaceous uplift

61

filled the karst relief of the top Jurassic

must have been of the order of 600 m. At the same time the northeastern area became mark

uplifted

the southwestern the Early

described

margin

In

Cretaceous

by Schrijder

ern margin

Austria,

constrained

Cretaceous

of

these

apis

by the age of the overlying 1, Fig. 1)

sandstones, shales, marly and calcareous which unconformably overlie Jurassic

are overlain

directly Bavarian

Cenomanian

by Late

by Late Eocene

Cretaceous

elastics.

part of the Molasse

is directly

deposits.

and Jurassic series

or

In the adjacent

Basin, Hauterivian-

marls which grade upwards glauconitic marine

trending

belt

Bohemian

the north

Basin.

are preserved

defor-

pulse. with a second pulse during the Aptian. These deformations correlate with rift and wrench tectonic

phases which affected

much of northwest-

ern Europe, and which can be related to crustal extensions in the North Atlantic and NorwegianGreenland Sea areas (Ziegler, 1982, 1987).

In areas to the southwest

of the Central

paralleling carbonates

The bulk of the Cenomanian

The

transgressive

the erotowards

the

series consists

range

Cenomanian

in thickness

overlain

by

of

glauconitic

mudstones Campanian derived Central

storm

Turonian

deposits

clays

in their

under outer-shelf

which

containing upper

parts.

Campanian mudstones conditions.

of the Central

sediwhich In areas

Swell Zone,

these

are overlain by some 300 m of Late shallow-marine sandstones which were

from the Bohemian Massif. Across the Swell Zone these sands shale out and give

way to mudstones. No Maastrichtian been

elastics,

up to 75 m, are conformably

Lower

and Danian

encountered

the Upper

Austrian

in the imbricated Alpine

sediments

in the autochthonous Cretaceous

Basin.

thrustbelt.

Late

have

series of However,

zone along the northern Campanian

margin and

Maastrichtian shallow-marine clays are preserved under the base-Tertiary unconformity. On the Swell

other hand,

in the allochthonous

Zone, the essentially Late Cretaceous sedimentary cycle had already commenced with the accumula-

outcropping in the record is continuous

tion of Apto-Albian

Early Oligocene

marine

NW-SE

storm-dominated, shallow-marine, glauconitic sandstones which were deposited on a broad shelf.

of the Late Cretaceous basin evolution

developed

Massif (Fig. 4).

to the northwest nature and tectonic

and east,

Poorly

accumulated

that the Early Cretaceous

the from

of the Upper

in a narrow

approximately

limit of the Jurassic

into shal-

advanced

the development

Cretaceous sands

Late basal

During

transgressions

and west towards

Austrian beach

sandstones.

bian and younger sediments (Lange 1971; Bachmann et al., 1987). This indicates

of

low-marine

Late Turonian to basal Late ments consist of shallow-marine

mations were probably of a polyphase involved a first Berriasian-Hauterivien

by

consist

These

Barremian marine sands overlie Jurassic strata and are, in turn, unconformably overlain by Aland Paulus,

carbonate

overlain

coal-bearing

sional

yielded Berriasian-Hauterivian microfossils. Elsewhere,

latter

and thus initiated

deformations

1 well (Mlbg

the

the south

strata.

carbonates, Cenomanian strata

timing

wrench

surface,

Cenomanian,

movements

Massif in Bavaria.

the

Only in the Mtihlberg marine sands,

phase correlates

(1987) from the southwest-

transpressional

poorly

that

of the Bohemian

inversion

of the Bohemian

Upper

parently

of the

along the fault systems

Massif (Fig. 5). This deformation with

parts

sands.

To the northeast of this long-standing tectonic lineament, the oldest Cretaceous deposits are locally developed, non-fossiliferous, fluvial, lightgrey to white, often coarse-grained sandstones which sometimes infill the Jurassic karst to depths of 100 m below the Jurassic surface. Where these so-called “Schutzfels Beds”, which are probably of Late Aptian to Albian age, have not totally in-

Helvetic

nappes.

same area, the sedimentary from the Senonian to the

(Lattorfian)

(Fig. 6).

In the easternmost part of the Upper Austrian Cretaceous Basin, Late Cretaceous series were deposited directly on the crystalline basement. Here the sequence begins with fluvial granite-wash, occasionally overlain by marsh deposits. The Late Cenomanian to earliest Turonian transgressive marine sediments consist of inner-shelf storm deposits and outer-shelf mudstones. These are over-

kl)

I

w

IO

I

20 I

3oKM 5,

c L

(b)

L-

-

I

,

I

BASEMENT

I

_

I

*

Mlbg

I

the prc-T’ertiary

FM. _ ~~ ~. ---

FORMATION

-_

I

Hmbg

AUSTRIA

FORMATION

U~~.PUCHKIRCHEN

HALL

CRYSTALLINE

--

INNVIERTEL

BAVARIA

Fig. 5. C;eohgical CKF.~sections A and B through

0

SW

i

_:

I

subcrep of the Molaase

---

Nk

Basin

in Upper

T3T2

Austria.

I

Wel

I

For geographical

Gei

locations

I

Obg I Win 2

see Fig. 1; for colour

Egdg W I

code

NE

see Fig. 2

s sa

i

J- g

3

I~I.-AUST~~IA,SALZ~URG)

SC4LE

y$l -I %

E HELVETK

GEOCHRONOl_OGlCAL

EASTERNMOUSSE 8. EASTERNMOLASSE 8. tM8R’CATED Z0NE K3ALLEURG,U.-BUSTR iA>

(UPPER AUSTRIA1 SWELL MNh

I

EOCENE

PALEOCENE

CONTINENTAL. LACUSTRM SANCISTOM?. CONSLOMERATE

CARBONATES.MAINLYSWALLOW-MARINE

DEEPER-MARS& [email protected]~lflC SAHDSTONE, [email protected]_OME??ATE

EROSIANAL MAT&S

SHALLOW-MARINESHALE

SHALLOW-MA= SANDSTONE,C~C~O~~AT~

a

COAL.

F &i

FOLDING. THRUSTHG HIOHAFGLE BOOTY,

JN~E~~~

DEEPER-MARINE SHALE

Fig. 6. Chronology and lithostratigraphic

lain by ~~~~d~~c

columns of the Molasse Basin and its Mesozoic subcrop in Upper Austria and Salzburg.

Later Turonkin to Senonian elastic fan deposits, which advanced in a southwestern direction from the Bohemian Massif (Wessely et al., 1981; Wessely, 1987). Throughout the Upper Austrian Basin, the top of the Cretaceous correponds to a regional unconformity. Depositional thicknesses of the Late Cretaceous series ranged between 750 and 1000 m. Due to their profound truncation by the base-

Eocene ~~nfo~ty, it is almost abbe to reconstruct the original geometry and outlines of the Upper Austrian Cretaceous Basin. Yet, judging from the thickness and facies development of the Cretaceous strata at their partly fat&-bounded erosional Emit towards the Bohemian h4assf (Fig 5), it must be assumed that the latter was formerly covered to a considerable extent by Late Cretaceous sediments.

71

Latest Cretaceous to Palaeocene basin inversion

1000 m (Figs. that

Figure

2 presents

zoic series the Upper

Austrian

map it is evident affected earliest

a subcrop

unconformity

and Salzburg

that major tectonic

this area in the latest

for

area. From

border

to the

wrench

and NNW-SSE

trending

fault blocks

the Central into evidence

faults. became

to the east, with the result that the

Late Cretaceous

series are generally

Swell Zone, during

basin

inversion,

fracture during

Cretaceous

reactivated.

patterns

the Permophases

which had already

ting

through

uplifted

come became

with erosion

its Cretaceous its remnant

of

For example.

the Early Cretaceous,

and sharply

cally even through

pre-

Early

reactivated down

and

had developed became

trans-

1987) it is likely

of intense

systems

and

suggest

with the southwest

zone (Schroder,

fault

faulting,

geometries

were of a dextral

In analogy

this phase

Carboniferous

At the same time, individual tilted uniformly

Bohemian

which probably

these deformations, the area under conbecame uplifted and transsected by a

system of NW-SE

nature.

pre-existing

deformations

Cretaceous

pressional that during

this

Tertiary.

During sideration

thickest

map of the Meso-

at the base-Eocene

5 and 7). Fault

these deformations

cover

Jurassic

cut-

and

lo-

series into

the basement. This major structural element extends northwestwards into the Landshut-Neuoet-

served in their eastern parts. The structural relief generated by these deformations is in the order of

END OF CRETACEOUS

PRE-CENOMANIAN

END OF JURASSIC

Fig. 7. Palinspastic Eocene.

0

II

CRETACEOUS

CRETACEOUS

reconstruction

ERODED

of the Mesozoic

m

JURASSIC

0

0

JURASSIC ERODED

at the end of the Jurassic.

400.4

the beginning

&

:o

lb

0

of the Cenomanian

and early

Upper

w

N

1130

Fig. 9. Tectonic

map of the haae of Tertia?.

showing Tertiary

faults only and oil dnd gas fields contained

in Eocene s&es

75

tinger

High of Bavaria

wards

under

and continues

the Alpine

fronts.

Salzbach

(Wasserburg)

southwest

from the remnant

sive Cretaceous of Upper

Schwanenstadt

Bad

the

by

Eocene.

Austria

to its exten-

by the development

Ried-

conditions,

Oligocene tensional weight

intraclas-

network

tensional

faults,

Puchkirchen

downbending

as

of a dense

antithetic

faulting

systems (Kittler last phase

formations.

the

foreland

rapidly

This phase crust

and Neumayer,

under

Alpine

1983). During

deformation

some

to in-

Hercynian tensionally

and Laramide reactivated

tectonic instability of the area which preculminated during the Middle to Late

During northward

the Oligocene and Miocene a gradual migration of the axis of the Upper

Upper Austrian Basin during Campanian probably reflects

Palaeocene

in the main

phase

Massif

of basin

Austrian

inversion.

Molasse

inversion (Fig. 7).

accompanied conglomeritic,

recognised

which were shed into this foredeep

Europe.

However,

in

phase became

This was

by the accumulation of thick, often turbidites in the Puchkirchen series.

the area of Upper Austria a distinction between these two phases cannot be made, partly in view

rising Alpine

and Early Miocene

phases

of the lack of a Maastrichtian graphic record.

and Danian

the southern

of the Molasse

Late Eocene and Oligocene Molasse Basin

subsidence

strati-

the sub-

Basin can be observed.

Such a timing is compatible with the subHercynian and Laramide foreland deformations in northwestern

during

this

of the

the Coniacian the gradually

Bohemian

were active

the

nappe

fault

the

which

of

the

from

systems

of syndisplace-

to the flexural

advancing

of foreland

to

in the overlaying

can be related

of

of the

Basin of rapidly

was accompanied

of which die out upwards

Cretaceous

The increasing

This

ments

NNW-SSE

Molasse

subsided

and

Late

is bracketed

Salzburg

thetic

major

record

by the present and

into

tic influx

creasing sumably

Upper

deeper-water

faults (Figs. 2 and 8)

sedimentary

to pre-Late

the

In the area

Braunau,

of these deformations

available

Senonian

Hall

separated

dextral wrench

The timing by

the erosional

and are

trending

Basin

of the formerly

cover to its northeast.

Austria

sub-basins

Cretaceous

the area occupied

southeast-

It separates

fold belt. During parts

basin

from the

the Late Oligocene

of the Alpine

orogeny.

Basin

became

overridden and partly scooped out by the AustroAlpine, Flysch and Helvetic nappes. The Middle of the

and Later Miocene Hall and Innviertel shales acd sandstones were deposited under upward-shallowing conditions

during

the Basin-filling

stage. Late

Rapid erosion of the structural relief induced by the latest Cretaceous to Paleocene inversion

and post-Miocene reactivations of the Upper Austrian Alpine deformation front were of minor

movements left an undulating peneplain onto which the Tethys Sea progressively encroached

importance structuration

during European

the

Eocene.

foreland

Tectonic

loading

crust by the advancing

systems caused the asymmetric subsidence Alpine foredeep, of which the area of Austria formed the northern Late Eocene and Oligocene.

margin

of

little

to the tectonic

the

nappe of the Upper

during

and contributed of the molasse.

the

In Upper Austria and Salzburg the basal Late Eocene series is formed by fluvial and shallowmarine transgressive sandstones. These grade upward into Lithothamnium carbonates. Their lateral equivalents in the southern parts of Salzburg are open-marine Nummulite-bearing limestones and Discocyclina marls (Kollmann and Malzer, 1980; Wagner, 1980). During the latest Eocene and Early Oligocene

Conclusions In the area of Upper Austria and Salzburg. Middle and Late Jurassic series ranging in thickness from 600 to 700 m were deposited on a tectonically quiescent shelf which was open to the south towards the Tethys Sea. Early Cretaceous deformations,

correlating

with

and related to major tectonic activity elsewhere in northwestern Europe. resulted in the partial disruption of the Late Jurassic carbonate shelves. Following a major hiatus that spanned much of the Early Cretaceous, the area under consideration began to subside again during the Cenomanian.

Late

Cretaceous

thickness

shallow-marine

of 750 to 1000 m. Severe

Jurassic

and

Paleocene

Cretaceous

and Early

struction

of

probably

extended

Bohemian Tertiary

the

sediments

Eocene

basin

is probably erogenic

of the North During

related

system

European

which

parts

of the

Austria

Alpine

foredeep,

latest Eocene

and

to the collision

of the

with the southern (Ziegler.

Salzburg

formed

the Molasse

Basin.

to Early Oligocene

phase of the Molasse of the crust under

and Early defor-

the Late Eocene to Miocene,

Upper

the

the recon-

foreland

craton

margin

1987). of the

During

the

rapid subsidence

Basin, flexural downbending the load of the advancing

Alpine nappes induced the development of a dense network of essentially basin-parallel synthetic and antithetic normal faults (Fig. 9). having throws of up to several hundred metres. The resulting structures

contain

important

oil and

Bachmann.

G.H..

gas accumula-

Miiller. M. and Weggen.

of the Molasse physics. Kittler.

Basin

(tiermany.

137 (this volume):

G. and Neumayer

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a Picture

Kollmann,

R., 1983. Austrian

and

Oberijsterreichs

log&her

und

and

during the Laramide reactivated during

inversion phase, the Oligocene

were partly and Early

Miocene phases of the Alpine orogeny. Their vertical throw is usually only in the order of some tens of metres. These young fault planes follow the strike of the original

faults but they sometimes

dip into opposite directions. However, the reactivated of minor tensional

importance faults.

Molasse-Untergrund. Malkovsky,

to the Ohgocene

The authors wish to thank the management of Roh~l-Aufsuchungs GmbH for authorising this publication, and the personnel of RAG’s geological drafting department for their technical assistance.

Molassezone (Editor). Museum.

(this volume): 0..

2.. 87: 150-162. and Tertiary

hasins of the

Tectonophysics,

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Erdiil- und Erdgastrkger 2. Die Konglomerate Erdgas

und Fazies des

Senke im Bayrischen

Massif and their evolution.

der wichtigsten

Charakeristik

der oberosterreichischen

und Sandsteine

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Erdol-

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gemacht-ein Bayerisches

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Fiihrer

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tectonics

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W., 1977. Perm

Geologischen logische Wagner.

van Zobing.

Bundesanstalt

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Charakteristik

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der oberiisterreichischen

des 0bereoz;in.

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Erdol-Erdgas

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96:

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Mesozoic

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137 (this volume):

and

Tertiary

in eastern

Geol. Bundesanst. Ziegler,

P.A., 1982. Geological

Europe. Ziegler,

im ostlichen (Austria),

Elsevier, Amsterdam,

dynamical 389-420.

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130 pp. and encl.

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Wessely. G., Schreiber. OS. and Fuchs. und Mikrostratigraphie der MittelMolasseuntergrundes

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and

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the area of part

References

of

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over considerable

of transpressional

;I

erosion during

prohibits

respective

attain

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series

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