Southern Margin of the Northern Calcareous Alps, Transalp Traverse)

Geol. Paläont. Mitt. Innsbruck, ISSN 0378–6870, Band 26, S. 1–20, 2003

5TH WORKSHOP OF ALPINE GEOLOGICAL STUDIES FIELD TRIP GUIDE E1 LOWER INN VALLEY (SOUTHERN MARGIN OF THE NORTHERN CALCAREOUS ALPS, TRANSALP TRAVERSE)

Hugo Ortner & Volkmar Stingl

With 20 figures

1 Introduction zone. Just recently the Inntal shear zone attracted additional attention in the course of interpretation In the Lower Inn Valley area a nearly complete of the TRANSALP deep seismic line, which crosses stratigraphic record of synorogenic deposits from the the Inn Valley near the western end of the Oligo- Early Cretaceous to the Late Oligocene on top of the cene deposits. A major reflector dips from the Inn Northern Calcareous Alps is present. The synorogenic Valley to the south. Therefore, the Inntal shear zone sediments record changes in environment and tec- previously thought to be a subvertical shear zone tonic regime during a period of intense tectonic ac- seems to be a major south dipping thrust fault. tivity that was characterized by continental collision between the Adriatic microplate (upper plate) and the European (lower) plate during the Eocene (e.g. 2 Stratigraphic framework Frisch, 1979). In the earliest Oligocene the peripheral foreland basin (Molasse basin) formed north of the Oligocene sedimentation in the investigated area Alpine orogen (Steininger et al., 1991) due to loading starts with fan-delta deposits (Lengerergraben Mb.) by the nappes. The Oligocene rocks preserved in the interfingering locally with bituminous marls (Bergpe- Inn Valley area were part of the foreland basin, also terl Mb.), which accumulated in local restricted ba- termed “Inneralpine Molasse” (Fuchs, 1976, 1980). sins. Transgression due to rapid subsidence led to deposition of pelagic calcareous marls (Paisslberg The study area comprises the Lower Inn Valley be- Fm.). The Paisslberg Fm. onlaps the southern basin tween Kramsach and Reit im Winkel in the eastern margin and is there in sedimentary contact with the part of the Tyrol and the southernmost part of Ger- Triassic bedrock. The Werlberg Mb. is a near-shore many (Fig. 1). The Oligocene sediments are preserved equivalent of the calcareous marls of the Paisslberg in a syncline-anticline system over 50 km lateral ex- Fm. In most cases, a few meters of biogen-rich car- tent along the Inntal shear zone, which is a major bonates in various sedimentary settings (beach rock, fault system in the Eastern Alps with approximately rocky coast, reef, …) underlie the Paisslberg Fm. The 40 km offset (Ortner, 1996). In the investigated area, Paisslberg Fm. grades into the Unterangerberg Fm. by the Inntal shear zone separates two nappe units of the increase in terrigenic input. The Unterangerberg the Northern Calcareous Alps, the Inntal nappe/Tirol- Fm. consists of a thick series of turbiditic sand-mud ic unit to the south and the Lechtal nappe/ Bajuvaric couplets in a prodelta setting showing the prograda- unit to the north in the structurally lower position. tion of a fluvial system approaching from the west. The field trip will focus on following two topics: The basin is progressively filled up by clastic sedi- • The sedimentary evolution of the Northern Calcare- ments. The advent of a fluvial system is marked by ous Alps during the Oligocene and the interpreta- the onset of conglomerate deposition, initially in a tion of the depositional environment marine environment (Höllgraben conglomerate), • and the Oligocene and younger deformation in the later under terrestric, fluviatile conditions (Oberan- area associated with slip along the Inntal shear gerberg Fm.).

1 3 Description of stops fills are sometimes extremely rich in foraminifera. 3.1 Brugger Mühle near Wörgl The neptunian dykes and the features in this outcrop 3.1.1 Location record a history of subsidence, uplift and renewed subsidence of the basin margin, characteristic for The location of stop 1 is immediately east of sedimentation in a tectonically active region. Wörgl at the end of the village Brugger Mühle, at a The Oligocene carbonates of this outcrop and the turn of a road branching to Gasteig from the main neptunian dykes seal brittle fault planes observed in road just below a quarry. (Fig. 2; ÖK 121, Bl. Neukir- the Triassic carbonates below, showing dextral chen am Großvenediger, coordinates 47,4981°N/ shearing along WNW-striking fault planes. 12,0972°E).

3.2 Lengerer Graben 3.1.2 Main features to be observed 3.2.1 Location

In the road cut the contact of the carbonates of Stop 2 is situated in the Lengerergraben valley be- the Werlberg Mb. to the underlying Triassic carbo- tween the mountains Pölven in the E and Paisslberg nates (Virgloria limestone) below, and, a few meters in the W. The lithological development can best be to the north, to the calcareous marls of the Paiss- studied in the Schuhreissergraben creek at the west- lberg Fm. above, is exposed. This short section is the ern slope of the Pölven mountain (type section: Fig. 3, type section of the Werlberg Mb. (Ortner & Stingl, in section 1). The outcrops are accessible ca. 1.1km SE press). The lowermost part of the section is built by a of the center of the village Bad Häring (ÖK 90, Blatt breccia made up of partly bored Virgloria limestone Kufstein, coordinates 47,5033°N/ 12,1333°E). clast. The matrix content rapidly increases upsection and is composed of bioclasts with abundant solitary corals. In the upper part of the Oligocene carbonates 3.2.2 Main features to be observed Triassic limestone clasts are rare. The contact to the calcareous marls is a wavy surface, which originally Facies development of the Häring Fm., which in- was overgrown by corals now preserved in a thin cludes the oldest Oligocene sediments in the area - layer of flattened corals on the surface. Karst voids as demonstrated by Stingl & Krois (1991) and Krois filled with calcareous marls prove subaerial exposure (1992) - clearly shows the possibility to separate two of the Oligocene carbonates before rapid resubmer- members. The “Lengerergraben Member” (basal se- gence and onset of deposition of calcareous marls. ries) comprises local coarse clastic wedges, the coal This autochthonous carbonate facies delineates measures and bituminous marls in the hanging wall the southern margin of the basin (Werlberg S of Bad are termed “Bergpeterl Member”. This stop is to study Häring, Bergpeterl quarry, S Kössen, S and E of Reit the coarse clastic deposits of the Lengerergraben im Winkl), or rims isolated horsts surrounding the Mb. (Fig. 5). Three lithofacies associations can be Häring basin (Osterndorf NE of Bad Häring, Kufstein- distinguished: er Wald, Widschwendter Rücken; Fig. 1). It consists of Facies A consists of massive, coarse-grained brec- pale limestones with lithoclasts and biogenics (coral- cias and conglomerates, resting on a rugged erosion- line algae, foraminifera, corals, bryozoans etc.: Ne- al bedrock relief. They show structureless and chaot- belsick et al., 2001). A remarkable feature are isolated ic textures, and consist solely of locally derived peb- rounded boulders of bioeroded limestones originating bles (Lower Triassic sandstones and Middle Triassic from a pebbly or rocky shore. carbonates). The clastics are interpreted as proximal In the vicinity of this outcrop neptunian dykes sediments of a small alluvial fan filling topographic with a polyphase fill are frequently observed. The lows and were transported mainly as cohesive debris oldest fills are flowstones alternating with spring flows with a small amount of fine-grained carbonat- tufas, which are characterized by their reddish color ic matrix. in the field. A second (younger) type of fill is bioclas- Facies B comprises a succession of coarse-grained tic debris, comparable to the Oligocene carbonates to fine-grained stratified conglomerates. In the type observed in this outcrop. The youngest type of fill are locality they show bed thicknesses of up to 0.5 m. calcareous marls, as observed in this outcrop. These Graded beds, cross-bedded sets, imbricated clasts in

2 Geol. Paläont. Mitt. Innsbruck, Band 26, 2003 t bel in ta n u o m

Reit im Winkl n

Tiroler Ache i

Kössen

a C E' E

investigated area

n i

SEMP s uoenplate European

9 a

PGL B TW

Alps e

ISZ

s s

Adriatic plate atr Alps Eastern

IL a

Southern D' l

upper plate units (Austroalpine, Southern Alps)

lower plate units (Helvetic, Penninic) o

M etr Alps Western DUXER KÖPFL

∆ KAISERGEBIRGE

N Kufstein 3 2

PAISSLBERG Inn 5 4 10 km 1 Bad Häring C Wörgl 6 Tectonic symbols dextral/sinistral strike slip fault thrust fault normal fault anticline syncline

7 UNTERANGERBERG 8 9 A' B' B

A OBERANGERBERG 10 Werlberg Mb. (littoral carbonates) Lengerergraben Mb. (sands and conglomerates) Legend Synorogenic deposits Oligocene of the Lower InnOberangerberg Valley Fm. (fluviatile conglomerates) Unterangerberg Fm. (turbiditic sandstones andPaisslberg marls) Fm. (pelagic calcareous marls) Häring Fm, Bergpeterl Mb. (bituminous marls, coal) ––––––––––––––––––––––––––––––––––––––––––––––––––– Oberaudorf beds. (Late Eocene) Gosau Group (Turonian - Middle Eocene) Branderfleck Fm. (Cenomanian) Preorogenic deposits

Geological sketch map of the study area. A-A’, …, E-E’ indicate positions of cross sections (Fig. 17). Inset: position of investigated area in the Alpine chain. ISZ … Inntal shear zone, Kramsach 11 Fig. 1: SEMP … Salzachtal - Ennstal - Mariazell - Puchberg fault, TW...Tauern window, IL … Insubric line, PGL … Pustertal-Gailtal line, numbers with arrows … field trip stops.

Geol. Paläont. Mitt. Innsbruck, Band 26, 2003 3 200m Kleinsöll 200m a 200m b motorway Section Section Angath Voldöpp road Breitenbach Kleinsöll dirt road

stream Brandenberger Inn river Ache Voldöpp section motorway Inn River motorway Kundl Inn river

Kramsach motorway c Angath

Bad Häring Rattenberg

Breitenbach Bruckhäusl Inn river

Wörgl Bad Häring

Kundl motorway d 200m Kramsach 3 motorway exit Wörgl Ost Gratten- bergl 200m 1 quarry 2 Rattenberg N section Julius- schacht Wörgl 2km Bruckhäusl Bergpeterl quarry e

Fig. 2: Geographical sketch map of the study area with position of stops of field trip E1. a) stop 10 (Voldöpp section), b) stop 8 (Höll- graben section), c) stop 7 (section Angath), d) stop 1., e) Location of stops in the Häring area: Häring Fm.: 1–3 … type section of the Lengerergraben Mb. (stop 2, see Fig. 5), Juliusschacht … type section of the Bergpeterl Mb. (stop 4, Bergpeterl quarry … type section of the Paisslberg Fm, stop 5.

the coarse-grained parts and additional flaser bed- least partly subaquatic fan delta body (Stingl & ding and horizontal lamination in the finer-grained Krois, 1991). The overall lithologic development parts point to sedimentation from density-modified points to a shallow water, near-shore environment. grain flows or as stream flow deposits in a channel The increase of total thickness and the increasing network of fluvial origin. content of facies C towards the N indicate basin Facies C (fine- to medium-grained carbonate sand- deepening towards the N or NW. stones and calcareous marls) shows horizontal lami- The Lengerergraben Mb. reflects a sedimentary nation with graded bedding and rare ripple bedding. evolution from subaerial alluvial fan deposits The sandstones are organized into coarsening- and through fan delta conglomerates to carbonate sand- thickening-upward sequences. The lower parts are stones of the prodelta area in shallow water at the fine-grained, laminated, and show a higher bitumi- mouth of a small fluvial system originating from the nous content (with pyrite concretions). The upper S. All occurrences of the Lengerergraben Mb. (type parts reach bed thicknesses of up to 5 cm and are less locality and some occurrences northeast of the Kai- bituminous. Shell fragments and small plant remains sergebirge mountain chain near Schwendt) are char- are rare. The sandstones may be interpreted as turbi- acterized by a solely locally derived clast spectrum of dite-like sediments deposited in shallow water. mainly Middle Triassic carbonates, which have been Intensive interfingering of facies B and C and supplied from a southern source. The vertical trend some textural evidences for shear-strength lowering of deepening is in contrast with models of fan delta in the conglomerates due to water entrainment in a evolution, which predict vertical shallowing and up- standing water body allow the recognition of an at ward coarsening due to progradation of the fan into

4 Geol. Paläont. Mitt. Innsbruck, Band 26, 2003

a a a a a Inn Valley a aa Molasse Basin a a a a a a a aa a a a a a a aa a a aaa a W E Wa a a a E aaaa a aaaa a a aa a Chattian sands a a a a aa a a a aa a ? ? ? a a aaaa a a a a a a a a aa aaaa aaaa a a a a Lowera Freshwater a beds a a Molassea a a a a a aa a a a

Oberangerberg Fm. Chattian a a a a aaa Chattian Puchkirchen a a a a a a

aa a a Bausteina a beds a a aaaa a a a a a a a a a a a aaa a a a a a ? a a aaaa a a a Rupelian marls Unterangerberg Fm. aa a a a a "Bändermergel" NW Paisslberg Fm. SE "Heller Mergelkalk" Werlberg Mb. Rupelian Rupelian Lengere rgr. Häring Fm. Mb. Fish Shale Mb. Alpine basal thrust Bergpeterl Mb. Lengerergr.

? ? Lower Marine Molasse Hiatus Katzenloch Stockletten Schichten Late Oberaudorf beds Late Eocene Eocene

Middle Middle Eocene Gosau Group (NCA) Eocene European Helvetic margin

Fig. 3: left side: Lithostratigraphy of the Oligocene in the Inn Valley (modified from Ortner, 1996); right side: Facies development of the Oligocene of the German Molasse Basin (modified from Bachmann & Müller, 1991). the basin. This means, that subsidence was faster locally rich in plant fossils, and most of the well pre- than progradation of the fan delta. served plant fossils (von Ettingshausen, 1853) were found in this unit. Upsection, the carbonate sand-

3.3 Western end of Kalkbruch 3.3.1 Location Paisslberg Fm.

The outcrop is located at the western end of the 4 Kalkbruch south of Häring (ÖK 90, Blatt Kufstein, co- calcareous marls ordinates 47,5083°N/12,1306°E).

3 3.3.2 Introduction reddish calcareous marls (base of Paisslberg Fm.)

The “Bergpeterl Member” (Facies D in Stingl & Werlberg Mb. Krois, 1991) comprises the well known coal measures 2 karst voids filled by calcareous marls and laminated bituminous marls („Häringer Kohle“ (Paisslberg Fm.) and “Bitumenmergel”; Fig. 4). The main distribution carbonate sandstones (debris flows) area is restricted to the Häring area and the Duxer Köpfl near Kufstein (Fig. 1). 1 breccia with bored The sediments of the Bergpeterl Mb. overlie brec- clasts cias of the Lengerergraben Mb. or the Triassic bed- bored Triassic rocks at base of Werlberg Mb. rock. The succession starts with a thick (1–10 m) faulted Triassic coal measure. Above the coal, a series of regularly bedrock 0 bedded bituminous carbonate sandstones rich in bi- Fig. 4: sec tion of the Werl berg Mb. at stop 1. Above: Orien ta tion valve debris, bryozoans and other biogenic detritus of nep tu nian dykes, sealed faults (open sym bols) and faults sea- follows. The bedding planes of these sandstones are led by nep tu nian dykes (black sym bols).

Geol. Paläont. Mitt. Innsbruck, Band 26, 2003 5 Paisslberg Fm.

calcareous marls

mud-chip breccia

laminated bituminous marls

20 Cataclasite Cataclasite bituminous carbonate

coal Bergpeterl Mb. Häring Fm.

10 bituminous carbonate-sandstones with bivalve debris, bryozoans Lower Triassic

Fig. 5: Type sec tion (1) of the Len ge rer graben Mb. in the Schuh- reißergraben val ley (stop 2). Sec tions 2 (Lenge rer graben val ley) and 3 (“Burg”) il lus trate the lat er al fa cies chang es in trans port di rec tion. A, B, C refer to the fa cies asso cia tions of STINGL & KROIS (1991). coal

0 stones start to al ter nate with thin ly lam i nat ed bitu - Fig. 6: Type sec tion of the Berg pe terl Mb. in the Ju liuss chacht in the Berg pe terl quar ry at stop 4. mi nous marls, and the car bonate sand stones disap - pear. The very top of the Berg pe terl Mb. is marked by a coarse-grained fos si lif er ous layer (up to 20 cm in 3.4 Around the Ju lius chacht thick ness), with re worked intra clasts, rare Tri as sic in the Berg pe terl quar ry car bo nates with bor ings, and small mud chips, 3.4.1 Lo ca tion (Heißel, 1956; Stingl & Krois, 1991; Krois, 1992). The type lo cal ity and type sec tion (Fig. 2) of the Berg pe terl Mb. of the Häring Fm. (see Fig. 3) is sit - 3.3.3 Main fea tures to be ob served u at ed in the NE cor ner of the Bergpe terl quar ry at the north ern side of the Paiss lberg moun tain (ÖK On the south ern side of the mid dle road to the 121, Neu kir chen am Großvenediger, co or dinates quar ry, the bi tu mi nous car bonate sandstones are ex - 47,4983°N/ 12,1233°E), in and near the so called posed. Plant fos sils are abun dant. Between the lower “Ju liuss chacht”. and the mid dle road, boul ders of bedrock (Wetter - stein lime stone) are sur round ed by a ma trix of bi tu - mi nous marls. This brec cia is inter preted as a scarp 3.4.2 Main fea tures to be ob served brec cia, which formed along a fault in side the basin. In map view, these scarp brec cias are arranged in The north east ern part of the Berg pe terl quar ry W(NW)-E(SE)-di rec tion. To geth er with the ev i dence pro vides good ex po sures of the Berg pe terl Mem ber of the sealed dex tral faults (see sec tion 4.1) we of the Häring Fm. Thin ly lam i nated bi tu minous marls inter prete this as ev i dence for active dex tral shear - al ter nat ing with equal ly bi tumi nous car bo nate sand - ing be fore dep o si tion of the cal care ous marls (Fig. 7). stones are present. Slump ing is com mon.

6 Geol. Paläont. Mitt. Innsbruck, Band 26, 2003

Paiss lberg Fm. also in lime Paiss also coarse brec Fm. cludes stone lberg - high nat shows one con upper clay the er ic, The tent. car more is part bo lower The 1999). Löffler, Ol (NP22, - Early i of go age m cene 200 about thick of ness green lime marly and marls ish over an with stones all 3.5.1 Mainfea tures to beob served 3.5 Cen tral part of Berg pe terl quar ry are sealed by Ol i go sim cene rocks. where out i 3.1, in crop tion lar orient faults ly ed con in ob is the This to (Fig.1). trast faults ser tral va - young by cut WNW-strik are er faults dex these ing - view, map In ver fold 8). with to (Fig. ti ing axes cal shear sin faults, steep Between ing. is shear tral com led ing pres sin com strong dur sion is po ing al tral nent faults. Fold ENE-strik sin seing par of ing a is allelries to the fault planes pointsto a by tral cut are above Geol. Paläont. Mitt. Innsbruck Paläont.Mitt. Geol. in mapview sin is tral faults off set dex tral faults. con in seen nec Ol with tion i go out the in Faults 8: Fig. sin cene Berg crop is pe shear tral terl Tilt Dex 7). stop also 4. (see area the & in ing 3 stops bruch, nor sin and ed tral pre faults mal is fold date shear tral Ol of ing post ing i fold dates go and ing, pos can and rocks cene be sibly

predating postdating PaissThe con Fm. lberg main sists to grey dark of ly bi cal The the tu ca marls and mi reuos marls nous

folding folding

faults inoutcropBerpeterlbruch

ss , Band 26, 2003 26, Band ,

in theJuliusschacht

tilted conjugate

normal faults

lberg Fm.(Werl berg Mem ber, see stop 3.1). sep ar map a a mem of able with Paiss car tion ber the dis in - the al bo these tri wide The lows nates of bu (2001). Ne al. tion and bel et (1951) sick Heißel by au toch thon shal ous car water low kalk bo brec men nates Ne cie”; tioned bel 2001;1996,al., et sick and 9) Fig. con and cias glom er for (the ates “Lith mer o tham nien - ed com pres sion. com set data pat in b) and a) with ible plane brit di fault c) Paiss tle cat Fm., the lberg Werl of di NNW-SSE ing Mb.the rect berg - WerlWNW-trend from b) by dex Mb., sealed ing berg faults tral de flow and bris ien by stones nep filled ta of tu dykes tion nian half-gra formed re small shaped ben strict ba ed Or a) Inset: sins. - Häring Fm. WNW-trend ing dex tral faults dis sect ed the area and di Block 7: Fig. a Inn the of gram dur area tal dep ing o si the of tion abc bedding rotated normal faults: to horizontal dykes of Neptunian Orientation a a

a aaa Mb. by Werlberg Faults sealed a a a aaa a

a aa a

a aaa aaaaa a a a aa parallel tofaults folds withaxes between faults aaaa steep axes folds with

Thrust faultoffsetstilted aa

fault surface scarp breccias(Bergp fan delta(Leng littoral conglomerates(Bergp.Mb.) aabituminous ma fa

normal fault aa

rls (BergpeterlMb.) erergraben Mb.) ss a aa

a eterl Mb.) 7

Breccia or erosion a deep marine, no coarse clastic influence Conglomerate deep marine, coarse clastic influence a a a a a ripple bedding a submarinea fan a aaa plant debris a 150 100 km aa aa

bivalves a

a MUNICHa a a aa a Molasse Basin Heller Mergelkalk

a a 1300 500 1000 a a Bändermergel Chiemgau fan 100 Lower LeitzachMarine fan a Molasse Nesselburg fans Alpine thrust front

a Hochgrat fan eastern part of Bergpeterl quarry aa a a a a a Pfänder fan a present day Position of IF INNSBRUCK Northern Calcareous Alps a a ? Paisslberg Fm. ? ? INNSBRUCK IF present day Ötztal Tauern Window Silvretta basement basement nappe DAV nappe

GF Southern Alps PGF

? Werlberg Mb. TF Lessini shelf ? carbonates and marls ? ? ? Fig. 10: Pa leo geo graph i cal sketch of the East ern and South ern Alps dur ing the Mid dle Ru pe lian, at the transi tion from trans gres sive to western part of Bergpeterl quarry

Paisslberg Fm. high stand systems tract in Mo lasse Basin (“Hell er Mergel kalk” = con - densed sec tion). Iso lines in north ern part of Mo lasse basin in di cate Fig. 9: Type sec tion of in crease of thick ness of Ru pe lian depos its to the south. Al pine nap- Werlberg Mb. the Paiss lberg Fm. in the pes are taken back to a pos sible Ru pe lian po si tion fol low ing Freu- Berg pe terl quar ry (with den ber ger & Schwerd (1996). Major ac tive faults at ap prox i mate ly inter ca la tions of car bo n - 33 Ma: IF...Inn tal shear zone (this study), TF...To nale fault, GF...Giu dicate brec cias of the Werl - a rie fault, DAV...De freg gen-An tholz-Vals line, PGF...Puster tal-Gail tal berg Mb., see chap ter fault (Manck te low et al. 1999). Most of the area of the Al pine oro gen 3.2.1.). For lo ca tion see was sub ject to ero sion. Gen er al ly, dur ing the Early Oli gocene the sed - 10m Bergpeterl Fm. Fig. 1. i men tary cover of the cen tral Al pine base ment units was erod ed.

The over all de vel op ment in di cates a transgres sive pro duc tion on intra bas i nal highs and dep osi tion of trend with in the marly sed i ments. As de duced from cal car e ous marls in deep er parts of the basin. The the in creas ing abun dance of plank tic fo rami nif era dep o si tion al area rap id ly sub sided from con ti nen tal (Lühr, 1962; Lin den berg, 1965; Cicha et al., 1971; sur face to ba thyal depth from the Ear li est Ol i go cene Hagn et al., 1981) sed i men tation depth in creas es on wards. The dis tri bu tion of horsts and gra bens is from 50–200 m in the lower part to 200–600 m clear ly a re sult of local tec ton ic move ments, where as (pos sibly up to 1000 m) in the higher part. Löffler the re gion al sub si dence must be a re sult of a more (1999) also in ferred water depths from the lower ne - re gion al pro cess, like the for mation of a fore land rit ic to the upper ba thyal zone from the anal ysis of basin. The pa leo geog ra phy re con struct ed for the mol lusc fau nas. The deep en ing of the sed imen ta tion Early Ru pe lian (Ort ner & Stingl, in press) with a area re sponds to the com bi na tion of sea level rise south ern basin mar gin (Werl berg Mb.) ex posed in the and tec ton ic sub si dence. The inter cala tion of coarse- Inn Val ley, and the basin open to the north is in fa - to fine-grained de bris flows and slump ing ho ri zons vour of the fore land basin inter pre tation. in the marls may re sult from local tec ton ic move - ments (Krois, 1992). 3.6 Ka kir ite Lang kamp fen 3.6.1 Lo ca tion 3.5.2 Sug gest ed points of dis cus sion The out crop is lo cat ed in a old grav el pit be hind Fa cies dif fe ren ti a tion in the basal part of the the mo tor way res tau rant near Lang kamp fen (ÖK 89, Paiss lberg Fm. in di cates con tem pora ne ous car bo nate Blatt An gath, co or di nates 47,4822°N/12,0667°E).

8 Geol. Paläont. Mitt. Innsbruck, Band 26, 2003

3.6.2 Main fea tures to be ob served normal grading inverse grading ripple bedding horizontal bedding The Inn tal fault is di rect ly exposed only in very structureless bed cross bedding few lo ca tions. In this out crop light grey dol o mite low angle cross b. 30 wavy bedding imbrication (Wet ter stein dol o mite) is per va sive ly sheared. In dis- slump load cast tinct shear zones, the dol o mite is crushed to silt- to flute cast 60 bioturbation sand-size par ti cles, and the shear zones are slight ly plant debris concretion

parting lineation ce ment ed. Lo cal ly, clay ey fault gouge is present in coal the shear zones, in di cat ing that the out crop is lo cat- 90 ed at the con tact between Oli go cene rocks and Wet- fine sandstone middle sandstone ter stein dol o mite. Between the shear zones, the coarse sandstone

conglomerate rocks are brok en to cm – to dm- size frag ments. The 20 ka kir ite has a thick ness of at least 100m. 50

3.6.3 Sug gest ed points of discus sion 80

Can off set of the Inn tal fault be es timat ed from the thick ness of ka kir ites in the Inn Valley? The prob - 10 lem is, that the con tri bu tion of thrust fault ing and strike slip fault ing can not be clear ly sep ar at ed. In 40 this out crop, the last in cre ment of shear ing was sin - is tral strike-slip fault ing, but pos sibly ka kirites 70 formed in a thrust re gime. Fig. 11: Sec tion An gath: Type sec tion of the Un teran ger berg Fm. at stop 7. 0m a a a a a a a a a a aa a a a a aa a a upper fan: a channelized a aaaa a a a a aa a sandmid lobes fan: a a a a a aaa a fluviatile system a a a a a a a a a a a a a

) inactive fault (Unterangerberg (Paisslberg Fm,)) Fm.) prodelta aa calcareous marlsWerlbergBergpeterl Mb. Mb.)

a carbonatesa ( bituminousLengerergraben marls ( Mb.

a fana delta ( abc fault surface soft-sediment shear zone in Unterangerberg Fm. and small scale, vergent fold axes within shear zone

hydroplastic slickensides in Unterangerberg Fm.

Fig. 12: Block di a gram of the Inn tal area dur ing depo si tion of the Paiss lberg and Un te ran ger berg For ma tions. Werl berg Mb. rims the south ern mar gin of the basin and iso lat ed horsts inside the basin. Fault blocks between ac tive sin is tral faults show half gra ben geom- e try. From the west, a flu vi a tile system ap proach es, with the Un te ran ger berg Fm. in a pro del ta po si tion. Inset: a) Top SW re verse faults with hy dro plas tic slick en sides in di cating ac tiv ity be fore final lithifi ca tion, b) shear planes in pseu do duc tile shear zone (great cir cles) and small scale fold axes with ver gence of folds indi cating a sin istral shear sense, c) brit tle fault plane data set com pat ible with b) in - di cat ing NNE-SSW com pres sion.

Geol. Paläont. Mitt. Innsbruck, Band 26, 2003 9 a b

c d tectonic shortening slumping

Fig. 13: Def or ma tion al struc tures in the Un te ran ger berg Fm. of the Un te ran ger berg. a) to e) il lus trate pro gres sive def or ma tion by in- creas ing bed-par allel short en ing. a) in cip i ent short en ing leads to „cren u la tion“ of the silt stone-marl-inter face at the base of a silt sone bed. b) cus pate-lo bate struc ture at the base of a sand stone bed. c) inter ac tion of slump ing and tec ton ic short en ing at base of sandstone bed, both over print ing flute casts. d) for ma tion of small scale blind thrusts above ramps, pre serv ing a flat bed top. e) stack ing of sand stone beds. f) shear zones with pen e trative def orma tion.

3.7 Inn prom e nade near An gath 3.7.2 Main fea tures to be ob served 3.7.1 Loca tion The Un te ran ger berg Fm., de velop ing from the The out crop is lo cat ed along the Inn prom e nade Paiss lberg Fm. by an in crease in silic iclas tic de tri tus, west of Angath (ÖK 89, Blatt An gath, co ordi nates con sists of sand stone-marl (or mud stone)-inter bed - 47,5000°N/12,0583°E). dings with some fine-grained con glom er ates, all ar -

10 Geol. Paläont. Mitt. Innsbruck, Band 26, 2003 ranged in fin ing-up ward cy cles. These small-scale fan area, poor ly strat i fied to structure less con glom - cy cles are stacked to fin ing-up ward and thin ninger ates rep re sent sub ma rine de bris flows. The se - up ward large-scale cy cles, reaching thick ness es from quence of the Höllgraben conglom er ate points to a 1 to 20 me ters. The over all trend in cycle stacking tran si tion from the mid-fan area to the upper fan dis plays a coars en ing- and thick en ing-up ward de - and con sists of an inter fin ger ing of chan nel fills, de - vel op ment from base to top of the Un te ran ger berg bris flows, and fine-grained un chan nel ized slope Fm., cul mi nat ing in the sed imen ta tion of the Ob e- sed i ments (Ort ner, 1996). ran ger berg Fm. Bed ding type (grad ed, hor i zon tal and rip ple bed - ding) and sed i men tary struc tures (typ i cal sole marks) 3.8.3 Sug gest ed points of dis cussion point to tur bi dit ic sed i men tation in a small sub marine fan. The large-scale cy cles can be interpret ed as A top o graph ic bar ri er must have formed dur ing chan nel fills or lev ees of su pra fan lobes in the distal dep o si tion of the upper part of the Paiss lberg Fm. to mid-fan area (Krois, 1992; Ort ner, 1996). The en- pre vent ing the de bris pro duced by ero sion of the tire Un te ran ger berg Fm. rep re sents a coars en ing- Alps being di rect ly shed into the Mo lasse basin. This and thicken ing-up ward meg a cy cle, which in di cates gives some in di rect ev i dence of the ex is tence of an the progra da tion of the fan. Trans port di rec tions vary steep fault form ing a top o graph ic bar ri er to the in a broad range, with an av er age trend from NW to north. SE, part ly to NE. The poor ly de vel oped fo ram inif er al fauna shows an in crease of the abun dance of ben thic forms to - 3.9 Brei ten bach wards the top and in di cates a Ru pe lian age (Hagn, 3.9.1 Lo ca tion 1960; Lin den berg, 1965; Hamdi, 1969). The Un te ran ger berg beds are fold ed with WNW- The Brei ten bach out crop is locat ed in a small trend ing axes in dek a met ric folds. West of the prom - creek, where it is crossed by a foot path with a wood - e nade along the Inn river, def or mation al struc tures en brig de (ÖK 120, Blatt Wörgl, co or di nates in the Un te ran ger berg beds in dicate syn sed i men tary 47,5211°N/11,9844°E). top SW thrust ing (Fig. 13, 14).

3.9.2 Main fea tures to be ob served 3.8 Kleinsöll 3.8.1 Loca tion In the Brei ten bach out crop, a thrust plane is exposed, which super im pos es ka kir ites of the Haupt do- The sec tion Kleinsöll is lo cat ed in a creek SW of lo mite Fm. onto Ol i go cene marls of the Un te ran ger - the vil lage of Kleinsöll and along the ad ja cent bank berg Fm. The gen er al ly south-dipping con tact could of the Inn river (ÖK 120, Blatt Wörgl, co or di nates be part of a major thrust of the Greywacke zone and 47,4800°N/11,9867°E). the south er ly ad ja cent units onto the Lech tal nappe of the North ern Cal car e ous Alps, as seen in the TRANS ALP seis mic sec tion (Fig. 16). 3.8.2 Main fea tures to be ob served

The Höllgraben sec tion rep re sents the lower 3.9.3 Sug gest ed points of dis cussion boun dary of the Ob e ran ger berg Fm. To wards the top, the Un te ran ger berg Fm. is dom i nat ed by marly sed i - The North ern Cal car e ous Alps are tra di tional ly men ta tion (Fig. 15). The coarse-grained clas tic se - sub di vid ed into thrusts of dif fer ent age. The out of quence upsec tion con sists of m-thick trough cross- se quence thrusts as seen on the seis mic section (Fig. bed ded con glom er ates with inter ca lat ed marls. The 16) do not fit the tra di tion al thrust ar chi tec ture of clast spec trum is dom i nat ed by Late Cre ta ceous and the North ern Cal car e ous Alps. They cut the Baj u var ic Pa leo gene peb bles (Mous sa vian, 1984). nappe stack; only the con tact between Tirol ic and While cross-bed ded con glom er ates are inter pret - Baj u var ic nappes co in cides with the thrust in the Inn ed as sub ma rine chan nel fills in the mid- to upper Val ley.

Geol. Paläont. Mitt. Innsbruck, Band 26, 2003 11 bedding planes in the fold axes constructed from Unterangerberg area (Rupelian deposits) small scale ramps (great circles, compare fold axis 295/24 Fig. 13d) and orientation of cuspate-lobate structures (black circles, see Fig. 13b) in the Unterangerberg Fm. fold axis 251/3 bedding planes in the fold axes constructed from Oberangerberg area (Chattian deposits) fold axis 249/19 Or ien ta tion of tec ton ic struc tures in the Un te ran ger berg- and Ob e ran ger berg area. ger ran e berg- and Ob ger ran te tures in the Un ic struc ton tion of tec ta ien Or Fig. 14: hydroplastic slickensides in the Unterangerberg Fm. (outcrop depicted in Fig. 13e) faults and folds in Unterangerberg Oberangerberg area

12 Geol. Paläont. Mitt. Innsbruck, Band 26, 2003 3.10 Voldöpp 3.11 Kram sach/Ma ri a tal 3.10.1 Lo ca tion 3.11.1 Lo ca tion

The section Voldöpp lies along a small road from The out crop is lo cat ed at the west ern side of the the north eat sern part of Kramsach to the Ob eran ger- road from Kram sach to As chau near the Ma ri a tal berg (ÖK 120, Blatt Wörgl, co or dinates 47,4533°N/ mon as tery (47,4528°N/11,8633°E). 11,9100°E).

3.11.2 Main fea tures to be ob served 3.10.2 Main fea tures to be ob served Con glom er ates of the Ob e ranger berg Fm. are in Sec tion Voldöpp is des ig nat ed as type sec tion for di rect con tact to Haupt do lo mite Fm. Therefore the the Ob e ran ger berg Fm. (Fig. 18). The dom i nat ing Ob e ran ger berg Fm. seals part of the to pogra phy lith o fa cies types present are com po nent sup port ed creat ed dur ing Ol i go cene shear ing along the Inn tal coarse con glom er ate beds with or with out nor mal fault. grad ing with im bri cat ed compo nents. Oc ca sion al ly pla nar cross bed ding is ob served in the topmost por- tion of con glom ar ate beds. Hor i zon tal lam i nated sand- to silt stones, oc ca sion al ly ripple cross bed ding 30 60 90 inter rupt the con glom er ate sed imen tation. The coarse con glom er ates of a slight ly sin u ous, braided river system (Krois & Stingl, 1991) indi cate per en ni al high en er gy run off. The main fa cies ele ments are chan nel fills with lon gi tu dinal bars and large-scale rip ples. The scar city of over bank fines (lev ees, cre- vasse splays and flood plain depos its, mud-filled Oberangerberg Fm. aban doned chan nels) sup ports the model of a high ly 20 50 80 mo bile chan nel system. Trans port di rec tions de rived from im bri cate clasts and cross-bed ding are oriented from NW-W to SE-E. Bi o strat i graph ic dat ing of the Obe ran ger berg

Fm. is not un equiv ocal. Plant fos sils (Cin nam o - Höllgraben conglomerate mum cf. scheuch ze ri and C. cf. spec ta bila Heer) in di cate an Ol i go cene to Mi o cene age (Hamdi, 1969). Only the se quence strat i graph ic interpre - 10 40 70 ta tion of the suc ces sion pro vides some evi dence for the lower boun dary of the Ob eran gerberg Fm. to be near the base of the Chat tian. As the first peb bles from rocks of the Ber ni na, Err, and Ju li er nappes in the Upper En ga dine Val ley ap pear in the Aqui ta nian of the Mo lasse zone, and are lack - Unterangerberg Fm. ing in the Ob e ran ger berg Fm., the ero sional upper boun dary of the Inn Val ley Ter tiary must still be 0m 30m 60m normal grading slump with in the Ol i go cene. Mod el ling of the ther mal inverse grading load cast ripple bedding flute cast fine sandstone his to ry of the Ol i go cene based on vitri nite re flec - horizontal bedding bioturbation middle sandstone structureless bed plant debris coarse sandstone cross bedding concretion conglomerate tance data in the Häring - Ob e ran ger berg area re - low angle cross bedding parting lineation wavy bedding coal sult ed in the pre dic tion of a total thick ness of imbrication 1300m of erod ed sed i ment (Ort ner & Sach sen hof - er, 1996). More than 1000m thick ness of the Obe - Fig. 15: Sec tion Kleinsöll: Ref er ence section for the upper boun- ran ger berg Fm. is pre served north of the Kai ser - dary of the Un te ran ger berg Fm., and the base of the Ob e ran ger- ge birge (Fig. 17, D–D’). berg Fm. (Höllgraben con glom er ate) at stop 8.

Geol. Paläont. Mitt. Innsbruck, Band 26, 2003 13 10000m 0m 20000m 30000m Fig. 16: North ern part of the TRANS ALP seis mic sec tion from the south ern Mo lasse Basin to south of the Inn Val ley. The most prom i nent re flec tors in the North ern Cal car e ous Alps are south- are Alps ous e car Cal ern North the in tors flec re nent i prom most The ley. Val Inn the of south to Basin lasse Mo ern south the from tion sec mic seis ALP TRANS the of part ern North 16: Fig. ly straight thrusts. tiv a ping, rel dip

14 Geol. Paläont. Mitt. Innsbruck, Band 26, 2003

C a C' 3.11.3 Sug gest ed points NW Quaternary Hauptdolomit Fm. SE Unterangerberg Fm. Raibl Fm.

1000 Paisslberg Fm. Wetterstein Fm. of dis cus sion Bergpeterl Mb. Buntsandstein Fm. Tiefbau- schacht a a a a 800 Bad Häring Neuschacht Well Niedernholz Well Oberlangkampfena a Kirchbichl aaa a

600 a a a a aErbstollen The distri bu tion of Ol i go cene 400 a a a a 200 coarse con glom er ates along the ? 0 ? ?

-200 Inn tal fault in di cates the presence 0 1000 ? 4000 5000 6000 200 3000 B 0 B'

of a flu vi al system guid ed by an N S

Well W Wörgl Well Well B1 Well oro gen-par allel, sub ver ti cal fault 600 B16 Well a a Fig. 17: Cross sec tions of the area. Geol o gy in

(Fig. 18). Au gen stein de pos its, only 400 200 the Erb stol len gal lery taken from Fuchs (1950). 0 1000 2000 present south of the Inn tal fault, A A' Depth to base ment NW and SE of Kirch bichl N S are inter pret ed to be re de posit ed 1600 after re sults from re frac tion seis mics by Pfeif fer grav els be long ing to old tribu tar ies 1400 (1950). For po si tion of cross sec tions see Fig. 1. 1200 Sec tion D-D’ re drawn from Ort ner (1996). In- of a paleo-Inn flu vi al system. Uplift 1000 a for ma tion from wells Tief boh rung I, BVIi and

800 Grub of the Au gen stein pene-plain a a 600 BIIi in sec tion E-E’ taken from Schulz & Fuchs might be a re sult of young er re - 400 (1991). 200 newed ac tiv ity of the (thick 0 1000 2000 skinned) thrust in the Inn Val ley. 1700 D D' N S

1500 a Oberangerberg Fm. Hauptdolomite Fm. a a a Paisslberg Fm. Muschelkalka Gr. 1300 Lengerergraben Mb.

a a aaa a a a 1100 a a a aaa a 4 Ad di tion al in for ma tion a a a a 900 a a a a 4.1 Sub si dence curves a a a a a a 700 a a a a

500 a a aaaa a a a a ? 300 aa The ther mal and sub si dence his - a a ? a a to ry of the Ol i go cene in the Lower 0 1000 2000 3000 1000 E E' a a a a a Inn Val ley was sim u lat ed by Ort ner N a a S 800 a Tiefbohrung I BIIi aaaa a a aa a (projected)

a a a BVIia & Sach sen hof er (1996). Sub sidence 600 a a aaaa a a a a a a a a curves in ac cor dance with the ob - 400 aa a a a a a a served co al ifi ca tion in di cate rapid or 200 aaaa a a a a a a a 0 Quaternarya Ammergau & Schrambach beds a a a a aaa a ac cel ler at ing sub si dence through out a Oberangerberg Fm. Ruhpolding beds -200 Paisslberg Fm. Klaus beds the Ol igo cene and Early Mi o cene Oberaudorf beds Scheibelberg beds -400 Gosau Group Kössen beds ? Wetterstein limestone (Aqui ta nian) com bined with a low 0 1000 2000 3000 4000 5000 heat flow (70 mW/m2; Fig. 20a). Sub se quent ly, sub si dence was slow until the Mid dle sive cy cles were main ly de pen dent on the interplay Mi o cene, when up lift and ero sion start ed be cause of between ac com o da tion space and sed i ment input thrust ing and shear ing along the Inntal shear zone. into the basin, both strong ly af fected by tec ton ics. The Mo lasse basin also rap id ly sub sid ed dur ing Ol i - Ac com o da tion space was creat ed by the flex u ral go cene and Early Mi o cene and slow ly sub sided af - event after col li sion of the Eu ro pe an and Adri at ic ter wards. Up lift in the Mo lasse basin start ed much plates in Eo cene times (e.g. Home wood et al., 1986), later in the Late Mi o cene (Fig. 20b; Zwei gel et al., as re flect ed by the sub si dence curve. Sedi ment input 1998; Jacob et al., 1982; Home wood et al., 1986). was main ly con trolled by ero sion rates and thus by Re mark ably the sub si dence curves for both the the tec ton ic his to ry of internal parts of the oro gen. Mo lasse basin and the Ol i go cene of the Lower Inn Pre vi ous stud ies of the tec ton ic devel op ment of Val ley do display uni form or even in creas ing sub si - the Ol i go cene in the Lower Inn Val ley put for ward a dence through out the Ol i go cene. Sub sidence did not pull apart or i gin of the basin (Ort ner, 1996; Ort ner & de crease, when the basin stopped be com ing deep er, Sach sen hof er, 1996). How ever, the open ma rine fa - but start ed to fill, and the onset of lim noflu vi a tile cies of the Paiss lberg Fm. is not in ac cor dance with a con di tions near the Ru pe lian - Chat tian boundary local basin, and the over all sim ilar ities in sub si dence was not re lat ed to up lift. and se quence de vel op ment between the Mo lasse There fore, the strat i graph ic de vel op ment in the basin and the Ol i go cene of the Lower Inn Val ley Mo lasse basin is gen er al ly con trolled by eus tasy rath er calls for a ge net ic link between the two dep o - (Zwei gel et al. 1998), but the transgres sive-re gres - si tion al areas.

Geol. Paläont. Mitt. Innsbruck, Band 26, 2003 15 4.2.1 Shear ing plant debris bioturbation Syn sed i men tary fault ing can be re con struct ed ripple bedding through out the Ol i go cene. The faults below are planar cross bedding thought to shape local to pog ra phy in the area, but they can not ac count for the over all sub si dence of the basin.

4.2.1.1 Early Ru pe lian (D1)

Scarp brec cias in the Berg pe terl Mb. of the Häring Fm. are bound to WNW-ESE trending faults. Nep tu - nian dykes in Mes o zo ic rocks underly ing Ol igo cene sed i ments, which are filled by re depos it ed car bonates (Werl berg Mb.) and calcar e ous marls (Paiss- lberg Fm.) trend in the same di rec tion (Figs. 4, 7a). In a few lo ca tions fault planes are sealed by carbo nates of the Werl berg Mb. (Figs. 4,7b). Anal y sis of the sealed fault planes and com par able planes in di cates NW-SE di rect ed short en ing ac como dat ed by domi - nant WNW-trend ing dex tral strike-slip faults and con ju gat ed N-S trend ing sin is tral strike-slip faults (Fig. 7c). Ver ti cal off set across dex tral faults is in the range of a few tens of me ters. Along the faults, el on gate de pres sions with half gra ben geom e try formed, filled by bi tu mi nous marls (e.g. Dux area; Fig. 2, 7).

4.2.1.2 Late Ru pe lian (D2)

The Un te ran ger berg Fm. was lo cally de formed prior to lith ifi ca tion. This led to forma tion of pseu - do duc tile struc tures in the sed i ments (Fig. 13, 14). Fig. 18: Type sec tion The Un te ran ger berg is cut by sev er al shear zones

10m Voldöpp of the Ob e ran - ger berg Fm. at stop 10. with top SW dis place ment. In the han ging wall of the shear zones deca met ric, SW-verg ing folds de - vel oped. In an early stage of fold ing, layer par allel 4.2 Basin for ma tion and def or ma tion short en ing led to the for ma tion of cuspate-lo bate folds at the inter face of sand stone and marl layers Basin for ma tion and def or mation were in flu enced with con trast ing com pe tence (Figs. 13b, 14). In - by pro cess es at two scales: 1) Ev olu tion of the Al pine creas ing short en ing formed sets of con ju gate ramp or o gen ic wedge and its fore land basin (Molasse faults in sand stone beds (Figs. 13d, 14), some times basin) and 2) shear ing along the Inn tal fault. In the with hy dro plas tic slick en sides (Fig. 13e, 14), that fol low ing par a graphs, local defor mation is short ly often dis ap pear with in the bed. Near a major branch dis cussed on the base of anal y sis of brit tle fault of the Inn tal shear zone, a ver ti cal E-W trend ing planes and dep o si tion al geom etries. A de tailed sur - shear zone with sin is tral sense of shear was ob - vey of brit tle def or ma tion in the inves ti gated area served. All these fea tures of late Ru pe lian def or ma - will be pub lished else where (compare Ortner, 1996; tion can be in te grat ed into a model of over all Ort ner & Sach sen hof er, 1996). oblique thrust ing along ENE-trend ing faults. Along

16 Geol. Paläont. Mitt. Innsbruck, Band 26, 2003

Fig. 19: Pa leo geo graph i cal sketch of erosion the East ern and South ern Alps dur ing a fluviatilea deep marine a a a aa a the Chat tian. Al pine thrust front drawn a a submarinea fan aa aaa a aaa at present day po si tion. Per i ad ri atic a A volcanism: A = Adamello, B = Bergell a a a a a a aa a aa vol can ics were erod ed, as doc u mented a R = Rensen, Ri = Rieserferner, Ba = Bacher, E = Eisenkappel a a a a a a aaaaa a a a by peb bles in Ob e ran ger berg Fm. and a Glassand a a a a a a a a aa MUNICH a a a a aaa a a Lower Marinea Molassea aa a aaaa a a a a Mo lasse basin. The west ern part of the a a a a a a a a a aa a aaaaa aa aa Lower Freshwater Molasse a a aa a a a a aaaa a a aa Mo lasse basin was filled, the east ern a aa a aaa a aa a aa aaa a aaaa a a a a a a a aaa a a a a a a a part re mained a deep ma rine basin. a aa Puchkirchen beds aaa aa a a a a a a a aaaa Nesselburg fans a Alpine thrust front aaa Hochgrat fan a a a a aa a a a The Au gen stein Fm. was de pos it ed east a a a a a aaa a a a aa a aa a a a a of the Inn tal fault on top of the North - a IF aaaa a a a a a a a aaaaa a aaa a aaa a aa a ern Cal car e ous Alps (Frisch et al. a Northerna AugensteinCalcareous beds Alps a a a a aaa a a a a a a a aaaa a a a aa a a a 1998). + in di cates up lift. Major faults a a aa a aa a a a a a aaa a INNSBRUCK a a Oberangerberg Fm. ac tive faults at ap prox i mate ly 25 Ma: IF aaa a aaaa a a a a presenta a day IF … Inn tal shear zone (this study), EL ? Ötztal Tauern Window Silvretta basement basement nappe Ri … En ga dine line (Schmid & Froit z heim, R nappe 1993), TF … To nale fault, GF … Giu dic- Southern+ Alps GF PGF a rie fault, PGF … Pus ter tal-Gail tal fault EL Tertiary of Monte Parei ? Ba (Schmid et al., 1989). South ern Alps E B ? ? drawn fol low ing Lu cia ni (1989) and TF A+ + + Lessini shelf 100 km Keim & Stingl (2000). carbonates and marls

branch es of the Inn tal shear zone, strike-slip faults pog ra phy. Dur ing sed i men ta tion of the lower part of con nect ed to the thrusts show sin is tral dis place- the Paiss lberg Fm., the basin mar gin, or up lift ed por - ments. tions of fault blocks with (half-) gra ben geome try On a larg er scale, the Paiss lberg and Unte ran ger- car ried car bo nate build ups (Werl berg Mb.). Debris berg Forma tions suc ces sively bur ied the evolv ing to- flows trans port ed ma te ri al from these buildups into the basin (al loch thon ous car bonates of the Werl - berg Mb.). Con tin ued shear ing increased the half- Oligocene Miocene Rupelian Egerian Eggen. OK Baden S Pann. Po. PlioQ a) 0 PB. F. gra ben re lief, re sult ing in large thickness es of the LG. M. BP. M. Paiss lberg Fm. ad ja cent to the faults, as doc u ment - OA. F. (eroded) ed by the out crops in the Häring mine and the well OA. F.

1 UA. F. Nie dern holz (Fig. 17, cross sec tion C-C’). Late r on, D epth (km) the local to pog ra phy was com pletely cov ered by the Fig. 20: a) Sub si dence curve Paiss lberg and Un te ran ger berg Fms. for the Ol i go cene in the 35 30 25 20 15 10 5 Ma. 2 Lower Inn Val ley re drawn b) 0 from Ort ner & Sach sen hof er (1996).Time scale after Stei- 4.2.1.3 Chat tian ning er et al. (1988/89) for Ol - i go cene sed i ments and Stei - Dur ing the Chat tian, the river system de pos it ing 1 ning er et al. (1990) for Mi o- the Ob e ran ger berg Fm. transport ed de bris from the cene sed i ments. b) Sub si - dence curve for a well SSE of west ern part of the cen tral Alps to the Chiem gau fan Mu nich in the Mo lasse basin west of Salz burg at the south ern mar gin of the Mo- 2 sim pli fied from Zwei gel et al. lasse basin, guid ed by the Inn tal fault (Fig. 19). Con -

D epth (km) (1998). Ab so lute ages taken Sequence2 glom er ates of the Au gen stein beds, which are inter - Chattian sands from Har land et al. (1990) Baustein beds pret ed to rep re sent re de pos it ed re mains of the Ob e - and Stei ning er et al. (1985). 3 Minor dif fer enc es between ran ger berg Fm. (Ort ner & Sach sen hofer, 1996) are the curves due to dif fer enc es only found south of the Inn tal shear zone, in di cating Sequence1 in time scales. Ab bre vi a tions: Rupelian marls that the North ern Cal car e ous Alps north of the shear “Bändermergel” BP. M. = Berg pe terl Mb., LG. 4 “Heller Mergelkalk” zone formed a top o graph ic bar ri er con strain ing the “Fischschiefer” M. = Len ge rer gra ben Mb., PB. Priabonian F. = Paiss lberg Fm., UA. F. = course of the paleo-Inn River (Fig. 19). There fore, Un te ran ger berg Fm., OA. F. = con tin ued (?sin is tral) ac tiv ity of the Inntal fault zone 5 35 30 25 20 15 10 5 Ma Ob e ran ger berg Fm. through out the Chat tian is prob able.

Geol. Paläont. Mitt. Innsbruck, Band 26, 2003 17 4.2.1.4 Post-Ol i go cene def or ma tions ment of the Al pine wedge to iso stat ic uplift in its cen tral parts. The main ef fect of post-Ol i go cene def or ma tion In sum mary, Ol i go cene and Mi o cene brit tle def or - was folding of the Pa leo gene depos its with WSW- ma tion in the Inn tal area is the re sult of the inter- trend ing axes (D3). Large scale folds sever al km in play of local and far-field stress es con trolled by dou - wave length formed (e.g. cross sec tion E - E’, Fig. 17). ble in den ta tion of Adri at ic crust into the Alps. Oli go - Prob ably this def or ma tion was ac com pa nied by re - cene in den ta tion in the Western Alps led to In sub ric newed thrust ing on the Inn tal thrust. The folds were back thrust ing and crus tal thick en ing, followed by cut by a set of ENE-strik ing, sinis tral transpres sive oro gen-par allel ex ten sion. Mi ocene inden ta tion in faults (D4) that re ac ti vate faults formed dur ing D2. the East ern Alps again led to thick en ing and sub se - In a late stage of this def or ma tional event, N-S- quent ly oro gen-par allel ex ten sion east of the Bren - strik ing oblique nor mal faults de vel oped, which are ner me rid ian. Pe ri ods of crus tal thicken ing led to kin - inter pret ed to rep re sent anti thetic rie dels to the Inn - e mat ic coupling across the Per i adri at ic line, so that tal fault zone. Dex tral nor mal offset across these the NNW-SSE orient ed far-field stress is observed in most ly east-dip ping faults led to west-plunging fold the Alps (D1, D3). Dur ing oro gen-par allel ex ten sion, axes in Ol i go cene de pos its. Nor mal faults striking local stress fields con trolled by large orogen-par allel slight ly oblique to the Inn Val ley overprint ed Quater - faults de lim it ing ex trud ing blocks are found in the nary rocks in the area west of Kufstein (D5). They Alps (D2, D4). were re sponsible for Qua ter nary gra ben for ma tion in the Inn Val ley. Ref er enc es

4.2.2 Inter pre ta tion Bach mann, G. & Müller, M. (1991): Sed i men tary and struc tu ral ev o lu tion of the Ger man Mo lasse Basin. Ec - NW-di rect ed short en ing dur ing Early Rupe lian lo gae Geo log i cae Helve tiae, 85, 519–530, 6 Abb., (D1) pos sibly re flects north ward trans la tion and con - Basel. cur rent counter clock wise rota tion of the Adri at ic Cicha, I., Hagn, H. & Mar ti ni, E. (1971): Das Oligozän und mi cro plate (Peres son & Deck er, 1997). Short en ing Miozän der Alpen und der Kar pa ten. Ein Ver gleich mit was re placed by oro gen-parallel ex ten sion dur ing Hilfe plank to nis cher Or ga nis men. Mitt. bayer. Staats - the Ru pe lian (see above) after crustal thicken ing in sammmlg. Paläont. hist. Geol., 11, 279–293, München. the Le pon tine area by back thrusting along the In- Freu den ber ger, W. & Schwerd, K.(1996): Erläuterungen zur sub ric line (Schmid et al., 1989). Central Alpine units geo log is chen Karte von Bayern 1:500 000. – 329 p., 67 mov ing to wards the east in the Late Ru pelian (con - Abb., 21 Tab., 8 Taf., München. tem po ra ne ous to Niem et-Bev erin/Turba ex tension) Frisch, W. (1979): Tec ton ic Prog ra da tion and Plate Tec ton- were de lim it ed to the north by sinis tral faults like ic Ev o lu tion of the Alps. Tec ton o phys ics, 60, 121–139, the Inn tal shear zone (D2; Fig. 8). 8 Abb., 1 Tab., Am ster dam. Post-Ol i go cene def or ma tions in the area are Fuchs, A.(1950): Be richt über tek to nis che Un ter su chun gen main ly the ef fect of the for mation of the South al - im Berg bau ge biet von Häring und in des sen Um ge- pine In dent er with its tip south of Innsbruck. Be - bung. Un publ. Re port, 10 p., 8 Taf., Kram sach. fore the Mid dle Mi o cene, the area ex pe ri enced Fuchs, W. (1976): Ge dank en zur Tek tog e nese der main ly fold ing as doc u ment ed in Oli go cene sed i - nördlichen Mo lasse zwis chen Rhone und March. Jahr - ments (D3). How ev er, short ening in the merid ian of buch der Geo log is chen Bun de san stalt, 119, 207–249, Inns bruck led to back thrust ing and up lift of the 1 Tab., 2 Taf., Wien. Tauern Win dow, and to major oro gen-parallel ex - Fuchs, W.(1980): Die Mo lasse des Un te rinn tales.- In: Obe - ten sion, lead ing to east ward move ment of Cen tral rhaus er, R. (eds.): Der geo lo gis che Auf bau Österreichs, Al pine units (Ratsch bach er et al., 1991, Fügen- 152–155, 1 Abb., Wien (Spring er). schuh et al., 1997). Again, eastward moving blocks Fügenschuh, B., Sew ard, D. & Manck te low, N. (1997): Ex - were de lim it ed to the north by ENE-trend ing sinis - hu ma tion in a con ver gent oro gen: the west ern Tauern tral faults. The Inn tal shear zone was reac ti vat ed win dow. Terra Nova, 9, 213–217, 3 Abb., Ox ford. (D4). Gra ben for ma tion in the Inn Valley (D5) dur - Hagn, H. (1960): Die stra tig ra phis chen, paläogeographi - ing the Qua ter nary might be an ef fect of adjust - schen und tek to nis chen Be zie hun gen zwis chen Mo -

18 Geol. Paläont. Mitt. Innsbruck, Band 26, 2003 lasse und Hel vet ik um im östlichen Ober bay ern. Geo- te rinn tal, Tirol). Tübinger geo wiss. Arb., Reihe A, 54, log i ca Ba var i ca, 44, 1–208, München. 207 p., Tübingen. Hagn, H., Hille brandt, A. V., Lin den berg, H. G., Malz, H., Lu cia ni, V. (1989): Strat i gra fia se quen zi ale del Ter zi a rio Mar ti ni, E., Mous sa vian, E. & Ur lichs, M.(1981): Kal kal - nella cat e na del Monte Baldo. Mem o rie di Scienze pines Me soz oik um und Alttertiär zwis chen Reit im Geo lo giche, 41, 263–351, 43 Abb., 1 Tab., 5 Taf., Pa do - Win kel und dem Inn. Ex kur sion C. In: Hagn, H. (ed.): Die va. Bay e ris chen Alpen und ihr Vor land in mikropaläontolo- Lühr, H. (1962): Geo lo gis che und mikropaläontologische gischer Sicht, Geo log i ca Ba var i ca, 82, 133–159, Un ter su chun gen im Alttertiär von Häring/Tirol. Un- München. veröff. Diss. TU München, 174 S., 16 Abb., 9 Taf., Hamdi, B.(1969): Das Tertiär des Ober - und Un te ran ger - München. berg es im Un te rinn tal (Tirol). Unveröff. Diss. Univ. Inns- Manck te low, N. S., Meier, A., Viola, G. A. M., Müller, W., bruck, 146 S., Inns bruck. Fügenschuh, B., Sew ard, D. & Villa, I. (1999): The Per i - Har land, W. B., Arm strong, R. L., Cox, A. V., Craig, L. E., ad ri at ic and ad ja cent fault systems in the East ern Alps Smith, A. G. & Smith, D. G.(1990): A geo log i cal time south and west of the Tauern win dow. In: Szeke ly, B., scale 1989. — 263 p., Cam bridge. Frisch, W., Kuh le mann, J. & Dunkl, I. (eds.): 4th Work - Heis sel, W. (1951): Beiträge zur Tertiärstratigraphie und shop on Al pine geo log i cal stud ies, 21.–24. Sep tem ber Quartärgeologie des Un te rinn tals. Jahr buch der Geo- 1999, Tübinger geo wis sens chaft liche Arbe it en 52, 7–9, log is chen Bun de san stalt, 94, 207–222, 2 Abb., 2 Taf., Tübingen. Wien. Mous sa vian, E. (1984): Die Gosau- und Alttertiär-Gerölle Heis sel, W. (1956): Zur Geo log ie des Un te rinn tal er Ter- der An ger bergs chich ten (Höheres Oligozän, Un te rinn - tiärgebietes. Mit tei lun gen der Österreichischen Geo - tal, Nördliche Kal kal pen). Fa cies, 10, 1–86, Erlan gen. log is chen Gesells chaft, 48 (1955), 49–70, 1 Taf., Wien. Ne bel sick, J., Stingl, V., Ort ner, H. & Krois, P. (1996): Sed i - Home wood, P., Allen, P. A. & Wil liams, G. D.(1986): Dy - men tol o gie und Palökologie der unteroligozänen Kalke nam ics of the Swiss Mo lasse Basin. In: Allen, P. A. & des Un te rinn tal er Tertertiärs (Tirol). Sed i ment ’96, Ab - Home wood, P. (eds.): Fore land Ba sins, Spe cial Pub li ca - stracts, 117, Wien. tion Nr. 8 of the Inter na tion al As so ci a tion of Sed i men - Ne bel sick, J., Stingl, V. & Ras ser, M. (2001): Au toch thon- tol o gists, 199–217, 16 Abb., Ox ford (Black well). ous fa cies and de bris flows com pared: Lower Ol i go cene Jacob, H. Kuck el korn, K. & Müller, M. (1982): In koh lung car bo nates of the Lower Inn Val ley (Tyrol, Aus tria). Fa- und Tek to nik im Be reich der ge fal te ten Mo lasse, ins be - cies, 44, 31–46, 4 Abb., 3 Tab., 2 Taf., Er lan gen. son dere am Beis piel der Boh rung Staf fels ee 1. Erdöl Ort ner, H. (1996): Def or ma tion und Di a ge nese im Un te - und Kohle, 35/11, 510–518, 9 Abb., Lein fel den. rinn tal er Tertiär (zwis chen Rat ten berg und Durch hol - Keim, L. & Stingl, V. (2000): Li thos tra tig ra phy and fa cies zen) und sei nem Rah men. Diss. Univ. Inns bruck, 234 S., ar chi tec ture of the Ol i go cene con glom er ates at Monte Inns bruck. Parei (Fanes, Dol o mites, Italy). Ri vis ta Ital i a na di Pa - Ort ner, H. & Sach sen hof er, R. (1996): Ev o lu tion of the leon to lo gia e Strat i gra fia, 106, 123–132, Mi la no. Lower Inn tal Ter tiary and Con straints on the De vel op- Krois, P.(1992): As pekte zu Sed i men tol o gie und Fa zies des ment of the Source Area. In: Liebl, W. & Wesse ly, G. in ne ral pin en Tertiärs (Oligozän) im Raum Häring- An - (eds.): Oil and Gas in Al pid ic Thrust Belts and Ba sins of ger berg, Tirol. Unveröff. Diss. Univ. Inns bruck, 158 S., Cen tral and East ern Eu rope, EAEG Spec. Publ. No. 5, 65 Abb., Inns bruck. 237–247, 8 Abb., 4 Tab., Lon don. Krois, P. & Stingl, V. (1991): Fa zie san a lyse flu vi a til er Sed i - Ort ner, H. & Stingl, V. (2001): Fa cies and Basin De vel op - mente – eine Fall stu die in den Ob e ran ger ber ger ment of the Ol i go cene in the Lower Inn Val ley, Tyrol/ Schich ten (Oberoligozän, Tirol). Jahr buch der Geo log is - Ba var ia. In: Pill er, W. & Ras ser, M. (eds.): Pa leo gene in chen Bun de san stalt, 134, 299–308, 9 Abb., Wien. Aus tria, Schrif ten reihe der Erd wis sens chaft li chen Kom - Lin den berg, H. G. (1965): Die Bol i vin en (Foram.) der mis sion en, 14, 153–196, Wien (Österreichische Akad e- Häringer Schich ten. Mikropaläontologische Un ter su - mie der Wis sens chaf ten). chun gen im Alttertiär des Un te rinn tal-Ge bietes. Peres son, H. & Deck er, K. (1997): The Ter tiary dy nam ics of Boll. Soc. Pal. It., 4/1, 64 - 160, 32 Abb., 8 Taf., Pa - the north ern East ern Alps (Aus tria): chang ing pa lae os- do va. tress es in a col li sion al plate boun dary. Tec ton o phys ics, Löffler, S. - B. (1999): System atis che Neu bear bei tung und 272, 125–157, Am ster dam. paläoökologische As pekte der unteroligozänen Mol lus - Pfeif fer, A. (1950): Be richt über die re frak tions-seismi - ken fau na aus den Ze ment mer geln von Bad Häring (Un- schen Un ter su chun gen im Auf trage der „Koh len berg -

Geol. Paläont. Mitt. Innsbruck, Band 26, 2003 19 bau Häring“ reg. Gen.m.b.H. Un publ. Re port, 8 p., Stei ninger, F. F., Wesse ly, G., Rögl, F. & Wag ner, L. (1991): Feuch ten. Ter tiary Sed i men tary His to ry and Tec ton ic Ev o lu tion of Ratsch bach er, L., Frisch, W., Linz er, G. & Merle, O. (1991): the East ern Al pine Fore deep. Gior nale di Geo logi a, Lat er al ex trusion in the East ern Alps, Part 2: Struc tu ral ser. 3, 48/1–2, 285–295, Bo log na. anal y sis. Tec ton ics, 10/2, 257–271, 8 Abb., 1 Tab., Stingl, V. & Krois, P. (1991): Ma rine Fan Delta De vel op - Wash ing ton. ment in a Pa leo gene Inter i or Al pine Basin (Tyrol, Aus - Schmid, S. M. Aebli, H. R., Hell er, F. & Zingg, A. (1989): The tria). Neues Jahr buch für Geo log ie und Paläontologie, Role of the Per i ad ri at ic Line in the Tec ton ic Ev o lu tion Mo nat shefte, 7, 427–442, Stutt gart. of the Alps.- In: Cow ard, M. P., Die trich, D. & Park, R. G. Von Et ting shau sen, C. (1853): Die tertiäre Flora von Häring (eds.): Al pine Tec ton ics, 153–171, 8 Abb., Ox ford. in Tirol. Abh. Geol. Re ich sanst., 2, 1–118, Wien. Schmid, S. M. & Froit zheim, N. (1993): Oblique Slip and Zwei gel, J., Aign er, T. & Lu ter bach er, H.(1998): Eus tat ic Block Ro tation along the En gadine Line. Ec lo gae Geol. ver sus tec ton ic con trols on Al pine fore land basin fill: Helv., 86/2, 569–593, 6 Abb., 1 Taf., Basel. se quence stra tig ra phy and sub si dence anal y sis in the Schulz, O. & Fuchs, H. W. (1991): Kohle in Tirol: Eine his- SE Ger man Mo lasse. In: Mas cle, A. (ed.): Cen o zo ic fore - to ris che, koh len pe trog ra phis che und lagerstätten- land ba sins of west ern Eu rope, Spe cial Pub li ca tion of kundliche Betrach tung. Ar chiv für Lagerstätten- the Lon don Geo log i cal So ci ety No. 134, 299-323, Lon - forschung der Geo log is chen Bun de san stalt, 13, don. 123–213, 60 Abb., 29 Tab., Wien. Stei ning er, F. F., Bemor, R. L. & Fahl busch, V. (1990): Eu rope an marine/con ti nen tal chron o log i cal cor re la tions. In: Lind say, E. H. et al. (eds.): Eu ro pe an Neo gene Mam mal Chro nol o gy, 15–46 (Ple num). Stei ning er, F. F., Rögl, F. Ho chu li, P. & Müller, C. (1988/89): Lig nite Dep o si tion and Ma rine Cy cles. The Aus trian Ter - Au thors’ ad dress: tiary Lig nite De pos its – A Case His to ry. Sit zungs ber. Dr. Hugo Ort ner, Dr. Volk mar Stingl, In sti tut für Geo log ie und math.-na tur wiss. Kl. Österr. Akad. Wiss., 197, 309–332, Paläontologie, Universität Inns bruck, Inn rain 52, 6020 Inns bruck Wien. email: hugo.ort [email protected], [email protected]

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