ORIGINAL PAPER

Apatite fission-track dating and low-temperature historyof the Bavarian Forest (southern Bohemian Massif)

A. Vamvaka • W. Siebel • F. Chen •

J. Rohrmuller

Received: 9 February 2013 / Accepted: 14 July 2013

� Springer-Verlag Berlin Heidelberg 2013

Abstract Apatite fission-track (AFT) dating applied to

uplifted Variscan basement blocks of the Bavarian Forest is

employed to unravel the low-temperature history of this

segment of the Bohemian Massif. Twenty samples were

dated and confined track lengths of four samples were

measured. Most samples define Cretaceous APT ages

between 110 and 82 Ma (Albian to Campanian) and three

samples give older *148–140 Ma (Jurassic–Cretaceous

boundary) ages. No discernible regional age variations

exist between the areas north-east and south-west of the

Pfahl shear zone, but [500 m post-Jurassic and post-Cre-

taceous vertical offsets along this and other faults can be

inferred from elevation profile analyses. The AFT ages

clearly postdate the Variscan exhumation history of the

Bavarian Forest. Thermal modeling reveals that the ages

are best explained by a slight reheating of the basement

rocks to temperatures within the apatite partial annealing

zone during the middle and late Jurassic and/or by late

Cretaceous marine transgression causing burial heating,

which affected marginal low-lying areas of the Bohemian

Massif and the Bavarian Forest. Late Jurassic period was

followed by enhanced cooling through the 120–60 �C

temperature interval during the subsequent exhumation

phase for which denudation rates of *100 m myr-1 were

calculated. On a regional scale, Jurassic–Cretaceous AFT

ages are ubiquitous in marginal structural blocks of the

Bohemian Massif and seem to reflect the exhumation of

these zones more distinctly compared to central parts.

Keywords Bohemian Massif � Bavarian Forest �Apatite fission-track dating � Thermochronology

Introduction

Previous geochronological research in the Bavarian Forest,

south-eastern Germany, was mainly aimed at revealing the

metamorphic, magmatic and hydrothermal history related

to the Variscan orogeny (Horn et al. 1986; Propach et al.

2000; Klein et al. 2008; Siebel et al. 2008, 2012) and to

pre-Variscan events (Grauert et al. 1974; Kohler and

Muller-Sohnius 1980, 1985; Gebauer et al. 1989; Teipel

et al. 2004). From differences in metamorphic grade, it

emerged that deeper crustal levels are exposed in the south-

west (so-called Vorderer Bayerischer Wald) and shallower

levels in the north-east (Hinterer Bayerischer Wald) (Kalt

et al. 1999, 2000; Teipel et al. 2008). It is not known,

however, whether this is also reflected in the low-temper-

ature exhumation history of these two basement units. In

this paper, AFT dating is applied to basement rocks from

this area to reveal the low-temperature thermo-tectonic

history. With the exception of one dated sample (Siebel

et al. 2010), fission-track ages were missing from the

Bavarian Forest.

A. Vamvaka

Department of Geology, Aristotle University,

52124 Thessalonıki, Greece

W. Siebel (&)

Department of Geosciences, University of Tubingen,

72074 Tubingen, Germany

e-mail: wolfgang.siebel@uni-tuebingen.de

F. Chen

School of Earth and Space Sciences, University of Science and

Technology, Hefei 230026, China

J. Rohrmuller

Bayerisches Landesamt fur Umwelt, 95615 Marktredwitz,

Germany

123

Int J Earth Sci (Geol Rundsch)

DOI 10.1007/s00531-013-0945-x

During the late Jurassic, late Cretaceous and Miocene,

marine transgressions inundated the margin(s) of the

Bavarian Forest, and at some localities, late Cretaceous or

Miocene sediment cover is still preserved (Schreyer 1967;

Wilmsen et al. 2010; Niebuhr et al. 2011). Since it is not

exactly known which areas of the basement were covered

by the sea, and to which extent, it is important to explore

and quantify by thermochronological modeling if the sed-

imentary overload had local influence on the low-temper-

ature history of the basement. Our thermochronological

data set and modeling aims to constrain the burial-unroo-

fing history of the Bavarian Forest and reveals new insight

into the shallow exhumation history of this part of the

Bohemian Massif.

Previous work on low-temperature thermochronology

of the Bohemian Massif

So far, AFT ages have been obtained from several struc-

tural units of the Bohemian Massif (Fig. 1). These studies

yield mainly late Jurassic to late Cretaceous AFT ages.

Such ages have been reported in north-eastern Bavaria

from the Munchberg Massif, the western Fichtelgebirge

and the Oberpfalz area (Bischoff et al. 1993; Coyle et al.

1997; Hejl et al. 1997). With few exceptions, Jurassic and

Cretaceous ages were also found further south in the Na-

abgebirge (Vercoutere 1994), in basement blocks south of

Weiden (Hejl et al. 1997) and in the Austrian Waldviertel

(Hejl et al. 2003). Granites and metamorphic rocks of the

Ruhla Crystalline Complex and the Thuringian Forest

reveal cooling during the late Cretaceous (Thomson and

Zeh 2000; Thomson 2001). Along the north-eastern mar-

gins of the Bohemian Massif (Vogtland, Erzgebirge, Sax-

onian Granulite Massif, Lusatia, West Sudetes), AFT data

demonstrate cooling during Jurassic and/or Cretaceous

times (Ventura and Lisker 2003; Lange et al. 2008; Voigt

2009; Danisık et al. 2010, 2012) and a single region, such

as the Lusatia or the Granulite Massif, shows a very uni-

form cooling history (Lange et al. 2008; Voigt 2009;

Ventura et al. 2009). In the Erzgebirge and the Gory Sowie

Massif (West Sudetes), a phase of young enhanced exhu-

mation during the Cenozoic was detected (Ventura and

Lisker 2003; Aramowicz et al. 2006). For the Erzgebirge,

this was related to the development of the east–west

trending Eger (Ohre) Rift (Ventura and Lisker 2003). The

Steinwald, NE Bavaria, also shows younger (Paleogene)

ages that are likely due to a thermal overprint connected

with lithospheric updoming and volcanism associated with

this rift zone (Bischoff et al. 1993).

Interestingly, all areas mentioned above are situated

along the rim zone of the Bohemian Massif. For interior

parts, like the Barrandian unit, older AFT ages

(Carboniferous to early Jurassic) have been reported

(Glasmacher et al. 2002). Hence, the enhanced Mesozoic

denudation deduced from the AFT ages is a feature of the

outer zones of the Bohemian Massif. In its current position,

the Bohemian Massif represents a huge fault-bounded

block bordered by major lineaments (Fig. 1). Prominent

examples are the Elbe Lineament, the Franconian Line, the

Bavarian Pfahl zone or the Danube and Rodl faults (e.g.

Brandmayr et al. 1995; Mattern 1995; Danisık et al. 2012).

Most authors agree that the Mesozoic AFT ages can be

related to tectonic activity along these crustal discontinu-

ities (Hejl et al. 1997; Thomson and Zeh 2000; Ventura and

Lisker 2003). Detailed modeling and track length distri-

bution led to different scenarios for the Mesozoic to Ter-

tiary track record ranging from increase in crustal heat flow

and paleogeothermal gradients (Thomson and Zeh 2000;

Ventura and Lisker 2003) and reburial by supracrustal

rocks (Hejl et al. 2003), to gradual or slow regional

denudation (Hejl et al. 1997; Glasmacher et al. 2002; Filip

and Suchy 2004). Irrespectively of the modeling results,

the general age pattern in the different areas of the Bohe-

mian Massif is very similar, and we can assume that late

Jurassic to Cretaceous cooling is a general feature in many

marginal regions of this massif, except interior parts for

which older AFT age have been reported (Glasmacher

et al. 2002) and the NE margin (Sudetes) where a model of

Cretaceous regional burial has been proposed (Danisık

et al. 2012).

Geological setting

Variscan evolution and basement structures

The Bavarian Forest is located along the south-western

margin of the Bohemian Massif in central Europe (Fig. 2).

It contains rocks from the deeply eroded basement crust of

the Moldanubian unit, the root zone of the Variscan

mountain chain (Behr et al. 1984; Fiala et al. 1995; Finger

et al. 2007; Kachlık 2008). The crystalline rocks of the

Bavarian Forest (gneisses, migmatites, anatexites and

granites) were dominantly produced during Carboniferous

high-temperature metamorphic and magmatic events. The

basement is characterized by a segmented block geometry

mainly controlled by north-west–south-east trending high-

angle strike-slip faults (Platzer 1992; Brandmayr et al.

1995; Mattern 1995; Siebel et al. 2010). The two major

fault zones are the Danube fault and the Pfahl shear zone

(Fig. 2). The north-western segment of the Danube fault

juxtaposes metamorphic rocks of the Bavarian Forest and

Mesozoic platform sediments and Alpine Molasse (Fig. 2).

Further to the south-east, the Danube fault runs through the

basement and the basement is also exposed south-west of

Int J Earth Sci (Geol Rundsch)

123

the fault, i.e., between Passau and Vilshofen and in the

Sauwald zone, Austria (Fig. 2). The Pfahl shear zone solely

cuts basement rocks and divides the Vorderer Bayerischer

Wald (VBW) from the Hinterer Bayerischer Wald (HBW).

The VBW consists of anatectic gneisses of a deep crustal

level, while a somewhat higher level with cordierite-bear-

ing gneisses and mica schists is exposed in the HBW

(Teipel et al. 2008). The last metamorphic overprint,

between 330 and 320 Ma in both areas, was characterized

by low-pressures and high-temperatures (800–850 �C and

0.5–0.7 GPa, Kalt et al. 1999, 2000) and was associated

with partial melting giving rise to widespread Carbonifer-

ous magmatism (Klein et al. 2008; Siebel et al. 2008).

Rocks shaped during these metamorphic conditions are

now exposed at the surface.

Post-Variscan evolution

During the Permo-Carboniferous, ductile and brittle normal

faulting, affecting basement rocks, started to develop

leading to crustal displacements along the Pfahl and Dan-

ube shear zones (Brandmayr et al. 1995; Mattern 1995;

Siebel et al. 2010). Wrench faulting was also active during

this period, probably related to intramontane basin devel-

opment (Peterek et al. 1997; Schroder et al. 1997). The

*2,800 m deep Naab basin (Paul and Schroder 2012) was

filled with post-orogenic, pre-platform Molasse deposits

and contains abundant detritus from Variscan uplands

revealing that basement rocks were already exposed by

erosion during this time. Subsided fault blocks with infill of

this basin are delineated by the Franconian Line and the

Pfahl zone (Holzforster and Peterek 2011). Surface out-

crops of Permian (Rotliegend) deposits occur along the

north-western segments of the Pfahl and Danube fault

zones and in several individual subbasins along the western

border of the Bohemian Massif (Mattern 1995; Paul and

Schroder 2012).

During the late Permian and early Triassic, large parts of

the Variscan basement had already been extensively eroded

(Franke et al. 2000). Triassic sedimentary rocks are not

exposed in the Bavarian Forest. The Triassic and early

Jurassic might represent a period when the Bavarian Forest

formed an emerged area as part of the Bohemian–Vindel-

ician basement high (Pienkowski et al. 2008; Scheck-

Wenderoth et al. 2008), and detritus was driven to lower

morphologically depositional areas. Alluvial fan deposits

and coarse-grained clastics were deposited in front of the

Franconian Line and are attributed to early Triassic tec-

tonic activity that caused further uplift of the basement

along the Bohemian border zone (Schroder et al. 1997).

The existing AFT age of *217 Ma from the Bavarian

Forest (Siebel et al. 2010) comes from a basement block

close to the Danube fault, Regensburg Forest area. The

Triassic age probably reflects unroofing of this region after

the Permian Molasse stage.

During Mesozoic and Paleogene times, the periphery of

the Bavarian Forest was affected by several transgressive–

regressive sedimentation and uplift cycles. In a first

transgressive stage, tectonic events and the high sea level

led to the formation of shallow water regions along the

Fig. 1 Location map of the

Bohemian Massif in Central

Europe

Int J Earth Sci (Geol Rundsch)

123

south-western margin of the Bohemian Massif and mar-

ginal parts of the Bohemian Massif were overstepped by

Dogger and Malm (Callovian–Oxfordian) sediments that

were deposited under fluvial and marine conditions

(Schreyer 1967; Fay and Groschke 1982). Heavy mineral

contents in the mid-Jurassic sandstones show that clastic

material is derived from crystalline rocks of the Bavarian

Forest (Fay and Groschke 1982). The Jurassic transgression

took place under global eustatic control, but probably also

by basin subsidence related to the opening of the Penninic

Ocean between the European and Austroalpine plates

(Ratschbacher et al. 2004). During the Malm, the Bohe-

mian Massif was the south-east margin of the mid-Euro-

pean carbonate platform partly covered by the sea, and in

places, it is recorded that more than 200 m of marlstone

and limestone was deposited (Unger 1984).

During the late Jurassic to early Cretaceous marine

regression, major parts of southern Germany were uplifted

and emerged above sea-level and then were subjected to

regional erosion and re-peneplaned (Voigt et al. 2008).

Older crustal discontinuities were reactivated, and the

basement of the western border zone of the Bohemian

Massif was uplifted by *1,000 m resulting in the erosion

of earlier Mesozoic strata (Schroder 1987; Schroder et al.

1997). Geological evidence for Cretaceous tectonic activity

along the Danube fault zone comes from Jurassic carbon-

ates which were strongly fractured or eroded, and this

process was accompanied by karstification of the carbonate

platform margins.

The late Cretaceous saw a second pronounced period of

eustatic sea-level rise (Hancock and Kauffman 1979; Zie-

gler 1990). In the Bavarian Forest, this is documented by

transgressive Cretaceous sediments (Danubian Cretaceous

Group, Niebuhr et al. 2009) that particularly occur in the

Regensburg–Kelheim area and in the Bodenwohr depres-

sion north of Regensburg. The depositional basin was

rimmed by basement units of the Bavarian Forest in the

south and the Oberpfalz Forest in the east. In the center of

the Bodenwohr depression up to 200 m of Cenomanian–

Coniacian, sediments were deposited (Wilmsen et al. 2010;

Niebuhr et al. 2011). The onset of this late Cretaceous

transgression is documented by the flooding of the

Kristallgranite of the Regensburg Forest south of Roding

during the Cenomanian–Turonian boundary interval

(Wilmsen et al. 2010) and well preserved in the Grub

quarry (Fig. 3). The transgression occurred diachronically

Fig. 2 Geological map of the

Bavarian Forest showing

sample localities and the

regional distribution of apatite

fission-track ages (±1r). The

locations of cross-sections

presented in Fig. 4 are

illustrated

Int J Earth Sci (Geol Rundsch)

123

onto the north-east-rising substrate of the Bohemian Mas-

sif (Wilmsen et al. 2010). According to Wilmsen et al.

(2010), the Cenomanian coastline transgressed within

*6 Ma from the Regensburg area onto exposed Kristall-

granite cliffs of the Bodenwohr depression (Fig. 3). Tec-

tonic overprints of the Cretaceous sediments in the

Bodenwohr depression that are interpreted to reflect uplift

of the Bohemian Massif occurred in the Turonian

(93–90 Ma) (Niebuhr et al. 2011).

During latest Cretaceous to earliest Paleogene, parts of

the Bohemian Massif experienced regional uplift and

denudation (Unger and Schwarzmeier 1987). Sedimentary

basins were inverted, previously deposited Cretaceous

strata eroded, and basement blocks were uplifted (Schroder

1987; Voigt 2009; Danisık et al. 2012). In the course of this

inversion tectonics, the Franconian Line was reactivated

and the basement blocks to the east of this line were up-

thrusted along this wrench fault (Peterek et al. 1997; Fig. 3

in Holzforster and Peterek 2011). The tectonic movements

took place under far-field compressional stresses probably

exerted by a change in relative motion between the Euro-

pean and African plates (Kley and Voigt 2008). Based on

AFT data from the northern Oberpfalz area, the magnitude

of basement denudation in the area east of the Franconian

Line during late Cretaceous time was up to 3,000 m (Hejl

et al. 1997).

Finally, during the Neogene, the Paratethys spread over

large areas of central Europe. In south-eastern Bavaria, this

flooding produced marine Molasse deposits (Burdigalian)

that cover marginal parts of the Bavarian Forest south of

the Danube fault (Schreyer 1967; Unger and Schwarzmeier

1987). Concomitant Miocene uplift of the northern parts of

the Bohemian Massif is attributed to lithospheric updoming

along the Eger (Ohre) Rift (Ulrych et al. 1999). During this

time, marginal blocks of the Bohemian Massif experienced

transpressional reactivation along the pre-existing faults

(Ziegler and Dezes 2007).

Dating method and analytical procedures

Fission-tracks in apatites form continuously through time

with a maximum length of *16 lm and start to accumu-

late at temperatures below 120 �C (Gleadow et al. 1986a).

Partial fading of the tracks occurs in the temperature

interval between 120 and 60 �C, which is called the apatite

partial annealing zone (APAZ, Green and Duddy 1989;

Laslett et al. 1987). How much the tracks will fade and

shorten depends primarily on the temperature and time

interval the grains spent in the partial annealing zone. In

the present study, fission-tracks in apatite were analyzed by

the external detector method (Gleadow 1981). For this

method, low-uranium muscovite mica was attached to the

apatite grain mounts with polished and already etched

minerals. The pair was then irradiated with thermal neu-

trons in a nuclear reactor, inducing fission of 235U and

formation of induced fission-tracks. Spontaneous and

induced fission-tracks were counted under a Zeiss optical

microscope (Axioscope 1) at Tubingen University. The

microscope was equipped with a positioning tablet

Fig. 3 Field photograph

showing major erosive

discordance between Variscan

basement rocks and

transgressive Cretaceous

(Cenoman–Turon) cover

sequences at the sample locality

Grub. The basement rock is the

Kristallgranite, whereas the

sediments (Regensburg

formation, Danubian Cretaceous

group) comprise Cenoman–

Turon near-shore siliciclastic

rocks, including glauconitic

sandstones (Wilmsen et al.

2010). Sample locality is

indicated. The sample was

collected from c. 30 m below

the Cretaceous palaeo-planation

surface

Int J Earth Sci (Geol Rundsch)

123

controlled by the computer program ‘FT Stage’ (version

3.11, Dumitru 1993). Spontaneous fission-tracks within the

apatite grains were counted with 1,0009 magnification

using a dry objective. Crystals with well-polished surfaces

parallel to the crystallographic c-axis, homogenous ura-

nium distribution and free of visible inclusions and dislo-

cations were considered. A minimum number of twenty-

five grains from each sample was counted.

For the determination of the f-factors, the fission-tracks

in the Fish Canyon Tuff (27.8 ± 0.7 Ma; Colorado, USA)

and Durango (31.4 ± 0.5 Ma; Cerro de Mercado, Mexico)

apatite age standards were counted from four different

irradiation series (Table 1). The personal value (A.V.) of

the f factor was calculated by ZETAMEAN program

(version 1.0, Brandon 1996) as 337.07 ± 7.95. AFT age

determination of the samples was carried out with the

TRACKKEY program (version 4.1, Dunkl 2002).

Dpar values (diameter of etched spontaneous fission-

tracks measured parallel to the crystallographic c-axis)

were used as the identical kinetic parameter to estimate the

chemical compositions of the samples and were further

taken as a basis for thermal history prediction (Crowley

et al. 1991; Burtner et al. 1994). For etch pit measurements,

at least four pits per grain were measured from which the

mean Dpar value was calculated.

Horizontal confined tracks, which are the best approxi-

mation of the true track length distribution (Gleadow et al.

1986b), were measured in order to investigate the thermal

history and cooling behavior of the rocks. The criteria for

track length measurements are as follows: (1) both ends are

defined, sharp and well visible, and (2) the track is close

parallel to the surface.

From the frequency and distribution of track lengths,

additional information on the thermal history of a sample

can be obtained. Thermochronological modeling based on

the annealing characteristics of the apatite fission-tracks

allows the determination of time–temperature (t–T) paths.

In the present study, the HeFTy program (Ketcham 2005)

was used with the multi-kinetic annealing model of Ket-

cham et al. (2007b), with c-axis projected confined track

length data (Ketcham et al. 2007a) and Dpar values as

kinetic parameter for the thermal history prediction. Input

parameters for the modeling of each sample were the AFT

age with 1r error, the fission-track length distribution and

the Dpar values of the apatites as kinetic parameter. Time–

temperature (t–T) paths were statistically evaluated and

categorized by a value of ‘goodness of fit’ (GOF), in which

a ‘good’ result corresponds to a value of 0.5, an ‘accept-

able’ result corresponds to a value of 0.05, and a GOF of 1

is the optimum (Ketcham 2005).

Results

AFT analyses were performed on twenty samples (ten

granites, eight gneisses and two orthogneisses) from the

two tectonic blocks (VBW, HBW) of the Bavarian Forest.

Geographical and geological locations and analytical

results are shown in Table 2 and in Fig. 2. All AFT ages

passed the chi-square probability test over the 73 % con-

fidence level indicating that all grains in each sample

belong to one homogeneous age population. The data are

displayed in Table 2 as central ages with errors of ±1r.

Our samples come from different elevation levels above

sea-level (between 350 and 1,350 m); thus, the maximum

difference in present-day elevation is 1,000 m.

All except three samples yield similar AFT ages ranging

from early (Albian) to late (Campanian) Cretaceous:

109.6 ± 4.2 to 82.8 ± 3.4 Ma. Granite samples Grub,

Neust-2 and the orthogneiss P1 display older Jurassic–

Cretaceous boundary ages (Kimmeridgian–Valanginian):

148.4 ± 6.8, 141.9 ± 6.2 and 140.2 ± 6.0 Ma, respec-

tively. A recounted AFT analyses of sample P1 does not

show any difference in age within the error limits com-

pared to the earlier age determination (central age insig-

nificantly shifted by *2 Ma). No regional cooling picture

Table 1 Determination of the f value for apatite

Age standard No qs (105/cm2) Ns qi (105/cm2) Ni P(v2) (%) qd (105/cm2) Nd Density ratio f ± 1r

AD 5 28 2.899 658 11.076 2,514 7 6.238 3,028 0.262 385.26 ± 19.27

AF 7 26 2.279 298 7.113 930 41 6.184 3,028 0.321 281.71 ± 20.08

AD 1 26 3.080 864 10.879 3,052 90 6.739 3,284 0.283 330.11 ± 14.92

AF 8 27 2.078 355 8.604 1,470 95 6.729 3,284 0.241 345.04 ± 22.16

AD 5 29 3.034 785 13.014 3,367 82 7.997 7,852 0.233 337.88 ± 14.93

AD 6 33 2.427 378 9.400 1,381 100 6.308 5,972 0.274 364.60 ± 22.45

Weighted mean age 337.07 ± 7.95

AF: Fish Canyon Tuff; AD: Durango; No.: number of grains; qs: spontaneous track density; Ns: number of spontaneous tracks; qi: induced track

density; Ni: number of induced tracks; P(v2): probability (v2 test); qd: track density of the dosimeter glass (CN 5); Nd: number of tracks in the

dosimeter glass

Int J Earth Sci (Geol Rundsch)

123

Table 2 AFT data for samples from the Bavarian Forest

Sample no. Rock type n qs Ns qi Ni qd Nd P(v2) (%)

VBW

P1 Orthogneiss 30 34.449 2,083 25.535 1,544 6.233 5,972 99.34

Met-1a Granite 26 40.535 1,871 46.059 2,126 6.188 5,972 100

PADR-2 Granodiorite 25 18.139 1,479 22.052 1,798 6.086 5,972 73.85

Hzbg-4 Granodiorite 25 17.758 898 17.580 889 6.113 5,972 100

Sa-1 Granite 26 13.745 691 14.182 713 6.053 5,972 100

La-1 Diatexite/gneiss 25 40.391 1,888 46.723 2,184 6.029 5,731 98.56

Ru-1 Metatexitic gneiss 25 30.691 1,164 37.336 1,416 6.223 5,731 99.88

Grub Granite 26 51.609 1,824 35.849 1,267 6.187 5,731 91.91

Ro-1 Diatexite 26 47.983 1,920 58.829 2,354 6.064 5,731 99.82

Neust-2 Granite 30 51.120 2,059 37.266 1,501 6.206 5,731 83.57

Hu-1a Orthogneiss 26 8.861 772 10.216 890 6.023 5,972 99.99

Sw-3 Diatexite 25 43.651 1,463 48.126 1,613 6.117 5,731 99.96

HBW

Bod-1 Cord-grt-gneiss 30 15.672 1,800 17.761 2,040 6.263 5,972 99.85

Stein Granite 30 23.933 2,064 22.890 1,974 5.979 5,972 92.43

Ho-1 Granite 25 46.497 2,570 50.912 2,814 6.143 5,972 87.17

Ne-1 Metatexitic gneiss 25 23.784 1,557 28.166 1,844 5.993 5,731 98.43

Fin-II Granite 25 35.754 2,684 33.170 2,490 6.084 5,972 100

Lu-1 Granite 26 52.048 2,127 51.290 2,096 6.173 5,972 100

Ch-1b Grt-cord gneiss 25 14.995 892 16.844 1,002 5.924 5,731 99.99

Sp-1 Cord-sill-grt gneiss 29 38.415 1,600 44.874 1,869 5.976 5,731 91.4

Sample no. Rock type n Central age (Ma) ±1r (Ma) Dpar value (lm) ±1r (lm) MTL (lm) ±1r (lm) NMT

VBW

P1 Orthogneiss 30 140.2 6.0 1.9 0.1

Met-1a Granite 26 91.1 3.8 2.0 0.1

PADR-2 Granodiorite 25 82.8 3.7 1.8 0.1

Hzbg-4 Granodiorite 25 103.2 5.6 2.3 0.4

Sa-1 Granite 26 98.1 5.9 1.7 0.1

La-1 Diatexite/gneiss 25 87.2 3.6 2.8 0.2

Ru-1 Metatexitic gneiss 25 85.6 4.1 2.7 0.2 13.6 2.0 108

Grub Granite 26 148.4 6.8 1.8 0.1 12.7 2.1 141

Ro-1 Diatexite 26 82.8 3.4 2.7 0.2

Neust-2 Granite 30 141.9 6.2 2.6 0.1

Hu-1a Orthogneiss 26 87.5 4.9 1.8 0.1

Sw-3 Diatexite 25 92.8 4.2 3.1 0.3

HBW

Bod-1 Cord-grt-gneiss 30 92.5 3.9 1.7 0.2 12.9 2.4 126

Stein Granite 30 104.5 4.3 1.6 0.1

Ho-1 Granite 25 93.9 3.6 1.8 0.1

Ne-1 Metatexitic gneiss 25 84.7 3.7 1.6 0.1

Fin-II Granite 25 109.6 4.2 1.8 0.2

Lu-1 Granite 26 104.7 4.3 2.5 0.2 12.7 1.9 136

Ch-1b Grt-cord gneiss 25 88.3 4.7 1.9 0.1

Int J Earth Sci (Geol Rundsch)

123

emerges, and thus, no pronounced age difference becomes

apparent for the rocks on both sides of the Pfahl zone or in

different parts of the Bavarian Forest.

In order to quantify the chlorine and fluorine content of

the apatite crystals, Dpar values were measured on all

samples. Most samples display the same range of Dpar

values, indicating that the annealing kinetics of the dif-

ferent apatites were similar (Table 2). In twelve samples,

single Dpar values display a narrow scatter between 1.6 and

2.0 lm (see Table 2 for mean Dpar). This denotes the

presence of fluorine-rich apatites (Donelick 1991) and a

low resistance to annealing (O’Sullivan and Parrish 1995).

The remaining eight samples show higher single Dpar val-

ues, ranging from 2.3 to 3.1 lm, indicating that the apatite

crystals have a mixed chemical composition (fluor-chlorine

apatite) and were more resistant to annealing. Sample

Hzbg-4 shows a significant Dpar scatter in a range of

*1 lm (1.8–3.0 lm), and the Dpar values of different

apatite crystals display a positive correlation with the sin-

gle grain AFT ages. Higher Dpar values correspond in

general to older AFT ages, and this correlates with the

chemical composition, i.e., more narrow etch pits are

indicative for more F-rich apatites that are more susceptible

to annealing (O’Sullivan and Parrish 1995).

Confined fission-track length distributions were deter-

mined on four samples in order to obtain information about

the thermal history of the samples (Table 2). Among these,

Bod-1a and Lu-1 are from the HBW, while samples Ru-1

and Grub are from the VBW. The track length distributions

of all samples are rather broad (Table 2). In general, the

confined track lengths in each sample range between 7 and

16 lm. There is no hint of clear bimodality, and the mean

track lengths and standard deviations of the samples Bod-

1a, Lu-1, Ru-1 and Grub are 12.9 ± 2.4, 12.7 ± 1.9,

13.6 ± 2.0 and 12.7 ± 2.1 lm, respectively. Samples

Bod-1a, Lu-1 and Grub are characterized by short mean

track lengths and high standard deviations, which are

indicative for a slow exhumation or a prolonged residence

in the apatite partial annealing zone (APAZ). Sample Ru-1,

despite its longer mean track length (*13.6 lm), is also

characterized by a wide track length distribution that

encounters for long stay in the APAZ.

Discussion and interpretation

General considerations

The Bavarian Forest exposes rocks from an uplifted core

region of Variscan continental crust. These rocks formed

and/or were metamorphosed at temperatures [750 �C

about 320–340 million years ago. From the clastic sedi-

mentation record, it is known that strong erosion of this

mountain belt was almost completed during the Permian.

From this, a significant fast cooling of the Variscan base-

ment during the Permo-Carboniferous can be inferred.

Rapid early post-Variscan exhumation is substantiated by

Permo-Carboniferous 40Ar/39Ar mica and fission-track

zircon cooling ages (Hejl et al. 1997; Thomson and Zeh

2000).

AFT ages show that the presently exposed crust of the

Bavarian Forest was at temperatures around 90 �C during

the Jurassic–Cretaceous period. Hence, the rocks pres-

ently at the surface were at depths of at least *2,000 m

at that time, for a paleogeothermal gradient of

30 �C km-1 (Hejl et al. 2003), which is similar to the

present value of 27 �C km-1 determined from the KTB

drill core (Coyle et al. 1997) and an average Cretaceous

surface temperature of 20 �C (Thomson and Zeh 2000).

Excluding three samples, no significant differences exist

between the AFT ages from different localities, indicat-

ing that the presently exposed crust was almost at the

same temperatures (60–120 �C) during the late

Cretaceous.

It could be assumed that the AFT ages reflect ongoing

slow exhumation during the Jurassic–Cretaceous. Our

confined track length data (i.e. short mean track lengths and

wide distributions, Table 2) could be a result of continuous

slow cooling from temperatures in excess of 120 �C to

surface temperatures (Gleadow et al. 1986b). From the

sedimentary record, it is known, however, that at least parts

of the western Bohemian Massif were buried by late

Jurassic platform sediments and part of the basement was

also capped by late Cretaceous marine sediments. Recor-

ded Mesozoic sediment thicknesses are generally low

(\200 m), but the overlying sediments and/or

Table 2 continued

Sample no. Rock type n Central age (Ma) ±1r (Ma) Dpar value (lm) ±1r (lm) MTL (lm) ±1r (lm) NMT

Sp-1 Cord-sill-grt gneiss 29 85.7 3.7 2.9 0.3

n: number of counted grains; qs/qi: spontaneous/induced track densities, respectively (105 tracks cm-2); Ns/Ni: number of counted spontaneous/

induced tracks; qd: dosimeter track density (105 tracks cm-2); Nd: number of tracks counted in dosimeter; P(v2): probability obtaining chi-square

value (v2) for n degree of freedom (where n is the number of crystals minus 1); Dpar: the mean etch pit diameter of fission-tracks, where each etch

pit diameter was averaged from four measurements per analyzed grain; MTL: mean horizontal confined track length; NMT: number of measured

track lengths. The ages were calculated using zeta calibration method (Hurford and Green 1983), glass dosimeter CN-5 and zeta value of

337.07 ± 7.95 year cm-2 (A. Vamvaka)

Int J Earth Sci (Geol Rundsch)

123

contemporaneous burial of the Bohemian Massif due to

lithospheric flexural response could have caused some

reheating of the basement crust. As outlined below, after

initial Permo-Carboniferous accelerated cooling and

exhumation, several intervals of higher and lower exhu-

mation occurred during the Mesozoic–Cenozoic era, with

even some slight reheating events during the Jurassic and

Cretaceous.

Significance of Jurassic–Cretaceous boundary ages

The presence of older AFT ages in the granite samples

Grub (*148 Ma) and Neust-2 (*142 Ma) and in the or-

thogneiss P1 (*140 Ma) reveals a different exhumation

timing of these sectors. These samples come from regions

close to tectonic lines (Pfahl and the Danube fault zones,

see Fig. 2), suggesting that their exhumation was probably

controlled by these faults. At two sites (Grub and Neust-2),

overlying Cretaceous or Miocene sediments are still pre-

served that help to interpret the exhumation history in more

detail. In the following paragraphs, we will focus on these

two localities.

Sample Grub (Kristallgranite, Regensburg Forest) is

overlain by a thin sequence (*20 m) of late Cretaceous

(Cenomanian–Turonian) sediments (Fig. 3). From the

stratigraphic age of these sediments, we can infer that this

sample, which was collected c. 35 m below the base of the

sediments, was close to the surface *96 million years ago,

before the locality received clastic input from the north-

easterly located crystalline basement substrate (Wilmsen

et al. 2010). The time and temperature information given

by the AFT age (*148 Ma, 120–60 �C) and the surface

exposure (i.e. *96 Ma, average Cretaceous surface tem-

perature of 20 �C) provide an estimate of the average

denudation rate during the lower Cretaceous. Under the

assumption of a geothermal gradient of 30 �C km-1 (see

above) and a steady exhumation rate during this period, the

latter would be *40 m myr-1, i.e., between 1.5 and

2 times higher than present-day erosion rates of the

Bavarian Forest using cosmogenic isotopes (Schaller et al.

2001). Thus, it seems likely that some tectonically forced

exhumation was active at the end of the Jurassic, and

evidence for tectonic unrest is also provided by the disin-

tegration of the Jurassic carbonate platform sequence dur-

ing the late Jurassic and early Cretaceous times (Ziegler

et al. 1995). On the other hand, the wide track length dis-

tribution and the short mean track length of sample Grub

are in favour of a prolonged stay of the sample in the

APAZ. The sample was either at temperatures around

80 �C before late Jurassic–early Cretaceous exhumation or

slightly reheated afterward. Although the thickness of the

late Cretaceous sediments at the Grub quarry cannot be

precisely constrained, from the older AFT age of sample

Grub, we can conclude that it was definitely not efficient

(i.e. [2 km) to cause vanishing of former apatite fission-

tracks. Nevertheless, some burial of the basement rocks

(B1,000 m) during late Cretaceous or early Paleogene

times might be responsible for partial reheating of this

sample. In the next chapter, we use thermochronological

modeling to explore the potential effect of burial of the

basement rocks.

Sample Neust-2 (Neustift granite near Ortenburg, south

of Vilshofen) comes from a locality south-west of the

Danube fault (Fig. 2). This sample was collected from a

quarry, where the granite is overlain by *15-m-thick

Neogene marine deposits (Obere Meeresmolasse, Schreyer

1967). To the east, the granite is separated by the Wolfach

fault from an area with outcrops of Jurassic sediments.

Jurassic sedimentation started with dolomitic sandstones

for which a mid-Jurassic stratigraphic age was assigned

(*160 Ma, Schreyer 1967). Since most of the Jurassic

succession has been eroded during the early Cretaceous,

the original thickness of the Jurassic strata remains un-

known. With this background information, the following

thermal evolution scenario is possible: The Neustift block

was covered by Jurassic sediments, and given its geo-

graphical location south-west of the Danube fault, burial of

basement could have occurred at least at the extent to cause

a resetting of the AFT age. Thus, the *142 Ma AFT age of

sample Neust-2 could indicate a cooling stage after a

Jurassic reheating event. This also raises the question

whether larger parts of the Bavarian Forest were reheated

during the Jurassic. Irrespectively of whether reheating

occurred or not, the Neustift block was affected by late

Jurassic–earliest Cretaceous uplift, and in places, this was

accompanied by erosion of overlying Jurassic sediments.

Renewed sedimentation took place in the late Cretaceous

as known from drilling evidence in the Ortenburg area

(150–170 m Cretaceous sediments; Unger 1984), but the

thickness of these sediments was obviously not sufficient to

reset the AFT age of the sample Neust-2.

Geological cross-sections

From the distribution of AFT ages in the Bavarian Forest, it

appears that the Pfahl zone does not delimit areas of dif-

ferent thermochronological histories (Fig. 2). Hejl et al.

(2003) made a similar observation for the areas on both

sides of the Vitis fault, Austria, and showed that the AFT

ages do not vary between the Moldanubian and Moravian

structural units, indicating that post-Cretaceous vertical

offsets were of minor significance in this area. Here, we use

elevation profiles to demonstrate that some later displace-

ments must have occurred along the fault zones in the

Bavarian Forest. Cross-sections (Fig. 4) show the location

of dated samples with different or similar AFT ages on

Int J Earth Sci (Geol Rundsch)

123

either side of a major fault. From Fig. 4a, b it becomes

apparent that samples with late Jurassic (Grub) and Cre-

taceous (Ro-1, Hoe-1, Ne-1, Ch-1b) AFT ages are more or

less at the same elevation in the present outcrop level. If the

basement would have been capped by *1,000 m Creta-

ceous sediments, for which, however, there is no firm

evidence, rocks being in the APAZ during the late Creta-

ceous (i.e. *100–80 Ma) might have only been less than

1 km deeper than rocks immediately under the sedimentary

cover which carry an older AFT age print. In this case,

areas with late Cretaceous AFT ages should be uplifted

only *1 km more than localities with Jurassic–Cretaceous

boundary AFT ages. Alternatively, if the Cretaceous cover

was of minor thickness, or lacking, then the difference of

uplift and denudation in the localities with different AFT

ages should be greater. Thus, initially, at least 1,000 m

vertical difference should have existed between Grub and

the other samples, and this was probably accommodated by

a fault zone (Fig. 4). In cross-sections of Fig. 4a, d, e

similar relationship is observed for samples P1 and Neust-2

and those with late Cretaceous AFT ages. On the other

hand, samples with consistent Cretaceous AFT ages show

250–650 m differences in the present-day elevation

(Fig. 4c, e). This clearly denotes that vertical tectonic

displacements occurred along the Pfahl zone after late

Cretaceous times. Furthermore, from correlation between

the AFT ages on either side of the Pfahl fault zone from the

northern to the southern part, it becomes apparent that

different relative displacement directions prevailed during

block rotation (Fig. 4a–e). There is no evidence for inten-

sive vertical movements along the major fault zones during

recent times, as this would have led to more intensive

erosion of the relatively uplifted side and therefore the

exposure of younger AFT ages.

Thermochronological modeling

Confined track length measurements accomplished on four

samples do not show clear evidence for accelerated cool-

ing. The data, however, do not preclude reheating during

the Mesozoic followed by one or more stages of enhanced

exhumation and cooling. Late Cretaceous reheating due to

sedimentary reburial was suggested by Hejl et al. (2003) as

explained for the AFT age record at the south-eastern

margin of the Bohemian Massif. Here, we employ ther-

mochronological modeling of AFT data using the Hefty

program (Ketcham 2005) in order to test whether Jurassic

or Cretaceous reheating was a likely process or not.

Modeling results display cooling rates for the time interval

during which the sample was within the temperature range

of the APAZ; time–temperature (t–T) paths outside this

range can only approach higher and lower temperature

limits without corresponding to actual cooling rates.

Fixpoint for a higher temperature (200 �C) was 300 Ma for

Grub and 200 Ma for other samples, while an average

geothermal gradient of 30 �C/km was assumed for the

calculation of cooling/exhumation rates.

Although the samples cooled through the temperature

range of APAZ at different times, they all yield similar

thermal histories. Confined track length distributions are

wide, indicating a prolonged stay in the APAZ or possibly

a moderate reheating event (Table 2). On the other hand,

there is no clear bimodal distribution observed in track

length, revealing that strong reheating after passing the

APAZ is unlikely.

For sample Grub, we were not able to obtain satisfying

t–T paths solely by using the geological constraint that the

sample was at the surface around *96 Ma (Fig. 5a). Good

results were achieved by providing a further t–T constraint

of a slight reheating at temperatures up to 80 �C between

90 and 50 Ma (Fig. 5b). Modeling was also performed for

the case that the rock was exhumed above the APAZ

during Triassic times and then reburied during the Jurassic

(Fig. 5c). Such assumption results in t–T paths similar to

those obtained in the previous model. Modeling of Jurassic

reheating without Cretaceous reheating produced unsatis-

fying results. Thus, thermal modeling of sample Grub is in

favor of a reheating event during the late Cretaceous, while

Jurassic reheating is not precluded. The best t–T paths

achieved by modeling indicate a reheating at *40–60 �C

between 90 and 70 Ma followed by a cooling phase around

60 Ma (Fig. 5b, c). If the temperature increase (i.e.

*20–40 �C) between 90 and 70 Ma was solely driven by

gravity loading, the thickness of the overburden must have

been *1,000 m. This is considerably higher than indicated

by the known Cretaceous sediment record (Wilmsen et al.

2010). Hence, our results demand for alternative thermal

reactivation of the crust. This could have been achieved by

internal processes, such as flexural subsidence as well as

fault activity.

Thermal modeling also shows that sample Grub passed

the APAZ with an enhanced cooling rate and actually

reached the upper crustal levels prior to Cretaceous trans-

gression, around 130–120 Ma (Fig. 5b, c). From this, an

accelerated exhumation rate of [100 m myr-1 can be

inferred during the Jurassic–Cretaceous boundary. Slower

exhumation rates of 20–40 m myr-1 were obtained for the

Tertiary era (40 m myr-1 if we accept a faster exhumation

during Paleogene, and 20 m Ma-1 if not).

Without external constraints, thermochronological

models for the three samples with Cretaceous AFT ages

(Lu-1, Bod-1a, Ru-1) show a prolonged stay in the APAZ

(Figs. 6, 7, 8), as would be expected from their confined

track length distributions. Partial annealing occurred at

120 Ma, or earlier, and lasted until the early Paleogene. All

three samples indicate fast exhumation around

Int J Earth Sci (Geol Rundsch)

123

Fig. 4 Elevation profiles across the Bavarian Forest through sample sites from which AFT ages have been obtained. For location of profiles, see

Fig. 2

Int J Earth Sci (Geol Rundsch)

123

130–120 Ma and also during the late Cretaceous–early

Paleogene (*75–50 Ma). We also performed thermal

modeling with additional t–T constraints including reheat-

ing during mid-late Jurassic (*160–140 Ma) or/and late

Cretaceous (*95–70 Ma) times as suggested by the

modeling results of the sample Grub.

Modeling of sample Lu-1 (AFT age: *105 Ma) shows a

stay inside the APAZ at temperatures above 90–80 �C

(Fig. 6a, b) and provides satisfying results for both Jurassic

and Cretaceous reheating (Fig. 6c, d). Reheating during

late Cretaceous (*90–80 Ma) is denoted only by a minor

temperature increase of *10 �C (Fig. 6c). This is in

compliance with a sedimentary reburial of *300 m or

slight increase in crustal heat flow. Late Jurassic reheating

(*150–140 Ma) is implemented by the modeling with a

*20–30 �C temperature increase (Fig. 6d), corresponding

to a greater burial of *600–1,000 m. Enhanced cooling

around *130–120 Ma, as indicated by the model, could

explain a higher denudation rate during erosion of the

Jurassic sediments. Considering the suggested model, early

Fig. 5 Modeled time–temperature (t–T) paths for the sample Grub (see text for explanation)

Int J Earth Sci (Geol Rundsch)

123

Fig. 6 Modeled time–temperature (t–T) paths for the sample Lu-1. In the second model (b), a complementary constraint assuming accelerated

exhumation in Paleogene is provided (see text for explanation)

Int J Earth Sci (Geol Rundsch)

123

Cretaceous exhumation rate is calculated at [60 m Ma-1

and up to 100 m myr-1, which is in good accordance with

the results from thermal modeling of the sample Grub.

Sample Bod-1a (AFT age: *92 Ma) displays a similar

thermal history as sample Lu-1, with temperatures inside in

the APAZ above 80 �C, while reheating events are also well

Fig. 7 Modeled time–

temperature (t–T) paths for the

sample Bod-1a (see text for

explanation)

Fig. 8 Modeled time–

temperature (t–T) paths for the

sample Ru-1 (see text for

explanation)

Int J Earth Sci (Geol Rundsch)

123

displayed (Fig. 7a–c). The similarity in results between

samples Lu-1 and Bod-1a possibly denotes a stagnation

period during mid-Cretaceous times (110–90 Ma) without

significant tectonic activity or sedimentation taking place.

Sample Ru-1 (AFT age: *86 Ma) shows evidence for a

longer stay in the APAZ at higher temperatures

([100–110 �C) compared to the other samples (Fig. 8).

Modeling yields no reasonably good fits for Jurassic or

Cretaceous reheating but does not preclude that tempera-

tures were high enough during this time interval to cause

complete disappearance of previously formed tracks.

Sample Ru-1 is characterized by a longer mean track length

than the other three samples (Table 2). This shows that the

sample has left the APAZ toward higher structural levels

with a faster cooling rate, and according to the thermal

modeling results, this could have happened between the

latest Cretaceous and earliest Paleocene. The exhumation

rate during this period should be at least *50 m myr-1

and possibly up to 100 m myr-1 (Fig. 8; from 90 to 30 �C

during 75–55 Ma). Within the last 50 million years, the

exhumation continued in low rates, ensuing at

*20 m myr-1 (from 60 to 18 �C) in line with the present-

day erosion rates obtained from 10Be concentrations in

quartz from bedload of the Regen River, which are in the

range 20–30 m myr-1 (Schaller et al. 2001).

In the three samples with Cretaceous AFT ages, shorter

track lengths become less abundant with decreasing AFT

age. As shown by modeling, the older samples (Lu-1,

Bod-1a) resided at the low-temperature range of the APAZ,

and thus, more tracks were shortened and less tracks disap-

peared than in the younger sample (Ru-1). For samples Lu-1

and Bod-1a that stood at the same temperatures in the APAZ,

the difference in track lengths can be explained by the more

narrow Dpars of Bod-1a (Table 2) that corresponds to a more

F-apatite composition and faster annealing.

Summarizing, thermal models support the possibility that

the basement of the Bavarian Forest experienced a first

reheating during mid- to late Jurassic (*160–140 Ma). This

was followed by tectonic activity and enhanced exhumation

and denudation during the early Cretaceous (*140–120 Ma).

After a phase of stagnation around *120–95 Ma, renewed

sedimentation during the late Cretaceous (*95–85 Ma)

caused subsidence and reheating of marginal parts of the

Bavarian Forest, at least at Grub locality. Tectonic activity

during the late Cretaceous and early Paleogene (*75–55 Ma)

gave rise to higher exhumation rates followed by a period of

slower exhumation after *50 Ma.

Conclusions

The Variscan orogeny of central Europe was subjected to

rapid uplift due to isostatic rebound during the Permo-

Carboniferous (e.g. Behr et al. 1984). In the Bohemian

Massif, AFT ages clearly postdate the late-Variscan heat

relaxation of the orogenic crust. AFT ages demonstrate

that the Bavarian Forest was moderately reheated or

experienced enhanced denudation during the Mesozoic.

During the Jurassic and Cretaceous, the basement blocks

of these regions were variously affected by sedimentation

and structural reactivation. Eustatic sea-level rise due to

the initial breakup of Pangaea in early Jurassic time and

the opening of the Penninic and North Atlantic oceans

was responsible for this. Sedimentary overburden was

probably the trigger for the reset of the AFT ages in some

areas, but at most sites sedimentary thicknesses were less

than 200 m, and besides, larger areas of the Bavarian

Forest probably remained completely uncovered by

supracrustal rocks. To fully explain the AFT age record, a

higher crustal heat flux during the Mesozoic is required.

Increase in heat can be caused by intense fault activity,

either during crustal extension and lithospheric thinning

resulting in steeper geotherms, or by flexural subsidence

due to the loading of the crust. It is concluded that tec-

tonic subsidence generated by lithospheric extension

caused reset of the AFT ages during late Jurassic to early

Cretaceous times and that subsequent uplift was com-

pensated by recurrent reactivation of crustal lineaments

along its border regions. During the late Cretaceous,

flexural subsidence and increased fault activity played a

part in contributing heat under a far-field compressional

stress field, followed by extension during the early

Paleogene accompanied by enhanced exhumation of the

Bavarian Forest, and reactivation of the Pfahl fault zone

has possibly taken place during this period.

Acknowledgments Our study was supported by the Chinese

Academy of Science Visiting Professorship for Senior International

Scientists (Grant No. 2011T2S39) and by the Bavarian Environment

Agency (Landesamt fur Umwelt). Thanks are due to Ulrich Teipel for

providing additional sample material, to Melanie Brandmeier for help

during mineral separation and to Birgit Niebuhr for information on

Cretaceous deposits. We also acknowledge suggestions and com-

ments from Martin Danisık and Ulrich Glasmacher, which helped to

improve the manuscript.

References

Aramowicz A, Anczkiewicz AA, Mazur S (2006) Fission-track dating

of apatite from the Gory Sowie Massif, Polish Sudetes, NE

Bohemian Massif: implications for post-Variscan denudation

and uplift. N Jb Miner Abh 182(3):221–229

Behr HJ, Engel W, Franke W, Giese P, Weber K (1984) The Variscan

belt in central Europe: main structures, geodynamic implica-

tions, open questions. Tectonophysics 109:15–40

Bischoff R, Semmel A, Wagner GA (1993) Fission-track analysis and

geomorphology in the surroundings of the drill site of the

German Continental Deep Drilling Project (KTB)/Northeast

Bavaria. Z Geomorphol Suppl 92:127–143

Int J Earth Sci (Geol Rundsch)

123

Brandmayr M, Dallmeyer RD, Handler R, Wallbrecher E (1995)

Conjugate shear zones in the Southern Bohemian Massif

(Austria)—implications for Variscan and Alpine tectonothermal

activity. Tectonophysics 248:97–116

Brandon MT (1996) Probability density plot for fission-track grain-

age samples. Radiat Meas 26:663–676

Burtner RL, Nigrini A, Donelick RA (1994) Thermochronology of

lower Cretaceous source rocks in the Idaho-Wyoming thrust belt.

Aapg Bull 78:1613–1636

Coyle DA, Wagner GA, Hejl E, Brown R, Van den Haute P (1997)

The Cretaceous and younger thermal history of the KTB site

(Germany): apatite fission-track data from the Vorbohrung. Geol

Rundsch 86:203–209

Crowley KD, Cameron M, Schaefer RL (1991) Experimental studies

of annealing of etched fission-tracks in fluorapatite. Geochim

Cosmochim Acta 55:1449–1465

Danisık M, Migon P, Kuhlemann J, Evans NJ, Dunkl I, Frisch W

(2010) Thermochronological constraints on the long-term ero-

sional history of the Karkonosze Mts., Central Europe. Geo-

morphology 117:78–89

Danisık M, Stepancıkova P, Evans NJ (2012) Constraining long-term

denudation and faulting history in intraplate regions by multi-

system thermochronology: an example of the Sudetic Marginal

Fault (Bohemian Massif, central Europe). Tectonics 31, TC2003.

doi:10.1029/2011TC003012

Donelick RA (1991) Crystallographic orientation dependence of

mean etchable fission-track length in apatite—an empirical

model and experimental observations. Am Mineral 76:83–91

Dumitru TA (1993) A new computer automated microscope stage

system for fission-track analysis. Nucl Tracks Radiat Meas

21:575–580

Dunkl I (2002) TRACKKEY: a Windows program for calculation and

graphical presentation of fission track data. Comput Geosci

28:3–12

Fay M, Groschke M (1982) Die Mitteljura-Sandsteine in Niederbay-

ern—Lithologie, Stratigraphie, Palaogeographie. N Jb Geol

Palaont Abh 166:23–48

Fiala J, Fuchs G, Wendt JI (1995) Stratigraphy of the Moldanubian

zone. In: Dallmeyer RD, Franke W, Weber K (eds) Pre-Permian

geology of central and eastern Europe. Springer, Berlin,

pp 417–428

Filip J, Suchy V (2004) Thermal and tectonic history of the

Barrandian lower Paleozoic, Czech Republic: is there a fission-

track evidence for Carboniferous-Permian overburden and pre-

Westphalian alpinotype thrusting? Bull Geosci 79:107–112

Finger F, Gerdes A, Janousek V, Rene M, Riegler G (2007) Resolving

the Variscan evolution of the Moldanubian sector of the

Bohemian Massif: the significance of the Bavarian and the

Moravo-Moldanubian tectonometamorphic phases. J Geosci

52:9–28

Franke W, Haak V, Oncken O, Tanner D (eds) (2000) Orogenic

processes: quantification and modelling in the Variscan belt.

Geological Society London, Special Publication 179, pp 1–3

Gebauer D, Williams IS, Compston W, Grunenfelder M (1989) The

development of the central European continental-crust since the

early Archean based on conventional and ion-microprobe dating

of up to 3.84 b.y. old detrital zircons. Tectonophysics 157:81–96

Glasmacher UA, Mann U, Wagner GA (2002) Thermotectonic

evolution of the Barrandian, Czech Republic, as revealed by

apatite fission-track analysis. Tectonophysics 359:381–402

Gleadow AJW (1981) Fission-track dating methods: what are the real

alternatives? Nucl Tracks Rad Meas 5:3–14

Gleadow AJW, Duddy IR, Green PF, Hegarty KA (1986a) Fission-

track lengths in the apatite annealing zone and the interpretation

of mixed ages. Earth Planet Sci Lett 78:245–254

Gleadow AJW, Duddy IR, Green PF, Lovering JF (1986b) Confined

fission-track lengths in apatite—a diagnostic tool for thermal

history analysis. Contrib Mineral Petrol 94:405–415

Grauert B, Hanny R, Soptrajanova G (1974) Geochronology of a

polymetamorphic and anatectic gneiss region: the Moldanubi-

cum of the area Lam-Deggendorf, eastern Bavaria, Germany.

Contrib Mineral Petrol 45:37–63

Green PF, Duddy IR (1989) Some comments on paleotemperature

estimation from apatite fission-track analysis. J Pet Geol 12:111–114

Hancock JM, Kauffman EG (1979) The great transgression of the late

Cretaceous. J Geol Soc London 136:175–186

Hejl E, Coyle D, Lal N, Van den Haute P, Wagner GA (1997) Fission

track dating of the western border of the Bohemian massif:

thermochronology and tectonic implications. Geol Rundsch

86:210–219

Hejl E, Sekyra G, Friedl G (2003) Fission-track dating of the south-eastern Bohemian massif (Waldviertel, Austria): thermochronol-

ogy and long-term erosion. Int J Earth Sci 92:677–690

Hurford AJ, Green PF (1983) The zeta age callibration of fission-track

dating. Chem Geol 1:285-317

Holzforster F, Peterek A (2011) KTB deep drilling site and Czech-

Bavarian geopark—two best practice examples of geoscience

outreach. Geol Soc Am Field Guides 22:7–27

Horn P, Kohler H, Muller-Sohnius D (1986) The Rb–Sr isotope

geochemistry of hydrothermal quartz from the Bayerischer Pfahl

and a fluorite-barite vein from Nabburg-Wolsendorf, Federal

Republic of Germany. Chem Geol 58:259–272

Kachlık V (2008) The Moldanubicum sensu stricto (Moldanubian

Zone). In: McCann T (ed) The geology of Central Europe, vol 1.

Precambrian and Paleozoic. The Geological Society, London,

pp 75–79

Kalt A, Berger A, Blumel P (1999) Metamorphic evolution of

cordierite-bearing migmatites from the Bayerische Wald (Vari-

scan belt, Germany). J Petrol 40:601–627

Kalt A, Corfu F, Wijbrans JR (2000) Time calibration of a P-T path

from a Variscan high-temperature low-pressure metamorphic

complex (Bayerische Wald, Germany), and the detection of

inherited monazite. Contrib Mineral Petrol 138:143–163

Ketcham RA (2005) Forward and inverse modeling of low-temper-

ature thermochronometry data. In: Reiners PW, Ehlers TA (eds)

Low-temperature thermochronology: techniques, interpretations,

and applications. Reviews in Mineralogy and Geochemistry,

Mineralogical Society of America 58, pp 275–314

Ketcham RA, Carter A, Donelick RA, Barbarand J, Hurford AJ

(2007a) Improved measurement of fission-track annealing in

apatite using c-axis projection. Am Mineral 92:789–798

Ketcham RA, Carter A, Donelick RA, Barbarand J, Hurford AJ

(2007b) Improved modeling of fission-track annealing in apatite.

Am Mineral 92:799–810

Klein T, Kiehm S, Siebel W, Shang CK, Rohrmuller J, Dorr W,

Zulauf G (2008) Age and emplacement of late-Variscan granites

of the western Bohemian Massif with main focus on the

Hauzenberg granitoids (European Variscides, Germany). Lithos

102:478–507

Kley J, Voigt T (2008) Late Cretaceous intraplate thrusting in central

Europe: effect of Africa-Iberia-Europe convergence, not Alpine

collision. Geology 36:839–842

Kohler H, Muller-Sohnius D (1980) Rb–Sr systematics on the

paragneiss series from the Bavarian Moldanubicum, Germany.

Contrib Mineral Petrol 71:387–392

Kohler H, Muller-Sohnius D (1985) Rb–Sr Altersbestimmung and Sr-

Isotopensystematik an Gesteinen des Regensburger Waldes,

(Moldanubikum NE-Bayerns). N Jb Mineral Abh 151:149–178

Lange JM, Tonk C, Wagner GA (2008) Apatitspaltspurdaten zur

postvariszischen thermotektonischen Entwicklung des

Int J Earth Sci (Geol Rundsch)

123

sachsischen Grundgebirges—erste Ergebnisse. Z dt Ges Geowiss

159(1):123–132

Laslett GM, Green PF, Duddy IR, Gleadow AJW (1987) Thermal

annealing of fission tracks in apatite, 2. A quantitative analysis.

Chem Geol 65:1–13

Mattern F (1995) Late Carboniferous to early Triassic shear sense

reversals at strike slip faults in eastern Bavaria. Zbl Geol Palaont

Teil I 1993:1471–1490

Niebuhr B, Purner T, Wilmsen M (2009) Lithostratigraphie der

außeralpinen Kreide Bayerns. Schriftenr dt Ges Geowiss

65:7–58

Niebuhr B, Wilmsen W, Chellouche P, Richardt N, Purner T (2011)

Stratigraphy and facies of the Turonian (upper Cretaceous)

Roding formation at the southwestern margin of the Bohemian

massif (Southern Germany, Bavaria). Schriftenreihe dt geol Ges

162:295–316

O’Sullivan PB, Parrish RR (1995) The importance of apatite

composition and single-grain ages when interpreting fission

track data from plutonic rocks: a case study from the Coast

Ranges, British Columbia. Earth Planet Sci Lett 132:213–224

Paul J, Schroder B (2012) Rotliegend im Ostteil der Suddeutschen

Scholle. Schriftenreihe dt Ges Geowiss 61:697–706

Peterek A, Rauche H, Schroder B, Franzke HJ, Bankwitz P, Bankwitz

E (1997) The late- and post-Variscan tectonic evolution of the

Western Border fault zone of the Bohemian Massif (WBZ). Geol

Rundsch 86:191–202

Pienkowski G et al (2008) Jurassic. In: McCann T (ed) The geology

of Central Europe, vol. 2: Mesozoic and Cenozoic. The

Geological Society, London, pp 823–922

Platzer R (1992) Kinematik und Alter der Donaustorung bei Schlogen

(sudliche Bohmische Masse, Oberosterreich). Frankf geowiss

Arb A11:141–144

Propach G, Baumann A, Schulz-Schmalschlager M, Grauert B (2000)

Zircon and monazite U-Pb ages of Variscan granitoid rocks and

gneisses in the Moldanubian zone of eastern Bavaria, Germany.

N Jb Geol Palaont Mh 6:345–377

Ratschbacher L, Dingeldey C, Miller C, Hacker BR, McWilliams MO

(2004) Formation, subduction and exhumation of Penninic

oceanic crust in the Eastern Alps: time constraints from40Ar/39Ar geochronology. Tectonophysics 394:155–170

Schaller M, von Blanckenburg F, Hovius N, Kubik PW (2001) Large-

scale erosion rates from in situ produced cosmogenic nuclides in

European river sediments. Earth Planet Sci Lett 188:441–458

Scheck-Wenderoth M, Krzywiec P, Zuhlke R, Maystrenko Y,

Froitzheim M (2008) Permian to Cretaceous tectonics. In:

McCann T (ed) The geology of Central Europe, vol 2. Mesozoic

and Cenozoic. The Geological Society, London, pp 990–1030

Schreyer W (1967) Geologie und Petrographie der Umgebung von

Vilshofen/Nieder-bayern. Geol Bavarica 58:114–132

Schroder B (1987) Inversion tectonics along the western margin of

the Bohemian massif. Tectonophysics 137:93–100

Schroder B, Ahrendt H, Peterek A, Wemmer K (1997) Post-Variscan

sedimentary record of the SW margin of the Bohemian massif: a

review. Geol Rundsch 86:178–184

Siebel W, Shang CK, Reitter E, Rohrmuller J, Breiter K (2008) Two

distinctive granite suites in the SW Bohemian Massif and their

record of emplacement: constraints from geochemistry and

zircon 207Pb/206Pb chronology. J Petrol 49:1853–1872

Siebel W, Hann HP, Danisık M, Shang CK, Berthold C, Rohrmuller J,

Wemmer K, Evans JN (2010) Age constraints on faulting and

fault reactivation: a multi-chronological approach. Int J Earth Sci

99:1187–1197

Siebel W, Shang CK, Thern E, Danisık M, Rohrmuller J (2012)

Zircon response to high-grade metamorphism as revealed by

U-Pb and cathodoluminescence studies. Int J Earth Sci

101:2105–2123

Teipel U, Eichhorn R, Loth G, Rohrmuller J, Holl R, Kennedy A

(2004) U-Pb SHRIMP and Nd isotopic data from the western

Bohemian Massif (Bayerischer Wald, Germany): implications

for upper Vendian and lower Ordovician magmatism. Int J Earth

Sci 93:782–801

Teipel U, Galadı-Enrıquez E, Glaser S, Kromer E, Rohrmuller J

(2008) Erdgeschichte des Bayerischen Waldes. Geologischer

Bau, Gesteine, Sehenswurdigkeiten. Bayerisches L.-Amt Um-

welt, Augsburg

Thomson SN (2001) Using apatite fission-track thermochronology to

investigate late Cretaceous inversion of the Variscan basement

blocks of central Germany (Harz and Thuringer Wald).

Exkursionsfuhrer und Veroffentlichungen der GGW 214:223

Thomson SN, Zeh A (2000) Fission-track thermochronology of the

Ruhla crystalline complex: new constraints on the post-Variscan

thermal evolution of the NW Saxo-Bohemian massif. Tectono-

physics 324:17–35

Ulrych J, Pivec E, Lang M, Balogh K, Kropacek V (1999) Cenozoic

intraplate volcanic rocks series of the Bohemian Massif: a

review. GeoLines 9:123–129

Unger HJ (1984) Geologische Karte von Bayern 1: 50 000.

Erlauterungen zum Blatt Nr. L 7545 Griesbach im Rottal. 245

pp; Munich (BGL)

Unger HJ, Schwarzmeier J (1987) Bemerkungen zum tektonischen

Werdegang Sudostbayerns. Geol Jb A 105:3–23

Ventura B, Lisker F (2003) Long-term landscape evolution of the

northeastern margin of the Bohemian massif: apatite fission-

track data form the Erzgebirge (Germany). Int J Earth Sci

92:691–700

Ventura B, Lisker F, Kopp J (2009) Thermal and denudation history

of the Lusatian Block (NE Bohemian Massif, Germany) as

indicated by apatite fission-track data. In: Lisker F, Ventura B,

Glasmacher UA (eds) Thermochronological methods: from

palaeotemperature constraints to landscape evolution models.

Geological Society London, Special Publication 324,

pp 181–192

Vercoutere C (1994) The thermotectonic history of the Brabant

massif (Belgium) and the Naab basement (Germany): an apatite

fission-track analysis. PhD Thesis Univ Ghent, 191 pp

Voigt S (2009) The Lusatia Krkonose high as a late Cretaceous

inversion structure: evidence from the surrounding Cretaceous

basins. Z Geol Wiss 37:15–39

Voigt S, Wagreich M, Surlyk F, Walaszczyk I, Ulicny D, Cech S,

Voigt T, Wiese F, Wilmsen M, Niebuhr B, Reich M, Funk H,

Michalık J, Jagt JWM, Felder PJ, Schulp AS (2008) Cretaceous.

In: McCann T (ed) The geology of Central Europe, vol. 2:

Mesozoic and Cenozoic. The Geological Society, London,

pp 923–997

Wilmsen M, Niebuhr B, Chellouche P, Purner T, Kling M (2010)

Facies pattern and sea-level dynamics of the early Late

Cretaceous transgression: a case study from the lower Danubian

Cretaceous Group (Bavaria, southern Germany). Facies

56:483–507

Ziegler PA (1990) Geological Atlas of western and central Europe.Shell International Petroleum Maatschappi BV, The Hague

Ziegler PA, Dezes P (2007) Cenozoic uplift of Variscan massifs in the

alpine foreland: timing and controlling mechanisms. Global

Planet Change 58:237–269

Ziegler PA, Cloetingh S, van Wees JD (1995) Dynamics of intra-plate

compressional deformation: the Alpine foreland and other

examples. Tectonophysics 252:7–59

Int J Earth Sci (Geol Rundsch)

123