INTERNATIONAL GEOLOGY REVIEW, 2015
http://dx.doi.org/10.1080/00206814.2015.1092097
Origin and evolution of the South Carpathians basement (Romania): a zircon
and monazite geochronologic study of its Alpine sedimentary cover
Adriana M. Stoicaa, Mihai N. Duceaa,b, Relu D. Robana and Denisa Jianua
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a
Faculty of Geology and Geophysics, University of Bucharest, Bucharest, Romania; bDepartment of Geosciences, University of Arizona,
Tucson, AZ, USA
ABSTRACT
ARTICLE HISTORY
This study investigates the advantages of a multi-mineral approach in detrital mineral geochronology, as tracers of regional tectonic events. We present new detrital zircon and monazite ages
on six sands and sandstones collected from the South Carpathians, Romania. They represent
clastic sediments derived from the pre-Alpine basement and related sedimentary cover, which
accumulated in distinct palaeogeographic and geotectonic environments, during the multiphase
Alpine tectonic evolution. Three samples are mid-Cretaceous sandstones from different depositional settings of the syn-tectonic clastic wedge that activated during the intra-Albian thrusting
phase. One is Upper Cretaceous sandstone from the South Carpathian foredeep, associated with
the intra-Maastrichtian thrusting phase. Two additional samples are Quaternary fluvial deposits
reworking the Upper Cretaceous hinterland basin siliciclastic deposits. Detrital zircon U–Pb ages
confirm periods of zircon-producing magmatism in the Neoproterozoic (ca. 590–850 Ma),
Cambrian–Ordovician (ca. 540–450 Ma), and, in one sample, Late Cretaceous (ca. 76–81 Ma).
Precambrian tectonics is documented by inherited zircons (ca. 0.9–1.2 Ga, 1.8–2.2 Ga, 2.6–
2.8 Ga), most likely recycled from metasedimentary rock units from the Getic basement. Zircon
age distribution patterns from all samples are consistent with derivation from eroded equivalents
to basement rocks of the Getic–Supragetic thrust sheets. In contrast, chemical ages on all detrital
monazites document a single metamorphic event of Late Devonian to Carboniferous ages (ca.
300–400 Ma), coincident with the Variscan orogeny in central Europe. A small proportion of the
zircon population is also of the same age range (ca. 380–320 Ma) – those zircons typically have
high U–Th ratios, characteristic of metamorphic zircons. Detrital monazite ages are consistent with
previous limited geochronological data on high-pressure metamorphic rocks from the Getic–
Supragetic basement. In addition to the timing of tectonic events in the Carpathian basement,
geochronology of detrital minerals brings new constraints regarding the duration of these events.
Received 16 May 2015
Accepted 6 September 2015
1. Introduction
With the refinement of analytical methods that can be
applied to detrital material, particularly single-grain isotopic analyses, the sedimentary record has become an
invaluable tool in understanding the tectonic evolution
of their source terrains (Gehrels 2014). U–Pb zircon geochronology is a well-established technique, being extensively used in provenance analyses, and palaeogeographic
and tectonic reconstructions (e.g. Rainbird et al. 1992;
Gehrels and Dickinson 1995; Gehrels et al. 1995;
Sircombe and Freeman 1999; Cawood and Nemchin
2000; Fedo and Farmer 2001). Furthermore, laser ablation
ICP-MS dating on zircons yields precise and accurate U–Pb
ages, while considerably reducing the time for data acquisition compared with conventional thermal ionization
mass spectrometry (TIMS) techniques, becoming the
Detrital; zircon; monazite;
provenance; palaeotectonic
evolution; geochronology;
South Carpathians
preferred method for studies requiring large numbers of
analyses (Kosler and Sylvester 2003). The majority of provenance studies rely solely on age information provided
by detrital zircon geochronology (more recently augmented by petrogenetic information using in situ Hf isotopes
on the same zircon grains), to trace back igneous and
high-temperature metamorphic events of basement
units that contributed to the sediment load.
Combined detrital zircon–monazite chronology
approaches in provenance studies have demonstrated
the utility of monazite as a reliable complementary tracer
of orogenic processes that were otherwise under-represented or even entirely missed by zircon ages alone (e.g.
Adachi and Suzuki 1994; Suzuki and Adachi 1994;
Fergusson et al. 2001; Moecher et al. 2011; Hietpas et al.
2010, 2011). Monazite is a common accessory mineral in a
CONTACT Adriana M. Stoica
stoica.mala@gmail.com
Supplemental data for this article can be accessed at http://dx.doi.org/10.1080/00206814.2015.1092097
© 2015 Taylor & Francis
KEYWORDS
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A. M. STOICA ET AL.
wide range of magmatic and metamorphic rocks, including granites, pegmatites, felsic volcanic rocks, mediumand high-grade metamorphic rocks, and low-grade metasedimentary rocks (Parrish 1990). Owing to its moderate
resistance to chemical and mechanical weathering, detrital monazite is a widespread occurrence in the heavy
mineral suite of clastic sediments and sedimentary rocks.
This study investigates the advantages of combining
two high-temperature chronometers (U–Pb on zircons
and U–Th/Pb on monazites) in deciphering the major
tectonic events that resulted in the magmatic and metamorphic making of the South Carpathians basement in
central Romania. We report 521 U–Pb ages on detrital
zircons and 178 Th–U–total Pb ages on detrital monazites collected from the siliciclastic sedimentary archive
derived from the South Carpathian basement and preserved in adjacent, tectonically controlled basins, during
the Cretaceous thrusting events. Integrating all the ages
obtained for this study allows additional interpretations
regarding the timescales of processes that were
involved in the genesis of the Carpathian pre-Alpine
terranes. We provide first-order constraints on the timing of magmatism and metamorphism and show that
the major episode of regional metamorphism that
shaped the South Carpathians would have been almost
entirely missed in the zircon record, whereas it dominates the monazite archive. We also provide constraints
on the duration and changes in the rates of magmatic
activity, from episodes of increased magmatic pulses to
periods of little to no magma production.
2. Geologic setting
The South Carpathians form a 300 km-long E–W-trending
segment of the Romanian Carpathian mountain belt. The
South Carpathians have a fold and thrust structure with
south vergence (Burchfiel and Bleahu 1976), assembled
during the Alpine continental collision that followed the
closure of the Ceahlău–Severin ocean, which was a relatively small oceanic basin within the Tethyan realm
(Schmid et al. 2008). It consists of several thrust nappes:
the Getic–Supragetic and Danubian nappe systems of
continental origin separated by the oceanic Severin tectonic melange (Figure 1). More detailed classifications of
the thrust units are found in Săndulescu (1984), Balintoni
(1997), and Iancu et al. (2005), among others. Their Alpine
tectonic evolution involves two Cretaceous and one Late
Miocene contraction events, separated by quiescent periods and some characterized by extensional basin formation (Săndulescu 1984; Iancu et al. 2005). The local
literature has several conflicting interpretations about
the relative timing of Alpine shortening events in the
South Carpathians; in part, these interpretations are
hampered by the limited syn-tectonic sedimentary cover
in the South Carpathians, which is in contrast with the
continuation of these structures in the East Carpathians
where Mesozoic and Cenozoic deposits abound
(Săndulescu 1984). One view is that the mid-Cretaceous
(intra-Aptian) phase emplaced the Supragetic units onto
the Getic nappes (Iancu 1985; Hann 1995), whereas the
Latest Cretaceous (intra-Maastrichtian) phase overthrust
the Getic–Supragetic nappe system and the Severin complex over the Danubian domain (Berza et al. 1994; Iancu
et al. 2005). The Late Miocene (intra-Sarmatian) phase is
responsible for thrusting of the entire South Carpathian
nappe stack onto the Getic Depression foredeep (Mațenco
et al. 1997). However, some intra-Oligocene contractional
discordances were documented into the foreland area of
South Carpathians (Răbăgia et al. 2011), as an effect of
transpression processes along the northern Moesian
margin.
Late Cretaceous times (Early Maastrictian) pre-dating
the intra-Maastrichtian shortening event was an extensional period, marked by the development of extensional
basins regionally known as Gosau-type basins (Schuller
2004) and the intrusion of a calc-alkaline magmatic suite,
locally known as the ‘banatitic suite’, into the Getic–
Supragetic nappe complex (Berza et al. 1998; Nicolescu
et al. 1999; Ciobanu et al. 2002). The Upper Cretaceous
magmatism extends to the south in Serbia and eastwards
in Bulgaria, forming a bending ore-bearing igneous belt –
The Banatitic Magmatic and Metallogenetic Belt, which is
part of the larger Apuseni–Banat–Srednogorie magmatic
arc extending into Bulgaria to the south and east (Berza
et al. 1998). Previously believed to have spanned a long
period (>50 Ma) (Berza et al. 1998, for a review), limited
modern geochronology data (e.g. Zimmerman et al. 2008
and references therein) suggest that magmatism was
short-lived and limited to the Upper Cretaceous
(between 75 and 85 Ma) in Romania.
The pre-Alpine basement of the South Carpathians
Metamorphic rocks, here referred to as basement, constitute more than 85% of the exposed rocks in the
South Carpathians. The pre-Mesozoic rock assemblages
preserved in the South Carpathian basement belong to
the Getic–Supragetic and the Danubian domain, and
mainly comprise Neoproterozoic and Palaeozoic preWestphalian metaigneous and metasedimentary units
with inferred Variscan high-grade metamorphism.
Upper Carboniferous to Permian sedimentary strata
and small volumes of associated magmatic rocks constrain the episode or episodes of metamorphism to be
pre-latest Palaeozoic (Iancu et al. 2005). A few eclogite
and garnet amphibolite facies metamorphic rocks from
INTERNATIONAL GEOLOGY REVIEW
3
(a)
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(b)
(c)
Figure 1. (a) Studied area in the context of geotectonic setting of Central and Southeastern Europe and Balcani Mountains. (b)
Simplified tectonic map of Southern Carpathian basement units and sedimentary cover, adapted after Săndulescu (1984), Berza et al.
(1994), Mațenco et al. (1997), and Schmid et al. (1998), showing detrital zircon and monazite localities (circles) and sedimentary logs
positions (squares). See Figure 3 for stratigraphic ages and depositional context of sampled units. (c). Schematic cross section of
Southern Carpathian basement, showing nappe structure. Modified from Csontos and Voros (2004).
the Getic have garnet Sm–Nd ages of Variscan age
(320–360 Ma, Medaris et al. 2003). Regarding the exact
origin of these units prior to their metamorphism and
the boundary between them, relatively little is known to
date. Balintoni and collaborators have initiated several
zircon geochronologic studies of these basement terranes, but focused most of their work on interpreting
the palaeogeographic origin of these basement rocks
rather than their petrologic origin. Nevertheless, their
growing database of U–Pb zircon ages from South
Carpathian basement rocks is the only one that provides
basement age distributions here. Of their zircon age
data bank, Getic–Supragetic zircons have been published (Balintoni et al. 2014, for a review), whereas
Danubian zircons, and particularly zircons from granitic
rocks constituting the upper part of the Danubian, are
mostly unpublished (Balintoni and Balica, personal
communication).
The third tectonic unit incorporated into the Alpine
South Carpathian belt – the Severin–Ceahlău nappe
complex – is entirely Mesozoic, including Upper
Jurassic oceanic crust rocks overlain by siliceous
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A. M. STOICA ET AL.
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pelagic strata of Azuga Formation and Lower
Cretaceous distal to mid-fan turbiditic deposits –
Sinaia and Comarnic Formations (Marunțiu 1983;
Seghedi and Oaie 1997).
Basement rocks of the Getic–Supragetic nappes
The Getic–Supragetic nappe system has been differentiated into several pre-Alpine basement units
(Drăgușanu and Tanaka 1999; Iancu et al. 2005;
Balintoni et al. 2009). It is unclear whether all of the
lithostratigraphic units within the Getic–Supragetic
basement can legitimately be characterized as individual terranes as reviewed in Balintoni et al. (2014).
Most Getic–Supragetic units are petrographically made
of metamorphosed volcanic and volcano-sedimentary
units and calc-alkaline metaigneous rocks suggestive
of former arcs mixed with accretionary wedge sediments and some back-arcs dominated by mafic rocks,
all of which were metamorphosed. Limited metamorphic geochronology data from the Getic–
Supragetic basement units (Sm–Nd garnet-whole-rock
isochron ages on Făgăraș and Sebeş–Lotru rocks,
Drăgușanu and Tanaka 1999; Medaris et al. 2003) suggest that high-grade metamorphism occurred during
the Variscan orogeny (320–360 Ma).
U–Pb zircon ages on several basement Getic and
Supragetic orthogneisses establish Ordovician intrusive
ages for Leaota, Padeș, and Caraș lithostratigraphic units,
or terranes (e.g. Balintoni et al. 2009, 2010). The Sebeş–
Lotru terrane, the most extensive basement fragment in
the South Carpathians, is dominated by calc-alkaline
metaigneous rocks, and comprises two units: the structurally higher, Ordovician, Cumpăna unit, and the structurally lower, Neoproterozoic to Cambrian, Lotru unit
(Balintoni et al. 2010). The Făgăraș terrane (Drăgușanu
and Tanaka 1999) is composed of pre-Variscan amphibolites, paragneisses, and mica-schist-dominated metamorphic units with large carbonate lenses.
There is little doubt that all of these terranes are
dominated by subduction-related arc magmatic rocks
that formed along the margin of Gondwana during
the Neoproterozoic and continuing into the Cambro–
Ordovician (Stern 1994; Nance et al. 2008) as most basement terranes of central and Eastern Europe are. It is
believed that they docked to the Eastern European
craton during the Variscan collision (von Raumer et al.
2013)
Basement rocks of the Danubian nappes
The pre-Alpine basement of the Danubian domain consists of Neoproterozoic metamorphic complexes,
intruded by Neoproterozoic granitoid bodies (Liégeois
et al. 1996) and post-Variscan Permian igneous rocks
(Balintoni and Balica, unpublished) and unconformably
overlain by thin Upper Ordovician–Lower Carboniferous
sedimentary strata of local extent. Structurally, the
Danubian basement has been differentiated into two
metamorphic units: the Lainici–Păiuş metasedimentary
rock sequence and the Drăgşan terrane comprising
metavolcanic rocks separated by a third terrane –
Tișovița with oceanic affinity (Berza and Seghedi 1983;
Berza and Iancu 1994; Seghedi et al. 2005; Balintoni
et al. 2010). The nappe stacking of these distinct units
is considered Variscan, constrained by the Permian–
Mesozoic low-grade metasedimentary successions that
seal the contact surface (Berza and Seghedi 1983; Berza
and Iancu 1994; Seghedi et al. 2005).
For the purpose of this study, we compiled a cumulative probability density diagram with all of the previously published zircon U–Pb ages for the Getic–
Supragetic and the Danubian basement units, respectively (Figure 2).
3. Sampling areas
Six samples were collected from several Cretaceous and
Quaternary detrital sedimentary deposits from the
South Carpathians: 1-DG, 2-BB, and 3-SP from the midCretaceous Bucegi Formation, 4-TR from the Upper
Cretaceous Turnu Formation, and 5-PS and 6-PSR from
Quaternary sediments along Sebeșel Valley, Pianu de
Sus area (details regarding the sampling locations are
provided in Figure 1 and in Supplementary Table 1 (see
http://dx.doi.org/10.1080/00206814.2015.1092097
for
supplementary tables), and the correlation with lithostratigraphic units is shown in Figure 3). We targeted
clastic sediments that accumulated in syn- or posttectonic environments related to the Cretaceous thrusting events: the syn-tectonic clastic wedge associated
with the intra-Albian thrusting phase (samples 1-DG,
2-BB, and 3-SP) and the South Carpathian foredeep
associated with the intra-Maastrichtian phase (sample
4-TR), as well as modern sediments (samples 5-PS and
6-PSR). Brief descriptions are provided for each sedimentary unit under investigation in this study.
Bucegi Formation
The Bucegi Formation outcrops over an area of ca.
200 km, in the easternmost part of South Carpathians,
structurally belonging to Severin–Ceahlău nappes.
Exceeding 2000 m in thickness, the Bucegi Formation
is dominated by bedded polimictic clast-supported conglomerates with sandstone intercalations and carbonate
and metamorphic olistoliths (Olariu et al. 2014; Patrulius
1969). Three stratigraphic units were recognized: a
INTERNATIONAL GEOLOGY REVIEW
5
Pooled detrital monazite and zircon
ages for the 6 analyzed samples
Total monazite: n=178
Total zircon: n=521
Getic basement units
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Total zircon: n=747
Danubian basement units
Total zircon: n=511
0
500
1000
1500
2000
2500
3000
Age (Ma)
Figure 2. Cumulative relative probability density plots for the combined monazite and zircon ages from all sampled locations, and
compiled existing U–Pb data for the two basement units: Getic–Supragetic domain (Balintoni et al. 2009; 2010; Profeta et al. 2013;
Balintoni et al., unpublished data) and Danubian domain (Balintoni et al. 2011).
Lower Member up to 100 m thick, poorly sorted conglomerates with shale and sandstone intercalations; a
Middle Member, about 1500 m thick, poorly sorted,
massive conglomerates and coarse sandstones; and an
Upper Member about 400 m thick, with frequent channelized and tabular fine conglomerates and sandstones
with lateral facies variations – Babele and Scropoasa–
Lăptici sandstones.
The Albian depositional age of the Bucegi Formation
was constrained by palaeontological dating of the underlying Barremian–Aptian turbiditic deposits and the
unconformably overlying upper Albian hemipelagic
deposits (Murgeanu and Patrulius 1957; Patrulius 1969;
Melinte and Jipa 2007). Olariu et al. (2014) interpreted the
depositional environment of the Bucegi Formation to be
a narrow (10–20 km) shelf margin of a relatively deepwater basin in a syn-tectonic setting. The coarse-grained,
sub-rounded sediment flux is explained by its proximity
to the actively deforming mountain range during the
intra-Albian thrusting phase. The Lower and Middle
Members are considered to be of deep-water slope and
basin-floor origin, whereas the Upper Member is interpreted as fluvial and shallow-marine deposits.
For the purpose of this study, we sampled and analysed coarse-grained sandstones from the Lower
Member (sample 3-SP) and Upper Member (samples
2-BB and 1-DG).
Turnu Formation
Turnu Formation is a coarse-grained clastic succession,
with variable thickness (from 400 to 2000 m) that crops
out along Olt valley, between the Supragetic basement
to the north and Palaeogene and younger sediments
towards the south. Turnu Formation is part of the South
Carpathian foredeep (also known as the Getic
Depression) that extends ca. 150–200 km southwards
from the orogen to the undeformed Moesian platform.
During its Late Cretaceous to late Pliocene sedimentation history, the South Carpathian foredeep accommodated more than 6 km of sediments (Mațenco et al.
1997). Turnu Formation comprises massive or normal
graded bedded conglomerates and coarse-grained
sandstones with laminated marl and shale intercalation,
and it is overlain by Căciulata Formation in a general
finning-up sequence. The Campanian–Maastrichtian age
for Turnu Formation is attributed to specific Upper
Cretaceous ammonite fauna occurrence (Murgeanu
et al. 1968).
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A. M. STOICA ET AL.
Figure 3. Schematic stratigraphic sections of Cretaceous to Quaternary strata from the three areas under investigation, showing the
depositional context of sampled units. (a) Lower Cretaceous Bucegi Formation section, drawn using data from Olariu et al. (2014); (b)
Upper Cretaceous Turnu and Căciulata formations, drawn using data from Murgeanu et al. (1968); and (c) Quaternary deposits
section, drawn using data from Savu et al. (1968).
These Upper Cretaceous detrital deposits lie discordantly on the Supragetic basement and mark the beginning of the latest Cretaceous to Palaeogene sedimentation
stage in the South Carpathians foredeep (Săndulescu 1984;
Mațenco et al. 1997). Turnu Formation is interpreted as
marine slope fanglomerates accumulating in a tectonically
controlled setting marked by transtension to extension,
during latest Cretaceous to Palaeogene, which generated
several E–W-trending basins (Mațenco et al. 1997).
We collected and analysed one sample (4-TR) from a
coarse-grained sandstone, towards the top of the sedimentary succession of Turnu Formation.
Pianu de Sus
The Pianu de Sus area, north from Sebeș Mountains, consists
of Upper Cretaceous and Quaternary sedimentary units covering uncomformably the Getic basement. The Cretaceous
deposits are a thick (ca. 1500 m) clastic succession comprising mainly poorly sorted conglomerates, breccia, and
coarse-grained sandstones, with shale and marl intercalations (Anastasiu et al. 2004). The Pleistocene–Holocene
sediments consist of unconsolidated polymictic sands and
gravels with quartzite boulders, unconformably overlying
the Cretaceous deposits (Tamaș-Bădescu et al. 2004).
INTERNATIONAL GEOLOGY REVIEW
7
shallow-water fanglomerates, and shelf siliciclastic deposits
in the latest Cretaceous. Quaternary deposits lay unconformably over the Upper Cretaceous strata. They formed in
a fluvial depositional environment, and are primarily
reworking the underlying Cretaceous sediments.
Two samples were collected and analysed from
Pianu de Sus area, one sample (5-PS) from a poorly
consolidated Quaternary terrace deposit and the
other from modern alluvial sediment from the
Sebeșel riverbed – right tributary of Pianu river (sample 6-PSR).
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4. Analytical methods
Approximately 10 kg of sample was collected at each
location. The samples were crushed, sieved through a
300 μm sieve, and washed. Heavy mineral concentrates
in <300 μm size fractions were separated with a heavy
liquid (diiodomethane with 3.3 g cm−3 density) and
magnetically using a Frantz Magnetic Barrier Separator
at 20° and 10° slopes. We further used the nonmagnetic fraction that concentrates the zircon crystals
and the 0.7A fraction concentrating monazites. Zircon
and monazite crystals were mounted en masse, along
with several age standard crystals, in epoxy resin and
polished using 2500 grit sandpaper, until their surface
was sufficiently exposed. The sample mounts were then
carbon coated to ensure good conductivity. All SEM
investigations, U–Pb isotopic analyses for zircons, and
chemical analyses for monazites were performed at the
University of Arizona.
Zircon analysis
Figure 4. (a) Cathodoluminescence image of a selected area of
sample 4-TR zircon grain mount, revealing complex internal
zonation of most zircons. Owing to the small size of zircon
crystals (<150 μm), ablation pits (30 μm) were placed within a
single domain, or overlapping two domains within the crystal’s
core, in some cases. (b) Backscatter electron image of a selected
area of sample 4-TR monazite grain mount. The mineral assemblage includes: 1, monazite; 2, zircon; 3, rutile; and 4, garnet.
All these sediments were accumulated on the southern
rim of the Transylvanian Basin, developed in the Carpathian
hinterland. The Transylvanian Basin is a post-Cenomanian
to Pliocene intra-Carpathian sedimentary basin bordered
by the Eastern and South Carpathians and delimited from
the adjacent Pannonian Basin by the Apuseni Mountains
(Kreszek and Filipescu 2005). The sedimentary fill, in our
sampling area, evolved from non-marine to marine,
Following mounting, zircon crystals were first identified
using a SEM equipped with an energy-dispersive spectrometry (EDS) detector. We also used cathodoluminescence (CL) imaging to identify potential defects or
inclusions in crystals (Figure 4a), as well as other CL
evidence for inherited zircon cores or zonal overlaps
to be avoided during laser ablation.
U–Pb isotopic analyses were performed in situ on
single zircon grains using a 193 nm Excimer laser ablation system with a laser beam diameter of 30 μm
attached to a Nu Plasma multicollector inductively
coupled plasma-mass spectrometer (LAMC-ICP-MS) at
the Arizona LaserChron Center (Gehrels et al. 2006,
2008). About 100 grains were measured from each
sample (by random selection), using the quantitative
approach of detrital zircon analysis, indicating that the
analysed sample was to be as representative of the
overall detrital zircon population as possible, thus capturing all potential zircon donor terranes (Fedo et al.
8
A. M. STOICA ET AL.
2003; Andersen 2005). In this sense, we systematically
analysed an array of the mounted zircons, irrespective
of their morphology or colour. The only selection made
was in terms of avoiding obvious imperfections, such as
inclusions, fractures, or domain boundaries (core–rim
interface or zone overlaps highlighted in CL).
A zircon age standard was analysed every 10
unknowns. We used the University of Arizona internal
standard, a Sri Lanka zircon crystal that yields an IDTIMS age of 563.5 ± 3.2 Ma (Gehrels et al. 2008).
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Monazite analysis
EDS identification and BSE imaging of the monazite
grains were carried out first using a Cameca 2 SEM
(Figure 4b). In situ chemical analyses of monazite in all
six rocks were carried out in polished mounts using the
Cameca SX-100 electron microprobe. About 30 monazite grains were analysed for each sample. Five spectrometers were employed using the crystal arrangement
thallium acid phthalate (TAP), large pentaerythritol crystal (LPET), lithium fluoride (LIF), and large lithium fluoride crystal (LLIF). An initial wavelength-dispersive
spectrometry scan was performed on a representative
monazite grain to determine the appropriate background, pulse height analyser settings, overlap corrections, and X-ray lines to use for the analyses.
During each analysis, Ca, P, S, and Si were measured at
15 kV, 40 nA using a focused beam and counting for
30 seconds on peak and 30 seconds on background.
Beam conditions were then changed to 15 kV and
299 nA, and U, Pb, Y, La, Ce, Pr, Nd, Sm, Gd, and Dy
concentrations were measured, again using a focused
beam. The Pb Ma line was measured simultaneously
using two LPET crystals counting for 120 seconds on
peak and 120 seconds on background, and the results
were combined to provide greater accuracy. Pb Ma X-ray
counts were adjusted for overlap from the Y Lc2 X-ray
line using adjustment factors determined by measurement on a YAG garnet interference standard. U Mb was
measured on an LPET crystal for 60 seconds on peak and
60 seconds on background, and the U Mb X-ray counts
were adjusted for overlap from the ThM3N4 X-ray line
using adjustment factors determined by measurement
on a ThO2 interference standard. Th Ma was measured on
an LPET crystal for 60 seconds on peak and 60 seconds on
background, and Y La was measured on a TAP crystal for
240 seconds on peak and 240 seconds on background. La
La, Ce La, and Nd Lb were measured on an LIF crystal for
60 seconds peak and 60 seconds background each. The
Lb lines of the remaining REE elements were measured
using an LLIF crystal for 60 seconds peak and 60 seconds
background each.
Well-characterized natural and synthetic standards
were used for all calibrations including synthetic UO2
and ThO2 from Cannon Microprobe Company for U and
Th, NBS glass K0229 for Pb, and synthetic YAG garnet from
C.M. Taylor Company for Y. Monazite 44,069 of Aleinikoff
et al. (2006) was used as a test standard. Matrix corrections
were performed using the PAP (Pouchou and Pichoir)
correction method (Pouchou and Pichoir 1984).
The monazite chemical ages were calculated using
the elemental concentrations of Pb, Th, and U in an
Excel spreadsheet developed by Michael J. Jercinovic
that solves the age equation given in Montel et al.
(1996). The reported errors on calculated ages are at
the 1σ level. The spreadsheet can be downloaded from
http://geoinfo.nmt.edu/labs/microprobe/monazite/
home.html.
5. Results
Probability density plots and histograms were generated
for the detrital zircon and monazite age spectra for each
of the six analysed samples (Figure 5). The diagrams
were plotted using the Isoplot add-on (Ludwig 2001).
Only those grains showing more than 90% concordance
were considered for this study. The only zircons that
yielded discordant ages are mainly Palaeoproterozoic
to Neoarchaean and were not the subject of any
interpretation. The isotopic analyses conducted for this
study are available in Supplementary Table 2.
Detrital zircon age spectra
The detrital zircon age spectrum of sample 1-DG (n = 85)
is dominated by Precambrian, mainly Neoproterozoic
between 580 and 850 Ma (48%) and Palaeozoic ages
peaking at 460 Ma (27%) (Figure 5). The NeoMesoproterozoic limit is represented by 6% of the zircon
ages. There is a paucity of detrital ages between 1.2 and
1.8 Ga. The age spectrum records contributions of
Palaeoproterozoic to Neoarchaean ages accounting for
15% of the total detrital zircon ages. The youngest
recorded age is Carboniferous (358.5 ± 3.3 Ma), represented by one zircon grain with a U–Th ratio of 44.3.
In sample 2-BB (Figure 5), the U–Pb ages of 84 detrital zircons reveal a prominent population of
Neoproterozoic ages (70% of the entire age population)
ranging from 540 Ma to 1 Ga, with two ~100 million
year hiatuses between 730–820 Ma and 860–960 Ma.
The Mesoproterozoic era is absent from the detrital
zircon record, whereas older, Palaeoproterozoic and
Archaean ages are present but less abundant, accounting for 11% of the total analysed zircons. The primary
signal in the Palaeozoic ages is Cambrian to Ordovician,
INTERNATIONAL GEOLOGY REVIEW
14
Detrital monazite ages
n=31
Detrital monazite ages
n=30
10
6
Number
6
2
Number
Sample 4TR
Sample 1DG
10
9
2
25
Detrital zircon ages
n=85
14
10
Detrital zircon ages
n=81
15
6
5
2
0
400
800
1200
1600
2000
2400
0
2800
400
800
20
Sample 2BB
Detrital monazite ages
n=30
2400
2800
Sample 5PS
Detrital monazite ages
n=30
4
Number
8
Number
2000
12
5
14
Detrital zircon ages
n=84
10
1600
16
10
45
Detrital zircon ages
n=87
35
25
6
15
2
5
0
400
800
1200
1600
2000
2400
2800
0
400
800
Age (Ma)
1200
1600
2000
2400
2800
Age (Ma)
18
14
Sample 3SP
14
Sample 6PSR
10
Detrital monazite ages
n=30
10
Detrital monazite ages
n=31
6
Number
6
Number
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15
1200
Age (Ma)
Age (Ma)
2
Detrital zircon ages
n=94
10
2
50
Detrital zircon ages
n=90
30
6
10
2
0
400
800
1200
1600
2000
2400
2800
Age (Ma)
0
400
800
1200
1600
2000
2400
2800
Age (Ma)
Figure 5. Detrital zircon and monazite age histograms and probability density plots for the six analysed samples. Reported errors are
at 1-sigma level, bin size for the histograms is 30 million years. N represents the number of grains analysed for each sample.
represented by 14 zircons (17%), followed by a minor
contribution of Silurian ages (n = 2).
The U–Pb age distribution of 94 detrital zircons in
sample 3-SP is dominated by Palaeozoic (28%) and
Neoproterozoic (48%) ages (Figure 5), with subordinate
inputs from Palaeoproterozoic to Archaean (24%). The
main contributor to Palaeozoic signal is the Cambro–
Ordovician population, clustering around two peaks at
460 Ma and 540 Ma. Three zircon crystals record Silurian
(444.3 ± 4.6 Ma; 437.3 ± 4.8 Ma) and Carboniferous ages
(342 ± 8.2 Ma). The Neoproterozoic ages cover the time
span between 550 and 830 Ma, with a more prominent
peak around 640 Ma. Neoarchaean–Palaeoproterozoic
ages account for 20% of the total analysed zircons.
The detrital zircon record in sample 4-TR (n = 81)
(Figure 5) is dominated by a Palaeozoic grain population,
mainly Cambro–Ordovician (46%), peaking at ca. 460 Ma.
Other minor contributors to the Palaeozoic signal are
Silurian (n = 6) and Carboniferous (n = 2) ages. The
Carboniferous zircon crystals (347.2 ± 13.6 Ma and
348.6 ± 4.5 Ma) exhibit high U–Th ratios of 158.7 and
64.6, respectively. Ten per cent of the dated detrital
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10
A. M. STOICA ET AL.
zircons document a Late Cretaceous 76−81 Ma
(Campanian) peak, and represent the youngest recorded
age in the six analysed sandstones. The Neoproterozoic
signal is less abundant (28%), spanning between 550 and
700 Ma, whereas a small age group clusters around 1 Ga.
Older zircons are scarce, accounting for less than 10% of
the analysed zircons.
The Palaeozoic signal (n = 59) heavily dominates the
detrital age spectrum in the sample 5-PS (n = 87)
(Figure 5), with a discernible age group at ca. 460 Ma
(n = 38). Neoproterozoic ages, mainly Ediacaran,
account for 23% of the ages. Mesoproterozoic to
Neoarchaean ages (n = 7) are negligible contributors
to the total detrital zircon age distribution.
Approximately 75% of the analysed zircon grains from
sample 6-PSR (n = 90) (Figure 5) record Palaeozoic ages,
with the majority of them clustering around 460 Ma
(54%). One zircon crystal records a Late Cretaceous age
(91.2 ± 1.7 Ma). A smaller U–Pb age population (n = 16)
indicates Neoproterozoic origin. Older ages account for
only 6% of the detrital zircon age spectrum.
Detrital monazite spectra
The chemical age spectra of detrital monazites in all
sampled areas are unimodal, revealing a narrow late
Palaeozoic age population. More than 80% of monazite
ages in each sample are Devonian to Carboniferous (ranging from ca. 300 to ca. 400 Ma). Other minor contributors
to the age spectra are Permian (256 ± 27 Ma, 274 ± 22 Ma in
sample 1DG; 244 ± 21 Ma in sample 2BB) and Silurian
(documented by one or two monazite grains in each sample). Two Ordovician ages were registered: 468 ± 28 Ma in
sample 1DG and 484 ± 34 Ma in sample 4-TR; and one
Neoproterozoic–Ediacaran age (596 ± 30 Ma) in sample 6PSR. (See Figure 5 for individual probability density plots
and number of analyses per sample.)
6. Discussions
Monazite versus zircon ages
This study underscores the importance of performing
multi-mineral age analyses in provenance studies, especially when the potential source terrains are regionally
metamorphosed rocks. We show that monazite ages
unravel a younger geologic event than the great majority of zircons in the studied area. The overwhelming
majority of monazites of the South Carpathians have
grown during Barrovian metamorphism associated
with the Variscan collision, whereas the U–Pb zircon
age range reflects the igneous formation of the Getic–
Supragetic terranes as island or transitional continental
arcs during the latest Precambrian to Ordovician. Even
older and rarer Precambrian zircons reflect the composition of the nearby terrigenous detritus transported
into the Getic–Supragetic arc terranes – their distribution is broadly consistent with a peri-Gondwanan origin
of these terranes (Balintoni et al. 2009, 2010). Very few
zircons in the South Carpathians formed or partially
recrystallized during the metamorphism accompanying
Variscan collision, although the metamorphic peak was
well into the amphibolite or even granulite facies in
most exposed units (Medaris et al. 2003).
Variscan metamorphism
The monazite age range of ~60 million years or longer
between 380 and 320 Ma suggests that the duration of
continental collision was significant, similar to the Cenozoic
Himalayan system. This is consistent with the hypothesis
that the Variscan collisional event that generated most
metamorphic rocks from European basement rocks to the
Alpine-Carpathian belt was a major continental collisional
event (Menard and Molnar 1988). The monazite age range
is consistent with existing Sm–Nd garnet isochron ages
performed on metamorphic rocks from the Getic–
Supragetic rocks (Drăgușanu and Tanaka 1999; Medaris
et al. 2003). Minor zircon formation accompanied this prolonged collision event – less than 1% of the zircon population in our study is of that age. Those zircon grains have
typical metamorphic high U–Th ratios, indicating they
most likely formed subsolidus. However, Variscan collision
was accompanied in the Carpathians by partial melting – in
some Getic–Supragetic units (e.g. the Făgăraș unit,
Krautner 1997), migmatization is regionally important,
whereas others contain numerous bodies of leucogranites
(the lower part of the Sebeș–Lotru unit, Hann 1983). Source
rocks for materials analysed in this study did not include
these crustal-derived melts formed during the Variscan.
Another common U–Pb age peak in central Europe, including the South Carpathians (Balintoni and Balica, personal
communication), is 290–310 Ma, an immediately postVariscan time of massive granitic magmatism, considered
by some to have formed synchronous with the collapse of
the Variscan orogen (e.g. Timmerman 2004). Such ages are
dominant within the upper half of the Danubian nappes,
but have not been reported from the structurally higher
Getic–Supragetic units. This suggests that the Danubian
thrust sheets did not contribute as source rocks to any of
the sedimentary rocks analysed here.
Zircon age ranges; implications for arc magmatism
All our samples display a rather wide age range of
zircons in the late Precambrian and continuing into
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INTERNATIONAL GEOLOGY REVIEW
the early Palaeozoic. Of particular interest is the range
starting at 850 Ma and continuing with few interruptions to the massive Ordovician magmatic event, the
youngest and perhaps the most important zircon generator in all of the Carpathians (Balintoni et al. 2014). All
of these zircons have U–Th <5 and are interpreted to be
magmatic. They most likely formed as a series of magmatic arcs as suggested by limited knowledge of the
exposed Getic and Supragetic rocks. Although no published study has elucidated the geologic history of these
rocks prior to metamorphism, our preliminary mapping
and geochemical data (Ducea in press) suggest that the
geology of the central and eastern South Carpathians is
most consistent with a series of arcs and back-arcs with
major element compositions indicative of either mature
island arcs or transitional continental arcs. The geology
of the Sebeş–Lotru terrane is dominated by calc-alkaline
amphibolites to tonalitic and granodioritic gneisses
interlayered with metamorphosed volcano-sedimentary
rocks, indicating that they formed in a low topography
arc environment, similar to island and transitional arcs
from the western Pacific today. The proximity of a craton if not the emplacement directly to continental crust
is inferred for these arcs by the existence of several
Neoarchaean to Palaeoproterozoic grains throughout
the South Carpathians (Balintoni et al. 2014 and references therein). Ductile shear zones of unknown but
probably pre-Alpine age (e.g. Pană and Erdmer 1994;
Profeta et al. 2013) mark the boundaries between these
different sub-terranes that, although different in detail,
overall share rather similar geologic histories.
The prolonged duration of arc magmatism sourcing the
Carpathian basement and subsequently the rocks analysed
here is indicative of continental margin and not island arc
magmatism. Magmatism appears to have been continuous since before the break-up of Rodinia and through the
Ordovician, possibly continuing into the Silurian. Jicha and
Jagoutz (2015) show that the lifetime of island arcs is
typically around 25–50 million years, whereas the continuous nature of magmatism for over 350 million years
preserved in these zircon populations is more typical for
transitional or continental arcs (Ducea et al. 2015).
Zircon record
Eroded since the Cretaceous, versus currently exposed. All
of the analysed samples have the same dominant populations of zircon ages, although their relative abundance
is different from sample to sample. From young to old
(excluding a few Alpine and Variscan grains) they are:
Ordovician (450–480 Ma), Cambrian (510–550 Ma),
Neoproterozoic (590–850 Ma), Grenville (900–1100 Ma),
and an array of less-common peaks between 2 and
11
2.8 Ga. Cretaceous sediments from the SE corner of
South Carpathians have twice the proportions of
Cambrian and earlier Precambrian (2–2.8 Ga) zircons
than the samples from the central South Carpathians.
About 6–8 km of bedrock unroofing is documented
since the mid-Cretaceous from the South Carpathians,
based on various low-temperature thermochronologies
(Merten et al. 2010). It appears that the higher nappe
units that were the source rocks for the Bucegi and
Dragoslavele areas contained a much higher proportion
of Precambrian zircons. Data presented here are limited,
but we suggest that a pattern of progressively older
dominant zircons may exist in the structurally higher
units of the Romanian Carpathians due to the higher
abundance of metasedimentary rocks in those units.
Overall, however, these units were part of the same terrane or were formed very close to each other (Balintoni
et al. 2014) and share the subsequent Variscan metamorphism, as evidenced by our monazite age distribution.
Alpine ages
The few 76–81 Ma zircons from the Turnu sandstone are
coincident with the age range of the banatitic intrusions
in southwest Romania (Zimmerman et al. 2008). The
main banatitic suite, which is hypabissal and intrusive
(Berza et al. 1998), is emplaced through the Getic–
Supragetic nappes along two narrow parallel lineaments. In addition to the intrusive banatitic suite,
age-equivalent volcanic rocks are found in several
Gosau-type extensional continental basins throughout
the South Carpathians and Apuseni mountains (Schuller
2004); the amount of volcanic material equivalent to the
banatitic intrusions is larger than previously believed
(Bârzoi and Șeclăman 2010); over 1 km of primary volcanic material can be found in some of the Gosau basins
in Romania, such as the Hațeg basin in the South
Carpathians. We believe that the Cretaceous zircons in
our study represent reworked Gosau-type materials in
the Turnu Formation.
No other Alpine ages (zircon or monazite) were found
in any of our samples, suggesting that Alpine magmatism
other than banatitic or metamorphism was insignificant
in the higher structural units of the South Carpathians.
7. Conclusions
We show that detrital zircon and monazite record very
different geologic events in the South Carpathians
(Figure 6): zircon ages correspond to the original formation of crust in the latest Precambrian to Ordovician,
whereas all monazites record collision-related regional
metamorphism (with minor associated magmatism)
12
A. M. STOICA ET AL.
900
800
Hiatus
700
Cadomian/
Pan-African
Orogeny
Island arc and transitional continental
magmatism (zircon ages)
Age (Ma)
600
500
Caledonian
Orogeny
400
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Variscan Orogeny
Cordilleran arc magmatism
(high-flux event at 460 Ma) (zircon ages)
Barrovian metamorphism & smallvolume leucogranite bodies (monazite ages)
Post-Variscan orogen collapse &
wide-spread magmatic pulse*
300
200
100
Alpine Orogeny
Subduction related magmatism
“Banatites” (zircon ages)
0
Figure 6. Timeline of major tectonic events that built and shaped the South Carpathian basement rocks. *In the South Carpathian
realm, 310–290 Ma igneous intrusions were mapped throughout the Danubian domain (Balintoni et al., unpublished data). This
signal is not visible in our zircon or monazite data.
during the Variscan orogeny (Devonian–Carboniferous).
The great majority of zircons were not reset during
metamorphism. Detrital zircons, which average the age
populations eroded from the Getic–Supragetic basement units, suggest that these basement terrains were
part of long-lived magmatic arcs formed in a periGondwanan setting along the outer edges of Rodinia.
Whereas eroded units of the South Carpathians basement had a higher proportion of meta-sedimentary
material in them, reflected by the significantly higher
proportion of Precambrian ages, they are clearly of the
same lineage as the currently exposed basement units.
Acknowledgements
We thank Nicky Giesler and Mark Pecha for help with the
Laserchron facility and Ken Domanik for his expert guidance
with monazite chronology at the LPL University of Arizona
Mike Drake electron probe laboratory. Reviews by Brian K
Horton, an anonymous reviewer, and editor Robert Stern
have greatly improved the quality of the manuscript.
Disclosure statement
No potential conflict of interest was reported by the authors.
Funding
This project was financially supported by the Romanian
National Sciences Foundation (UEFISCDI) [grant number PHII-ID-PCE-2011-3-0217].
References
Adachi, M., and Suzuki, K., 1994, Precambrian detrital monazites and zircons from Jurassic turbidite sandstones in the
Nomugi area, Mino terrane: Journal of Earth and Planetary
Sciences, Nagoya University, v. 41, p. 33–43.
Aleinikoff, J.N., Schenck, W.S., Plank, M.O., Srogi, L., Fanning, C.
M., Kamo, S.L., and Bosbyshell, H., 2006, Deciphering
igneous and metamorphic events in high-grade rocks of
the Wilmington Complex, Delaware: Morphology, cathodoluminescence and backscattered electron zoning, and
SHRIMP U-Pb geochronology of zircon and monazite:
Geological Society of America Bulletin, v. 118, p. 39–64.
doi:10.1130/B25659.1
Anastasiu, N., Tamaș-Bădescu, S., and Tamaș-Bădescu, G.,
2004, Depozitele cretacice din Nordul Sebeșului –
reconsiderări sedimentologice: Abstract Volume, București
S.G.R., p. 60.
Andersen, T., 2005, Detrital zircons as tracers of sedimentary
provenance: Limiting conditions from statistics and numerical simulation: Chemical Geology, v. 216, p. 249–270.
doi:10.1016/j.chemgeo.2004.11.013
Downloaded by [University of Arizona] at 10:52 24 September 2015
INTERNATIONAL GEOLOGY REVIEW
Balintoni, I., 1997, Geotectonica terenurilor metamorfice din
România, Cluj-Napoca, Ed. Carpatica, 176 p.
Balintoni, I., Balica, C., Ducea, M., Chen, F., Hann, H.P., and
Şabliovschi, V., 2009, Late Cambrian–Early Ordovician
Gondwanan terranes in the Romanian Carpathians: A zircon
U–Pb provenance study: Gondwana Research, v. 16, p. 119–
133. doi:10.1016/j.gr.2009.01.007
Balintoni, I., Balica, C., Ducea, M., and Stremţan, C., 2011, PeriAmazonian, Avalonian-type and Ganderian-type terranes in
the South Carpathians, Romania: The Danubian domain
basement: Gondwana Research, v. 19, p. 945–957.
doi:10.1016/j.gr.2010.10.002
Balintoni, I., Balica, C., Ducea, M.N., and Hann, H.-P., 2014, PeriGondwanan terranes in the Romanian Carpathians: A
review of their spatial distribution, origin, provenance and
evolution: Geoscience Frontiers, v. 5, p. 395–411.
doi:10.1016/j.gsf.2013.09.002
Balintoni, I., Balica, C., Ducea, M.N., Hann, H.P., and Şabliovschi,
V., 2010, The anatomy of a Gondwanan terrane: The
Neoproterozoic–Ordovician basement of the pre-Alpine
Sebeş–Lotru composite terrane (South Carpathians,
Romania): Gondwana Research, v. 17, p. 561–572.
doi:10.1016/j.gr.2009.08.003
Bârzoi, S., and Șeclăman, M., 2010, Petrographic and geochemical interpretation of the Late Cretaceous volcaniclastic
deposits from the Hateg Basin: Palaeogeography,
Palaeoclimatology, Palaeoecology, v. 293, p. 306–318.
doi:10.1016/j.palaeo.2009.08.028
Berza, T., Balintoni, I., Iancu, V., Seghedi, A., and Hann, H.P.,
1994, South Carpathians, ALCAPA II field guidebook:
Romanian Journal of Tectonics and Regional Geology, v.
75, p. 37–49.
Berza, T., Constantinescu, E., and Vlad, S.-N., 1998, Upper
Cretaceous magmatic series and associated mineralisation
in the Carpathian–Balkan Orogen: Resource Geology, v. 48,
p. 291–306. doi:10.1111/rge.1998.48.issue-4
Berza, T., and Iancu, V., 1994, Variscan events in the basement
of the Danubian nappes (South Carpathians): Romanian
Journal of Tectonics and Regional Geology, v. 75, p. 93–103.
Berza, T., and Seghedi, A., 1983, The crystalline basement of
the Danubian units in the Central South Carpathians:
Constitution and metamorphic history: Anuarul Institutului
De Geologie Și Geofizică, v. 61, p. 15–22.
Burchfiel, B.C., and Bleahu, M., 1976, The geology of Romania:
Geological Society of America Special Paper, v. 158, 82 p.
Cawood, P.A., and Nemchin, A.A., 2000, Provenance record of
a rift basin: U/Pb ages of detrital zircons from the Perth
Basin, Western Australia: Sedimentary Geology, v. 134, p.
209–234. doi:10.1016/S0037-0738(00)00044-0
Ciobanu, C.L., Cook, N.J., and Stein, H., 2002, Regional setting
and geochronology of the Late Cretaceous Banatitic
Magmatic and Metallogenetic Belt: Mineralium Deposita, v.
37, p. 541–567. doi:10.1007/s00126-002-0272-9
Csontos, L., and Voros, A., 2004, Mesozoic plate tectonic reconstruction of the Carpathian region: Palaeogeography,
Palaeoclimatology, Palaeoecology, v. 210, p. 1–56.
doi:10.1016/j.palaeo.2004.02.033
Drăgușanu, C., and Tanaka, T., 1999, 1.57-Ga magmatism in the
South Carpathians: Implications for the pre-Alpine basement and evolution of the mantle under the European
continent: The Journal of Geology, v. 107, p. 237–248.
doi:10.1086/jg.1999.107.issue-2
13
Ducea, M.N., Paterson, S.R., and DeCelles, P.G., 2015, Highvolume magmatic events in subduction systems:
Mineralogical Society of America, Elements, v. 11, p. 99–
104. doi:10.2113/gselements.11.2.99
Fedo, C.M., and Farmer, G., 2001, Constraints on the evolution
of the Cordilleran margin from detrital zircon analyses in
the middle member Wood Canyon Formation, Marble
Mountains, Southeastern California: Geological Society of
America Annual Meeting Abstract, p. 94–0.
Fedo, C.M., Sircombe, K.N., and Rainbird, R.H., 2003, Detrital
analysis of the sedimentary record, in Hanchar, J.M., and
Hoskin, P.W.O., eds., Reviews in mineralogy and geochemistry, Volume 53. Zircon. Mineralogical Society of America
and Geochemical Society.
Fergusson, C.L., Carr, P.F., Fanning, C.M., and Green, T.J., 2001,
Proterozoic-Cambrian detrital zircon and monazite ages
from the Anakie Inlier, central Queensland: Grenville
and Pacific-Gondwana signatures: Australian Journal of
Earth Sciences, v. 48, p. 857–866. doi:10.1046/j.14400952.2001.00904.x
Gehrels, G., 2014, Detrital zircon U-Pb geochronology applied
to tectonics: Annual Review of Earth and Planetary Sciences,
v. 42, p. 127–149. doi:10.1146/annurev-earth-050212124012
Gehrels, G., Valencia, V., and Pullen, A., 2006, Detrital zircon
geochronology by Laser-Ablation Multicollector ICPMS at
the Arizona LaserChron Center, in Loszewski, T., and Huff,
W., eds., Geochronology emerging opportunities pap 12:
Washington, DC, The Paleontological Society, p. 67–76.
Gehrels, G.E., and Dickinson, W.R., 1995, Detrital zircon provenance of Cambrian to Triassic miogeoclinal and eugeoclinal
strata in Nevada: American Journal of Science, v. 295, p. 18–
48. doi:10.2475/ajs.295.1.18
Gehrels, G.E., Dickinson, W.R., Ross, G.M., Stewart, J.H., and
Howell, D.G., 1995, Detrital zircon reference for Cambrian
to Triassic miogeoclinal strata of western North America:
Geology, v. 23, p. 831–834. doi:10.1130/0091-7613(1995)
023<0831:DZRFCT>2.3.CO;2
Gehrels, G.E., Valencia, V., and Ruiz, J., 2008, Enhanced precision, accuracy, efficiency, and spatial resolution of U–Pb
ages by laser ablation-multicollector-inductively coupled
plasma-mass spectrometry: Geochemistry, Geophysics,
Geosystems, v. 9. doi:10.1029/2007GC001805
Hann, H.P., 1983, Sur Deutung der Eklogit-Vorkommen im
Capatana Massiv (Sud-Karpaten): Revue Roumaine de
Géologie et Géophysique, v. 27, p. 18–21.
Hann, H.P., 1995, Central South Carpathians: Petrologic and
structural investigations: Romanian Journal of Petrology, v.
76, p. 13–19.
Hietpas, J., Samson, S., and Moecher, D., 2011, A direct comparison of the ages of detrital monazite versus detrital
zircon in Appalachian foreland basin sandstones:
Searching for the record of Phanerozoic orogenic events:
Earth and Planetary Science Letters, v. 310, p. 488–497.
doi:10.1016/j.epsl.2011.08.033
Hietpas, J., Samson, S., Moecher, D., and Schmitt, A.K., 2010,
Recovering tectonic events from the sedimentary record:
Detrital monazite plays in high fidelity: Geology, v. 38, p.
167–170. doi:10.1130/G30265.1
Iancu, V., 1985, Lower Supragetic nappes of the Banat,
Moniom-Dognecea zone: Dari De Seama Ale Institutului
De Geologie Si Geofizica, v. 69, p. 31–36.
Downloaded by [University of Arizona] at 10:52 24 September 2015
14
A. M. STOICA ET AL.
Iancu, V., Berza, T., Seghedi, A., Gheuca, I., and Hann, H.P.,
2005, Alpine polyphase tectono-metamorphic evolution of
the South Carpathians: A new overview: Tectonophysics, v.
410, p. 337–365. doi:10.1016/j.tecto.2004.12.038
Jicha, B.R., and Jagoutz, O., 2015, Magma production rates for
intraoceanic arcs: Mineralogical Society of America, Elements,
v. 11, p. 105–111. doi:10.2113/gselements.11.2.105
Kosler, J., and Sylvester, P.J., 2003, Present trends and the
future of zircon in geochronology: Laser Ablation ICPMS,
in Hanchar, J.M., and Hoskin, W.O., eds., Reviews in mineralogy and geochemistry, Volume 53, Zircon. Mineralogical
Society of America.
Krautner, H.G., 1997, Alpine and pre-Alpine terranes in the
Romanian Carpathians and Apuseni Mountains: Annales
Geologiques des Pays Helleniques, v. 37, p. 331–400.
Kreszek, C., and Filipescu, S., 2005, Middle to late Miocene
sequence stratigraphy of the Transylvanian Basin
(Romania): Tectonophysics, v. 410, p. 437–463.
doi:10.1016/j.tecto.2005.02.018
Liégeois, J.P., Berza, T., Tatu, M., and Duchesne, J.C., 1996, The
Neoproterozoic Pan-African basement from the Alpine
Lower Danubian nappe system (South Carpathians,
Romania): Precambrian Research, v. 80, p. 281–301.
doi:10.1016/S0301-9268(96)00019-8
Ludwig, K.J., 2001, Isoplot/Ex (rev 2.49): Berkeley Geochronol.
Center, Berkeley, CA, Spec. Pub. 1a, 56 p.
Marunțiu, M., 1983, Contributions to the petrology of ophiolite
peridotites and related rocks of the Mehedinti Mts.
(Southern Carpathians): Anuarul Institutului de Geologie și
Geofizică, București, p. 215–222.
Mațenco, L., Bertotti, G., Dinu, C., and Cloetingh, S.C., 1997,
Tertiary tectonic evolution of the external South
Carpathians and the adjacent Moesian Platform (Romania):
Tectonics, v. 16, p. 896–911. doi:10.1029/97TC01238
Medaris, J.G., Ducea, M.N., Ghent, E., and Iancu, V., 2003,
Conditions and timing of high-pressure Variscan metamorphism in the South Carpathians, Romania: Lithos, v.
70, p. 141–161. doi:10.1016/S0024-4937(03)00096-3
Melinte, M.C., and Jipa, D., 2007, Stratigraphy of the Lower
Cretaceous Sediments from the Carpathian Bend Area: Acta
Geologica Sinica, English Edition, v. 81, no. 6, p. 949–956.
doi:10.1111/acgs.2007.81.issue-6
Menard, G., and Molnar, P., 1988, Collapse of Hercynian
Tibetan Plateau into a Late Paleozoic European Basin and
Range province: Nature, v. 334, p. 235–237. doi:10.1038/
334235a0
Merten, S., Mațenco, L., Foeken, J.P.T., Stuart, F.M., and
Andriessen, P.A.M., 2010, From nappe stacking to out-ofsequence postcollisional deformations: Cretaceous to
Quaternary exhumation history of the SE Carpathians
assessed
by
low-temperature
thermochronology:
Tectonics, v. 29, TC3013. doi:10.1029/2009TC002550.
Moecher, D., Hietpas, J., Samson, S., and Chakraborty, S., 2011,
Insights into southern Appalachian tectonics from ages of
detrital monazite and zircon in modern alluvium:
Geosphere, v. 7, p. 494–512. doi:10.1130/GES00615.1
Montel, J.-M., Foret, S., Veschambre, M., Nicollet, C., and
Provost, A., 1996, Electron microprobe dating of monazite:
Chemical Geology, v. 131, p. 37–53. doi:10.1016/0009-2541
(96)00024-1
Murgeanu, G., Mihaiță, N., Stancu, J., Giurgea, P., DessilaCodarcea, M., Bombiță, G., and Lupu, M., 1968,
Geological map of Romania: 1:200.000, L-34-XXV, I.G.R.,
Bucharest.
Murgeanu, G., and Patrulius, D., 1957, Le Crétacé supérieur de
la Leaota et l’âge des Conglomerats de Bucegi: Revue
Roumaine De Géologie Et Géographie, v. 1, p. 109–124.
Nance, D.R., Murphy, B.J., Strachan, R.A., Keppie, D.J., GutierrezAlonso, G., Fernandez-Suarez, J., Quesada, C., Linnemann,
U., D’Iemos, R., and Pisarevsky, S.A., 2008, Neoproterozoicearly Palaeozoic tectonostratigraphy and palaeogeography
of the peri-Gondwanan terranes: Amazonian v. West African
connections: Geological Society, London, Special
Publications, v. 297, p. 345–383. doi:10.1144/SP297.17
Nicolescu, Ș., Cornell, D.H., and Bojar, A., 1999, Age and tectonic setting of Bocşa and Ocna de Fier – Dognecea granodiorites (southwest Romania) and of associated skarn
mineralisation: Mineralium Deposita, v. 34, p. 743–753.
doi:10.1007/s001260050235
Olariu, C., Jipa, D.C., Steel, R.J., and Melinte-Dobrinescu, M.C.,
2014, Genetic significance of an Albian conglomerate clastic
wedge, Eastern Carpathians (Romania): Sedimentary
Geology, v. 299, p. 42–59. doi:10.1016/j.sedgeo.2013.10.004
Pană, D., and Erdmer, P., 1994, Alpine crustal shear zones and
pre-Alpine basement terranes in the Romanian Carpathians
and Apuseni Mountains: Geology, v. 22, p. 807–810.
doi:10.1130/0091-7613(1994)022<0807:ACSZAP>2.3.CO;2
Parrish, R.R., 1990, U-Pb dating of monazite and its application
to geological problems: Canadian Journal of Earth Sciences,
v. 27, p. 1431–1450. doi:10.1139/e90-152
Patrulius, D., 1969, Geologia Masivului Bucegi și a Culoarului
Dâmbovicioara: Bucharest, Romanian Academy Publishing
House, 321 p.
Pouchou, J.L., and Pichoir, F., 1984, Un nouveau modele de
calcul pour la microanalyse quantitative par spectrometrie
de rayons X: La Recherche Spatiale, v. 3, p. 167–192.
Profeta, L.R., Ducea, M.N., and Jianu, D., 2013, Sibișel shear
zone: A late Variscan megashear and implications for the
assembly of the South Carpathians basement (Romania):
GSA Annual Meeting Abstracts, v. 45, p. 598.
Răbăgia, T., Roban, R.-D., and Tărăpoancă, M., 2011,
Sedimentary records of paleogene (Eocene to Lowermost
Miocene) deformations near the contact between the
Carpathian thrust belt and Moesia: Oil & Gas Science and
Technology – Revue D’ifp Energies Nouvelles, v. 66, p. 931–
952. doi:10.2516/ogst/2011146
Rainbird, R.H., Heaman, L.M., and Young, G.M., 1992, Sampling
Laurentia: Detrital zircon geochronology offers evidence for
an extensive Neoproterozoic river system originating from
the Grenville orogen: Geology, v. 20, p. 351–354.
doi:10.1130/0091-7613(1992)020<0351:SLDZGO>2.3.CO;2
Săndulescu, M., 1984, Geotectonica României: București,
Editura tehnică, 336 p.
Savu, H., Pavelescu, M., Stancu, J., and Lupu, D., 1968,
Geological map of Romania: Bucharest, I.G.R., 1:200.000,
L-34-XXIV.
Schmid, S.M., Bernoulli, D., Fugenschuh, B., Mațenco, L.,
Schefer, S., Schuster, R., Tischler, M., and Ustaszewski, K.,
2008, The Alpine-Carpathian-Dinaridic orogenic system:
Correlation and evolution of tectonic units: Swiss Journal
Downloaded by [University of Arizona] at 10:52 24 September 2015
INTERNATIONAL GEOLOGY REVIEW
of Geosciences, v. 101, p. 139–183. doi:10.1007/s00015-0081247-3
Schmid, S.M., Berza, T., Diaconescu, V., Froitzheim, N., and
Fügenschuh, B., 1998, Orogen-parallel extension in the
Southern Carpathians: Tectonophysics, v. 297, p. 209–228.
doi:10.1016/S0040-1951(98)00169-3
Schuller, V., 2004, Evolution and geodynamic significance of
the Upper Cretaceous Gosau basin in the Apuseni
Mountains (Romania): Tubinger Geowissenschaftliche
Arbeiten Reihe A, v. 70, 112 p.
Seghedi, A., Berza, T., Iancu, V., Marunțiu, M., and Oaie, G.,
2005, Neoproterozoic terranes in the Moesian basement
and in the Alpine Danubian nappes of the South
Carpathians: Geologica Belgica, v. 8/4, p. 4–19.
Seghedi, A., and Oaie, G., 1997, Sedimentology and petrology
of sandstones in cover nappes in the central South
Carpathians: Constraints for geotectonic setting, in Grubic,
A., and Berza, T., eds., Geology of the Djerda area.
International symposium geology in the Danube Gorges,
Orsova-Donji, Geologija Djerdap, p. 277–279.
Sircombe, K.N., and Freeman, M.J., 1999, Provenance of detrital zircons on the Western Australia coastline –
Implications for the geologic history of the Perth basin
and denudation of the Yilgarn craton: Geology, v. 27, p.
879–882. doi:10.1130/0091-7613(1999)027<0879:PODZOT>
2.3.CO;2
Stern, R.J., 1994, ARC assembly and continental collision in the
Neoproterozoic East African orogen: Implications for the
15
consolidation of Gondwanaland: Annual Review of Earth
and Planetary Sciences, v. 22, p. 319–351. doi:10.1146/
annurev.ea.22.050194.001535
Suzuki, K., and Adachi, M., 1994, Middle Precambrian detrital
monazite and zircon from the Hida gneiss on Oki-Dogo
Island, Japan: Their origin and implications for the correlation of basement gneiss of Southwest Japan and Korea:
Tectonophysics, v. 235, p. 277–292. doi:10.1016/0040-1951
(94)90198-8
Tamaș-Bădescu, S., Anastasiu, N., and Tamaș-Bădescu, G., 2004,
Sedimentele Cuaternare din bazinul văii Pianu, M-tii Sebeș –
secvențe și caracteristici hidrotermale: Abstract Volume, S.G.R.,
București.
Timmerman, M.J., 2004, Timing, geodynamic setting and character of Permo-Carboniferous magmatism in the foreland of
the Variscan Orogen, NW Europe: Geological Society,
London, Special Publications, v. 223, p. 41–74. doi:10.1144/
GSL.SP.2004.223.01.03
von Raumer, J.F., Bussy, F., Schaltegger, U., Schulz, B., and
Stampfli, G.M., 2013, Pre-Mesozoic Alpine basements – Their
place in the European Paleozoic framework: Geological Society
of America Bulletin, v. 125, p. 89–108. doi:10.1130/B30654.1
Zimmerman, A., Stein, H.J., Hannah, J.L., Kozelj, D., Bogdanov,
K., and Berza, T., 2008, Tectonic configuration of the
Apuseni-Banat-Timok-Srednogorie belt, Balkans – South
Carpathians, constrained by high precision Re-Os molybdenite ages: Mineralium Deposita, v. 43, p. 1–21. doi:10.1007/
s00126-007-0149-z