High-precision U–Pb zircon age from the Anfiteatro de Ticó Formation: Implications for the timing of the early angiosperm diversification in Patagonia

The Baqueró Group is one of the most relevant units regarding the study of the early diversification of angiosperms in South America. Whereas the age of the upper part of the Group, namely the Punta del Barco Formation, has been recently dated at 114.67 ± 0.18 Ma, the rest of the unit still lacks precise dating. In this contribution a CA-TIMS U–Pb zircon age of 118.23 ± 0.09 Ma for a tuff interlayered with fossiliferous rocks of the Anfiteatro de Ticó Formation (lower part of the Baqueró Group) is reported. This age constrains the duration of deposition of the Baqueró Group to approximately 4 Ma and provides new evidence for the age interpretation of the previously described angiosperm flora and associated pollen assemblages from this unit, until now interpreted as early Aptian or possibly Barremian in age. The Aptian age of the Baqueró Group allows a better comparison between the paleofloras from this southernmost region.     

Cenomanian-? early Turonian minimum age of the Chubut Group,Argentina: SHRIMP U–Pb geochronology

Four new SHRIMP U–Pb zircon ages older than 93 Ma from samples of the two uppermost formations accumulated in two different depocenters (Golfo de San Jorge and Cañadón Asfalto basins) of the Chubut Group in central Argentinean Patagonia, establish a pre-late Cenomanian-? early Turonian age for the group. It also confirms a coeval and comparable evolution of the two depocenters, where distal pyroclastic material was deposited together with fluvial and lacustrine facies.     

A high precision U–Pb radioisotopic age for the Agrio Formation,Neuquén Basin,Argentina: Implications for the chronology of the Hauterivian Stage

A new CA-ID TIMS U–Pb age of 130.39 ± 0.16 Ma is presented here from the Pilmatué Member of the Agrio Formation, lower Hauterivian of the Neuquén Basin in west-central Argentina. This high precision radioisotopic new age, together with the two former ones from the upper Hauterivian Agua de la Mula Member of the Agrio Formation and modern cyclostratigraphic studies in the classical sections of the Mediterranean Province of the Tethys indicate that the Hauterivian Stage spans some 6 Ma, starting ca. 132 Ma and ending ca. 126 Ma. These radioisotopic ages are tied to ammonite biostratigraphy and calcareous nannofossil bioevents and biozones recognized in the Neuquén Basin which in turn are correlated with the Mediterranean standard zones. A new geological time scale for the Valanginian–Hauterivian stages in the Mediterranean region integrating astrochronological and radiochronological data differs with the current official geological time scale which still maintains poorly constraint absolute ages for the Berriasian-Aptian interval.     

First U–Pb SHRIMP age for the Pilmatué Member (Agrio Formation) of the Neuquén Basin,Argentina: Implications for the Hauterivian lower boundary

Ammonite-based biostratigraphic schemes for the Lower Cretaceous are fairly well refined across the world, from the standard zonation in the West Mediterranean province to the Boreal and Austral provinces in the northern and southern hemispheres, respectively. However, the lack of radioisotopic ages associated to the fossil-rich, Lower Cretaceous marine successions has hindered the accurate establishment of the numerical ages for the lower boundaries of its several stages (from Berriasian to Albian). Geochronological dating by U–Pb SHRIMP of a tuff layer that occurs within beds belonging to the Holcoptychites neuquensis Zone in the Pilmatué Member of the Agrio Formation in the Austral province (Neuquén Basin, Argentina) has resulted in an absolute age of 130.0 ± 0.6 Ma (2 sigma internal errors only) or 130.0 ± 0.8 Ma (including calibration and decay constant uncertainties). This age is interpreted to represent the time of eruption and thus the timing of the pyroclastic deposit. The H. neuquensis Zone is the equivalent of the A. radiatus Zone in the West Mediterranean province. Therefore, the obtained age is the first numerical data that could help constrain the Hauterivian lower boundary. Indeed, there is reasonable agreement with the latest proposed lower boundary of the Hauterivian at ∼132.9 Ma. On the other hand, the duration recently established for this stage would be hard to reconcile with the stratigraphic record of the entire Hauterivian in the study region (northeastern Neuquén Basin). Therefore, the results of this contribution could also help to assess the extent of the Hauterivian and associated stages.     

A new Late Triassic age for the Puesto Viejo Group (San Rafael depocenter,Argentina): SHRIMP U–Pb zircon dating and biostratigraphic correlations across southern Gondwana

The Puesto Viejo Group crops out in the San Rafael Block, southwest Mendoza, at approximately 35° S and 68°20′ W. It consists of the basal mainly grayish Quebrada de los Fósiles Formation (QF) overlying by the reddish Río Seco de la Quebrada Formation (RSQ). The basal unit includes both plant remains (pleuromeians and sphenopsids) and vertebrates (scattered fish scales, dicynodont synapsids and remains of an archosauriform). In contrast, the RSQ beds have yielded only tetrapods, although a more diverse fauna. The latter includes cynodonts as Cynognathus, Pascualognathus and Diademodon, and also dicynodonts (Vinceria and Kannemeyeria). Based on the assemblage of tetrapod taxa the bearing levels were correlated to the Cynognathus AZ of South Africa and thus referred to the Middle Triassic (Anisian). We obtained a SHRIMP ²³⁸U/²⁰⁶Pb age of 235.8 ± 2.0 Ma from a rhyolitic ignimbrite interdigitated between the QF and RSQ formations at the Quebrada de los Fósiles section. This new radiometric date for the Puesto Viejo Group suggests that the tetrapod fauna in the RSQ beds existed, instead, during the Late Triassic (early Carnian) some 10 Ma later than the currently accepted age. Two scenarios might explain our results: first, the Cynognathus AZ of South Africa is wrongly assigned to the lower Middle Triassic (Anisan) and should be considered younger in age, Late Triassic (Carnian); second, the relative age of the Cynognathus AZ of South Africa is correct but the inferred range of Cynognathus and Diademodon is incorrect as they were present during the Late Triassic (Carnian) at least in South America. In any case, this new date pose serious doubts about the validity of biostratigraphic correlations based solely on tetrapod taxa, a common practice for Triassic continental successions across Gondwana.     

U‐Pb zircon age for the Etheridge Group,Georgetown region,north Queensland: Implications for relationship with the Broken Hill and Mt Isa sequences*

The Einasleigh Metamorphics are the lowest exposed component of the Etheridge Group, part of the Etheridge Province, in the Georgetown region of north Queensland. Previous dating of granites has imposed a younger age limit of about 1550 Ma for the depositional age of the Etheridge Group. Based on SHRIMP U‐Pb analyses of zircon from mafic (1674.9 ±3.3 Ma and 1655.9 ±2.2 Ma) and felsic (1695.8 ± 1.5 Ma and 1684.2 ± 2.1 Ma) intrusive rocks in the Einasleigh Metamorphics, it can now be demonstrated that deposition commenced at about 1700 Ma, and continued for an estimated 100 million years. The stratabound, base‐metal deposits in the Mt Isa Inlier, Broken Hill Block and McArthur Basin formed in the early part of this time span, thereby suggesting potential for these styles of mineralisation in the Georgetown region.     

Zircon U–Pb age constraints on the Paleoproterozoic sedimentary basement of the Ediacaran Porongos Group,Sul-Riograndense Shield,southern Brazil

Thick quartzites record significant information on cratonic environments during long geological periods. The capacity to resist weathering and deformation turn the quartzite covers especially useful in the provenance studies of Precambrian basins. Provenance of 194 detrital zircon grains from two samples of thick quartzite cover on the Paleoproterozoic Encantadas Complex displays mostly Paleoproterozoic (95%) and minor Archean (5%) sources. The results indicate that sediments were derived from the La Plata Craton with the maximum depositional age at 2.03 Ga possibly up to 1.7 Ga. In comparison, the adjacent Porongos Group has provenance data of 61 detrital zircon grains indicating mostly Mesoproterozoic (69%), subordinately Paleoproterozoic (26%) and minor Archean ages (5%). Considering previous published data, the Porongos Group is Ediacaran in age and probably chronocorrelated with sedimentary basins from the Tandilia Belt (Argentina). Therefore, the quartzite cover and the Porongos Group require distinct evolution in time and in tectonic environment.     

Meso-Cenozoic tectonics of the southern Patagonian foreland: Structural evolution and implications for Au–Ag veins in the eastern Deseado Region (Santa Cruz,Argentina)

Located in the centre of the Argentinean Patagonia between 46° and 49°S, the Deseado Region represents the foreland domain of the Southern Patagonian Andes. Its geology is characterized by thick Mesozoic sequences which, at its eastern sector, present a Mesozoic and Cenozoic geologic evolution which has been strongly determined by the development of three major tectonic phases. The present research is based on field geological mapping, interpretation of seismic and aeromagnetic data, as well as satellite image analysis. This approach has allowed us to identify and characterize the deformation that occurred throughout Jurassic, Cretaceous and Miocene times. We interpret that the most relevant structural features are the result of normal faulting generated as a response to the Jurassic rifting stage. These extensional features have strongly influenced the subsequent geometry and distribution of younger Cretaceous and Cenozoic structures.The Jurassic extensional deformation, which affected major areas of Southern Gondwana, is the product of a major intra-continental rifting stage which was accompanied by synkinematic volcanism. This tectonic regime is characterized by SW-NE directed extension that generated major oblique WNW trending faults accommodating regional dextral-extension. In the study area, this tectonic regime is inferred from the geometries of major fault systems interpreted from available seismic reflection data, as well as from the spatial distribution and orientation of the extensional fracturing associated with the opening of hybrid and dilatational siliceous epithermal Au–Ag veins.Following the Jurassic rifting stage, a more restricted Cretaceous -post-Neocomian-compressional tectonic phase took place. Throughout this period, we interpret the previously formed Jurassic extensional structures to have been reactivated under sinistral transpression. Deformation during this period generated sinistral-reverse WNW belts of deformation, which accommodated reverse faulting, imbricate thrusts, dextral and sinistral R₁ and R₂ shears and disharmonic folds due to a buttress effect.Under the post-Oligocene Andean regime, W–E directed compression acted on previously-formed N to NNE-oriented normal faults. Compression and shortening uplifted a series of narrow and sub-meridional ranges which run as a 200 km long inversion-related tectonic front along the Patagonian foreland. Between 47°11′ and 48°40′S, one of these NNE ranges divides the entire Deseado Region into two distinctive structural domains. Whilst the western domain presents dominant NNW morphotectonic features, that to the east appears highly dominated by WNW fabrics of Jurassic and Cretaceous age.The structural features of the Eastern domain appear to extend further north of the Deseado Region towards the vicinity of the San Jorge Gulf. This WNW-trending belt hosts pre-Upper Cretaceous rocks and pre-drift basement rocks which include igneous Paleozoic metamorphic rocks and Permian to Triassic sedimentary units.The Deseado region’s epithermal Au–Ag Jurassic vein systems result from the infilling and deposition of low temperature hydrothermal fluids within dilatational and hybrid structures. These spectacular vein systems are compatible with the regional SW-NE extension direction controlled by the Jurassic intra-continental rifting of southern Gondwana. Dilatational and hybrid veins are preferentially hosted by fractures in the Jurassic volcanic rocks, while the veins located within the pre-volcanic basement preferentially infill normal faults. Finally, most of these epithermal vein fields where exhumed during a moderate phase of inversion during Cretaceous times.     

SHRIMP zircon U–Pb age and tectonic significance of the Palaeoproterozoic Boolaloo Granodiorite in the Ashburton Province,Western Australia

The age of the Ashburton Province, comprising an older divergent‐margin megasequence and a younger convergent‐margin megasequence, is poorly constrained. The Boolaloo Granodiorite, which intruded the divergent‐margin megasequence on the western margin of the Ashburton Province, has given a SHRIMP zircon U–Pb age of 1786 ± 5 Ma, and therefore post‐dates convergent‐margin, backarc basin sequences, with established conventional zircon U7sbnd;Pb ages of ca 1843–1828 Ma. However, it pre‐dated deformation of convergent‐margin, remnant‐ocean sequences. Similarly aged (ca 1797–1791 Ma) granitoids are present in the adjacent Gascoyne Province, thereby identifying a magmatic fold‐thrust belt that abutted a remnant ocean in the Ashburton Province.     

Dolomite pipes in the Crato Formation fossil lagerstätte (Lower Cretaceous,Aptian), of northeastern Brazil

Pipe-like structures filled with massive and brecciated Fe-rich dolomites occur within a 5–6 m sequence of otherwise horizontal, millimetre-laminated limestones of the Nova Olinda Member of the Crato Formation (Aptian, Lower Cretaceous) of north east Brazil. The pipe-fills predate compaction, contain hydro-brecciated host strata, developed penecontemporaneously with a carbonate laminite, and may represent methane seeps. Such seeps may have developed above buried topographic highs as fluids emanating from deeper strata migrated along buried discontinuities such as the basement/Cretaceous unconformity and buried faults in the basement.     

Petrogenesis,zircon U–Pb age,and geochemistry of the A-type Mogou syenite,western Henan Province: Implications for Mesozoic tectono-magmatic evolution of the Qinling Orogen

The Mogou syenite intruded into the Mesoproterozoic Xiong’er Group is the main lithostratigraphic unit, along the southern margin of the North China Craton (NCC). This paper reports zircon LA-ICP-MS data, whole-rock major and trace element compositions of late Triassic magmatic rocks in the Mogou syenite, in order to constrain the formation age of the Mogou syenite, research the origin and evolution of the magma and analyse the geodynamic setting of the Qinling Orogen (QO) in Late Triassic. These rocks consist of medium- to coarse-grained syenite and fine-grained quartz syenite. Zircon U–Pb dating yields a crystallization age of 226.5±2.7 Ma. The syenites are characterized by high SiO₂ (63.49–72.17%), alkali (K₂O+Na₂O of 11.18–15.38%) and potassium (K₂O/Na₂O of 2.88–28.11), are peralkaline or metaluminous (molar A/CNK of 0.87–1.02) and belong to shoshonite series. The syenites have ΣREE of 33.01–191.30 ppm, LREE/HREE of 14–20, (La/Yb)_N of 11–24, with LREE-rich distribution pattern and obvious differentiation between HREE and LREE. Eu anomalies are positive for the medium- to coarse-grained syenite and weakly negative for the fine-grained quartz syenite. In addition, the syenites are enriched in large-ion lithophile elements (Ba, K, Sr, and Pb) but depleted in high strength field elements (Ti, Ta, Nb, Zr, and Hf), and have high differentiation indices of 91.69–97.06. These geochemical features indicate that the primary magma of the Mogou syenite most likely originated from a mantle source with minor crustal component, and underwent a fractional crystallization process during its emplacement. The late Triassic A-type Moguo syenite along the southern margin of the NCC was generated in the late stage of the syn-collision event of QO, recording a transition period from compression to extension at around 227 Ma.     

40Ar/39Ar age and oxygen isotope temperature of the Centinela Formation,southwestern Argentina: An Eocene age for crustacean-rich “Patagonian” beds

The presence of a prominent volcanic ash enclosed within sediments of the Centinela Formation, southwestern Argentina, permits establishment of an ⁴⁰Ar/³⁹Ar age of approximately 46 Ma for these rocks. Oxygen isotopic analysis of shell material from the oyster Crassostrea? hatcheri Ortmann, 1897, suggests seasonal fluctuation of temperature from about 15°C to about 21°C. In concordance with this, a diverse crustacean fauna, including nine families within the order Decapoda and one within Isopoda, bears strong affinities with temperate and subtropical faunas of the Atlantic Ocean basin and documents the southernmost extension of low latitude oceanographic influence on this region during the Paleogene. Establishment of an Eocene age for the rocks in the Centinela Formation provides the first definitive documentation of rocks of that age in the region of Calafate, permits correlation of these rocks with Eocene strata southward to the vicinity of Rı́o Turbio, and suggests that these rocks, assigned to the Patagonian sequence, may be substantially older than those in eastern Argentina.     

The Temaguessine Fe-cordierite orbicular granite (Central Hoggar,Algeria): U–Pb SHRIMP age,petrology, origin and geodynamical consequences for the late Pan-African magmatism of the Tuareg shield

The Temaguessine high-level subcircular pluton is intrusive into the LATEA metacraton (Central Hoggar) Eburnian (2 Ga) basement and in the Pan-African (615 Ma) granitic batholiths along a major NW–SE oriented major shear zone. It is dated here (SHRIMP U–Pb on zircon) at 582 ± 5 Ma. Composed of amphibole–biotite granite and biotite syenogranite, it comprises abundant enclaves: mafic magmatic enclaves, country-rock xenoliths and remarkable Fe-cordierite (#Fe = 0.87) orbicules. The orbicules have a core rich in cordierite (40%) and a leucocratic quartz–feldspar rim. They are interpreted as resulting from the incongruent melting of the meta-wacke xenoliths collapsed into the magma: the breakdown of the biotite + quartz assemblage produced the cordierite and a quartz–feldspar minimum melt that is expelled, forming the leucocratic rim. The orbicule generation occurred at T < 850° and P < 0.3 GPa. The Fe-rich character of the cordierite resulted from the Fe-rich protolith (wacke with 4% Fe₂O₃ for 72% SiO₂). Strongly negative ε_Nd (−9.6 to −11.2), Nd T_DM model ages between 1.64 and 1.92 Ga, inherited zircons between 1.76 and 2.04 Ga and low to moderately high I_Sr (0.704–0.710) indicate a Rb-depleted lower continental crust source for the Temaguessine pluton; regional considerations impose however also the participation of asthenospheric material. The Temaguessine pluton, together with other high-level subcircular pluton, is considered as marking the end of the Pan-African magma generation in the LATEA metacraton, resulting from the linear delamination along mega-shear zones, allowing asthenospheric uprise and melting of the lower continental crust. This implies that the younger Taourirt granitic province (535–520 Ma) should be considered as a Cambrian intraplate anorogenic event and not as a very late Pan-African event.     

Precise conventional and SHRIMP baddeleyite U‐Pb age for the Binneringie Dyke,near Narrogin,Western Australia

A precise baddeleyite U‐Pb age of 2418 ± 3 Ma is reported for the westerly extension of the Binneringie Dyke in the south‐western Yilgarn Craton of Western Australia. The Binneringie Dyke is a member of the large and extensive Widgiemooltha dyke swarm that trends east‐west across the craton. This age is similar to ages of major dyke swarms In other Archaean Cratons and supports the hypothesis that dykes of the Widgiemooltha swarm are part of a worldwide Palaeoproterozoic mafic magmatic event at ca 2420 Ma.     

A Late Ordovician U–Pb age for the Tromsø Nappe eclogites,Uppermost Allochthon of the Scandinavian Caledonides

The Scandinavian Caledonides contain the record of several high-pressure events reflecting distinct episodes of collision and subduction in the course of the global Caledonian plate reorganization process. In this study, the timing and speed of one of these events in the Tromsø Nappe of the Uppermost Allochthon are detailed using multiple U–Pb geochronometers. This unit contains eclogites, the largest of which forms a whole mountain top, whereas many others occur as smaller lenses enclosed within a metamorphosed supracrustal sequence. A minimum age for the sedimentation is provided by a zircon age of 493 +5/-2 Ma for an eclogitized felsic intrusion. Formation of the eclogite, at pressures reaching 2.8 GPa, occurred at 452.1±1.7 Ma as evidenced by U–Pb in eclogitic zircon. Similar ages of 451–450 Ma are also provided by high-Al titanite in eclogite and titanite in leucosome veins, the latter of which was formed by partial melting during the exhumation of the eclogite. An age of 449 Ma for a rutile porphyroblast in another vein further confirms the rapidity of this high-pressure process. Matrix rutiles in two other eclogites yielded ages of 436 Ma and younger, probably indicating partial resetting during a subsequent metamorphic overprint. Lead isotopic compositions with high ²⁰⁷Pb/ ²⁰⁴Pb ratios are indicative of old crustal sources, thus supporting the previously proposed notion that the Uppermost Allochthon was derived from the Neoproterozoic margin of Laurentia.     

The Oldest Vendian (Ediacaran) Fossils of Eurasia: U–Pb Isotope Age of the Basa Formation (Asha Group,Southern Urals)

Doklady Earth Sciences - U–Th–Pb (SHRIMP II) isotopic dating of accessory zircons from Vendian (Ediacaran) ash tuffs of the Basa formation section (Asha Group, Southern Ural) was...     

The Pacific Gondwana margin in the late Neoproterozoic–early Paleozoic: Detrital zircon U–Pb ages from metasediments in northwest Argentina reveal their maximum age,provenance and tectonic setting

U–Pb detrital zircon ages are reported from Puncoviscana Formation (late Neoproterozoic–Early Cambrian) and Mesón Group (Late Cambrian) greywackes of northwest Argentina, to constrain provenance and depositional environment.The new data are combined with previously-published detrital zircon ages, to show that Puncoviscana Formation age patterns contain two broad groups: late Mesoproterozoic–early Neoproterozoic (1150–850 Ma) and late Neoproterozoic–Early Cambrian (650–520 Ma); with their relative proportions varying inversely with youngest component age. The 1150–850 Ma age components are dominant in greywackes with oldest late Neoproterozoic components > 600 Ma. The former diminish considerably when late Neoproteozoic components become dominant and younger, to 520 Ma. A northernmost greywacke sample from Purmamarca, Jujuy, is distinctive: whilst its zircon age pattern partly resembles other Puncoviscana Formation samples, it contains no Cambrian–late Neoproterozoic ages, the youngest ages being early Neoproterozoic. This may reflect an early, Neoproterozoic, passive-margin depocentre for the Formation, or an older (early Neoproterozoic) succession within it, which may predate the Brasiliano orogeny in Brazil. The youngest age components, c. 520 Ma, in a greywacke from Rancagua (Cachi, Salta province), dominate an almost unimodal pattern suggestive of contemporary volcanic sources at a late Early Cambrian depocentre. Detrital zircon age patterns of the Mesón Group (Lizoite Formation) have major Cambrian–latest Neoproterozoic components resembling those of the Puncoviscana Formation, but its Mesoproterozoic component is diminished, and there are no significant age components of this age. Small youngest components at c. 500 Ma suggest a maximum Late Cambrian stratigraphic age. The Puncoviscana Formation detrital zircon patterns suggest a provenance in a continental hinterland having a stabilised, extensive late Mesoproterozoic orogen (with minor Paleoproterozoic and Archean precursors), and a more variable late Neoproterozoic orogen containing an evolving sequence of less extensive subcomponents. A direct relationship with the Brazilian Shield is suggested; with sediment supplies originating within active-margin orogens of the interior and collisional orogens at the suture between African and South American cratons, but ultimate deposition in passive-margin environments of western Gondwanaland.     

Late Cretaceous U–Pb tuff ages from the Skunk Ranch Formation and their implications for age of Laramide deformation,Little Hatchet Mountains,southwestern New Mexico,U.S.A.

LA-ICPMS U–Pb ages of individual zircon crystals from reworked ash-fall tuff beds in lacustrine strata of the Skunk Ranch Formation, a synorogenic unit deposited in a Laramide intermontane basin in the Little Hatchet Mountains, southwestern New Mexico, indicate an early Maastrichtian depositional age of 71–70 Ma. The dated beds are equivalent to nearby growth strata that are partially cut by, and folded over, a Laramide reverse fault. The strata thus record final displacement on the reverse fault and indicate an early Maastrichtian age for fault offset. The Skunk Ranch Formation was previously interpreted as Eocene in age and inferred to record the second event in a two-stage Laramide deformational history in the mountain range. In addition to significantly condensing the age range of the Laramide section and clarifying stratigraphic correlation in the Little Hatchet Mountains, the new ages of the formation also indicate that Laramide deformation in the range was likely restricted to a single Late Cretaceous episode.     

Detrital zircon U–Pb ages and whole-rock geochemistry of the Neoproterozoic Paulistana and Santa Filomena complexes,Borborema Province,northeastern Brazil: implications for source area composition,provenance, and tectonic setting

The Paulistana and Santa Filomena Complexes are situated in the southern part of the Borborema Province (northeastern Brazil), in the Riacho do Pontal Orogen, and represent meta-volcano-sedimentary sequences. We present compositional variations in the metasedimentary rocks and new U–Pb detrital zircon data. Major and trace elements indicate that the metasedimentary rocks from the Paulistana and Santa Filomena Complexes are composed mostly of immature to mature sediments derived from felsic-intermediate sources with moderate to slightly high chemical weathering. The geochemical signatures of the sediment protoliths for both complexes are characteristic of continental magmatic arc settings with minor contribution from recycled sediment sources. The source area for the Paulistana Complex rocks follow the compositional trend between calc-alkaline granites and granodiorites, whereas the Santa Filomena Complex rocks have a more restricted composition trending to more granodioritic sources. For the Paulistana Complex, two main source ages were identified: (1) Tonian (ca. 950 Ma – sample RPE-58) and Tonian–Stenian (ca. 1.0 Ga – sample RPE-103). These data coupled with geochemical information suggest that the Cariris Velhos arc system was the main source area for the Paulistana Complex. Regarding the Santa Filomena metasedimentary rocks, potential source-areas include: (1) Neoarchaean rocks (~2.6 Ga) represented by the adjacent basement rocks of the Riacho do Pontal Orogen; (2) Rhyacian–Orosirian rocks (2.2–2.0 Ga) of the Riacho do Pontal Orogen and the Pernambuco–Alagoas terrain, which include an augen-gneiss with arc-related geochemical signature; (3) Statherian granites (1.7–1.6 Ga); and (4) Cariris Velhos crust (1000–920 Ma). The metasedimentary rocks of the Paulistana Complex were deposited in a rift stage (ca. 900 Ma), which is related to the break-up of the Rodinia supercontinent. The metasedimentary rocks of the Santa Filomena Complex most probably were deposited in another rift stage (ca. 750–700 Ma) and could be correlatives of the rift formation of the Canindé Domain (Sergipano Orogen).