Palaeogeographic setting of a deep-water trilobite fauna from the Early Devonian (Pragian) of the Upper Yarra,central Victoria. Phacopidae of Victoria,Part 3

A Pragian (Early Devonian) trilobite fauna from the Norton Gully Formation in the Upper Yarra area of central Victoria consists exclusively of the phacopid Prokops moorei sp. nov., a species with a highly variable visual surface including greatly reduced and blind morphologies. Several trilobites are preserved as moult assemblages, but most occur as isolated tergites on bedding-planes crowded with dacryoconarids and small bivalves. The autecology and taphofacies of the fauna indicate a deep-water setting, with the biofacies associations closely resembling deep-water assemblages described from Devonian sequences elsewhere. The distributions of laterally equivalent late Pragian facies from eastern areas of the Melbourne Zone indicate an inclined shelf between Lilydale and the Upper Yarra area, deepening eastwards from shoreline to outer shelf settings. To the northwest and northeast of the Upper Yarra area, the shelf was bounded by tectonically active margins associated with the converging Benambra Terrain, and to the south by the Waratah Bay Platform.     

A new Ordovician rostroconch mollusc from Kazakhstan

The rostroconch mollusc Eopteria aiteneria sp. nov. is described from the Late Ordovician Angrensor Formation of north-eastern Central Kazakhstan; it is the first and only known representative of this group from the Ordovician of central Asia. By the beginning of the Late Ordovician Eopteria and the family Eopteriidae were on the verge of extinction and the new Kazakhstan species represents the youngest preserved record of the family in the Ordovician. It is likely that the group found a refuge in the diverse, but rather conservative, faunal assemblage of the Hiberno-Salairian type associated with Late Ordovician carbonate algal build-ups and mud mounds which spread widely during the late Caradoc to mid Ashgill across Kazakhstanian volcanic island arcs and microplates.     

Trilobite faunas and palaeoenvironmental setting of the Silurian (early Ludlow) Melbourne Formation,central Victoria

Trilobites are common faunal elements in the Melbourne Formation, a unit of early Ludlow (upper nilssoni Biozone) age, which crops out extensively in the Darraweit Guim Province of the Melbourne Zone, central Victoria. New diagnoses are given for species previously described, including Maurotarion euryceps (McCoy, 1876; = Cyphaspis spryi Gregory, 1901), Raphiophorus jikaensis (Chapman, 1912; = Ampyx yarraensis Chapman, 1912), Cromus simpliciculus (Talent, 1964), Cromus spryi (Chapman, 1912), Sthenarocalymene kilmorensis (Gill, 1945; = Gravicalymene hetera Gill, 1945) and Trimerus harrisoni (McCoy, 1876). A new phacopid genus, Orygmatos is described, represented by the species O. yanyeani gen. et sp. nov. Other species newly described include Cromus melbournensis sp. nov., Arcticalymene australis sp. nov., “Ananaspis” woiwurrungi sp. nov. and Kettneraspis hollowayi sp. nov.

Species composition of the trilobite fauna varies spatially, and a number of distinct assemblages can be defined. Abundant trilobite moult configurations are conclusive for interpretation of the benthic fauna as autochthonous, inferring depth estimations based on benthic community distribution to be valid. A depth-related succession of communities is recognised and indicate the Melbourne Formation was deposited at relatively shallow depths on a broad, eastwardly deepening shelf, with deposition dominated by storm processes. The palaeoenvironment comprised a BA-1 community including the Arcticalymene australis trilobite assemblage, restricted to very shallow depths (～20 m) on the SW coastal margin of the shelf and preserved in proximal tempestite lithologies; and a BA-5 community group containing three distinct trilobite assemblages dominated by species of Cromus and a deeper water fauna, preserved in distal tempestite lithologies and ranging widely over the shelf at depths in the range of maximum storm wave base (～50 – 80 m).     

A new assemblage of graptolites,rhabdopleuran hemichordates and chitinous hydroids from the late Arenig (Ordovician) of the Banestan area,east-central Iran

A rich benthic and planktonic graptolite fauna is associated with encrusting rhabdopleuran hemichordates and chitinous hydrozoans in the late Arenig (Ordovician) part of the Katkoyeh Formation at Banestan, east-central Iran.

New taxa described here are the dendroid graptolites Callograptus huckriedei sp. nov. and Dictyonema bitubulata sp. nov. Other dendroid graptolites Dendrograptus sp. cf. D. flexuosus J. Hall, 1865; Acanthograptus divergens Skevington, 1963; and Thallograptus ?succulentus Ruedemann, 1904 are described. The tuboid graptolite Galeograptus sp., the rhabdopleuran hemichordates Rhabdopleura sp. aff. R. primaevus (Kozlowski, 1967) and Kystodendron sp., and the chitinous hydroid Palaeotuba sp. are also described. Graptoloid graptolites described here are Aulograptus? sp., Didymograptus incertus Perner, 1895, Undulograptus formosus (Mu & Lee, 1958), and Yutagraptus sp. cf. Y. mantuanus Riva, 1994. All but two species-level taxa are described from Iran for the first time.

The fauna is confirmed as being late Arenig or, less likely, early Llanvirn and thus probably correlates with the early part of the Darriwilian stage. It resembles the Atlantic cold water faunas in lacking isograptids and sinograptids.     

Long‐term stability of fracture systems and their behaviour as flow paths in uplifting granitic rocks from the Japanese orogenic field

In granitic rocks, fracture networks typically provide pathways for groundwater flow and solute transport that need to be understood to assess the long‐term performance of deep underground storage or disposal facilities such as radioactive waste repositories. However, relatively little is known about the long‐term processes of fracturing and/or the longevity of flow paths (FP) in granitic rocks distributed within orogenic belts. To clarify these issues, Japanese plutons of different ages and in situ fractures in granite at the Mizunami Underground Research Laboratory (MIU) located in central Japan were studied. Detailed structural characterization and geochemical analysis of in situ fracture fillings sampled from a depth of 300 m were carried out to clarify the relationship between fracturing and mineral infilling processes. Different plutons show identical episodes of fracturing and fracture filling, consisting of: brittle tensile fracturing, due to decreasing temperature through the ductile–brittle transition after plutonic intrusion (Stage I); relatively rapid uplifting (ca. a few mm/year) accompanied by hydrothermal water circulation, which produced uncrushed layered mineral fillings (Stage II); and a period of low‐temperature meteoric water circulation following exposure after uplift (Stage III). The parageneses of carbonate mineral fracture fillings and their carbon isotopic compositions (¹⁴C, δ¹³C) show that there were distinct episodes of carbonate mineral precipitation during the rapid uplifting of a pluton. The carbonate minerals that formed during each episode incorporated carbon from a distinct source. The evolution of fillings identified here enables development of a specific model of fracturing and persistence of fluid‐conducting systems in the plutons of the orogenic field.     

Fluid environment for preservation of pore spaces in a deep dolomite reservoir

Well TS1 reveals many uncemented pores and vugs at depths of more than 8000 m in a deep Cambrian dolomite reservoir in the Tarim Basin, northwestern China. The fluid environment and mechanism required for the preservation of reservoir spaces have yet not been well constrained. Carbon, oxygen, and strontium isotope compositions and fluid inclusion data suggest two types of fluids, meteoric water and hydrothermal fluid, affecting the Lower Paleozoic carbonate reservoirs in the Tarim Basin. Based on simulation using a thermodynamic model for H₂O‐CO₂‐NaCl‐CaCO₃ system, meteoric water has the ability to continuously dissolve carbonate minerals during downward migration from the surface to deep strata until it reaches a transition depth, below which it will begin to precipitate carbonate minerals to fill preexisting pore spaces. In contrast, hydrothermal fluid has the ability to dissolve carbonate in deep strata and precipitate carbonate in shallow strata during upward migration. Based on the dissolution–precipitation characteristics of the two types of fluids, the ideal fluid environment for the preservation of preexisting reservoir spaces occurs when carbonate reservoir is neither in the CaCO₃ precipitation domain of meteoric water nor in the CaCO₃ precipitation domain of hydrothermal fluid. Taking the Lower Paleozoic carbonate reservoirs in the north uplift area as an example, the spaces in the deep Cambrian dolomite reservoir near well TS1 were seldom filled because thick Ordovician deposits blocked meteoric water from migrating downward into the Cambrian dolomite reservoir and because the Cambrian dolomite reservoir has been in the domain of hydrothermal dissolution since the Permian. The deep carbonate layers in basins elsewhere with a similar fluid environment may have high uncemented porosity and consequently have good hydrocarbon exploration potential.     

A phosphatic stromatolite (Ilicta cf. composita Sidorov) from the Middle Cambrian,northern Australia

Phosphatic stromatolites from the early Middle Cambrian (Ordian) of the Georgina Basin are described and identified as Ilicta cf. composita Sidorov. Based on Öpik's interpretation of the early Middle Cambrian, the age of the Georgina Basin specimens is similar to that of the type specimens described from the late Early Cambrian of Eastern Siberia. Phosphatic stromatolites occur at the base of dolomitized and partially silicified bioherms up to 4 m thick. The phosphatic forms overlie impermeable, cemented pavement surfaces which were covered by stratiform stromatolites from which rose columnar forms up to 5 cm in height. The stromatolites were phosphatized by penecontemporaneous diagenetic reactions that took place just below the sediment water interface and above the impermeable substrates.     

Metamorphic and basin fluids in quartz–carbonate–sulphide veins in the SW Scottish Highlands: a stable isotope and fluid inclusion study

Metalliferous (Fe–Cu–Pb–Zn) quartz–carbonate–sulphide veins cut greenschist to epidote–amphibolite facies metamorphic rocks of the Dalradian, SW Scottish Highlands, with NE–SW to NW–SE trends, approximately parallel or perpendicular to regional structures. Early quartz was followed by pyrite, chalcopyrite, sphalerite, galena, barite, late dolomite–ankerite and clays. Both quartz–sulphide and carbonate vein mineralisation is associated with brecciation, indicating rapid release of fluid overpressure and hydraulic fracturing. Two distinct mineralising fluids were identified from fluid inclusion and stable isotope studies. High temperature (>350°C) quartz‐precipitating fluids were moderately saline (4.0–12.7 wt.% NaCl equivalent) with low (approximately 0.05). Quartz δ¹⁸O (+11.7 to +16.5‰) and sulphide δ³⁴S (?13.6 to ?1.1‰) indicate isotopic equilibrium with host metasediments (rock buffering) and a local metasedimentary source of sulphur. Later, low‐temperature (T_H = 120–200°C) fluids, probably associated with secondary carbonate, barite and clay formation, were also moderately saline (3.8–9.1 wt.% NaCl equivalent), but were strongly enriched in ¹⁸O relative to host Dalradian lithologies, as indicated by secondary dolomite–ankerite (δ¹⁸O = +17.0 to +29.0‰, δ¹³C = ?1.0 to ?3.0‰). Compositions of carbonate–forming fluids were externally buffered. The veins record the fluid–rock interaction history of metamorphic host rocks during cooling, uplift and later extension. Early vein quartz precipitated under retrograde greenschist facies conditions from fluids probably derived by syn‐metamorphic dehydration of deeper, higher‐grade rocks during uplift and cooling of the Caledonian metamorphic complex. Veins are similar to those of mesothermal veins in younger Phanerozoic metamorphic belts, but are rare in the Scottish Dalradian. Early quartz veins were reactivated by deep penetration of low‐temperature basin fluids that precipitated carbonate and clays in veins and adjacent Dalradian metasediments throughout the SW Highlands, probably in the Permo‐Carboniferous. This event is consistent with paragenetically ambiguous barite with δ³⁴S characteristic of late Palaeozoic basinal brines.     

Oceanic palaeoenvironment of the Miocene Fyansford Formation from Fossil Beach,near Mornington,Victoria, interpreted on the basis of Ostracoda

Study of an ostracode assemblage from the Miocene Fyansford Formation near Mornington allows determination of the principal characteristics of the hydrologic environment at that time.

Palaeodepth was upper epibathyal (about 150–250 m). The oxygen minimum zone mostly was weakly demarcated at about O₂ 5 ml/l. Productivity was good and the benthic ostracode microfauna was rich and varied. Occasionally, a sudden and strong increase in productivity occurred which correlated to a rapid and well marked increase in the oxygen minimum zone. Physico-chemical factors, which developed following bacterial breakdown of organic matter that had accumulated on the bottom, are reflected in Bradleya shells by distinct signs of aggradation/degradation. A few allochthonous forms from the nearby continental shelf were transported downwards onto this part of the upper slope. Bottom currents contributed (by furrowing) to the formation of calcareous ‘hard grounds’.

Bradleya morningtonensis n.sp. is described as new.     

Acanthodian fish remains from the Lower Devonian Cavan Bluff Limestone (Murrumbidgee Group), Taemas district,New South Wales

A well-preserved acanthodian fish fauna from the Lower Devonian (early Emsian) Cavan Bluff Limestone (Murrumbidgee Group), Taemas, Yass district, New South Wales, consists of dentigerous jawbones, fin spines and scales. Four taxa belonging to the Order Ischnacanthida are recognized including Taemasacanthus erroli Long, 1986 and newly described genera and species Cavanacanthus warrooensis gen. et sp. nov., Cambaracanthus goodhopensis gen. et sp. nov. and Taemasacanthus porca sp. nov. An amended diagnosis is provided for T. erroli. The jawbone of C. warrooensis gen. et sp. nov. is of moderate size and bears a single row of teeth with a circular parabasal section. The jawbone extends in an anterior direction beyond the foremost tooth. C. goodhopensis gen. et sp. nov. is a small to moderate sized jawbone bearing two teeth rows separated by a longitudinal ridge. The teeth of the mesial tooth row, the main tooth row, are circular in parabasal section. The lateral tooth row is weakly developed, bearing one or two incipient teeth. T. porca sp. nov. is represented by a small curved jawbone (mesially concave) bearing two teeth rows separated by a prominent longitudinal ridge. The teeth of both tooth rows have a circular parabasal section. The anterior extension of this ridge beyond the foremost tooth represents approximately one quarter the length of the jawbone. These fishes inhabited a Lower Devonian carbonate platform consisting of patch reefs built upon a muddy substrate on a low energy shallow marine shelf which was subjected to frequent storm surges.     

Australian Cainozoic Bryozoa, 1: Nudicella gen. nov. (Onychocellidae,Cheilostomata): taxonomy,palaeoenvironments and biogeography

The new bryozoan genus Nudicella (Onychocellidae, Cheilostomata) is proposed to accommodate the common and widespread Australian Cainozoic cheilostome bryozoan Eschara clarkei Tenison Woods, which is redescribed and subdivided into four species: N. clarkei (Tenison Woods), N. cribriforma sp. nov., N. latiramosa sp. nov. and N. tenuis sp. nov. Cellaria gigantea Maplestone is also reassigned to Nudicella. Colonies of this genus display a wide variety of growth forms, including cribrate fenestrate, flat robust branching, foliose, delicate branching and encrusting; their occurrences correlate with changes in sedimentary facies and palaeoenvironments. The distinctive cribrate style of fenestrate growth form has evolved convergently in unrelated bryozoan groups at various geological intervals. It is found in a wide variety of sedimentary facies, as in other coexisting opportunistic genera such as Celleporaria, indicating a wide ecological tolerance. The oldest recorded occurrence of Nudicella is in the Paleocene of north western Australia. From there it appears to spread south in the Eocene and then east towards the Otway Basin in southeastern Australia, where it occurs in the Oligocene and Miocene; no post-Miocene representatives of this genus are yet known.     

Ordovician trilobite faunas and depositional history of the Taebaeksan Basin,Korea: implications for palaeogeography

The Taebaeksan Basin occupies the central-eastern part of the Korean peninsula and was a low-relief shallow marine carbonate shelf on which the Cambro-Ordovician Choson Supergroup was deposited. In the Taebaeksan Basin trilobites are among the most dominant fossil groups in the Lower Ordovician, but they become less important in Middle Ordovician faunal assemblages. The Early Ordovician trilobite faunas of the Taebaeksan Basin are characterised by the common occurrence of pandemic genera such as Jujuyaspis, Leiostegium, Asaphellus, Protopliomerops, Hystricurus, Apatokephalus, Shumardia, Asaphopsoides, and Kayseraspis. Biogeographically significant trilobite taxa include Yosimuraspis, Dikelokephalina, Koraipsis, and Chosenia. These Ordovician trilobite faunas, which thrived in shallow marine environments, show a remarkable similarity with faunas from North China, implying that the Taebaeksan Basin was connected through contiguous shallow waters to North China. These Sino-Korean faunas exhibit a close biogeographic connection with Australian faunas, with which they share some endemic genera, whereas they are more distantly related to the faunas of South China, South America, and North America. Based on these palaeobiogeographical features, it is suggested that in the early Palaeozoic much of the present Korean peninsula including the Taebaeksan Basin belonged to the Sino-Korean block, while part of the peninsula was derived from the Yangtze block.     

Cretaceous foraminiferal biostratigraphy of Queensland

The distribution of foraminiferids within Aptian-Albian marine deposits of the Laura, Carpentaria, Eromanga, and Surat Basins in Queensland is described. The foraminiferal distribution patterns are largely a reflection of environmental differences which existed within the basins. Among the benthonic foraminiferids, two major faunal associations are recognized: the Ammobaculites association reflecting hyposaline, cool, shallow water conditions; and the Marssonella association indicating normal marine, open continental shelf environments. As the faunal content of these associations is markedly different, separate time-stratigraphic zonations are proposed: the Ammobaculites association is divided into the Textularia cushmani zone (early Aptian), T. cushmani-Bigenerina pitmani zone (late Aptian), B. pitmani zone (late Aptian), B. pitmani-Riyadhella crespinae zone (early Albian), and R. crespinae zone (early-late Albian); the Marssonella association contains the Anomalinoides intermedia zone (early-middle Albian in Queensland), and the A. cenomanica zone (late Albian in Queensland). Planktonic foraminiferids, which occur with both benthonic associations, are used to correlate the benthonic zonal schemes, and are themselves zoned separately: Hedbergella planispira zone (early-middle Albian), H. infracretacea zone (middle-early late Albian), and the H. delrioensis zone (late Albian). International stage correlations are based on certain foraminiferids and associated ammonites.

The distribution of foraminiferids in Queensland during the late Early Cretaceous suggests that 1, climate exerted a uniform influence over the region; 2, cool, hyposaline, shallow water conditions prevailed over much of Queensland; 3, open marine shelf conditions (of normal salinity) existed during the Albian in the Laura and northeastern Carpentaria Basins; and 4, during the Albian, at least, there was a northern seaway to the open ocean.     

Oligocene-Miocene calcareous nannofossils from the Torquay Basin,Victoria, Australia

Oligocene-Miocene rocks of the Torquay Basin contain at least 55 different species of calcareous nannofossils. These species allow zonation of an offshore subsurface section (Nerita No. 1 Well) and two onshore sections (near Torquay). The Angahook Formation and the base of the Jan Juc Formation in the Nerita No. 1 Well belong to Martini's (1971) NP 22 calcareous nannofossil Zone (early Oligocene). The NP 23 Zone could not be identified with certainty, but Zones NP 24/25 (late Oligocene) to NN 2 (early Miocene) were recognized in the Jan Juc Formation. The Oligocene-Miocene boundary is present between 122 m and 135 m below the sea floor at this site. The Puebla Formation, exposed at the sea floor, contains NN 5 spanning the early-middle Miocene boundary.

Onshore along the Torquay coast, NP 24/25 (late Oligocene) is present in the Angahook Formation; the Jan Juc Formation at Bird Rock also contains NP 24/25, except the uppermost 2.5 m which belongs to NN 1. The NN 2 Zone begins at the contact between the Jan Juc and Puebla Formations and continues upward for at least 3 m. After a covered interval, NN 4 was identified 10 m above the contact. The Oligocene-Miocene boundary is placed at the base of the hard band capping Bird Rock in the type section of the Jan Juc Formation.

Nannofossil assemblages in the Torquay sections suggest deposition in cool, shallow continental shelf waters. The assemblages in Nerita No. 1 Well also suggest cool shelf waters, although deeper than at Torquay.     

Miocene scleractinian corals from a mixed siliciclastic–carbonate system: Bakhtiari succession,Zagros Basin (central-western Iran)

Colonial scleractinian corals were sampled from three levels within a Miocene marine unit of the Bakhtiari succession, Zagros Basin, central-western Iran. The first two coral-bearing intervals, A and B, contain small-scale scattered colonies and show a poor coral diversity, whereas the third, consisting of a strongly lithified limestone package, reflects a well-developed biostromal framework with higher coral skeletal volume within the Bakhtiari succession. The Bakhtiari succession coral assemblages are characterized by Porites sp. cf. P. maigensis, Porites sp. cf. P. mancietensis, Porites sp. cf. P. collegniana, Tarbellastraea reussiana, Favia sp., Montastrea sp. cf. P. tchihatcheffi, Favites sp. cf. P. neugeboreni, Favites sp. cf. P. neuvillei, Agathiphyllia sp. and Acropora sp. Sedimentological and palaeontological data indicate that the depositional environment is consistent with a mixed carbonate–siliciclastic ramp that was gently deepening basinwards from the shoreline. The hemispherical and massive growth forms of colonies and sparse branching forms dominated the well-illuminated euphotic zone. Abundant domestone and dense pillarstone coral growth fabrics interdigitating with coarse-grained terrigenous sediments developed in the shallow inner ramp environment. Branching forms and meandroid branching colonies together with some massive forms mostly inhabited the low-energy conditions of the lower euphotic to oligophotic zones of the middle ramp. In the middle parts of the mixed carbonate–siliciclastic ramp, sparse pillarstone together with domestone comprises a mixstone coral growth fabric. Fluctuations in nutrient and clastic sediment input, salinity and the growth of red algae likely terminated coral growth.     

MARINE RESOURCES IN THE MESOLITHIC AND NEOLITHIC AT THE GROTTA DELL’UZZO (SICILY): EVIDENCE FROM ISOTOPE ANALYSES OF MARINE SHELLS*

Oxygen isotopes in shell carbonate samples from the marine rocky‐shore intertidal gastropod Monodonta turbinata (Born) are investigated in both modern analogue specimens and in archaeological specimens from the Grotta dell’Uzzo (Sicily). Variations in shell edge values of δ¹⁸O in living specimens collected monthly over two years are closely correlated with monthly seawater temperatures measured at the time of collection, showing that the species can be used for palaeoseasonality studies. Analyses of shell edge δ¹⁸O values in archaeological specimens, from Mesolithic through to early Neolithic phases at the Grotta dell’Uzzo, enabled the inference of various seasons of collection of shellfish and how such seasonality varies between the different phases of occupation. Interesting similarities and differences exist between the seasons of marine shellfish exploitation and the seasons inferred from the vertebrate zooarchaeological assemblages. A major inference drawn from the analyses and discussion is that the exploitation of all marine resources (fish and shellfish) increased in the later Mesolithic and early Neolithic periods.     

Significance of new species of Cryptorhynchia (Brachiopoda) from the Middle Jurassic of Kutch,India

Cryptorhynchia is a brachiopod genus, until recently known only from the late Bathonian. Two new species C. karuna and C. jhooraensis are here described from the middle Bathonian at Kutch, western India and record the earliest known occurrences of the genus. They constitute ancestor-descendant lineages with the two existing younger species C. pulcherrima and C. rugosa respectively. Evolution in both cases shows ‘parallel’ trends and the descendants are scaled-down versions of their respective progenitors. Statistical analyses reveal that this evolutionary miniaturization involves allometry-induced heterochrony, especially progenesis, and is marked by a rapid speciation event compatible with the punctuational model. Evolution appears to be anagenetic and may be attributed to the unstable nature of environment where onshore innovation produced smaller descendants that adopted r-strategy. Facies distribution and functional morphology suggest that species of Cryptorhynchia were well adapted to shallow, unstable carbonate shelf. However, they disappeared suddenly at the Bathonian - Callovian boundary which was marked by a global transgression. The possible causal factors of their extinction may be the consequent changes in bathymetry and substrate condition.     

Origin of deep saline groundwaters in the Vienne granitic rocks (France): constraints inferred from boron and strontium isotopes

As part of a preliminary geological characterization programme to assess the feasibility of an underground laboratory in granitic rock, a series of 17 deep boreholes (maximum depth, 900 m) was drilled by ANDRA in the Vienne district, France. A salinity gradient was demonstrated in the granitic waters with concentrations varying from approximately 1 g L^?1 at 150 m depth at the top of the basement (beneath the sedimentary cover) to 10 g L^?1 in the deeper part (from 400 to 600 m depth). Sr and B isotope ratios were measured in order to better understand the origin of the salinity and to evaluate the degree of water–rock interaction in the system. The results obtained were compared to those of mineral spring waters emerging from the granitic basement in the Massif Central. Evidence in support of a significant marine contribution include: (i) the Cl–Br investigations agree with a marine origin for the saline groundwaters without evolution from seawater; (ii) the ⁸⁷Sr/⁸⁶Sr ratio of the Vienne deep groundwaters (0.7078–0.7084) is in agreement with a palaeo‐seawater isotopic signature; (iii) measured δ¹¹B values for the deepest brine samples are enriched in ¹¹B (up to 36.1‰) relative to the granitic springs. The combined use of δ¹¹B, Cl, B, Br, Sr contents and ⁸⁷Sr/⁸⁶Sr ratios makes it possible to define and quantify a mixing model between marine and crustal end‐members in order to explain the origin of the deep saline groundwaters in the Vienne granitic rocks.