Paleoceanographic changes at the Jurassic–Cretaceous boundary in the Western Tethys, northeastern Mexico

Mexico is usually considered to have formed the western end of the Tethys during Late Jurassic and Early Cretaceous times. The circumstances of the opening of the Gulf of Mexico Basin towards the Tethys and the exact stratigraphic timing, however, are not clear. Four sections covering this time interval, located in northeastern Mexico, have been measured and sampled in detail, in order to clarify their stratigraphic position during the Late Jurassic to Early Cretaceous time interval and the paleogeographic and oceanographic changes that accompanied this opening. Our studies include microfacies, micro- and macropaleontology, whole rock and clay-mineral x-ray diffraction and stable isotopes analyses. Our data indicate that the Jurassic-Cretaceous boundary, as defined by the Lyon-Neuchâtel Colloquium of 1973, cannot be determined precisely in northeastern Mexico due to the near-absence of calpionellids and endemism of ammonite taxa. In the lower and upper Berriasian sediments, we detected Mediterranean ammonite taxa so far unknown from Mexico, corresponding to the appearance of typical calpionellid-rich facies. These faunas allow direct biostratigraphic correlation with European ammonite and calpionellid zones.We propose that a major oceanographic change occurred in the upper part of calpionellid Zone B of the Early Berriasian. At this time, sediments in northeastern Mexico present increasingly pelagic facies, a dramatic appearance of Tethyan microfossils (calpionellids) and ammonites, changes in stable isotopic values, whole rock and clay-mineral mineralogy. We suggest that these changes are due to a global sea-level rise that connected directly northeastern Mexico to the European Tethys and ended the endemic, semi-restricted and anoxic environment of the Late Jurassic La Casita and equivalent La Caja and La Pimienta Formations.     

Calpionellids and calcispheres from the upper Jurassic-lower Cretaceous deposits in the Resita-Moldova Noua zone, Southern Carpathians, Romania

An assemblage of calpionellids and calcispheres identified in five lithostratigraphic units allows the identification of eight biozones in the upper Oxfordian-Hauterivian interval. Since the biozonation according to calpionellids has already been accurately defined by Pop (1974, 1989) for the Marila Limestones and Crivina Marls, the novelty of our approach resides mainly in the extension of this biozonation to the over- and underlying lithostratigraphic units using calcispheres. The possibility of micropalaeontologically delimiting the Valea Aninei Limestones is extremely significant, since the age of these limestones has been estimated so far only by their geometrical setting in the lithostratigraphic sequence of formations in the area.     

Early Berriasian ammonites from Shal, Talesh region (NW Alborz Mountains, Iran)

An early Berriasian (Berriasella jacobi Zone) ammonite fauna is described for the first time from the Alborz Mountains in northwest Iran. It has been collected from a section located near the village of Shal (Talesh region); in addition to rare phylloceratids, lytoceratids and Neolissoceras, the majority of ammonites belong to the neocomitid subfamily Berriasellinae. With the exception of a new genus and species, Taleshites fuersichi, these taxa are common in European and North African Tethyan successions. Associated calpionellids confirm the early Berriasian age of the ammonite-bearing levels.     

The Jurassic/Cretaceous boundary in the Apulco area by means of calpionellids and calcareous dinoflagellates: An alternative to the classical Mazatepec section in eastern Mexico

A detailed bed-by-bed sampling within the Pimienta and the Lower Tamaulipas Formations from a section in the Apulco area (Puebla State, Eastern Mexico), allows the delimitation of the Jurassic/Cretaceous boundary. The Late Tithonian was identified by the presence of calpionellids of the Crassicollaria Zone (Colomi Subzone) and calcareous dinocysts of the Proxima Zone. The Tithonian/Berriasian boundary was placed at the acme of Calpionella alpina (small forms) between samples MZT 45–46. The Berriasian was divided into two main units, namely the Calpionella Zone, further subdivided into the Alpina, Ferasini and Elliptica subzones, and the Calpionellopsis Zone, within which only the Oblonga subzone was identified. The vertical distribution of calpionellids and their assemblages in the biozones of this Mexican section fit those from other Tethyan areas.     

Cretaceous stratigraphy of the Ionian Zone,Hellenides, western Greece

The Cretaceous sedimentary successions of the Ionian Zone, Hellenides, western Greece, are composed of pelagic limestones intercalated with cherty layers. The micritic and biomicritic beds with abundant chert nodules and cherty horizons, which were deposited during late Tithonian to early Santonian times, belong to the Vigla Limestone Formation, while the sediments deposited during the late Santonian to Maastrichtian, formed clastic limestone beds in which chert nodules also occur sparsely.In the Cretaceous beds calpionellids, planktonic and benthonic foraminifera characteristics of the Tethyan realm, and radiolaria have been recorded. The calpionellids, together with radiolaria, colonized the entire basin during the Berriasian to early Valanginian, the latter becoming dominant during the Hauterivian to early Albian as a result of anoxia. Planktonic foraminifera first appeared in the basin during the late Albian and persisted until the Maastrichtian. The numbers decreased, however, during the Cenomanian-early Turonian interval, when radiolaria increased owing to anoxic conditions, and during the Campanian-Maastrichtian interval because the basin became shallow. During this interval larger benthonic foraminifera colonized the basin. Zonal markers have been recognized in calpionellid and planktonic foraminiferal assemblages on the basis of which two calpionellid zones are distinguished, viz. the Calpionella alpina and Calpionellopsis Zones (Berriasian-early Valanginian) along with seven planktonic foraminiferal zones, viz. the Rotalipora ticinensis, Rotalipora appenninica (late Albian), Rotalipora brotzeni (early Cenomanian), Helvetoglobotruncana helvetica (early to middle Turonian), Marginotruncana sigali(late Turonian to early Coniacian), Dicarinella concavata (late Coniacian to early Santonian) and Dicarinella asymetrica (late early-late Santonian) Zones.The anoxic conditions that prevailed in the Ionian basin during the Barremian-early Albian, Cenomanian-early Turonian and Coniacian-Santonian intervals probably arose as a result of (a) the accumulation of large amounts of organic matter because the palaeotopography of the basin periodically hindered the circulation of water from the ocean and (b) the oxygen content of the intruding oceanic waters was low.     

Ophiolitic melange and flyschoidal sediments of the Tithonian–Lower Cretaceous in Albania

Ophiolitic melange and flyschoidal sediments of the Tithonian-Lower Cretaceous age are widespread in the Eastern Albanides. They lie transgressively or normally on top of the ophiolitic sequence through radiolarian cherts of the Kimmeridgian-Tithonian age, or on top of the carbonate sequence of the periphery of the ophiolites through Middle Liassic-Dogger-Malm pelagic limestones with manganese nodules and radiolarian cherts. They are overlain by conglomerates or neritic limestones of the Lower Cretaceous age. Ophiolitic melange consists of ophiolitic conglobreccias, often of homogenous composition: serpentinite melange with a ‘sedimentary’serpentinite matrix, or basaltic ‘sedimentary’tuffagglomerate. Less commonly they have a heterogeneous composition with small amounts of fine-grained matrix and marls with calpionellids. In other examples, the ophiolitic melange contains heterogeneous exotic blocks including all the members of the ophiolite suite: serpentinite, ophicalcite, gabbro, plagiogranite, diabase, basalts, dacites, amphibolite, sulphide and chromite ores as well as blocks of radiolarites, limestones etc. in the argillic matrix. They are overlain by conglomerate-sandstone-marly flyschoidal deposits with abundant ophiolitic detritus and calpionellids. These deposits are linked with Tithonian-Lower Cretaceous tectogenesis, which led to the fragmentary uplift of ophiolites and partly of their sedimentary periphery, and to the formation of the faulted topography. The presence of the ophiolitic melange and flyschoidal sediments both over the ophiolites and the associated sedimentary rocks of their periphery indicate that the latter were not the basement of an ophiolite nappe during the Late Jurassic time.     

Les Calcisphaerulidae: Intérêt stratigraphique et paléoécologique

Les quatre genres qui composent la famille des Calcisphaerulidae emend. (Villain, 1977) ont pour point commun la structure de leur paroi; c'est ce caractère qui permet la définition d'un ensemble, qui comporte non seulement des formes uniloculaire (Pithonella, Bonetocardiella), qui proviennent de la dispersion d'individus initialement groupés, mais aussi des formes pluriloculaires (Asterosphaerella).The four genera constituting the Calcisphaerulidae are united with respect to wall structure. It is suggested that they derive from Jurassic calpionellids.     

The eroded Late Jurassic Kurbnesh carbonate platform in the Mirdita Ophiolite Zone of Albania and its bearing on the Jurassic orogeny of the Neotethys realm

Several Late Jurassic (Kimmeridgian?-Tithonian) to Early Cretaceous (Late Berriasian-Valanginian) shallow-water carbonate clasts of different facies are contained in mass-flow deposits in a pelagic sequence in the Kurbnesh area of central Albania. These clasts are used to reconstruct shallow-water carbonate platforms, which formed on top of the radiolaritic-ophiolitic wildflysch (ophiolitic mélange) of the Mirdita Zone. Stratigraphic interpretation of the platform carbonates was compiled on basis of calcareous algae, benthic foraminifera, and calpionellids. From biostratigraphic data and microfacies analysis, the Neocomian clasts can be directly correlated with autochthonous platform carbonates of the western part of the Munella carbonate platform, which at least reaches up to the Late Aptian. A Late Jurassic precursor platform (Kurbnesh carbonate platform; nomen novum) was completely eroded until the Valanginian and is only documented by the clasts described here. It was deposited on top of the Mirdita Ophiolite Zone nappe stack, which formed during the Middle to Late Jurassic Kimmeridian orogeny. Thrusting and imbrications as well as the formation of the syntectonic wildflysch (mélange) therefore occurred much earlier than previously assumed. Our results constrain the Kimmeridian orogeny, which was controlled by the closure of the Neotethys Ocean, and show excellent correlation with the Eastalpine-Dinaric- Hellenic orogenic system.     

The influence of seismotectonics on precursory changes in groundwater composition for the 1995 Kobe earthquake, Japan

It is shown that temporal variation in hydrochemistry may be attributed, in part, to continuous seismotectonic activity occurring before the onset of the 1995 “Kobe” earthquake, Japan, challenging the “one earthquake–one signal” hypothesis with respect to potential precursory signals to this devastating event. A possible continuous seismotectonic influence on chloride and sulphate ion-concentration is evaluated with aggregate earthquake-information by transforming a multivariate earthquake time series (including coordinates and magnitude) into a one-dimensional time series (considering geometric relationships between earthquakes and the well-site). A piecewise analysis of ion-concentration and seismotectonic-activity time series compares trends and change points between the two time series: a positive correlation (before the proposed onset of the preparation stage) is followed by a negative correlation (during the proposed preparation stage) which, in turn, is succeeded by a positive correlation (after the heaviest aftershock sequences). This suggests that seismotectonic processes occurring before the Kobe earthquake dynamically influenced aquifer characteristics, leading to temporal variations in the hydrochemical time series. Accordingly, a dynamic change in the mixing ratios of waters with different hydrochemical characteristics is proposed as a mechanism for explaining observed variation. The research can be extended by considering vectors in the stress field that lead to changes in the aquifer-well system.The influence of seismotectonics on precursory changes in groundwater composition for the 1995 Kobe earthquake, Japan.     

Demarcation of fluoride vulnerability zones in granitic aquifer,semi-arid region,Telengana, India

This study has been carried out in the granitic aquifer of Maheshwaram watershed, Telengana, India. In this study, groundwater sample data of 8 years were analyzed for the fluoride content with other chemical quality parameters. The correlation and factor analysis were employed to understand the mechanisms for fluoride (F) enrichment as well as the hydrochemistry of the area. These analyses addressed that the observed groundwater quality was due to water-rock interaction in the aquifer and fluoride is coming from the dissolution of fluorite and other silicate minerals like biotite and hornblende by the groundwater. Land use/land cover (LULC) study from 2002 to 2008 revealed there were significant positive changes in build-up land and negative changes in vegetation cover after 2003. The main agriculture (paddy) has been reduced to 0.97 km² in 2008 from 2.39 km² in 2003. The studied watershed has been characterized on the basis of F concentration into safe, transition, and unsafe groups following the WHO and BIS guidelines. The temporal variation of the three groups showed that 57.6% area of the watershed was in unsafe zone in 2000–2003, but 69.2% of the area became safe in 2006–2009. It has been found that F concentration reduced in 12.59% of the area (became safe from unsafe) accompanied by the reduction of paddy field area. After validation with present (2016) fluoride concentrations, it was found that 16.28% are vulnerable in near future. The results of this study showed that (a) the safe and unsafe zones of fluoride concentrations vary with time with the changes in other parameters associated with it like crop pattern and (b) vulnerable zone can be identified based on the susceptibility to change of safe and unsafe zones. Such studies are useful for planning and management purposes.     

Astronomical calibration of the Valanginian “Weissert” episode: The Orpierre marl–limestone succession (Vocontian Basin,southeastern France)

A high-resolution, biostratigraphic (calcareous nannofossils, calpionellids), chemostratigraphic (C-isotope) and cyclostratigraphic (magnetic susceptibility) study was performed on the marl–limestone alternations of the Upper Berriasian–Valanginian Orpierre section, deposited in the hemipelagic setting of the Vocontian Basin (SE France). The main aims of this study were to detect orbital forcing, to estimate the duration of the Valanginian “Weissert” episode, and to discuss the palaeoenvironmental implications. Detailed calcareous nannofossil biochronology allowed the recognition of Upper Berriasian–Lower Hauterivian biohorizons. The general trends of the δ¹³C curve and the major positive C-isotope excursion (amplitude of 1.8‰) recorded at the Orpierre section are very similar to those found in other sections worldwide. Spectral analysis applied on high-resolution magnetic susceptibility (MS) variations coupled with frequency ratio method reveals a strong cyclic pattern related to the Earth's orbital parameters (precession, obliquity and eccentricity). The prominent 405 kyr eccentricity cycle in the MS signal and has been used as a geochronometer to time calibrate the section. The duration of the Weissert episode was estimated as 2.08 Myr. This duration is coherent with those obtained from the Umbria Marche Basin (∼2.3 Myr) and from the Angles section (∼2.14 Myr). Durations of more than 2 Myr suggest that a long perturbation in the dynamic of the global carbon cycle that is not compatible with the rapid and intense volcanic activity. Our cyclostratigraphic study indicates a minimal duration of 4.29 Myr for the Valanginian stage. The comparison between the MS signal at Orpierre and the spectral gamma-ray signal recently obtained in two composite sections of the Vocontian Basin allows to propose a revised duration for the Valanginian stage of 4.695 Myr instead of 5.08 Myr.     

Deep sea rock record exhumed on oceanic volcanic islands: the Cretaceous sediments of Maio,Cape Verde

Revising the deep water stratigraphy exposed on Maio offers a key section recording the sedimentary evolution in the distal domain of the Central Atlantic and the related North West African Atlantic margin (NWAAM). The oceanic volcanic island is one of nine islands in the Cape Verde archipelago, and is unique to the Central Atlantic due to the exposures of ophiolites and the overlying Mesozoic deep water sediments uplifted during the Cenozoic. This provides the opportunity to assess at outcrop, the exhumed sediments, stratigraphy and palaeo-environments of the early Central Atlantic and contribute towards the knowledge of passive margin evolution along the NWAAM, part of the largest continental remnant of Gondwana.Combined with the previous recording of calpionellids, the first collection of lower Valanginian ammonites from the lowest sedimentary succession provides conclusive evidence that Jurassic sediments are not present on Maio. Bed-by-bed sampling and ensuing micro-palaeontological analysis of these 71 samples, together with a re-interpretation of Stahlecker's remaining historical palaeontological collection providing a comprehensive dataset to build a high-resolution stratigraphic framework for the Mesozoic sediments. This reveals pelagic deep water limestones of the Morro Fm. were deposited until the upper Barremian. A major lithological change from carbonate- to siliciclastic-dominated facies, corresponding to the Morro-Carquiejo Fm. boundary is recognised as a regional hiatus spanning part of the Aptian identified across the Central Atlantic. The overlying Albian and younger Carquiejo Fm. is seen as an equivalent to the Albian-Cenomanian black shales of DSDP Leg 41, yet organic content is absent due to degradation. Future studies can build on this multi-disciplinary investigation revising the stratigraphy of Maio.     

Quaternary environmental changes in tropical Lake Towuti,Indonesia, inferred from end-member modelling of X-ray fluorescence core-scanning data

Continental and marine sediments are composed of a mixture from different sources and are influenced by a variety of environmental factors and transport processes prior to deposition. For analysis and interpretation, these sources and processes are often challenging to disentangle. We show that end-member modelling of X-ray fluorescence (XRF) core-scanning data helps to overcome these challenges by unmixing different environmental signals from high-resolution sediment geochemical records. We apply this approach to a 100 m long lacustrine succession from Lake Towuti, Indonesia, to separate the regional climate and tectonic history from local ecological and diagenetic processes. The resulting six end-members (EMs) are interpreted to represent changes in ecological (EM1), climatic (EMs 2–4), tectonic (EM 5) and geomorphic (EM6) processes determining changes in sediment composition. Because end-member analysis allows for the tracking of transient and overlapping processes, climatic changes can be followed throughout the 100 m-long succession, suggesting alternating wet and dry periods in Central Sulawesi over long (several 100 000 years) time scales. We show that end-member analysis on elemental data sets offers a detailed and objective means to disentangle depositional processes in sedimentary successions resulting from varying tectonic and environmental factors involved in sediment formation and deposition.     

An Evaluation of Temporal Changes in Sediment Accumulation and Impacts on Carbon Burial in Mobile Bay,Alabama, USA

The estuarine environment can serve as either a source or sink of carbon relative to the coastal ocean carbon budget. A variety of time-dependent processes such as sedimentation, carbon supply, and productivity dictate how estuarine systems operate, and Mobile Bay is a system that has experienced both natural and anthropogenic perturbations that influenced depositional processes and carbon cycling. Sediments from eight box cores provide a record of change in bulk sediment accumulation and carbon burial over the past 110 years. Accumulation rates in the central part of the basin (0.09 g cm^?2) were 60–80 % less than those observed at the head (0.361 g cm^?2) and mouth (0.564 g cm^?2) of the bay. Sediment accumulation in the central bay decreased during the past 90 years in response to both anthropogenic (causeway construction) and natural (tropical cyclones) perturbations. Sediment accumulation inevitably increased the residence time of organic carbon in the oxic zone, as observed in modeled remineralization rates, and reduced the overall carbon burial. Such observations highlight the critical balance among sediment accumulation, carbon remineralization, and carbon burial in dynamic coastal environments. Time-series analysis based solely on short-term observation would not capture the long-term effects of changes in sedimentation on carbon cycling. Identifying these relationships over longer timescales (multi-annual to decadal) will provide a far better evaluation of coastal ocean carbon budgets.     

湖南慈利江垭剖面二叠系-三叠系界线层序的沉积微相类型、沉积环境和海平面变化

本文对湖南慈利江垭剖面二叠系-三叠系界线层序(大隆组顶部9.4m和大冶组底部7.5m)进行了详细的沉积微相分析,划分出八种微相类型,并结合露头和光面上的沉积特征,对每种微相的成因和沉积环境进行了分析和讨论。在此基础上,研究了界线附近的沉积环境和相对海平面变化。大隆组顶部层序沉积于相对海平面持续上升阶段,随着相对海平面的上升,沉积环境逐渐由盆地边缘向盆地内部迁移。在大隆组最顶部,相对海平面有一快速的大幅度下降,沉积环境由深水盆地突然转变为浅水台地。之后自大冶组底部向上,相对海平面又逐渐上升,沉积盆地依次经历了滞流盆地、半循环盆地和循环盆地的转换;在距离大冶组底部约7m处,相对海平面开始下降,气候变得极为干燥,沉积盆地转变为蒸发盆地。值得指出的是,大隆组-大冶组界线处的快速海退面正好对应于二叠纪末生物灭绝面,从而表明大海退很可能是造成二叠纪末生物大灭绝的重要原因。     

Origin of silicate minerals in carbonatites from Alnö Island,Sweden: magmatic crystallization or wall rock assimilation?

Textural, electron microprobe and whole rock geochemical evidence from carbonatites and associated silicate rocks on Alnö Island, Sweden, suggest that the carbonatite, at the time of emplacement, could have been an (almost) pure CaCO₃ liquid with a high volatile (H₂O–CO₂) content and that most silicate minerals, which are ubiquitously present, are either (1) assimilated from the surrounding wall rock, by progressive and coupled fragmentation and corrosion; or (2) by‐products of corrosive interaction between the carbonatite liquid and the wall rock. This interpretation is supported by balancing a reaction to describe interaction between carbonatite and a cpx + ne‐bearing (ijolite) wall rock. Although our analysis does not preclude the possibility that fenitizing agents (e.g. Na, Fe) were transported by the carbonatite liquid, these components are not required to drive the observed mineralogical changes in the carbonatite.     

Asian Hydroclimate Changes and Mechanisms in the Preboreal from an Annually‐laminated Stalagmite,Daoguan Cave,Southern China

One-year-resolved and annually-counted stalagmite multi-proxies(δ~(18)O, δ~(13)C, and layer width) from Daoguan Cave, Guizhou Province revealed detailed variability regarding the Asian Summer Monsoon(ASM) and local humidity across Bond events(BE) in the Preboreal. During BEs 8 and 7, 1.5‰ enrichments in δ~(18)O values were generally consistent with high-to low-latitude climate changes. In detail, the decadal-scale minor δ~(18)O oscillations in BE8 were broadly less than the mean value, in contrast to the significant changes in local soil moisture derived from the δ~(13)C values and layer records. In the mid-BE7, δ~(18)O variability was generally above the average level, and higher-amplitude variations were observed in the three proxy indicators. Wavelet analysis on the total δ~(18)O time series and across the specific time windows of BEs 8 and 7 identified periodicities of about 130, 60, and 20-a, respectively. Exceptionally strong in BE7, the 60-a cycle, pervasively observed in instrumental studies, became prominent starting at 11.4 kaBP. Thus, glacial background conditions are important for suppressing the ASM intensity in BE8, while during BE7, tropical hydrological circulations were potentially actively involved. Consequently, climate internal oscillations, analogous to modern conditions, might have occurred in the distant past once the link between the tropical ocean and atmosphere was established as occurs today.     

青海省海西州德令哈地区近千年来年降水量变化特征分析

试图揭示位于我国青藏高原东北部的青海省海西州德令哈地区近千年来世纪尺度年降水量变化规律。分析结果表明,该地区近千年年降水量变化存在显著的多尺度周期变化特征,其中以13～18世纪中的200年主控周期最为明显,并在15～17世纪达到最强,而近200年则以准120年的周期振荡为主,且在19世纪两种主要周期变化趋势相反,在近百年又趋向一致。年降水量序列的均值突变一般以30～100年尺度最为明显,世纪尺度的均值突变时段分别为公元1100～1111年、1403～1449年及1615～1661年,表现为年降水量的减少,以及公元1321～1348年、1497～1557年、1728～1743年及1885～1891年,表现为年降水量的增加。200年以上时间尺度的方差突变主要表现为序列的低频变化幅度,从公元1220年前后至1580年前后持续增大,且以15世纪的方差突变最为明显。     

Sensitivity analysis of lake mass balance in discontinuous permafrost: the example of disappearing Twelvemile Lake, Yukon Flats, Alaska (USA)

Many lakes in northern high latitudes have undergone substantial changes in surface area over the last four decades, possibly as a result of climate warming. In the discontinuous permafrost of Yukon Flats, interior Alaska (USA), these changes have been non-uniform across adjacent watersheds, suggesting local controls on lake water budgets. Mechanisms that could explain the decreasing mass of one lake in Yukon Flats since the early 1980s, Twelvemile Lake, are identified via a scoping analysis that considers plausible changes in snowmelt mass and infiltration, permafrost distribution, and climate warming. Because predicted changes in evaporation (2  cmyr^?1) are inadequate to explain the observed 17.5 cmyr^?1 reduction in mass balance, other mechanisms are required. The most important potential mechanisms are found to involve: (1) changes in shallow, lateral groundwater flow to the lake possibly facilitated by vertical freeze-thaw migration of the permafrost table in gravel; (2) increased loss of lake water as downward groundwater flow through an open talik to a permeable subpermafrost flowpath; and (3) reduced snow meltwater inputs due to decreased snowpack mass and increased infiltration of snowmelt into, and subsequent evaporation from, fine-grained sediment mantling the permafrost-free lake basin.     

Multiple rifting pulses and sedimentation pattern in the Çameli Basin,southwestern Anatolia,Turkey

The neotectonic development of western Anatolia was characterized by the formation of numerous graben-type basins, which have been well documented by general mapping, although the cause and timing of the Neogene regional tectonic extension remain controversial. Previous interpretations of the origin and evolution of these Neogene basins were based mainly on regional-scale tectonic inferences, rather than detailed basin-fill analysis. The present study of the terrestrial intramontane Çameli Basin in the western Taurides combines detailed facies analysis with biostratigraphic dating (mammalian and molluscan fossils) and documents three pulses of crustal extension that are reflected in changes in the palaeogeography and sedimentary architecture of the basin.Development of the Çameli graben commenced in the Vallesian time (early Tortonian), and is marked by alluvial-fan, fluvial and lacustrine depositional systems, with freshwater molluscan fauna. A second pulse of tectonic extension occurred in the late Ruscinian time (early–middle Pliocene), producing a new normal fault that split the basin longitudinally into two compartments. The lake environment expanded and deepened, coastal peat-forming mires developed and abundant mammal fauna appeared by the early Villanian time (middle Pliocene), with the lacustrine deposits onlapping the basin-margin and intrabasinal fault escarpments. The lacustrine environment subsequently shrank, as the progradation of axial river deltas and basin-margin fan deltas caused water shallowing and shoreline regression. A third pulse of extension occurred at the end of Villanian time (late Pliocene), when the development of a new generation of normal faults further split the basin into still narrower half-graben compartments. The third pulse of rifting is estimated to have accounted for little more than 10% of the sub-basinal crustal extension, but caused the most striking changes in the basin palaeogeography and drainage pattern. The inward development of the successive normal faults indicated a high-rate crustal extension. This is the first regional case study of a terrestrial neotectonic graben employing detailed sedimentary facies analysis and mammal biostratigraphy and providing a time-stratigraphic framework for the rifting pulses in western Anatolia.