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Abstract: Stratigraphic successions are deposited under the influence of three primary controls, which tend to vary systematically through time. These controls are tectonism (basin subsidence and uplift), sea-level change, and sediment supply. The development of sequence stratigraphy has enabled the introduction of systematic, quantitative methods for the analysis of these controls. The use of the sequence approach requires the establishment of a regional sequence framework and detailed chronostratigraphic control. Working with the Phanerozoic record this approach has revealed a variety of sequence types reflecting long-term tectonostratigraphic processes caused by continental rifting, continental collisions and cratonic dynamic topography, high-frequency thrust-loading cycles in foreland basins, and high-frequency cycles caused by orbital forcing. Glacioeustasy (104–5-year periodicity) and eustasy driven by changing rates of sea-floor spreading (107–8-year periodicity) have emerged as two significant global processes. Documenting the sequence record in the Precambrian has proved difficult owing to fragmentary preservation and structural deformation. Methods of dating are at present not precise enough to permit reliable regional correlation or testing of high-frequency sequence-generating mechanisms. Some studies of Precambrian sequence architecture have been achieved, but these indicate tectonic processes acting at a much slower rate than during the Phanerozoic. Further analysis of this problem is required. [Copyright &y& Elsevier]

Abstract: The southern Australian shelf is the largest area of the globe composed of cool-water carbonates and provides the basis for the development of actualistic models of such sediments. Ocean Drilling Program Leg 182 drilling of the sedimentary succession provides essential information to also decipher the dynamics of this depositional system. Sediment samples and geophysical logs from a core drilled on the Eucla Plateau off the coast of southern Australia (Site 1127) have been used to study sedimentary cyclicity in an 800-m-thick cool-water carbonate Pleistocene wedge. This periplatform succession is dominated by bioclastic packstone and wackestone with minor intercalations of bioclastic grainstone. Fluctuations of stable oxygen-isotope values in bulk carbonate samples parallel global climatic and related sea-level fluctuations as predicted in the SPECMAP-curve. The sea-level-controlled sedimentary cycles of the slope succession are several tens of meters thick. Lowstand deposits are relatively fine grained and include abundant sponge spicules, whereas highstand deposits are coarser grained and contain abundant high-Mg calcite bioclasts. Aragonite content makes up to 36% of the cool-water carbonates. Aragonite originates from tunicate spicules. Primary, sea-level-controlled carbonate mineralogical and textural changes are likely to promote facies-dependent differential diagenesis during later burial stages of such successions. [Copyright &y& Elsevier]

Integrated palaeoecological studies of two fiord sediment sequences in the province of Blekinge, SE Sweden, covering the time span 11,000–5000 cal BP, reveal the timing and the environment for the Ancylus Lake/Littorina Sea transition 9800–8500 cal BP. The first ingression of saline water into the Baltic Sea through the Danish Straits occurred earlier than formerly assumed. New evidence, particularly mineral magnetic and palaeobotanical analyses, demonstrate that on the general trend of the eustatically caused Littorina transgression several minor fluctuations of the water level can be identified between 8500 and 5000 cal years BP. A distinct regression phase around 8100 cal BP is correlated with the Greenland ice-core cold event dated to 8200 ice-core years BP. This is described as a regional climatic catastrophe for the Baltic Sea region. The coastal stratigraphy is compared with the offshore stratigraphy earlier studied. A tentative shore displacement curve for Early and Middle Holocene is presented. [Copyright &y& Elsevier]

Venetian land subsidence, both natural and induced by groundwater withdrawal, and northern Adriatic Sea eustasy have caused 23 cm of relative land subsidence referred to as the mean sea level over the last 100 years. This relative elevation loss has been vital for Venice''s existence, inasmuch as Venice lives in the water. After a short overview of the process during the past decades, the actual trend of relative ground-sea movement is presented by integrating high precision leveling, remote sensing measurements and tide gauge records. Geodetic and Interferometric Synthetic Aperture Radar (InSAR) data evidence the present ground stability of the central part of the lagoon, where the city of Venice is located, and slight sinking rates at the northern and southern extremities of the lagoon edges (3–5 mm/year) and at some places in the central and northern littorals (1–3 mm/year). At the same time, the latest tide gauge records indicate a renewal in the sea-level rising trend. Within the average secular eustatic rate of 1.13 mm/year, the value of -0.89 mm/year, observed near Venice during the period 1971–1993, increased to 1.53 mm/year when adding the records up to 2002. [Copyright &y& Elsevier]

Consideration of eustatic and hydro-isostatic effects on late Quaternary sea levels in the tropical Pacific Ocean indicates that the configuration of modern atolls with emergent annular reef flats is a transient morphology not developed until post-mid-Holocene time. Annular atoll reefs, perched atop carbonate platforms which cap buried volcanic edifices, are underlain by 8–28 m of Holocene limestone disconformably overlying a substratum of last-interglacial or older limestone. Comparable thicknesses (9–23 m) of Holocene sediment are present beneath atoll lagoons that are uniformly <85 m deep. During glacio-eustatic drawdowns in global sea level by 120–125 m, carbonate platforms of modern atoll provinces rose abruptly from the sea as clusters of subaerial limestone plateaus flanked by steep cliffs. Modern analogues are provided by emergent atolls uplifted on the flexural arches of trench forebulges. Slow subsidence coupled with karstic erosion of emergent atolls during the last glaciation lowered the surfaces of last-interglacial reef edifices by the amounts needed to provide accommodation space for Holocene reef growth during the postglacial eustatic rise in sea level. Modern atoll reef caps began to grow after ∼9 ka when rising Holocene sea level overtopped degraded remnants of interglacial reefs, but remained submerged until carbonate buildups approached sea level in mid-Holocene time (6–4 ka). Classic atoll morphology, with circlets of multiple islets dotting annular reefs, formed in combination with late Holocene hydro-isostatic drawdown in tropical Pacific sea level in response to equatorial ocean siphoning, a facet of global isostatic adjustment (GIA) to deglaciation. Early Holocene eustatic rise in sea level and late Holocene hydro-isostatic decline in sea level combined to produce a regionally variable mid-Holocene highstand in tropical Pacific sea level that stood 1.0–2.6 m above modern sea level. Cemented mid-Holocene paleoreef flats now stranded well above sea level serve as resistant foundations for non-migratory (pinned) islets that were not present along atoll rims until after the local crossover date, when ambient high-tide level first fell below mid-Holocene low-tide level. Existing atoll landforms have a time depth generally <1–2 ka. [Copyright &y& Elsevier]

δ18Obenthic values from Leg 194 Ocean Drilling Program Sites 1192 and 1195 (drilled on the Marion Plateau) were combined with deep-sea values to reconstruct the magnitude range of the late middle Miocene sea-level fall (13.6–11.4 Ma). In parallel, an estimate for the late middle Miocene sea-level fall was calculated from the stratigraphic relationship identified during Leg 194 and the structural relief of carbonate platforms that form the Marion Plateau. Corrections for thermal subsidence induced by Late Cretaceous rifting, flexural sediment loading, and sediment compaction were taken into account. The response of the lithosphere to sediment loading was considered for a range of effective elastic thick- nesses (10 < Te < 40 km). By overlapping the sea-level range of both the deep-sea isotopes and the results from the backstripping analysis, we demonstrate that the amplitude of the late middle Miocene sea-level fall was 45–68 m (56.5 ± 11.5 m). Including an estimate for sea-level variation using the δ18Obenthic results from the subtropical Marion Plateau, the range of sea-level fall is tightly constrained between 45 and 55 m (50.0 ± 5.0 m). This result is the first precise quantitative estimate for the amplitude of the late middle Miocene eustatic fall that sidesteps the errors inherent in using benthic foraminifera assemblages to predict paleo-water depth. The estimate also includes an error analysis for the flexural response of the lithosphere to both water and sediment loads. Our result implies that the extent of ice buildup in the Miocene was larger than previously estimated, and conversely that the amount of cooling associated with this event was less important. [ABSTRACT FROM AUTHOR]

A succession of Frasnian mounds on the southern border of the Dinant Synclinorium (Belgium) was investigated for their facies architecture, sedimentary dynamics and palaeogeographic evolution. Seven mound facies were defined from the Arche (A) and Lion (L) members, each characterized by a specific range of textures and association of organisms (A2/L2: red or pink limestone with stromatactis, corals and crinoids; A3/L3: grey, pink or green limestone with stromatactis, corals and stromatoporoids; A4/L4: grey limestone with corals, peloids and dasycladaceens; A5/L5: grey microbial limestone; A6/L6: grey limestone with dendroid stromatoporoids; A7/L7: grey laminated limestone with fenestrae; and A8/L8: grey bioturbated limestone). Laterally equivalent sediments include substantial reworked material from the buildups and background sedimentation. Textures and fossils suggest that A2/L2 and A3/L3 facies developed close to storm wave base, in a subphotic environment. Facies A4/L4, occurring near fair weather wave base in the euphotic zone, includes lenses of A5/L5 with stromatolitic coatings and thrombolithes. A6/L6 corresponds to a slightly restricted environment and shows a progressive transition to fenestral limestone of A7/L7. This facies was deposited in a moderately restricted intertidal area. A8/L8 developed in a quiet lagoonal subtidal environment. The mounds started with A2/L2 or A3/L3 in which microbial lenses and algal facies A4/L4 became progressively more abundant upwards. Following 20 m of laterally undifferentiated facies, more restricted facies occur in the central part of the buildups. This geometry suggests the initiation of restricted sedimentation, sheltered by bindstone or floatstone facies. The facies interpretation shows that after construction of the lower part of the mounds during a transgression and a sea-level highstand, a lowstand forced reef growth to the margin of the buildups, initiating the development of atoll-like crowns during the subsequent transgressive stage. The persistence of restricted facies results from the balance between sea-level rise and reef growth. [ABSTRACT FROM AUTHOR]

The Upper Ordovician Montoya Group in southern New Mexico and westernmost Texas records predominantly subtidal deposition on a gently dipping carbonate ramp that was subsequently nearly entirely dolomitized. The medial unit of the Montoya Group, the Aleman Formation is unique because it contains abundant chert (10–70% by volume). The chert occurs as: (1) thin continuous beds of sponge spicules within mudstone or calcisiltite; (2) discontinuous, lenses or nodules within skeletal wackestones and packstones; or (3) as a replacement of skeletal grains and burrows. Coeval skeletal grainstones and muddy peritidal facies contain little chert. Phosphate (up to 5 wt.%) occurs within the underlying Upham Formation and the Aleman Formation as replacement of fossils and peloids. The abundance of chert and phosphate in these subtidal facies indicates they formed within a region of strong upwelling. Regional correlation with Upper Ordovician cherty units along the periphery of southern Laurentia and other low latitude continents suggests that upwelling was widespread and long-lived during the Late Ordovician. The upwelling is interpreted to record vigorous oceanic circulation produced by the onset of glaciation on Gondwana during this period. Late Ordovician relative sea-level curves around the periphery of Laurentia indicate correlative third-order (1–3 my duration) fluctuations that may provide a means for high-resolution global correlations. However, the mechanism(s) that produced these long-term fluctuations are unclear. [Copyright &y& Elsevier]

Shoreline displacement in the eastern part of the Gulf of Finland during the past 9000 radiocarbon years was reconstructed by studying a total of 10 isolated lake and mire basins located in Virolahti in southeastern Finland and on the Karelian Isthmus, and in Ingermanland in Russia. Study methods were diatom analyses, sediment lithostratigraphical interpretation and radiocarbon dating. In southeastern Finland, the marine (Litorina) transgression maximum occurred ca. 6500–6200 14C yr BP (7400–7100 cal. yr BP). In areas of the slower land uplift rate on the Karelian Isthmus and in Ingermanland, the transgression maximum occurred ca. 6400–6000 14C yr BP (7300–6800 cal. yr BP). The highest Litorina shoreline is located at ca. 23 m above present sea-level in southeastern Finland, whereas in the eastern part of the Karelian Isthmus, near St. Petersburg, it is located at ca. 8 m above present sea-level. The amplitude of the Litorina transgression in Virolahti area is ca. 4 m, whereas on the Karelian Isthmus and in Ingermanland the amplitude has varied between 5 and 7 m. The regional differences between areas are solely due to different glacio-isostatic land uplift rates. The seven basins studied in this research were connected to the Baltic Sea basin during the Litorina Sea stage and their diatom and lithostratigraphical records indicate a single, smooth Litorina transgression. [Copyright &y& Elsevier]

The Hushpuckney Shale Member of the Swope Formation (Missourian Stage, eastern Kansas) is the core shale of a Kansas-type cyclothem, formed during the late transgressive to early regressive phases of a Late Pennsylvanian glacio-eustatic cycle. Coeval high-frequency climato-environmental dynamics of the Midcontinent Seaway are preserved in the KGS Orville Edmonds No. 1A study core as centimeter-scale variation in major components (organic carbon, authigenic sulfides and phosphate, detrital siliciclastics), organic macerals, trace-element redox proxies (Mo, U, V, Zn), and ichnofabric features. Benthic O2 levels declined sharply from the base of the black shale (0 cm), went sulfidic at ∼4 cm, and reached a redox minimum at ∼21 cm; above this level, redox potential gradually rose, fluctuating between sulfidic and nonsulfidic conditions from ∼35 cm to the black shale/gray shale contact at 52 cm. Onset of dysoxic conditions at that contact allowed establishment of a benthic community of soft-bodied organisms comprised of deep-tiered tracemakers tolerant of low-O2 conditions (Trichichnus), and shallow-tiered tracemakers favoring “soupground” (Helminthopsis) or “firmground” substrates (the Zoophycos–Phycosiphon–Schaubcylindrichnus–Planolites association). Most geochemical records exhibit a “low-order” cycle spanning the full 52 cm thickness of the black shale submember, reflecting a dominant glacio-eustatic control. The base and top of the black shale submember record lateral migration of the pycnocline across the Midcontinent Shelf during the transgressive and regressive phases, respectively. The maximum flooding surface (MFS) is at ∼17–23 cm, an interval containing the euxinic peak and characterized by high concentrations of illite (representing a cratonic siliciclastic flux) and terrestrial organic macerals, the product of transient increases in humidity, weathering rates, and the export of coal-swamp vegetation associated with the interglacial highstand of the Swope cyclothem. Although a transgressive “surface of maximum starvation” (SMS) cannot be confidently identified, a phosphate-rich “regressive condensation surface” at ∼28–34 cm records pycnoclinal weakening due to increased aridity associated with renewed southern hemisphere icesheet growth; a correlative shift in dominance from terrestrial- to marine-derived organic macerals reflects increased upwelling of nutrient-rich deepwaters and enhanced primary productivity. Penecontemporaneous paleogeographic and -climatic factors (e.g., semirestricted circulation, monsoonal precipitation) predisposed the Midcontinent Seaway toward sensitivity to high-frequency climato-environmental fluctuations, which are preserved as 2- to 7-cm-thick cycles in the study core. The 52-cm-thick black shale submember contains ∼12 such “high-order” cycles, which have an estimated average duration of ∼2 to 9 kyr, implying a sub-Milankovitch-band (i.e., millennial scale) climatic control. The results of this study are relevant to the sequence stratigraphic interpretation of Kansas-type cyclothems, the dynamics of Gondwanan Ice Age glacio-eustatic cycles, and the development of boundary conditions for Late Pennsylvanian paleoclimate models. [Copyright &y& Elsevier]

The Souss Basin of the Anti-Atlas, Morocco is located on the northwestern margin of the West African Craton and preserves a thick early Palaeozoic, predominantly marine, succession recording rift basin development and subsidence following Pan-African arc accretion. In contrast, the Taoudeni Basin of southern Mauritania is located within the craton interior and preserves a comparatively condensed, continental and marine succession. This study contrasts the sedimentological relationships of the Cambrian and Ordovician successions of these two contemporary basins in the light of our current understanding of global eustatic sea-level fluctuations and the regional tectonic framework. [Copyright &y& Elsevier]

We developed a Late Cretaceous sealevel estimate from Upper Cretaceous sequences at Bass River and Ancora, New Jersey (ODP [Ocean Drilling Program] Leg 174AX). We dated 11-14 sequences by integrating Sr isotope and biostratigraphy (age resolution ±0.5 m.y.) and then estimated paleoenvironmental changes within the sequences from lithofacies and biofacies analyses. Sequences generally shallow upsection from middle-neritic to inner-neritic paleodepths, as shown by the transition from thin basal glauconite shelf sands (transgressive systems tracts [TST]), to medial-prodelta silty clays (highstand systems tracts [HST]), and finally to upperdelta-front quartz sands (HST). Sea-level estimates obtained by backstripping (accounting for paleodepth variations, sediment loading, compaction, and basin subsidence) indicate that large (>25 m) and rapid («1 m.y.) sea-level variations occurred during the Late Cretaceous greenhouse world. The fact that the timing of Upper Cretaceous sequence boundaries in New Jersey is similar to the sea-level lowering records of Exxon Production Research Company (EPR), northwest Euro- pean sections, and Russian platform outcrops points to a global cause. Because backstripping, seismicity, seismic stratigraphic data, and sediment-distribution patterns all indicate minimal tectonic effects on the New Jersey Coastal Plain, we interpret that we have isolated a eustatic signature. The only known mechanism that can explain such global changes— glacio-eustasy—is consistent with foraminiferal δ18O data. Either continental ice sheets paced sea-level changes during the Late Cretaceous, or our understanding of causal mechanisms for global sea-level change is fundamentally flawed. Comparison of our eustatic history with published ice-sheet models and Milankovitch predictions suggests that small (5-10 × 106 km³), ephemeral, and areally restricted Antarctic ice sheets paced the Late Cretaceous global sea-level change. New Jersey and Russian eustatic estimates are typically one-half of the EPR amplitudes, though this difference varies through time, yielding markedly different eustatic curves. We conclude that New Jersey provides the best available es- timate for Late Cretaceous sea-level variations. [ABSTRACT FROM AUTHOR]

The mid-Cenomanian Dunvegan Formation represents a delta complex deposited on a foreland basin ramp over about 2 my. The Dunvegan is divided into 10 transgressive–regressive allomembers, labelled J–A in ascending order, each defined by regional marine transgressive surfaces. Parasequences within allomembers show an aggradational to offlapping stacking pattern that reflects alternate generation and removal of accommodation. The upper surfaces of allomembers H–E are incised by extensive valley systems traceable for up to 320 km and over about 50 000 km2. Valley depths range up to 41 m and can change significantly over short distances. However, the average depth of incision (mean 21 m) shows no systematic variation in longitudinal profiles and no evidence of headward shallowing. Valleys are typically 1–2 km wide, but locally widen to about 8 km. Widening is sometimes associated with confluence zones, but elsewhere it is not. Updip reaches of valleys are dominated by cross-bedded fluvial sandstone forming multistorey point-bar deposits. Sandstones contain widespread but uncommon paired carbonaceous drapes recognizable as tidal bundles. Inclined heterolithic stratification is locally well developed at the top of the valley fill. Downdip reaches of valleys, typically within 50 km of the lowstand shoreline, have a sandstone-dominated lower part and, locally, a mud-rich upper portion consisting of a variety of laminated heterolithic facies with a clear tidal signature. These heterolithic deposits may represent central basin, tidal flat, bayhead delta and point-bar environments. Valley filling took place mainly during the transgressive systems tract (TST) when tidally influenced environments migrated upvalley. Semi-diurnal tidal backwater effects extended at least 30 km landward of the regional maximum transgressive marine shoreline. The aggradational late TST and highstand systems tract (HST) includes deltaic and coastal plain deposits comprising lake and anastomosed river deposits that suggest a very low gradient (≈ 1:3000). Delta parasequences of the falling stage systems tract (FSST) offlap seaward and have no equivalent coastal plain deposits. The FSST has an average width of 60 km and an inferred gradient of 1:2500. The upper surfaces of the HST and FSST are extensively incised by valleys. The lowstand systems tract (LST) is subtly aggradational, lacks valleys and is characterized by large delta lobes fed by major distributaries. The width and inferred slope of the FSST, coupled with the thickness of aggradational TST and HST deposits on the coastal plain, suggest a vertical accommodation of about 35 m per transgressive event. About 11 m of this is attributed to isostatic subsidence resulting from water and sediment loads; the residual 24 m is attributed to eustatic rise. This sea-level change is of the same order of magnitude as the valley depths. The length of valleys, however, does not seem to be explicable solely in terms of downstream forcing by sea-level change, and an additional, upstream-forcing mechanism, possibly related to precipitation cycles in the Milankovitch band, might be inferred. [ABSTRACT FROM AUTHOR]

A correlation and sequence stratigraphy study of Jurassic successions has been carried out in the main sedimentary basins of northeast Iberia, i.e., Asturias, Basque-Cantabrian, and Iberian basins, based on the identification of transgressive–regressive cycles. The development and palaeogeographic evolution of the epicontinental carbonate platforms of northeast Iberia were largely controlled by major tectonic activity at three main intervals, at the beginning of the Jurassic, in the Lower–Middle Jurassic transition, and during the uppermost Jurassic, respectively. During Early Jurassic times, northeast Iberia was the site of a single and large carbonate ramp opened to the north. This carbonate ramp suffered a progressive drowning, evolving from an inner to hemipelagic ramp systems, with the local development of suboxic environments in the deepest areas located to the north. During the Middle Jurassic, different open carbonate platforms were formed including the development of swells in intermediate areas. During the Upper Jurassic, the outer ramp areas were progressively moving to the east Iberian Basin, and the ammonite faunas showing a markedly Tethyan affinity thereafter.Three first order T–R cycles bounded by major discontinuities associated with significant time gaps are identified. They extend respectively from the latest Rhaetian to the Early Aalenian, from the Middle Aalenian to the Early Oxfordian and from the Early Oxfordian to the Late Berriasian. Major transgressive peaks occurred at the Middle Toarcian (Bifrons Zone), at the Late Bajocian (upper Niortense and Garantiana zones) and at the mid-Kimmeridgian (Divisum Zone). Each of the first order cycles includes four second-order T–R cycles. Cycles 1.1–1.4 are identified in the northern basins. Cycles 2.1–2.4 display some differences in age of transgressive peaks from one basin to another. Cycles 3.1–3.4 are mainly identified in the Iberian Basin. The correlation with other separated Boreal and Thethysian basins demonstrates that the number and age of T–R cycles varies from one basin to another and are mainly controlled by the local or regional tectonic development. The transgressive peaks may reflect episodes of eustatic rise during the Jurassic. However, their different age from one basin to another is explained by different subsidence evolution. [Copyright &y& Elsevier]

Variations in nitrogen isotopic composition (δ15N) and total chlorin accumulation rate (AR) are employed as proxies to reconstruct oceanic nitrate inventory, the balance between denitrification and N fixation, and paleoproductivity in a rapidly accumulating sediment drift deposit beneath the Western Pacific Warm Pool for the last 145 Kyr. Subsurface and deep waters of the northern South China Sea (SCS) are sourced from the shallow Kuroshio Current (KC) and Pacific Intermediate Water, respectively. Their relative importance in determining sedimentary δ15N and paleoproductivity have been altered by changes in equatorial circulation, summer- and winter-monsoon intensity and relative sea level. The location and basin configuration of the marginal SCS renders it especially sensitive to such changes. Assuming complete annual nitrate utilization, low δ15N values during glacial stages are interpreted as a reflection of reduced remote denitrification in the Eastern Tropical North Pacific (ETNP) source waters, while much of marine isotope stage (MIS) 3 and the last interglacial were characterized by high denitrification. However, intervals of anomalously low δ15N values are interpreted as reflecting the contribution from regional N fixation in West Pacific surface waters, transmitted to the site by the shallow KC. Unusually, the Holocene is characterized by declining δ15N values and an inverse correlation with organic matter content since ca. 8.2 Ka. Millennial-scale variations during MIS 3 indicate higher frequency variations in both ETNP denitrification and local N fixation, which may be coherent with a hemispheric response to Dansgaard–Oeschger events recorded at high latitudes. For much of the last 145 Kyr, paleoproductivity was decoupled from δ15N, and instead seems to reflect the extent of the global nitrate inventory stimulated by elevated dust fertilization, and regional mixed-layer deepening associated with the relative intensity of the SE Asian winter monsoon. Despite evaluation of possible conflicting influences on the record of each proxy, we interpret our data as clear evidence of glacial/interglacial changes in marine nutrient inventory across the whole of the North Pacific, with a corresponding biogeochemical response and important implications for global CO2 drawdown via an invigorated biological pump. The relative importance of local, regional and global contributions to our records appears to be strongly modulated by relative sea level, controlling trans- and extra-basinal circulation in the SCS. [Copyright &y& Elsevier]

Interpretation of the recent high-resolution survey, CANADOU 2000, in the Bay of Douarnenez (Finiste&grave;re, France) allowed us to restore the morphology of the substratum and the sedimentary filling of the bay. The Brioverian and Palaeozoic substratum reveals a well-defined network of incised valleys as results of successive emergence stages of the Bay during the Quaternary. Valleys join in a westward-widened mean valley, called Ys Valley. The present-day sedimentary fill of the bay of Douarnenez appears mainly controlled by the Holocene rise and the consecutive highstand. It comprises fluvial and estuarine deposits filling up incised valleys and marine sedimentation extending out of the incised valleys. To cite this article: G. Jouet et al., C. R. Geoscience 335 (2003). To cite this article: G. Jouet et al., C. R. Geoscience 335 (2003). [Copyright &y& Elsevier]

During the late Frasnian, 11 fourth-order progradational/retrogradational marine sedimentation cycles were deposited in the Appalachian foreland basin. Mapping based primarily on subsurface data demonstrates the continuity of these cycles over a distance of 700 km. Cyclicity in distal facies occurs as alternations of organic-rich and organic-poor shales, two of the organic shales can be correlated with the transgressive “Kellwasser Beds” of Europe. In more proximal facies, recurring lobes of siltstone and sandstone were deposited. Based on lithologic indices, the temporal pattern shows significant variation in the strength of relative facies change during deposition. In particular, two times of particularly pronounced progradation correspond to previously recognized eustatic sea-level falls. The correlation of portions of Appalachian basin depositional cyclicity with global sea-level events suggests that the entire sequence of 11 cycles, with estimated average duration of around 100–150 ka, were the result of high-frequency eustatic sea-level changes. This in turn would be consistent with a brief period of late Frasnian glaciation, as others have previously suggested. [Copyright &y& Elsevier]

The Niigata-Shin''etsu basin, which occurs along the eastern margin of the Sea of Japan, was generated in Middle Miocene time as a failed rift basin in relation to the backarc opening of the Japan arc, and was converted to a compressional basin in Late Miocene time. The basin-filling succession can be divided into four tectonostratigraphic units (stages), based on characteristics of depositional systems, depositional sequences, tectonic-subsidence rate, and sediment supply. These units coincide in time with major tectonic events during backarc rifting and subsequent basin inversion. Unit I (16–13.5 Ma) represents a syn-rift stage, characterized by rapid basin subsidence. The rate of accommodation exceeded the rate of accumulation, resulting in a retrogradational stacking pattern of muddy slope to basin floor systems. Unit II (13.5–6.5 Ma) represents a post-rift thermal-subsidence stage. The rate of accommodation nearly equaled the rate of accumulation, resulting in an aggradational stacking pattern of five third-order depositional sequences, mainly comprising submarine-fan turbidite systems affected by supply of coarse clastics. Unit III (6.5–1 Ma) represents the basin-inversion stage, showing no subsidence or uplift. The accumulation rate exceeded the rate of accommodation, resulting in rapid progradation of depositional sequences composed of slope, shelf, shallow-marine, delta, and fluvial systems. Unit IV (1 Ma–present) represents an intense compressional stress field; sedimentation has been restricted to a synclinal area due to syndepositional folding and uplift.Changes in basin subsidence rate and sediment supply, resulting from tectonics and climate change in the basin and the provenance, strongly affected characteristics of the depositional systems and sequences. The change in basin subsidence also created a basinwide depositional cycle, whereas eustasy-affected relative sea-level changes created higher-order depositional sequences during relatively stable phases of tectonics. [Copyright &y& Elsevier]

An exceptionally high sea level in Frasnian times (early Late Devonian) changed many peneplained, cratonised and tectonically undisturbed continental margins of tropical belts into carbonate platforms which became covered by thick banks of limestone. The stages marked by very pure carbonates developed during partial sea-level highstands since, when the flooding reached its maximum, the shoreline was distant and conditions for reef growth were good. An increased extension of emerged, flat, coastal areas was coupled with an opposite situation, when oscillating sea level fell to its momentary minimum and the accommodation space available for accumulation of carbonate material was low. Subaerially exposed surfaces were subject to weathering and the products were dispersed by aeolian or aquatic means to form layers when these weathering materials were trapped in carbonates. This overall scenario relating to the trapping of weathering products in pure carbonates was tested at geographically isolated platform with a stable and only slowly subsiding basement (Eastern Moravia, Czech Republic). The amounts of weathering products dispersed in limestone were documented using the combined methods of γ-ray logging, γ-ray spectrometry and magnetic susceptibility measuring, i.e. according to their radioactivity (K, Th and U) and magnetism (Fe). Six third-order Frasnian eustatic cycles have been inferred from the data, with an estimated period of 1 Ma. The Late Frasnian and especially the Frasnian/Famennian (F/F) transition brought the total destruction or at least a strong overlay on this hypothetical background setting. The record of strong sea-level fluctuations in the F/F interval is shown in strong oscillations and offsets related to pronounced hiatuses and flooding surfaces. Such rapid sea-level fluctuation is typical for glacioeustatic control, although the present estimates of the maximum amplitudes are larger than realisable by glaciation events and may be explained in combination with tectonoeustatic models. Comparison of sections between the centre and periphery of the platform substantiates the concept that oscillating Late Frasnian shorelines were rapidly prograding. Very low sea-level stages of early Famennian times changed the depositionary systems from extensive platforms to narrow carbonate ramps which were positioned out and down on the extinct reef bank slopes. The central parts of the Eastern Moravian and also other Frasnian platforms in the world were not normally covered by F/F sediments, the transgressive onlaps above any crystalline highs were not observed and therefore the drowned Frasnian reefs on their periphery, although emphasised by many geologists, may reflect sliding or tectonic subsidence on the margins of platform blocks rather than eustatic rise of sea level. [Copyright &y& Elsevier]

During ODP Leg 166, the recovery of cores from a transect of drill sites across the Bahamas margin from marginal to deep basin environments was an essential requirement for the study of the response of the sedimentary systems to sea-level changes. A detailed biostratigraphy based on planktonic foraminifera was performed on ODP Hole 1006A for an accurate stratigraphic control. The investigated late middle Miocene–early Pliocene sequence spans the interval from about 12.5 Ma (Biozone N12) to approximately 4.5 Ma (Biozone N19). Several bioevents calibrated with the time scale of Berggren et al. (1995a,b) were identified. The ODP Site 1006 benthic oxygen isotope stratigraphy can be correlated to the corresponding deep-water benthic oxygen isotope curve from ODP Site 846 in the Eastern Equatorial Pacific (Shackleton et al., 1995. Proc. ODP Sci. Res. 138, 337–356), which was orbitally tuned for the entire Pliocene into the latest Miocene at 6.0 Ma. The approximate stratigraphic match of the isotopic signals from both records between 4.5 and 6.0 Ma implies that the paleoceanographic signal from the Bahamas is not simply a record of regional variations but, indeed, represents glacio-eustatic fluctuations. The ODP Site 1006 oxygen and carbon isotope record, based on benthic and planktonic foraminifera, was used to define paleoceanographic changes on the margin, which could be tied to lithostratigraphic events on the Bahamas carbonate platform using seismic sequence stratigraphy. The oxygen isotope values show a general cooling trend from the middle to late Miocene, which was interrupted by a significant trend towards warmer sea-surface temperatures (SST) and associated sea-level rise with decreased ice volume during the latest Miocene. This trend reached a maximum coincident with the Miocene/Pliocene boundary. An abrupt cooling in the early Pliocene then followed the warming which continued into the earliest Pliocene. The late Miocene paleoceanographic evolution along the Bahamas margin can be observed in the ODP Site 1006 δ13C values, which support other evidence for the beginning of the closure of the Panama gateway at 8 Ma followed by a reduced intermediate water supply of water from the Pacific into the Caribbean at about 5 Ma. A general correlation of lower sedimentation rates with the major seismic sequence boundaries (SSBs) was observed. Additionally, the SSBs are associated with transitions towards more positive oxygen isotope excursions. This observed correspondence implies that the presence of a SSB, representing a density impedance contrast in the sedimentary sequence, may reflect changes in the character of the deposited sediment during highstands versus those during lowstands. However, not all of the recorded oxygen isotope excursions correspond to SSBs. The absence of a SSB in association with an oxygen isotope excursion indicates that not all oxygen isotope sea-level events impact the carbonate margin to the same extent, or maybe even represent equivalent sea-level fluctuations. Thus, it can be tentatively concluded that SSBs produced on carbonate margins do record sea-level fluctuations but not every sea-level fluctuation is represented by a SSB in the sequence stratigraphic record. [Copyright &y& Elsevier]

Earlier workers have established sea level curves for the Ashgillian–Llandovery sequence on Anticosti Island, Que´bec, Canada, based on sedimentology and on brachiopod and reef communities. The complete Anticosti sequence has been collected for conodonts to provide a database of over 77 600 conodonts derived from 272 samples through the 800–1100 m sequence. This paper uses a statistical analysis of the database to establish the pattern of conodont communities and their interpreted water depths. This allows the establishment of a eustatic sea level curve for the sequence. This curve is in general agreement with those of the earlier workers, but is more detailed and better constrained stratigraphically given the large sampling program. The curve reflects more oscillating sea level changes for the whole sequence than those constructed earlier, and different water depths for certain intervals from those established earlier. The curve is valuable given that the Anticosti sequence is one of the most complete in the world for this interval, and its divergence from global eustatic curves for this interval is noted. [Copyright &y& Elsevier]

During the Keuper, the Paris Basin was an intracratonic sedimentary basin filled by continental deposits. Using paleo-environmental, isopach and paleo-altitude maps, we estimate the variations of accommodation rate at the scale of stratigraphic minor hemi-cycle (1–3 Ma). An analysis of the short- and long-wavelength accommodation variations allows us to assess the relative influence of tectonics, eustasy and sediment supply on the stratigraphic record. Our data suggest a pattern of subsidence along three trends: E–W in the Carnian, E–W to NNE–SSW in the Norian and NE–SW in the Norian–Rhaetian. During the Keuper, the Paris Basin accurately records the different phases of the opening of the Tethys Ocean associated with a rotation of the extension direction. The Norian cycle could thus reflect the intraplate stresses in a transitional period between the Triassic and the Liassic. [Copyright &y& Elsevier]

We have previously shown that the coralline algal assemblages (CAAs) of the South China Sea may indicate post-Pliocene paleo-water depth changes; however, the pre-Pliocene coralline algal compositions and related sea-level significance remain to be elucidated. In the present study, we explore the Miocene coralline algal compositions and their role in recording the sea level, and show the distribution, classification, type, abundance, and diversity of Miocene coralline algae from 213 petrologic thin sections using a coral-reef carbonate sequence from the northern South China Sea. The diversity and abundance of coralline algae in the early and late Miocene are higher than those in the middle Miocene. Eleven genera were identified and grouped into seven CAAs, showing a water depth range from <5 m to >25 m. At 18.67–17.98 Ma, the coral reef was in a stagnation/drowning stage, with rising sea levels exceeding the development of the coral reef. At 17.98–16.78 Ma, the coral reef was in a rapid development during a rapid rise in sea level. Additionally, at 16.78–14.79 Ma, low coralline algal abundance was observed, and the corals were sporadically distributed at a relatively stable sedimentation rate, suggesting a decline in coral reef development. At 14.79–10 Ma, the coral reef development was remarkably slow or stagnant. Furthermore, at 10–5.3 Ma, the coral reefs developed slowly, indicating a gradual rise in the sea level. The sea-level changes indicated by coral reef development are consistent with the long-term global sea-level changes, indicating that the composition and assemblage of Miocene coralline algae can be used to accurately relay the sea-level history. • Eleven coralline algal genera were identified in a Miocene carbonate sequence. • Miocene coralline algae were divided into 7 coralline algal assemblages (CAAs). • Sea-level changes due to coral reef development were consistent with global values. [ABSTRACT FROM AUTHOR]

Diatom and sedimentological analyses of a 7.6-m core of the Albufeira coastal lagoon, western Portugal, provide information about the forcing factors and environmental history of the evolution of this lagoon during the last 2500 years. At this timescale, eustasy is considered to be a minor environmental control on the dynamics of the barrier-lagoonal system. Instead, these dynamics are forced by local factors, such as changes in the sand-barrier permeability. Lithological and diatom facies are compared with present-day environ-ments and show that the lagoon evolved essentially as a slightly brackish water body with a salinity of around 1‰. This pattern was disturbed by three major episodes of sedimentation associated with threshold responses in the permeability of the barrier. The first (c. 2370 BP) did not produce a specific lithological signal and is characterized by a peak in freshwater euplanktonic diatoms, implying an almost permanent isolation of the basin and freshwater flooding. A second episode was identified at c. 1600 BP, when a dramatic opening of the tidal inlet provoked a significant change in the sedimentation regime, which became dominated by inorganic, minerogenic sediments and allowed marine/brackish epiphytic diatoms to flourish together with allochthonous marine planktonic species. Finally, a third threshold occurred at c. 1225 BP corresponding to the establishment of the present-day muddy or sandy-muddy sedimentation pattern. Both the sedimentological features and the diatom assemblages indicate the establishment of a more tidally influenced environment. This reflects regular artificial breaching of the barrier associated with increasing anthropogenic intervention in the system. [ABSTRACT FROM AUTHOR]

A poorly understood Mississippian to basal Pennsylvanian succession is preserved in parts of northern Utah, western USA. The mudrock- and carbonate-dominated Manning Canyon Formation and lateral equivalents have been referred to as "cyclothems" and might therefore be expected to preserve a record of repeated, late Paleozoic sea-level excursions similar to cyclothemic successions elsewhere in the paleotropics. In this paper, we document the sedimentology and stratigraphy of the Serpukhovian to earliest Bashkirian Manning Canyon Formation, focusing on surface exposures in the Oquirrh and Uinta Mountains and a cored subsurface intersection from central Utah. Four facies associations were identified in the Manning Canyon Formation: Mid-Shelf, Muddy Inner Shelf, Deltaic, and Coastal Plain, which are herein interpreted in the context of a muddy, semi-enclosed, epicontinental carbonate shelf fringed by a low-relief coastal plain. These facies associations are broadly comparable to recent and extant environments from a range of equatorial, clay-rich, deltaic, coastal plain, and offshore carbonate-producing environments in the Caribbean Sea, northern Australia, and SE Asia, which can be used as first-order analogues for the Manning Canyon Formation. These modern analogues suggest that several relative sea-level excursions of <40 m are recorded in the unit. The stratigraphically oldest records of substantial relative sea-level oscillations are in the lowermost Manning Canyon Formation. These preceded a more sustained pattern recorded by at least nine 4th-order, high-frequency and high-magnitude (≥40 m) sea-level cycles that characterize the upper two-thirds of the formation. Sea-level highstands are recorded by open marine shelf facies, whereas lowstands are recorded by incised channel and valley fills, and (presumed) laterally equivalent paleosols and thin coals. No record of high frequency/high magnitude relative sea-level oscillations comparable in character to those preserved in the Manning Canyon Formation was documented in the underlying stratigraphy. It is concluded that the Manning Canyon Formation may record the main onset of the eustatic signal associated with the main phase of the late Paleozoic Ice Age at ~330 Ma. • Late Paleozoic cyclothems are well-preserved in the late Mississippian record of Utah. • Cyclothems are dominated by mudrocks and carbonate lithologies. • Four facies associations record an embayed shallow marine to coastal plain setting. • Repeated sea-level excursions of at least 22–40 m are recorded in the formation. • The onset of cyclothemic stratigraphy occurred at about 330 Ma. [ABSTRACT FROM AUTHOR]

The opening and closure of marine gateways have been suggested to substantially affect ocean current circulations and global climatic changes. In the Miocene, the closure of the Tethyan Seaway, which connected the proto-Mediterranean Sea with the Indian and Atlantic Oceans, blocked thermohaline exchanges between them and possibly caused a major climate change in the Middle Miocene Climatic Transition. However, the timing, process, and forcing mechanism of the closure of this seaway are controversial. To address this question, we focus on the chronology and sedimentary facies of Miocene strata in the Zagros foreland basin in the Western Iranian Plateau. Based on magnetostratigraphy and biostratigraphy, we establish a chronology of 17 to 10 Ma for the studied Miocene strata and constrain the timing of the permanent closure of the northwestern segment of the Tethyan Seaway to 12.8 Ma. By comparison with global sea-level fluctuations, we suggest that middle Miocene marine transgressions and regressions in the studied region were mainly driven by global climatic change through its control on the growth and decay of ice sheets and thus sea level changes. Our detailed depositional sequence analysis exhibits 100-kyr Earth's eccentricity cycles of marine transgressions and regressions between 15.0 and 12.8 Ma implying they were controlled by astronomical factors. Moreover, the Tethyan Seaway experienced stepwise evolution changing from partially opened seaway, restricted marine connection, intermittent connections, to permanent closure in its northwestern segment during the early and middle Miocene. • New chronology of the Cenozoic marine-terrestrial strata in the Zagros foreland. • Permanent closure of the northwestern segment of the Tethyan Seaway at ca. 12.8 Ma. • Marine transgressions/regressions were driven by global sea-level fluctuations. • 100-kyr cycles of marine transgressions/regressions were recorded. • The Tethyan Seaway experienced stepwise evolution from early to middle Miocene. [ABSTRACT FROM AUTHOR]

The Late Ordovician late Katian was a period of generally warm, transitional greenhouse to icehouse climate with sea-level oscillations dominated by moderate-amplitude eustasy. This study aims to improve the understanding of the climatic and sea-level fluctuations prior to the end-Ordovician glaciation, using a comprehensive core, wireline log, and thin-section dataset spanning the topmost Red River-Stony Mountain Formation within the subsurface of North Dakota, Williston Basin, North America. Eleven facies are identified, interpreted, and grouped into four facies associations, including salina to peritidal evaporative, restricted-marine subtidal, open-marine subtidal, and open-marine deeper water. Stratigraphic trends, basin-wide facies variations, and correlation of individual surfaces for ~380 km across the study area, suggest that the facies were deposited under different climatic and sea-level regimes as part of the long-term Stony Mountain sequence. The sequence (37–52 m) is bounded by anhydrites (basin center) and their correlative thin exposure-related breccias (updip proximal basin), and contains a set of high-frequency sequences (HFS; 2–26 m) that can be traced across the study area. The lowstand systems tract (LST) anhydrites formed in a shallow and well‑oxygenated setting under an arid climate during relatively short periods of the basin restriction. The sea-level rise during the early transgressive system tract (TST) resulted in a higher evapotranspiration rate and an increasingly humid climate that peaked during the late TST with the input of siliciclastics off the Transcontinental Arch. The increased precipitation and runoff resulted in quasiestuarine circulation. Return to semi-arid conditions characterizes the highstand systems tract (HST), with increasingly more restricted, shallow-marine and oxygenated setting with antiestuarine circulation. The work provides insight into the interaction of siliciclastic input, climate, and sea-level changes on depositional dynamics and sequence architecture of a mixed carbonate-siliciclastic-evaporite succession that formed in a tropical epicontinental basin setting prior to the end-Ordovician glaciation. • Williston Basin Katian sequence documents major climate and sea-level change. • Climate trends tracked by mineralogy, facies stacking, fossils, and spectral GR-logs. • Transcontinental Arch source of siliciclastics during humid episode. • Tropical aridity thru sea-level lows aided by dry winds descending lee side of Arch. [ABSTRACT FROM AUTHOR]

Abstract: Each high-quality regional study of relative sea-level changes may contribute to the understanding of global eustatic mechanisms. In particular, it is intriguing to compare the Carboniferous sea-level changes established in the Donbass (a large domain in the southwest of Russia and the east of Ukraine) by Eros et al. (2012) with the available global eustatic curve. At least two significant discrepancies between these reconstructions are found. The long-term early Moscovian lowstand that is reported from the Donbass coincides with the global eustatic rise. In contrast, the early Bashkirian global sea-level lowstand occurred when the relative sea level did not experience any extraordinary fall in the Donbass. Sea-level fluctuations across the Mississippian/Pennsylvanian boundary also differed slightly. At other time intervals, the regional and global curves are comparable. It is possible to hypothesize that either the regional signatures of the global eustatic fluctuations were altered by tectonic activity (e.g., in the form of dynamic topography) or that the available eustatic curve is incorrect in some places. Only further broad inter-regional correlations of Carboniferous sequences will permit choosing between these hypotheses. And it is not excluded that some different conclusions would be drawn if the observed stratigraphy of the Donbass is instead caused by regional vertical tectonic motions. [Copyright &y& Elsevier]

• The BZK0402 core from the southern edge of the Paleo-Danyang Lake records the Gothenburg geomagnetic excursion. • This excursion occurs during the Pleistocene–Holocene transition and is recorded in an area with high sedimentation rates. • The Gothenburg excursion can be used to correlate between sedimentary cores in East Asia. • It also has potentially wider correlative and chronostratigraphic uses. • The Gothenburg geomagnetic excursion is contemporaneous with an abrupt temperature decrease since the last deglaciation. This paper aims to identify the Gothenburg geomagnetic excursion as a stratigraphic marker and presents the results of a paleomagnetic investigation of deposits within the southern part of the Paleo-Danyang Lake area of eastern China. These paleomagnetic data provide evidence for the Gothenburg geomagnetic excursion at 12,494 to 13,081 cal year BP at depths of 6.5–7.2 m within the paleo-lake. We also analyzed the spatial distribution of localities that both record and do not record the excursion event and the estimated timing of this excursion event in East Asia. The presence of uninterrupted sedimentation at a high depositional rate during the Pleistocene–Holocene transition appears to be the key factor in preserving evidence for this excursion in the localities that record this event. The non-existence of the excursion appears to be the result of low sedimentation rates, under-sampling and the presence of sedimentary hiatuses associated with erosion. The fact that these types of excursions can be correlated between sedimentary cores separated by angular distances of less than 30° on Earth's surface means that the Gothenburg excursion can be used to correlate between lacustrine and marine deposits in East Asia (and potentially further afield) as well as being useful for chronostratigraphic purposes. Comparisons between cave stalagmite δ18O records and the polarities of the lacustrine sediments also indicate that the timing of the Gothenburg geomagnetic excursion is consistent with an abrupt decrease in temperature since the last deglaciation although the meaning of this correlation requires further research. [ABSTRACT FROM AUTHOR]

The benthic foraminifera from the Campanian rocks (Globotruncanita elevata to Globotruncana aegyptiaca zones) exposed in the Kopeh-Dagh Basin (northeast Iran) are studied quantitatively to reconstruct the Campanian paleoenvironment. Based on unconstrained heriarchial clustering, Nonmetric Multidimensional Scaling (NMDS), and analysis of similarity (ANOSIM), three statistically significant benthic foraminiferal assemblages are noted, Paralabamina lunata (lower and upper), Haplophragmoides spp., and Gyroidinoides nitida. Based on benthic foraminiferal marker species, the following paleodepths are assigned - lower P. lunata : upper bathyal; upper P. lunata : upper-middle bathyal boundary; Haplophragmoides spp. and G. nitida : outer neritic. The P. lunata Assemblage can be further subdivided into a lower Coryphostoma incrassata -dominated interval, whereas the upper interval is P. lunata -dominated, and reflects a change in the quality of food; the upper experienced higher input of fresh phytodetritus. The overall P. lunata Assemblage reflects a stable bottom water environment. The Haplophragmoides spp. Assemblage is characterized by reduced paleoproductivity and environmental instability, whereas the G. nitida Assemblage is marked by increasing oligotrophy within a well-oxygenated bottom water and ventilated basinal conditions. The Partial Least Squares regression yielded significant correlations with % Planktic (positive; proxy for sea level) and % agglutinated species (negative; proxy for shallow depths and low organic-flux); the Reduced Major Axis regression models also yielded significant negative correlations with % agglutinated and % infaunal species (nutrient availability), suggesting that these factors were responsible for the inferred benthic foraminiferal distribution patterns. Two globally comparable shallowing trends are also noted - one in the middle of the R. calcarata Zone (= Haplophragmoides spp. Assemblage) and the other in the G. aegyptiaca Zone (= Gyroidinoides nitida Assemblage) that coincide with KCa6 and KCa7 sequence boundaries and lowstands, respectively. For the KCa6 event, the occurrence of Spiroplectammina (= Haplophragmoides spp. Assemblage) represents a shallow-water outer neritic fauna invasion event within a deeper upper bathyal setting (= Paralabamina lunata Assemblage) and for the KCa7 event, a similar shallowing from upper-middle bathyal boundary to outer neritic depths is noted (= G. nitida Assemblage), and attributed to eustasy and basinal paleohighs and lows. Unlabelled Image • Three distinct benthic foraminiferal assemblages were quantitatively identified. • Sea level, % of agglutinated and infaunal species govern the distribution patterns. • Two eustasy-driven shallowing events (KCa6 and KCa7) are noted. • Bathymetry plays a major role in the benthic foraminiferal distribution patterns. [ABSTRACT FROM AUTHOR]

• Water-loaded Neogene subsidence of New Jersey (NJ) margin is up to 1000 m. • Residual (i.e. non-plate cooling) subsidence is negligible ∼500 km from NJ margin. • Anomalous Neogene subsidence cannot be easily explained by glacio-eustasy. • Sub-plate support estimated from shear wave tomography and gravity. • Anomalous subsidence of NJ margin generated by upper mantle drawdown. Global sea-level (eustatic) histories generated by backstripping stratigraphy are predicated upon the lithosphere having a well understood tectonic history. However, sub-plate processes play a role in governing lithospheric vertical motions with timescales and amplitudes akin to eustasy, which are difficult to predict. We examine how stratigraphic and geophysical observations combined with simple isostatic models can be used to disentangle histories of sub-plate support and eustasy. We focus on the passive margin of Eastern North America, where a generally accepted history of eustasy has been estimated. Negative long wavelength free-air gravity anomalies, residual ocean-age depth estimates, fast upper mantle shear wave velocities, and geodynamic models suggest that Cenozoic evolution of this passive margin has been influenced by upper mantle drawdown. We build on existing analyses to backstrip sixteen wells, which, combined with seismic data, constrain timing and extent of Cenozoic subsidence. Results indicate up to ∼1000 m of water-loaded subsidence between ∼20–0 Ma centered on the Baltimore Canyon Trough. Seismic data from the trough shows Neogene aggrading clinoforms. There is little evidence for faulting or stratigraphic growth, which indicates that Neogene lithospheric strain rates were low. Amplitude and spatial extent of Neogene subsidence are difficult to explain by glacio-eustasy or glacio-isostatic adjustment. Instead, sub-plate support calculated from conversion of shear wave velocities to temperature and isostatic calculations indicate that upper mantle drawdown was responsible for subsidence of the margin. Because mantle convection is vigorous such observations are expected throughout the stratigraphic archive. [ABSTRACT FROM AUTHOR]

The study of the Miocene carbonate platform of the Maldives allows understanding the controlling factors triggering the stepwise drowning of carbonate platforms. This research presents high-resolution seismic profiles and sediment cores retrieved from Sites U1465, U1469, and U1470 drilled during International Ocean Discovery Program (IODP) Expedition 359. A microfacies analysis of the platform deposits was conducted and correlated with a sequence stratigraphic analysis of seismic reflection data. The Neogene evolution of the Maldives encompasses a series of drowning steps. Two of these steps are compared with regard to the carbonate factory type to unravel if fossil assemblage surviving the first drowning step are different from younger assemblages. In both cases the shallow water carbonate facies are formed by coral-coralline algal boundstone and foralgal floatstone that change basinwards into slope facies dominated by large benthic foraminifera grainstone to packstone, locally floatstone and rudstone. The red algae and large benthic foraminifera assemblages are similar before and after the first drowning step. After this first drowning, the carbonate platform developed under enhanced bottom current conditions, as deduced by the coeval drift deposits. The carbonate platform and the drift deposits were balanced for circa 2 Myr, until a global sea-level fall at 10.6 Ma and later reflooding of the platform, which destroyed the equilibrium between both depositional systems, favouring the current-controlled deposits. The drowning of the Miocene carbonate platform of the Maldives was the result of the combined effect of the fluctuating sea-level during the Neogene and the intensification of oceanic currents due to the invigoration of the South Asian Monsoon during the middle Miocene. • There are two main phases of Miocene drowning of the Maldives carbonate platform. • The drowning occurred at 13 Ma and 10.6 Ma. • The fossil assemblages do not show evidences of nutrient input at that time. • Sea-level and currents drowned the Miocene Maldives carbonate platform. • The invigoration of the South Asian Monsoon enhanced oceanic currents. [ABSTRACT FROM AUTHOR]

Despite great practical achievements, sequence stratigraphy failed to elaborate until now the reliable technique for establishing relative sea-level fluctuations (RSLF). The method proposed recently by Yu.A. Volozh with colleagues for determining the RSLF represents one of interesting but unconvincing attempts in this respect. Use of their method for fundamental and practical purposes requires prudence because of potential errors. [ABSTRACT FROM AUTHOR]