Amplitude Of Sea-level Changes Research Articles

Sea-level fluctuations in the late Middle Permian estimated from palaeosols of the Sichuan Basin, SW China

AbstractTwo upper Middle Permian palaeosols, consisting of coal and pyrite intercalated with a 20 cm thick limestone, were found near Mount Emei in the SW Sichuan Basin, China. The macro- and micromorphology and physico-chemical properties, in conjunction with the mineralogical composition of the palaeosol horizons were investigated. This type of palaeosol is common within the Permian intertidal facies of the Upper Yangtze Craton. The section reflects fluctuations within the range of 0–25 m in relative sea-level, with the depositional environment changing from shallow-marine to littoral, followed by tidal-flat to littoral, and finally to continental volcanic rocks, based on a combination of palaeopedological and carbonate microfacies analyses. Such short-term relative sea-level fluctuations in late Middle Permian times in the SW Sichuan Basin of South China are consistent with the long-term falling trend on a global scale in late Middle Permian times, and may be related to regionally variable subsidence and global cooling. The combination of coastal palaeosol and carbonate microfacies analyses is proposed as an additional tool for estimating the amplitude of sea-level changes.

Amplitude calculation of the end-Permian sea level drop in Northeastern Sichuan Basin, China

An extensive unconformity surface has been reported on top of the Changxing Formation in northeastern Sichuan Basin, which was formed by the end-Permian sea level drop globally. The amplitude of sea level change has never been studied in Changxing Formation, however, this is a problem of vital importance in petroleum exploration. Logging curves of boreholes located in Longgang, Puguang and Yuanba areas are used to analyze the intensity of karst, which can be used to represent the amplitude of sea level drop. Four, two and two logging phases are identified in Longgang, Yuanba and Puguang areas, respectively, which indicate different combinations of sedimentary facies and diagenesis features. By analyzing the thickness of karst formations in the studied sections, the amplitudes of sea level drop are identified in different areas. Combined with karst features reflected from Permian Panlongdong Outcrop, the amplitude of end-Permian sea level drop is at least 190 m in Sichuan Basin.

APPROACHES TO FORECASTING THE DEVELOPMENT OF MARINE SHORES OF THE EUROPEAN RUSSIA (PAPER 1. MORPHOGENETIC TYPES OF SEASHORES)

The variety of morphological features and physiographic differences of sea coasts in European Russia is described from arctic deserts and tundra on the Barents Sea coasts to the Submediterranean landscapes, semi-deserts and deserts in the coasts of the Caspian and Black Seas, as well as differences in economical development of the coasts. The problems of forecasting of sea shore development are discussed: the general approach to forecasting; set of necessary maps to make; direction and amplitude of sea-level changes over the period of interest. The scenario approach is substantiated that answers the question – how will the coast develop under different changes of sea level and climate conditions. Morphogenetic types of the sea coasts and the legend of sea coast morphogenetic map are described as the basis for further researches.

Formation of sequence boundaries and amplitude of sea level change in Pleistocene: Results from IODP, New Zealand shelf-slope drilling

Formation of sequence boundaries and amplitude of sea level change in Pleistocene: Results from IODP, New Zealand shelf-slope drilling

Revisiting the Quaternary development history of the western New Caledonian shelf system: From ramp to barrier reef

The present paper is based on the study of a new core (Ténia 3,151.20m long) and revisitation of previous core data from the western New Caledonian barrier reef. Based on variations in lithology and stable isotope signatures, and the occurrence of unconformity surfaces, the Ténia 3 sequence is subdivided into ten units, regarded as deposited during interglacial, high sea levels. Five detrital and two framework facies are delineated using their biological and textural attributes, including coral growth forms and assemblages. These facies are interpreted as representative of outer to inner carbonate shelf (ramp to barrier reef) environments. Variations in the facies within each stratigraphic unit occur mainly as vertical transitions from lower energy (and probably deeper) to higher energy (probably shallower) settings. The succession of depositional events is reconstructed using all available age criteria including lithostratigraphy, magnetostratigraphy, uranium-series dating, and nannofossil biostratigraphy. Shallow-water, coral communities appear to have been developed as soon as carbonate deposition started at around 1.2million years (Ma), but the initiation of typical coral reef tracts is likely to have occurred not prior to 0.40million years during Marine Isotope Stage (MIS) 11. Carbonate deposition previous to MIS 11 is considered to have operated along an open shelf margin, i.e. a ramp or non-rimmed platform. Based on the re-examination of the core dataset previously acquired from the New Caledonian reefs, the coral communities, dominated by massive forms (mainly poritids) are assumed to have remained stable in composition over the past 1.4Ma. Similarly, as indicated by a preliminary study of pollen assemblages in the core, the composition of terrestrial flora, dominated by Podocarpaceae and Araucariaceae, has not apparently suffered significant change over the past 1Ma, and reflects climate conditions cooler and drier than today. Mean subsidence rates are derived tentatively over the past 1Ma from the stratigraphic position at present reached by the top of depositional units; mean rates of ≤0.08mmyr−1 for the western New Caledonian margin are consistent with past sea-level estimates. The Quaternary depositional history of the New Caledonian shelf margin appears to have been controlled by both the amplitude of sea-level changes and by differing vertical tectonic movements. Comparison between the depositional shelf histories from western New Caledonia, north-eastern Australia, southern Belize and the Ryukyu Islands supports the assumption that coral populations over the early and mid Pleistocene developed as non-reefal communities along ramp systems, not forming continuous outer-shelf reef rims. At a global scale, Quaternary reef-rimmed platforms are likely to have initiated after the Mid-Pleistocene Climate Transition, from marine isotope stage 11, at about 0.4Ma.

Responses of coral reefs to increased amplitude of sea-level changes at the Mid-Pleistocene Climate Transition

We show responses of coral reefs to increased amplitude of sea-level changes at the Mid-Pleistocene Climate Transition (MPT) based on lithostratigraphic, sedimentologic and calcareous nannofossil biostratigraphic investigations on Pleistocene reef-complex deposits (Ryukyu Group) on the Motobu Peninsula, Okinawa-jima, Central Ryukyus. Our data show that reef growth started in earliest Quaternary time (1.45–1.65 Ma) and that extensive reef formation dates back to ∼ 0.8 Ma. The mode of Quaternary sedimentation changed at ∼ 0.8 Ma in the study area. Before this time, thick siliciclastics and mixed carbonate-siliciclastics accumulated, which were followed by the deposition of bioclastic sediments (detrital limestone). No indications have been found of episodic subaerial exposures in these deposits and no calcareous nannofossil biozones are lacking. Since the detrital limestone includes biogenic components characterizing fore-reef to shelf environments, the coastal areas of the northern Motobu Peninsula mostly lay in fore-reef to shelf environments for > 0.6 million years (between ∼ 0.8 Ma and 1.45–1.65 Ma), when the sediments had not been subaerially exposed due to sea-level changes characterized by relatively small amplitudes. Coral limestone that formed in the latest Early to Middle Pleistocene between 0.4 Ma and 0.8 Ma extends over the study area, ranging in elevation from 0 to 70 m. This coral limestone grades upward into fore-reef to shelf carbonates (rhodolith, Cycloclypeus-Operculina, and detrital limestones) which is in turn overlain by coral limestone. This succession, combined with configuration of the lithofacies and paleobathymetry inferred from lithology and biogenic components, implies that the reef-complex deposits formed responding to sea-level changes with amplitude of > 60 m. Consequently, we suggest that the change in the mode of sedimentation results from increased amplitude of sea-level fluctuations at ∼ 0.8 Ma. This timing corresponds roughly to the timing of the Mid-Pleistocene Climate Transition (MPT).

Echinoid distribution and sequence stratigraphy in the Cenomanian (Upper Cretaceous) of southern England

Almost 3500 individual occurrences of echinoid have been recorded and correlated against a sequence stratigraphie framework for the entire Cenomanian and basal Turonian from three regions of southern England, representing onshore, mid-shelf and deeper-shelf habitats. There are marked differences in the composition and diversity of faunas both across the shelf at a single time interval and through time at the same locality, driven primarily by factors such as sedimentary facies, which are controlled by changing sea-levels. The ranges of individual taxa expand and contract across the shelf as sea-levels change. In mid-shelf environments more onshore taxa appear only near sequence bases, at times of lowest sea-level, while those from more outer shelf settings are found during highstand intervals, and this creates a cyclical pattern of diversity. By comparison with modern faunas, the Middle and Upper Cenomanian of the Sussex coast is likely to have been deposited in water depths of between 100 m and 150 m and the amplitude of sea-level change appears to increase through the Cenomanian.

Latest Chesterian (Carboniferous) initiation of Gondwanan glaciation recorded in facies stacking patterns and brachiopod paleocommunities of the Antler foreland basin, Idaho

Stacking patterns of facies and brachiopod communities of Latest Chesterian (Middle Carboniferous) units of east-central Idaho record an increase in the frequency and amplitude of sea level changes. Water depth, as inferred from lithology and paleoecology, provides the basis for quantifying sea level fluctuations. The Surrett Canyon Formation is dominated by thick sequences of subtidal carbonates. The Arco Hills Formation consists of thin parasequences of mixed carbonate and siliciclastic lithologies, representing sea level changes up to 50 m in amplitude, bounded by flooding surfaces. Overlying the Arco Hills, the Bluebird Mountain Formation (very fine-grained quartz arenite, dolomite, and unfossiliferous limestone) records a major lowstand just below the mid-Carboniferous boundary. Increased amplitude and frequency of sea level changes in the Antler foreland basin initiated at the C. naviculus/ A. unicornis conodont zone boundary which occurs at the base of the Arco Hills Formation. These are interpreted as 4th-order glacio-eustatic sea level changes related to the onset of Gondwana glaciation comparable to those seen in the Illinois Basin, Alaska, and elsewhere.

Evaluating the Development of Upper Jurassic Reefs in the Smackover Formation, Eastern Gulf Coast, U.S.A. through Fuzzy Logic Computer Modeling

ABSTRACT A three-dimensional (3D) numerical stratigraphic model has been built to simulate the development of microbial reefs on a Jurassic carbonate platform using fuzzy logic modeling methods. The flexibility of the model allows for the examination of a large number of variables. The relative importance of local environmental conditions and global changes on the frequency of reef development are examined relative to the temporal and spatial constraints from Upper Jurassic (Oxfordian) Smackover reef datasets from two Alabama oil fields. The fuzzy model simulates the deposition of reefs and carbonate facies by integrating local and global variables. Local-scale factors include basement relief, sea-level change, climate, latitude, water energy, water depth, background sedimentation rate, and substrate conditions. Regional and global-scale changes include relative sea-level change, climate, and latitude. The model confirms preexisting theories that background sedimentation rate, water energy, substrate, relative sea-level change, and climate influenced the development of Jurassic reefs. Additionally, the model determines the degree of control each variable has on 'IF,' 'WHERE,' and 'WHEN' reefs develop. The variables that control 'IF' reefs develop are the global parameters of climate and amplitude of sea-level change. The model specifies that the variables that influence the lateral distribution of reefs (or 'WHERE' reefs occur) are substrate, water energy, and background sedimentation rate. The model also indicates a strong correlation between 'WHEN' reefs develop and the rate of sea-level rise. In all simulations, reefs initially develop in conjunction with the greatest rate of sea-level rise (i.e., the inflection point on the sea-level curve) and reach peak development before the time of deepest water.

Silurian sedimentation in East Siberia: evidence for variations in the rate of tectonic subsidence occurring without any significant sea-level changes

Abstract It is widely accepted that major variations of sea-level have occurred in the Phanerozoic. Third-order cycles, 1–10 Ma long with amplitudes of 20–100 m, are of special interest for geochronology and petroleum geology. The amplitude of sea-level changes in the Silurian was estimated based on highly detailed data on the East Siberian Basin, which was 2×10 6 km 2 in size. Fischer plots were compiled based on the thickness of 54 chronostratigraphic units — chronozones, each corresponding to a time interval c. 0.5 Ma long. The synchronicity of the chronozones ensures reliable comparison of the changes occurring with time in accommodation space in different regions. The subhorizontal Fischer plots derived for several regions indicate that sea-level changes were very small in the Silurian (<-5–10 m). A mathematical analysis of relative sea-level changes, which takes into account the finite rate of crustal subsidence and different possible forms of eustatic fluctuation, shows that from the observed structure of numerous Silurian successions in East Siberia, eustatic third-order sealevel changes could not have exceeded 6–20 m. In several regions of East Siberia, the rate of crustal subsidence varied as much as several hundred per cent at different times. These variations showed good similarity in form, but their amplitudes were different at different places in the basin. Most probably they were caused by variations in the rate of phase transformations in mafic rocks in the lower crust. Based on the example of the East Baltic, the absence of large-scale third-order cycles in eustatic changes of sea-level has been proven earlier for the Cambrian and earliest Ordovician. Probably, a similar situation was characteristic of many other epochs, when no large glaciations occurred, while many rapid changes of water depth in cratonic areas actually resulted from vertical crustal movements.

Syndepositional deformation of the Permian Capitan reef carbonate platform, Guadalupe Mountains, New Mexico, USA

Permian shelf strata equivalent to the Capitan reef are cut by at least 13 closely spaced syndepositional dip-slip faults in Slaughter Canyon, Guadalupe Mountains, New Mexico, USA. The control of five of these faults on platform development, architecture, stratigraphy and diagenesis is revealed by an integrated stratigraphic, sedimentological and structural framework within a 500-m-wide and 200-m-high outcrop window. Here, faulting and fault-related deformation acted as a primary control on changes in thickness, facies and stratal geometry, and resulted in the local steepening, shallowing and even the reversal of dip in shelf strata. The role of primary depositional relief in controlling changes in thickness and stratal geometry was of secondary importance. The relationship between geopetal fabrics (average dip=12° towards 141°) and bedding shows that during deposition of the Yates Formation fault growth was concurrent with down-to-the-basin tilting (and rotation?) of at least 6–8°. This tilting appears to have been the main control on the down-dip expansion of shelf strata towards the basin. A further 4–6° of basinward tilt occurred after fault growth, during deposition of the Tansill Formation and later. The syndepositional faults reported here have a maximum displacement of 24 m. Most tip-out below asymmetric growth folds and have high displacement-distance gradients typical of growth faults and faults cutting unlithified strata. The average rate of fault displacement (0.021 m/ka) and the maximum rates of fault propagation (0.088–0.123 m/ka) were normally less than the platform accumulation rates (0.053–0.336 m/ka). Thus, the faults were normally blind and rarely broke the platform top so that slumps and fault-scarp degradation breccias are rare. The fault zones were substantially modified by diagenesis during platform development. They are up to 9 m wide, taper both up and downward, have irregular margins and complex fills mainly of sedimentary origin. Their margins and fill were subject to extensive modification by karstic(?)/mixing zone dissolution, gravitational collapse and dolomitising fluids. Consequently, tectonic fabrics and kinematic indicators are rare. Preserved tectonic fabrics consistently indicate a normal and reverse dip-slip sense of movement. Previously, these faults were mistaken for ‘neptunian’ dykes and fissures, so that the Seven Rivers and Yates 1–2 HFS shelf stratigraphy has been miscorrelated across them. It is apparent that the stratal relationships exposed in the Guadalupe Mountains do not simply preserve the original depositional morphology of the Capitan-equivalent shelf. The subsidence history, stratigraphy and development of the platform succession is more complex than previously thought. The study has important implications for many aspects of the Capitan system, including: (i) shelf-reef correlations, (ii) the controls on platform architecture and development, (iii) Capitan reef palaeobathymetry, (iv) diagenesis, and (v) the amplitude of sea-level changes affecting the platform's stratigraphic development.

A full sea-level cycle in 65years: barrier dynamics along Caspian shores

The Caspian Sea, being a closed basin, shows much higher rates of sea-level change (up to 340 mm/yr) than the oceans. It experienced a full sea-level cycle with an amplitude of 3 m between 1929 and 1995. Its coasts therefore present an attractive physical model to test predicted changes along oceanic coasts as a result of expected eustatic sea-level rise, and to validate sequence-stratigraphical interpretations of ancient sediments. Along the wave-dominated coasts with intermediate shore-face slopes in Dagestan, low onshore bars were formed during the 1929–1977 sea-level fall. They represent minor short lived (1–2 years) transgressive oscillations within the major regressional trend. After the 1977 lowstand a prominent barrier–lagoon system was formed, which during the first phase of sea-level rise (1977–1988) encroached landwards about 18 m each year by washover during storms (continuous retreat). Between 1988 and 1995, however, barrier size diminished, lagoons widened and deepened, apparently due to lack of coarse-grained sediment supply (discontinuous retreat). The 1995 highstand prevented the barriers from being overstepped altogether. Sea-level fall after 1995 again produced low bars without lagoons. The Caspian Sea barrier coast demonstrates that for the formation of barrier–lagoon complexes the combination of transgression and storms is essential. Barriers may show either continuous or discontinuous development at constant rate of sea-level rise and constant offshore slope, depending essentially on the availability of coarse-grained sediments. The rate of sea-level rise as a factor in barrier behaviour cannot be viewed independently from barrier dimensions, which in turn depend on wave base depth and maximum storm wave height. Relations between (para)sequence thickness, and frequency and amplitude of sea-level change in closed basins with an independent sea-level regime may differ markedly from those in basins influenced by eustasy.

Facies and paleoecology of the late ordovician (Caradoc-Ashgill) stromatoporoid bioherms of Tasmania, Australia

Stromatoporoids, together with other sedentary organisms, form bioherms in the Ordovician Gordon Group which were deposited on a carbonate platform of the Western Tasmanian Terrane. The shallow marine carbonates of the older formations show monotonous lithofacies and biota. The variety of the lithofacies and the diversity of sedentary organisms increases in the younger formations which exhibit evidence of subaerial exposure (fissure fillings and mud-cracks). These phenomena partly reflect the tectonic history of the Western Tasmania Terrane, and probably indicate a general increase in amplitude of sea-level change during the late Ordovician (Caradoc-Ashgill).

Paleozoic Depositional Sequences; Comparisons and Contrasts in Magnitude and Amplitude of Sea-Level Changes: ABSTRACT

Paleozoic Depositional Sequences; Comparisons and Contrasts in Magnitude and Amplitude of Sea-Level Changes: ABSTRACT

New Zealand Pleistocene and late Pliocene glacio-eustatic cycles

A correlation diagram relates the numbered oxygen isotope stages of Shackleton and Opdyke's oxygen isotope curve for core V28–239, as extended by Gardner, to Nukumaruan, Castlecliffian and younger sedimentary cycles in Hawke's Bay, southern Wairarapa, and Wanganui districts and to the flight of marine terraces (Castlecliffian and younger) recognised by Pillans near Wanganui. Local correlation is principally by biostratigraphy, but also by lithostratigraphy and fission-track dates on tephras. Important calcareous nannofossil datums for both local and international correlation are: (1) FAD of Gephyrocapsa sinuosa in the mid-Nukumaruan of the New Zealand region, both in DSDP site 284, just above the (base Olduvai) LAD of Discoaster brouweri, and in three on-land sequences (within the Olduvai at Mangaopari Stream); (2) LAD of Pseudoemiliania lacunosa, during isotope stage 12, last known in the Castlecliffian Upper Kai-Iwi Siltstone at Wanganui; and (3) FAD of Emiliania huxleyi during isotope stage 8, and recorded tentatively from the Waipuna Delta Conglomerate (Ngarino Terrace cover beds; Hawera Series) near Wanganui. Magnetic polarity is also used for external correlation. Most of the prominent oxygen isotop events in core V28–239 are inferred in New Zealand on-land sequences (about twenty cycles). The Wanganui area demonstrates an apparently unique occurrence of coeval marine terrace deposits and offshore marine rocks representing all major high sea levels between isotope stages 11 and at least 17. Nukumaruan sedimentary cycles recognised in eastern North Island are relatively complete, most inferred glacial periods being represented by shallow marine strata. In contrast, Castlecliffian and younger marine sedimentary cycles in southwestern North Island are less complete, each inferred interglacial deposit being bounded by disconformities. The difference between Nukumaruan and younger sedimentary cycles possibly supports the hypothesis of an increase in the amplitude of sea-level change about a million years ago. The Pliocene/Pleistocene boundary lies above the middle of the New Zealand Nukumaruan Stage.

大正12年の關東大地震に依る東京灣の振動に就て

In their investigation of the tunami due to the greate Kwantô earthquake occurred on the September 1 st. 1923, Prof. T. Terada and S. Yamaguti pointed out that the curious oscillations of sea level happened on that occasion at some places on the coast around the Tokyo Bay. At Yokosuka, situated SW-ern coast of the Bay, were observed the oscillations of sea level having the period of about 120 min, at Sibaura situated NW-ern coast of the Bay, that of 75 min.Mareograms at some places illustrated in the paper of cited above are reproduced in the Fig.1.Whether the oscillation at Yokosuka may be due to the seiche of the Tokyo Bay having a a period of about 120 min or not was not certainly ascertained by these authors, because that no oscillations having such a period was observed at Sibaura and Hukagawa.Recently by means of comparison of the mareogram at Yokosuka with that at Tiba, T. Suzuki discovered that the oscillation at Tiba has also the period of almost 120 min which is nearly equal to that of Yokosuka and the phases nearly opposite to those at Yokosuka.According to these facts, these oscillations were considered by him to be the proper oscillations of the Tokyo Bay. But his discussion was mainly directed to the phenomenon of the land upheaval which took place at the great earthquake and he considered that this had to be the cause of oscillation of the Tokyo Bay, so that the discussion with reference to the sea level change occurred at Sibaura and Hukagawa were scarcely treated in his papers.In the present paper is mainly treated of these oscillations.At first, if we suppose the oscillation at Sibaura be due to the secondary or lateral one of the Bay, it may be also expected in the observation at Tiba situated on the NE-ern coast and opposite to Sibaura. But it was not the case as the mareogram at Tiba does not show obviously any oscillation having the similar period. Accordingly we must give up this consideration.On the other hand, the possibility of another oscillation of sea water has come to us. Let us look at the chart about the Tokyo Bay shown in Fig. 3 and let our attention give to the form of its coastal line about Sibaura and Hukagawa, and we may see that it curves inwardly like the form of a cup and embrace within it an inlet or a little bay refered as the Sinagawa Bay. While the vertical displacement of the earthsurface which took place at the great earthquake and the local distribution of whose magnitude is shown in Fig. 3 caused the tilting of the sea bottom of the Sinagawa Bay. These conditions seem to lead the oscillation like secondary one in the Sinagawa Bay.For a rough estimation, let the Sinagawa Bay be a rectangular one with uniform depth, length and breath, magnitude of which are measured roughly from the chart to be 4m, 8km and 12km respectively.Then we have its period equal to 75min, provided that the mouth correction be without consideration. Thus roughly estimated period agrees well with what observed at Sibaura and Hukagawa.But the calculated amplitude of sea level change at the head of the Bay amounts to about 20cm which is far different from 2m that was observed, and if the tilting of the sea bottom be assumed to take place at the same moment as the earthquake, its first heighest of sea level change at the head of the Bay is reckoned to occur at 37min after the earthquake, which is far different from 91min that was observed. Consequently, we are obliged to abandon the idea of secondary oscillation of Sinagawa Bay as it contradicts the facts.At last, only one case remains for us, in which the forced oscillation of Sinagawa Bay was caused by that of Tôkyô Bay. If it be so, we may reasonably expect the occurrence of the phase of forced one in the mareogram at Sibaura. And it is shown to be the case by Fig. 2 which expresses the cansidarable coincidence of phases observed at Tiba with corresponding phases at Sibaura.