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Tidal characteristics in the Gulf of Khambhat, northern Arabian Sea – based on observation and global tidal model data

Mitra Aditi, Kumar V. Sanil, Jena Basanta K.

Oceanologia

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2020

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No. 62 (4PA)

443--459

EN

Tidal characteristics of the Gulf of Khambhat are described based on measured and modelled sea-level data. Data were recorded at three locations inside and two locations outside the Gulf with record lengths of 6-12 months to study the tidal propagation. A northward increase in tidal amplitude is noticed from Daman (eastern side) and Diu (western side) and attains maxima at Bhavnagar. A similar trend is followed by the amplitude of the major tidal constituents, although there are discrepancies for that of the minor constituents. The non-tidal factor which influences the sea-level is the local wind, especially the alongshore component of wind. A positive correlation is obtained between the sea-level and the meridional component of wind at each location. Harmonic analysis of sea-level data shows that M2 is the major tidal constituent which propagates in a non-linear fashion inside the Gulf. Tides from two global tide models (MIKE21 and FES2014) have been compared with the measured data, which could be used for further prediction of the tides and sediment transport in the Gulf. The tide elevation derived from the MIKE21 model has further been used for the harmonic analysis of tide. The tides predicted using one-month data are up to 10% smaller than those predicted using the one-year data. The global tide model FES2014 data performs well with measured data for offshore locations, whereas it fails to predict the same for the inner Gulf locations. The study manifests the fact that to understand the dynamics of complex tidal areas, regional models should better be used than global tidal models.

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Fossils from the Silesian-Subsilesian series of the Polish Western Carpathians : the implications for changes in sea-level and the marine environment during the Albian-Turonian

Szydło A., Jugowiec-Nazarkiewicz M., Olszewska M.

Geological Quarterly

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2015

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Vol. 59, No. 1

215--228

EN

Fossils and exotics from the Albian-Cenomanian deposits of the Western Polish Carpathians are discussed in relation with changes in depositional environments. Environmental conditions were controlled by geotectonic activity, sea-level changes and also anoxic and biotic events. During the Albian-the Early Cenomanian, and in the Turonian the fall in sea level led to increased supply of coarse-grained material rich in siliceous and sometimes calcareous bioclasts and exotics. This cyclic process has contributed to changes in the marine biota. In the Albian monogenic foraminiferal assemblages with the surficial epifauna corresponding to the organic influx and oxygen deficiency (OAE 1b) were evolved into more variable associations including deep infauna, which indicated more aerobic conditions. Under these conditions also preserved planktonic and calcareous benthic fossils, which indicated the supply of terrigenous material from shallow-water environments and land. During the Albian-Turonian transition intensive subsidence and volcanic activity associated with eustatic sea-level rise led to intensive production of phytoplankton. The sea-surface productivity and enhanced upwelling resulted in expanded short-term oxygen minima at the end of the Albian (OAE 1d) and the Cenomanian (OAE 2). In the latter interval benthic forms almost extinct while siliceous and calcareous plankton survived. In the Turonian changes in sea-level and sedimentary regime led to recolonization of the basin bottom.

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Litostratygrafia dolnego syluru w odsłonięciu Bardo Stawy (południowa część Gór Świętokrzyskich) - związek ze zmianami poziomu morza i cyrkulacją oceaniczną

Trela W., Salwa S.

Przegląd Geologiczny

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2007

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Vol. 55, nr 11

971-978

EN

The lower Llandovery black radiolarian cherts and shales of the Bardo Formation are interpreted as transgressive to highstand deposits produced by the marine flooding initiated in latest Ordovician time (persculptus graptolite zone). This formation was divided into the Rembów radiolarian chert Member and Zbrza shale Member. The sedimentary record of the Rembów Member was folded due to the late Caledonian tectonic activity. The accumulation of the radiolarian cherts was influenced by an upwelling system generated by the SE trade winds, which were active along the southern margin of the southern Holy Cross Mountains.