NOPR Collection:

Morphological variation and sediment dynamic in a cape-bay beach with a tidal channel around (Sanshan Daobeach, west coast of Laizhou Bay, China)

2017-05-01T00:00:00Z

Title: Morphological variation and sediment dynamic in a cape-bay beach with a tidal channel around (Sanshan Daobeach, west coast of Laizhou Bay, China) Authors: Liu, Shihao; Li, Peiying; Du, Jun; Feng, Aiping; Zhang, Zhiwei; Yu, Xiaoxiao; Zhu, Zhengtao Abstract: Grain size distrbution of surface sediments exhibits a transverse regular as well as slight biannual variations. Futher analysis indicates that morphodynamic process varies in the four sedimentary units and the tidal channel plays a significate role on the sedimentation of the subaqueous area. An analysis combined Grain Size Trend Analysis model (GSTA) with topographic changes and collected hydrodynamic reveals the sediment dynamic process in both subaerial beach and subaqueous beach. They jointly indicate that: 1) the westward tidal current (ebb current)is the donimant force in the subaqueous beachas well as the key factor for the formation of tidal channel system;2) wave strength dominates the morphodynamic at the subaerial beach; 3) the effects of swash wave and boundary current are presumed the secondary dynamics at low-tidal beach and edges of the tidal channel system, respectively. Page(s): 847-859

Contrasting characteristics of colored dissolved organic matter of the coastal and estuarine waters of Goa during summer

2017-05-01T00:00:00Z

Title: Contrasting characteristics of colored dissolved organic matter of the coastal and estuarine waters of Goa during summer Authors: Dias, Albertina Balbina; Thayapurath, Suresh; Sahay, Arvind; Chauhan, Prakash Abstract: The colored dissolved organic matter (CDOM) was investigated during the summer for the coastal and estuarine waters of Goa using the spectral absorption characteristics of CDOM. Accessions of CDOM were seen all along the estuary through multiple sources of CDOM with relatively insignificant sink, while in the coastal waters there was a sink due to photo bleaching. Measure of CDOM indicated by the absorption at reference wavelength a_g(412) varied with a mean value of 0.470 m^-1 in the Mandovi, 0.420 m^-1 in Zuari and 0.176 m^-1 in the coastal waters. Slope of CDOM S_250-600 was found to vary from 0.080-0.017 nm^-1 in coastal waters and 0.017-0.020 nm^-1 in the estuaries. High values of S_275-295 observed in the coastal waters were indicative of photobleaching. Point of inflection was observed at a distance of about 8 km from the mouth of the estuary at a salinity of about 34 psu. Page(s): 860-870

Morphology and chemical composition of ash layer of about 8 Ma old from ODP-758 site, Bay of Bengal

2017-05-01T00:00:00Z

Title: Morphology and chemical composition of ash layer of about 8 Ma old from ODP-758 site, Bay of Bengal Authors: Jumaila, C P Ummu; Pattan, J N; Ahmad, S M; Parthiban, G; Khedekar, V D; Padmakumari, V M; Milindraj, P Abstract: Glass shards from an ash layer of about 8 Ma old extracted from a core drilled at an ODP-758 site in the Bay of Bengal (BOB) were studied for morphology and chemical composition in order to trace their possible source. Glass shards are of bubble wall, platy and pumice shard type indicating magmatic type of eruption. Electron probe micro analysis (EPMA) of glass shards suggesta rhyolite composition and high K cal-alkaline series. FeO (1.23%) and TiO₂ (0.1%) contents of these glass shards are distinctly higher compared to the earlier known Youngest (~74 ka), Middle (~0.54 Ma) and Oldest (~0.84 Ma) Toba Tuffs. Tectonomagmatic, triangular (Ti-Zr-Y) plot and chondrite- normalized REE pattern, are all indicative of volcanic arc source most probably from the nearby Indonesian arc volcanism. Page(s): 871-876

Water rock interaction in deep groundwater aquifers of coal mining area: qualitative and quantitative approaches based on hydrochemistry

2017-05-01T00:00:00Z

Title: Water rock interaction in deep groundwater aquifers of coal mining area: qualitative and quantitative approaches based on hydrochemistry Authors: Sun, Linhua; Gui, Herong Abstract: Present study indicates that groundwater from three aquifer systems have different concentrations of major ions. This implies that kinds and degrees of water rock interactions in them are different with each other. Relationships between major ions or their ratios (e.g. Gibbs diagrams, Na⁺-Cl^- relationships), as well as statistical analyses (correlation and factor analyses) suggested that water rock interaction is the main mechanism controlling the groundwater chemistry. EPA Unmix model has identified two sources responsible for the hydrochemistry of the groundwater, sulfate-carbonate (source 1) and silicate-chloride (source 2) sources. Groundwater from the limestone and coal bearing sandstone aquifer systems are mainly contributed by source 1 and 2, respectively. As to the groundwater from the loose layer aquifer system, the contributions of the source 1 and 2 are 4: 6, respectively, and the result is consistent with previous exploitation. Page(s): 877-883