Showing papers on "Sea-level curve published in 2019"

Reconstruction of Late Pleistocene and Holocene Sea Level Curve for the East Coast of India

Abstract: Holocene sea level curve has been generated for the East Coast of India. About seventy five 14C dates which are available from published works on coastal plains and offshore regions of the East Coast were considered and were subsequently calibrated into calendar years for analysis and plotting thereof. From the 100m depth, a moderate rate of sea level rising at the rate of about 0.88m/100 years is observed during 14,800 to 10,800 YBP. In between 10,800 to 9,200 YBP, a steep rise (Sea Level Rise - SR1) is noticed at the rate of 2.06m/100 years. Following a brief sluggish phase (for nearly about 1,100 years) of slow rising around 0.82m/100 years, another steep rate of rising of about 2.22m/100 years (SR2) is observed during 8,100 to 7,200 YBP. After that period to the Recent, there were 5 minor fluctuations with regression phases dominating over transgression phases in terms of duration and magnitude. It is also observed that the magnitude of all five high stands in between 7,200 to the recent has a decreasing trend from +4m to 0m. It obviously indicates that the most of the present day coastal plains were once under the sea as evidenced by the presence of many inland leftover paleo delta signatures in the East Coast of India.

Postglacial relative sea level change and glacier activity in the early and late Holocene: Wahlenbergfjorden, Nordaustlandet, Svalbard

Abstract: Sediment cores from Kloverbladvatna, a threshold lake in Wahlenbergfjorden, Nordaustlandet, Svalbard were used to reconstruct Holocene glacier fluctuations. Meltwater from Etonbreen spills over a threshold to the lake, only when the glacier is significantly larger than at present. Lithological logging, loss-on-ignition, ITRAX scanning and radiocarbon dating of the cores show that Kloverbladvatna became isolated from Wahlenbergfjorden c. 5.4 cal. kyr BP due to glacioisostatic rebound. During the Late Holocene, laminated clayey gyttja from lacustrine organic production and surface runoff from the catchment accumulated in the lake. The lacustrine sedimentary record suggests that meltwater only spilled over the threshold at the peak of the surge of Etonbreen in AD 1938. Hence, we suggest that this was the largest extent of Etonbreen in the (mid-late) Holocene. In Palanderbukta, a tributary fjord to Wahlenbergfjorden, raised beaches were surveyed and organic material collected to determine the age of the beaches and reconstruct postglacial relative sea level change. The age of the postglacial raised beaches ranges from 10.7 cal. kyr BP at 50 m a.s.l. to 3.13 cal. kyr BP at 2 m a.s.l. The reconstructed postglacial relative sea level curve adds valuable spatial and chronological data to the relative sea level record of Nordaustlandet.

Sequence stratigraphic framework of the Maastrichtian shelfal to deep marine strata of Lower Indus Basin, Pakistan: implications for the petroleum potential

Abstract: The present study integrates the facies and planktonic foraminiferal biostratigraphic data to construct a sequence stratigraphic model of the Mughal Kot Formation of Maastrichtian age in the Lower Indus Basin, Pakistan. The Mughal Kot Formation is comprised of 1000-m-thick sequence of hemipelagic sediments, interrupted by random influxes of coarse-grained sandy turbidites. The petrographic details revealed six sub-microfacies, indicating deposition in the middle shelf, slope and deep marine basin. The sequence stratigraphic model is based on the integration of biostratigraphic age and local depositional signals in the study area. The studied sedimentary succession is divided into one second-order and two third-order cycles while ten parasequences are identified within the complete cycles of transgressive, highstand and lowstand systems tracts. The depositional trends within the relative sea level curve of the Maastrichtian strata of the study area and the global sea level charts are quite dissimilar, which suggest a sustained transgression with pulsated tectonics in Lower Indus Basin. The integrated results of plug porosity/permiability and petrography reveal poor reservoir potential for the sandy turbidites and pelagic carbonates of the Mughal Kot Formation.