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Geoscience e-Journals





An International Year of Planet Earth-2008 Initiative

Current Issue Technical

Year 2017

Volume X

A Late Pliocene Baby Stegodon cf. Stegodon insignis (Proboscidea) from Upper Siwalik of Samba District, Jammu and Kashmir, India
Som Nath Kundal, Gyan Bhadar and Sandeep Kumar


One complete molar of a baby Stegodon is reported from the road-cutting section of the mudstone horizon of Nagrota Formation exposed about 2km south of Labli village. The molar yielding horizon underlies geochronologically dated (2.48 ma) volcanic ash bed which is the extension of Barakheter-Uttarbaini ash bed in the Uttarbaini Formation (Nagrota Formation/ Pinjor Formation), Upper Siwalik Subgroup, Samba district, Jammu & Kashmir, India. Based on the molar morphological parameters, the specimens have been identified and tentatively referred to Stegodon cf. Stegodon insignis (a baby Stegodon). A brief about the age, migration and distribution of Stegodon is also discussed in the present paper.


Keywords: Late Pliocene, Stegodon cf. Stegodon insignis, Upper Siwalik, Samba District, Jammu and Kashmir, India

Biological Weathering and Geochemical Fractionation by Termites: A Case Study of Loessic Sediments from Jawaharlal Nehru University, New Delhi, India
Swati Singh1, Anurag Chaudhary1, Sumi Handique2, Saurabh K. Singh1 and Jayant K. Tripathi1

Termites are ecosystem engineers who transform soil and sediments and make mounds. They transport and mix large quantities of sediments across the horizons of the mounds, modify their immediate environment at different depths. We have tried to understand the role of termites in weathering and geochemical transformations of homogeneous sediments of termite mounds of Delhi ridge area. The samples and respective parent sediments were collected from the seven locations of Jawaharlal Nehru University, New Delhi. It has been observed that bioturbation of termites caused fining of the mound samples compared to the parent sediments. The mound samples show higher weathering than the parent sediments. Carbonate precipitation in the alkaline conditions imposed by termites could have enriched Ca and Mg. Whereas, the clay enrichment caused K, Al enrichment. Fe got enriched in the oxic condition of mounds. Ti and Zr got enriched by the enrichment of finer grains of their minerals already present in the parent material. The enrichment of  Co, Ni, Cu, Cr, and V show the biogeochemical role of the termites. The organic carbon brought by the termites, and iron oxides, both enriched phosphorus in the mounds. It has found that the termite mounds also have potential in sequestering CO2 by accumulating organic matter, precipitating carbonate minerals, and increasing chemical weathering of silicate minerals.


Keyword: Termite, Bioturbation, Geochemistry, Weathering, Trace elements
Canny Edge Detection Algorithm Application for Analysis of the Potential Field Map
A. Eshaghzadeh and R.S Kalantari


Determination of potential fields' anomaly borders is a useful help to their interpretation. There is various technique of edge detecting that is applied in image processing. In this paper, the canny edge detection (CED) method has been proposed as boundary enhancement of the magnetic and gravity potential field data. The Canny operator works in a multi-stage process. This method is based on the characteristic of intensity values of considered pixel. The edge detector should have a good signal-to-noise ratio, so that edges can be found even if potential field data quality is poor. For 2-dimensional bounds, residual potential field map is first smoothed by using a 2-D Gaussian filter. Afterwards, computing the horizontal gradients of the smoothed map and then using the gradient magnitude and direction to estimate borders strength and direction at every pixel. The Canny edge detection algorithm uses double threshold for edges revelation. In this research, a new procedure to define the thresholds has been suggested. The results obtained from the synthetic data set, with and without random noise, have been discussed. The method is demonstrated on real gravity and magnetic data set surveyed from Iran. The CED results are compared with three common methods as edge detector, namely the analytic signal, tilt angle and total horizontal derivative of the tilt angle.


Keywords: canny edge detection (CED), Gaussian filter, horizontal gradients, potential fields

Middle Eocene Planktonic Foraminifera Inordinatosphaera aff. indica from Jabal Hafit, Al Ain area, United Arab Emirates
Haidar Salim Anan

The Middle Eocene (Bartonian) planktic foraminiferal species Inordinatosphaera aff. indica Mohan and Soodan is recorded for the first time from the Middle Eocene Orbulinoides beckmanni Zone (E12) of Jabal Hafit, Al Ain area, United Arab Emirates (UAE), Northern Oman Mountains (NOM). Thirteen commonly occurring planktic foraminiferal species associate the new one in the biozone are also recorded. The record of Inordinatosphaera aff. indica in the UAE suggests that Arabia had marine link with India during Paleogene. 


Keywords: Inordinatosphaera aff. indica, Middle Eocene, Jabal Hafit, United Arab Emirates, Northern Oman Mountains