Integrated geo-microbial and trace metal anomalies for detection of hydrocarbon microseepage in Ahmedabad block of Cambay basin,India     

M. A. Rasheed  P. L. Srinivasa Rao  Annapurna Boruah  Syed Zaheer Hasan  Bougi Mohamoud Mohamed Seddik  Disha Pandey  T. Harinarayana 《Journal of the Geological Society of India》2016,88(4):433-439

The aim of the present work is to define the geo-microbial signatures along with trace metals, and to investigate whether the geo-microbial anomalies have correlation with trace metal anomalies in Ahmedabad block of Cambay basin. The surface geochemical techniques are based on seepage of light hydrocarbon gases from the oil and gas pools to the shallow surface and can bring up near-surface oxidation reduction zones that favor the development of a diverse array of chemical and mineralogical changes. The paper reports the role of hydrocarbon microseepage in surface alterations of trace metal concentrations and hydrocarbon oxidizing bacteria and its interrelationship. For the purpose a total of 90 soil samples are collected in grid pattern of 2 x 2 km interval. The paper reports the chemical alterations associated with trace metals in soils that are related to hydrocarbon microseepages above some of the major oil and gas fields of this petroliferous region. The concentrations of V (0 to149 ppm), Cr (2 to 192 ppm), Cu (4 to 171 ppm), Se (98 to 440 ppm), Zn (56 to 1215 ppm) are obtained. It is observed that the concentrations of trace elements are tremendously increased when they are compared with their normal concentrations in soils. In this study the hydrocarbon oxidizing bacterial counts ranged between 1.0 x 10³ and 1.59 x 10⁶ cfu/g of soil sample respectively. The attempt has made for the first time, which revealed good correlation as both these anomalies are found as apical in relation. Integrated studies between trace elements and hydrocarbon oxidizing bacterial anomalies showed positive correlation with existing oil and gas wells in the study area.  相似文献   

Pivotal principles for digital earth development in the twenty-first century     

Cheryl Desha  Timothy Foresman  Annapurna Vancheswaran  Angela Reeve  John Hayes 《International Journal of Digital Earth》2017,10(4):371-385

ABSTRACT

Reductionist thinking will no longer suffice to address contemporary, complex challenges that defy sectoral, national, or disciplinary boundaries. Furthermore, lessons learned from the past cannot be confidently used to predict outcomes or guide future actions. The authors propose that the confluence of a number of technology and social disruptors presents a pivotal moment in history to enable real time, accelerated, and integrated action that can adequately support a ‘future earth’ through transformational solutions. Building on more than a decade of dialogues hosted by the International Society for Digital Earth (ISDE), and evolving a briefing note presented to delegates of Pivotal 2015, the paper presents an emergent context for collectively addressing spatial information, sustainable development, and good governance through three guiding principles for enabling prosperous living in the twenty-first century. These are: (1) open data, (2) real-world context, and (3) informed visualization for decision support. The paper synthesizes an interdisciplinary dialogue to create a credible and positive future vision of collaborative and transparent action for the betterment of humanity and planet. It is intended that these Pivotal Principles can be used as an elegant framework for action toward the Digital Earth vision, across local, regional, and international communities and organizations.  相似文献   

Gravity and magnetic surveys and interpretation in the northern part of the K-G basin     

D. Bhaskara Rao  T. Annapurna 《Journal of the Geological Society of India》2016,87(5):601-609

The gravity and magnetic data along three profiles across the northern part of the K-G basin have been collected and the data is interpreted for basement depths. The first profile is taken from Gadarada to Yanam covering a distance of 60 km and the second starts from Zangareddiguddem to Samathkur covering a distance of 110 km and the third is from Kotturu to Biyyapuppa covering a distance of 100 km. The gravity lows and highs have clearly indicated various sub-basins and ridges. The density logs from ONGC, Chennai, show that the density contrast decreases with depth in the sedimentary basin, and hence, the gravity profiles are interpreted using variable density contrast with depth. From the Bouguer gravity anomaly, the residual anomaly is constructed by graphical method correlating with well data, sub-surface geology and seismic information. The residual anomaly profiles are interpreted using polygon model. The maximum depths to the khondalitic basement are obtained as 5.61km, 6.46 km and 7.45 km for the first, second and third profiles respectively. The regional anomaly is interpreted as Moho rise towards coast. The aeromagnetic anomaly profiles are also interpreted for charnockite basement below the khondalitic group of rocks using prismatic models.  相似文献