Dr. (Inoka) Hasanthi Widanagamage
Areas of Expertise
Trace metal Geochemistry, Environmental isotopes, Bio-mineralization and environmental Mineralogy
My research goals intersect among trace metal geochemistry/isotope geochemistry and bio-geochemistry of environments. My goal as a scientist is to investigate how the microbial world affects and drives metal cycling in both modern and ancient environments. Trace metal cycling influence the geochemical environment, often on a time-scale much more rapid than abiotic geochemistry could explain. Microorganisms exert fundamental controls on the chemistry of their environments. Their activities are shaped by inter-organism interactions and the geochemistry of their surroundings. Studying relationships between modern microbial environments and trace metal cycling could be an important tool to understand presence of life in early earth and extraterrestrial systems. My overarching research interests revolve around the interactions between microbial communities, their geochemical environments and the resulting modifications of the rock substrate and other aspects in environmental geochemistry.
Contact me if your research interests overlap with mine.
Controls on barite crystal morphology during abiotic precipitation
This piece of work is to determine what changes can expect in barite crystals during abiotic 'precipitation of barite at different laboratory conditions. Temperature, initial saturation index, Sr/Ba ratio in solution, presence of organics were some of the parameters tested. Crystals were imaged under SEM and Confocal Raman Microscope followed by bulk XRD analyses. Different morphologies were identified in particularly at higher Sr/Ba ratios and temperatures. This work has been submitted for a publication.
Trace metal cycling and bio signatures in White Sand Monument (WSM)
White Sands are rich in mineral Gypsum and the occurrence is considered as extreme environmental condition. Trace metal concentrations and DNA data were collected in the study and in the process of building up relationship between metal cycling and metabolism of those biosignatures in the sand. This information will be important in understanding potential analogues conditions in Mars.
Unravelling metamorphism and collisional history of Highland-Vijayan Boundary- Sri Lanka
Sri Lanka, a small-scale aggregate of contrasting crustal domains, has been the focus of lower crustal research for the past two decades. The timing of high-grade granulite metamorphism in the central Highland Complex (HC) of Sri Lanka is well-constrained at 570-550 Ma (Kroner et al., 1994; Sajeev et al., 2010). Amphibolite facies metamorphism of the adjacent Vijayan Complex (VC) to the east is less well constrained but apparently somewhat younger (Holzl et al., 1994). Additionally, the timing and nature of juxtaposition (via thrusting) of the HC above the VC is uncertain. The contact between the HC and VC, characterized by strong deformation, exotic tectonic slivers, migmatites, local serpentinite bodies, magnetite deposits, and gold mineralization is a major suture separating the Paleoproterozoic HC from the Grenville-age VC. EMPA in-situ spot-dating of monazite grains record timing of peak and retrograde metamorphism of HC rocks. Thirty spot ages from eight monazite grains from the HC reveals a dominance of Pan African ages (533-613 Ma), and minor Paleoproterozoic and Mesoproterozoic ages (1069-1872 Ma). The qualitative monazite textural descriptions suggest that the age data are a function of chemical domains formed during and/or re-absorption of monazite. The average age for higher Y concentrations (>4000 ppm) is 558 Ma and 572 Ma age for lower Y concentrations (<\4000 ppm). These ages consistent with a regionally widespread peak metamorphic age of 570 Ma for HC followed by retrograde metamorphism during exhumation at about 555-545 Ma (Sajeev et al., 2010). The Boundary Zone age data suggest shearing of HC rocks at moderate P-T conditions at 595-635 Ma and may therefore date the initial juxtaposition of the HC and VC terranes. The crustal thickening during and after the juxtaposition may have ultimately led to the peak metamorphism of Highland Complex at 570 Ma. Peak metamorphism was followed closely by rapid exhumation of the HC rocks beginning at 558 Ma in the east and 551 Ma in the western HC terrane.
Widanagamage I.H., Griffith E. M., Singer D.M., Scher H.D., Buckley W. and Senko J.M. (2015) Controls on stable Sr isotope fractionation in continental barite, Chemical Geology, v. 411 p. 215-227
Widanagamage I.H., Schauble E.A., Scher, H.D. and Griffith E.M. (2014) Stable strontium isotopic fractionation in synthetic barite, Geochimica Cosmochimica Acta, v. 147 p. 58-75
Singer, D.M., Griffith, E.M., Senko, J.M., Fitzgibbon, K. and Widanagamage, I.H. (2016) Celestine in a sulphidic spring barite deposit - a potential biomarker?, Chemical Geology, v.440, p. 15-25
Widanagamage I.H., Glamoclija, M. and Waldron, A. Controls on barite crystal morphology during abiotic precipitation, Crystal Growth and design (under review)
Widanagamage I.H. (2015). Stable Strontium isotope fractionation in abiotic and microbially mediated barite in modern continental settings. Ph.D. Dissertation published
Widanagamage, I.H. (2011). EMPA dating of monazite from metamorphic rocks along the Highland-Vijayan boundary zone, Sri Lanka M.S. thesis published
Widanagamage I.H., Singer D.M., Scher, H.D. and Griffith E.M. (2014) Mass dependent stable Sr isotopic fractionation and coordination environment in continental barite from Zodletone Springs, Oklahoma Graduate Research Symposium, Kent State University.
Griffith E.M., Paytan A., Schauble E., Scher H.D., Widanagamage I.H., Senko J.M. (2014) Combined stable strontium, oxygen and sulfur mass dependent isotopic measurements and radiogenic strontium in barite to identify origin Goldschmidt international conference.
Poluga, S.L., Widanagamage, I.H., Griffith, E.M. (2013) Testing methods to determine Sr/Ba in natural terrestrial barite samples on an ICP-OES Geological Society of America publications.
Widanagamage, I.H., Griffith, E.M. and Scher, H.D. (2013) Stable Sr isotope fractionation in synthetic barite Goldschmidt international conference.
Widanagamage I.H., Singer D.M., Scher, H.D. and Griffith E.M. (2013) Mass dependent stable Sr isotopic fractionation and coordination environment in continental barite from Zodletone Springs, Oklahoma Geological Society of America publications.
Griffith E.M., Widanagamage I.H., Scher, H.D and Senko, J. (2013) Stable strontium mass dependent isotopic fractionation in authegenic continental barite American Geophysical Union publications.
Widanagamage I.H., Scher, H.D., Senko, J. and Griffith E.M. (2012) Mass dependent stable isotopic fractionation during the precipitation of barite, Zodletone Spring, Oklahoma Goldschmidt international conference.
Widanagamage, I.H. and Holm, D.K.(2012) EMPA monazite geochronology from the eastern Highland Complex and Highland-Vijayan boundary zone, Sri Lanka Geological Society of America publications
Widanagamage, I.H. and Holm, Palmer, D.F., Ranasinghe, P.N. 2011 Preliminary characterization of the Highland-Vijayan boundary zone, Sri Lanka Geological Society of America publications