My research interest primarily involves the application of metal (e.g., Ca, Mg, Sr, Fe and Cu) and non-metal (e.g., S) isotopes in understanding biogeochemical cycles of elements in modern environment as well as in the geologic past. Moreover, I am also interested in the development of metal stable isotopes as geochemical proxies to reconstruct the paleoclimatic and paleoceanographic conditions. Ongoing (Post-doctoral) research Projects I am working primarily as an experimental and analytical geochemist. My research involves multiple projects to investigate stable isotope fractionation of Fe, Mg, and S during mineral precipitation and mineral-fluid exchange at low temperature under both biogenic and abiogenic conditions. Following are …show more content…
In the soil, ferrihydrite is a common mineral that co-occurs with organic carbon. Ferrihydrite is also known to exchange with aqueous Fe(II) and transform into more stable Fe-oxide phases at low temperature.Therefore, understanding the role of organic carbon in the long-term stability of ferrihydrite and in the fractionation of Fe isotopes due to low temperature mineral-fluid exchange is critical to evaluate the preservation potential of the Fe isotopic composition of ferrihydrite in the soil. Previous research projects on isotope geochemistry 1. Doctoral research In my Ph.D. dissertation, I explored the influence of diagenesis of deep marine carbonates using Ca, Mg, and Sr isotopes and evaluated the potential of marine carbonate δ26Mg in preserving ambient seawater δ26Mg under different diagenetic regime with variable extent of reactive-transport processes (i.e., advection, diffusion, and reaction). For this purpose, I analyzed trace elemental (e.g., Mg/Ca and Sr/Ca) and isotopic compositions (δ26Mg, δ44/40Ca, and 87Sr/86Sr) of numerous pore fluids and bulk carbonates from multiple deep marine sedimentary sections using a Quadrupole ICP-MS and a Neptune Plus MC-ICP-MS respectively. I employed multiple reactive transport modeling techniques (1-D depositional model coded in R, CrunchFlow, and PHREEQC) to constrain the calcite recrystallization rates,
A radioactive element does not have any stable isotopes, which means it may spontaneously degenerate, emitting alpha particles, beta particles and occasionally gamma rays. Some examples of radioactive elements are uranium, promethium and curium. Radioactive elements could be used either negative or positive.
Lutgens, F. K. & Tarbuck, E. J. (2011). Foundations of earth science (6th ed.). Upper Saddle River, NJ: Prentice
Strontium is a chemical element with symbol Sr and atomic number (protons in nucleus) 38 and atomic weight 88.1 It is a soft, silver-gray metal, and has physical and chemical properties like to Calcium and Barium. It is available as four stable isotopes ubiquitously (Isotopes are differ in forms of an by number of protons in nucleus but possess a variable number of neutrons.) Strontium-88 is the most dominant among other forms, comprising 83% of natural strontium, where in additional three stable isotopes and their relative abundance are strontium-84 (0.6%), strontium-86 (9.9%), and strontium-87 (7.0%). Strontium is available ubiquitous vitally as as celestite (SrSO4) and strontianite (SrCO3), and it comprises about 0.025% of the earth’s crust. There are 16 major radioactive isotopes of strontium, but only strontium-90 has a half-life sufficiently long (29 years). In comparison with half-lives of remaining strontium radionuclides are fewer than 65 days. Strontium-90 decays to yttrium-90 by decaying a beta particle, and yttrium-90 decays by decaying a energetic beta particle with a half-life of 64 hours to zirconium-90. The key health concerns for strontium-90 are associated to the energetic beta particle from yttrium-90.2
L. Vardiman, A.A. Snelling and E.F. Chaffin (Eds.), Radioisotopes and the Age of the Earth: Results of a Young-Earth Creationist Research Initiative, Institute for Creation Research, Santee, California, and Creation Research Society, St. Joseph, Missouri, 2000.
This project focuses on preparing samples for major and trace element analyses of the Cat Hills volcanic field. Fourteen rock samples were collected from different locations from the Cat Hills volcanic field. Whole rock samples were crushed with a Chipmunk jaw crusher to obtain gravel-sized particles. Samples were separated using sieves with a mesh spacing of 0.0037 inches and 0.0195 inches. Gravel-sized samples collected from the 0.0195 sieve fraction were leached in 5% nitric acid for 25 minutes, rinsed in distilled water, and allowed to dry. After drying, gravels were powdered using a tungsten carbide
The purpose of this experiment is to establish the most efficient way to identify an unknown alkaline earth cation and an unknown halide anion based on observations of various precipitation and redox reactions. These observations are dependant on whether or not a precipitant formed or there was a color change. Both of these indicate a reaction has taken place. The alkaline earth metals are barium, beryllium, calcium, magnesium, radium, and strontium. And the halogens are fluorine, chlorine, bromine, iodine, and astatine.
Although magnesium-23 wasn’t completely gone, titanium, a metal found in other FUN CAIs before the Allende meteorite’s, was. Because of this, researchers found that titanium must not
Increased terrestrial influx could have served as nutrients for algae and plankton and stimulated high bioproductivity at surface water. The oxygen in surface water would have been over-consumed by respiration and decaying of marine organisms, which was thought to trigger marine anoxia (Algeo et al., 1995). In this process, lighter isotope of carbon was preferentially taken up by aquatic organisms and therefore removed from the system, producing heavy carbon anomalies (Wang et al., 1996). Consequently, positive excursions in δ13C values were observed across the F-F boundary (Figure 2). In addition, higher bioproductivity would bring about elevated burial rate of organic carbon (Wang et al., 1996; Chen et al., 2002)
Glaciation that are widespread can be identified based on the subglacial tillite, which is a thick layer of sediments that settle down beneath glaciers or ice caps. On top of this subglacial tillite layer is deposited marine carbonate, also known as cap carbonate. Based on their paleolatitude designated by glacial sediments’ paleomagnetism, it can be determined that these deposits are from equator region. The interaction between two types of sediments, marine (like carbonate) and subgacially deposited sediments, indicate that the glaciers had approached marine coastlines.
Research included conducting a geologic survey of the Congo craton, facies of Ghaub formation fill valleys. Rock specimens were taken from the lower glacial intervals (Chugs Formation) to just beneath the unconformity at the base of Mulden group, Southern Damara margin of the craton and Kaoko craton, Kalahari craton, Amadeus basin. These rock specimens were microdrilled and the elements Sr, Mn, Fe, Ca, Mg were measured for abundance using inductively coupled plasma emission spectoscopy to assess diagenetic alteration. These sample were analyzed offline for DELTA 13 CARBON AND DELTA 18 OXYGEN after digestion for 3 hours in H2po4 at 50'C to insure complete reaction of dolomite: the evolved gas was measured on a finnigan mat, other research consisted of fisions secter mass spectrometer, graphite -furnace atomic absorption spectoscopy, leached in NH4CH3COO, digestion in weak acetic acid. (Hoffman, et. al. 1998)
Anyone interested in cosmology or the origins of the Solar System should definitely research into this topic. It provides good details with background and evidence on its subject. I would have personally not have known much of this if it was not for reading this article. I wasn’t formerly aware of the stability, or lack thereof, during our Solar System’s formation and the creation of terrestrial objects. Nor did I know of how much one small detail, such as similar levels of an element’s isotope, could change our point of view on a subject of this importance. This information is potentially advantageous when it comes to conversations or debates on this topic, or even for personal questioning of our general creation and existence in our Solar
It was also found that the amplitude of δ18O was greater in specimens gathered from shallow water because of greater environmental variability (1989). Specimen found deeper had higher δ18O and δ13C when compared to the shallow specimen due to lower temperatures and the lesser influence of 13C depleted carbon from oxidation of organic matter in sediments and meteoric water (Romananek et al.,
Iron is the first element in the eighth column of the periodic table. It is classified as a transition metal. Iron atoms have 26 electrons and 26 protons with 30 neutrons. It is the sixth most abundant element in the universe. It is a fairly soft, grayish metal. It is very reactive and will corrode or rust when exposed to moisture and oxygen. It is the most naturally magnetic of the elements. Iron becomes significantly harder when alloyed with other elements such as carbon. Iron is the most abundant element in the Earth. The Earth's core is mostly made up of an iron-nickel alloy. Iron also makes up about 5% of the Earth's crust where it is the fourth most abundant element. Because iron oxidizes when it comes into contact with air, most of the
Dolomite (CaMg〖(CO_3)〗_2) is found in carbonate rocks of all ages that formed under a variety of conditions, but today it only forms in hypersaline lagoons, lakes and tidal flats. This suggests that most dolomite is secondary in origin as a result of dolomitization: the replacement of calcite or aragonite (CaCO_3) by dolomite soon after deposition or during
As such, the materials reported in this study will cluster primarily around a time bracket of c. 13,000-9,000 BP, which is an approximate temporal median of the Paleoamerican period [c. 15,000-7,000 BP].