Geochemistry

Hagit Affek

Hagit Affek

Associate Professor
Room 201 North
972-2-6584654

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My research focuses on global climate change and the use of isotope geochemistry to understand climatic and atmospheric processes. I am interested in the parameters and mechanisms that control paleotemperature proxies; in particuler, my group develops and uses the novel proxy carbonate clumped isotopes. We examine biological parameters that affect clumped isotopes and develop its use in new archive materials; we study the effect of non equilibrium processes on clumped isotopes and oxygen isotopes. We apply clumped isotpes to reconstruct paleotemperature and paleo-rainfall in different time periods during the Cenzoic. I am also interested in the use of isotopes to understand the modern carbon cycle and the effect of the biosphere of atmospheric chemistry.

 

What is clumped isotopes geochemistry?

Analysis of an isotopic composition is a measurement of the relative abundance of a heavy, rare, isotope within a group of molecules. The term ‘clumped isotopes’ refers to the natural abundance of molecules containing two heavy isotopes, such as 13C18O16O, and is a measure of the preference of two heavy isotopes to clump together into a chemical bond. This preference is temperature dependent with the isotopes distributed randomly among all molecules at very high temperatures and are clustered together into a more ordered system at low temperatures.

This results in an isotopic parameter, ∆47, that can record the temperature in which these bonds were formed. ‘Clumped isotopes’ measurements are currently applied for 13C-18O bonds in CO2 molecules that are extracted either from carbonate minerals or from the atmosphere. In carbonates ‘clumped isotopes’ are used to determine the formation temperature of the mineral with most applications associated with reconstruction of past climatic conditions. In atmospheric CO2 it is used as a tracer for partitioning and quantifying the different CO2 sources and sinks of the global carbon cycle.

 

Curriculum Vitae

 

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Alon  Amrani

Alon Amrani

Associate Professor
Head of the Environmental Science Department
Room 204 North
972-2-65-85477

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Interests: 

Organic geochemistry and biogeochemistry, stable isotopes, sulfur cycle, organic-inorganic interactions

 

 

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YBD sampling GFZ

Dr. Yoav Ben Dor

Postdoctoral fellow, advised by Yigal Erel and Mordechai Stein
Room 17

 

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Research interests: Paleoclimate, hydrology, limnology, sedimentary petrography, sedimentology, pedology, quaternary research, geochronology

Reasearch Topic: Saharan dust & the Neolithic Agriculture Revolution in the Jordan Valley

 

Abstract:

My current study focuses on the environmental and soil-related conditions in the Levant that could have provided prehistoric humans with the advantages required to initiate the Neolithic Agriculture Revolution (NAR) following the end of the last glacial period (~15th to 11th millennium BP). We investigate the properties and origins of soils and sedimentary sequences that accumulated prior, during and after the NAR with close context to renowned archaeological sites including Gilgal, Netiv Hagdud and Fazael, and analyze them within the broad climatological and hydrological framework. Through this inter-disciplinary study of the soils that served the earliest farmers of the Levant, we wish to see whether local conditions that followed the last glacial period provided an unplanned natural advantage to the people that inhabited the Jordan Valley. This research relies on establishing the chronology of the studied sections using OSL and 14C dating techniques, and further sedimentary and soil-related analyses, which include detailed field description and mapping, soil texture and grain-size measurements, and other fertility-related properties such as exchangeable cations composition, sodium and potassium adsorption, available sulfur and phosphorus, as well as chemical and multiple isotopic analyses.

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Michal Ben-Israel

Michal Ben-Israel

Postdoctoral researcher

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I am a postdoc working with Dr. Uri Ryb on understanding dolomitization processes using different geochemical methods.

I am generally interested in surface processes and finding new ways to understand how different natural forcings shape the surface of our planet.

 

 

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Simon

Simon Emmanuel

Professor
Room 306 South
972-2-65-86875

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Our group studies nano-scale geological processes central to hydrology and the oil and gas industry. We use a diverse array of methods, combining cutting edge lab technology, state-of-the-art modeling, and field work. Current research projects include:

  • Measuring mineral reaction rates during geological carbon sequestration
  • Imaging crystal growth in nano-pores
  • Analysing mechanical properties of rocks at the nano-scale

I am currently looking for creative students with backgrounds in Earth Sciences, Chemistry, and Physics to join our team. Students in the group are part of a dynamic research program that is developing exciting new projects at the interface between hydrology, geology, and geochemistry. For further information concerning MSc, PhD and postdoctoral opportunities, contact Dr Simon Emmanuel (swemmanuel@gmail.com).

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yigal

Yigal Erel

Kozenitsky-Rosenbach Professor of Geology
Room 007 North
972-2-65-86515

 

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My research involves the application of trace-element ratios and Sr, Nd, Pb, Mo and Fe isotopic compositions to follow the fate of metals in the environment, in archaeological artifacts and in humans. The clean lab and our sensitive analytical instruments enable me and my students to study small-samples and/or materials with low elemental concentrations (e.g., dust samples, teeth and brain). Currently, my group is involved in research projects centering around:

1.     Records of aeolian, fluvial and lacustrine sediments as tracers of paleo-environment conditions and sediment sources.

2.     Tracing metal artifacts in antiquity.

3.     The dark side of ancient metallurgy: Measuring toxic metals and metallic isotopes (and aDNA) in human populations and in artifacts to trace the impact of early industries through time.

4. The association between elemental anomalies in the human brain and mental diseases.

We carry out these projects in collaboration with researchers from the Hebrew University (Earth Science, Archaeology, Medicine), the Geological Survey of Israel, Israel Oceanographic and Limnological Research, The Israel Antiquities Authority, Tel Aviv University, Haifa University, GFZ - Potsdam, Germany, Columbia University, University of California San Diego, University of Michigan, and the Institute of Geology and Geophysics, Chinese Academy of Sciences. 


 

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Yoni Goldsmith

Yonatan Goldsmith

Senior Lecturer
Room 14 South

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Research Interests 

Understanding how global warming will effect water availability is one of the crucial questions of our time.

My research is aimed at quantifying past changes in rainfall and evaporation in different places around the world (China, Mongolia, western US, Middle East) in order to understand the natural variability of rainfall and evaporation and the processes that govern this variability.

I combine geomorphology with isotope geochemistry (compound specific stable isotopes (dD, d13C), traditional stable isotopes (dD, 18O, d13C), clumped isotopes and U/Th dating) to investigate how the status of lakes has changed through time. I use hydrological models and outputs of climate models to quantify and evaluate the empirical data I collect.

I’m also interested in how human societies respond to climate change throughout history and in the present.

Ongoing projects:

  • Quantifying the migration of the East Asian Monsoon during the Late Quaternary in China and Mongolia
  • Reconstructing paleo-intensity of the Indian Monsoon using lake-area fluctuations from Lake Chenghai, Southern China
  • Developing and applying compound specific stable isotope biogeochemistry to problems in terrestrial hydroclimate, East Asia, West Asia, Western USA
  • Chemical and isotopic processes of shoreline tufa formation in Mono Lake, USA.

Curriculum Vitae

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Yoni Israeli

Yoni Israeli

Ph.D student, supervised by Simon Emmanuel
Room 129 North

Impact of mineral dissolution and precipitation on the wetting behavior of non-aqueous phase liquids in groundwater systems.

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During the past few years the focus of my research has been to develop state-of-the-art microscopy and numerical techniques to study the interaction between minerals and fluids at a macro and nanometer scale. My main study is aimed at exploring a fundamental scientific problem of exploring how mineral alterations influence wetting behavior. My research is aimed to determine the way mineral precipitation, dissolution and replacement impact the wetting behavior of non-aqueous phase liquids (NAPLs) in rocks and soils at the micrometer and nanometer scales. We expect that alteration of wettability at the pore scale will affect field scale phenomena, such as pollutant mobility. Since wetting behavior controls the adhesion of liquid contaminants to minerals, my study is expected to have important practical implications to the quality of groundwater and to the environment.
I am also studying the way in which minerals undergo weathering from the macro to the nanoscale. I developed a numerical model to assess the effect of grain size and rock composition on chemical weathering and grain detachment. The model simulates the weathering of a rock comprising grains with various sizes composed of two different minerals with different reactivities. Our simulations showed that grain detachment represents more than a third of the overall weathering rate. We also found that as grain size increases, the weathering rate initially decreases; however, beyond a critical size, the rate became approximately constant. Our results could help predict the sometimes-complex relationship between rock type and weathering rate (for more details: https://www.earth-surf-dynam.net/6/319/2018/esurf-6-319-2018.html).

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Ronit  Kessel

Ronit Kessel

Associate Professor
Head of the Geology Program
Room 210 South
+972-2-65-85584

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The combination of experimental petrology and thermodynamic modeling provides powerful insights into the igneous and metamorphic processes by which Earth and other planets evolved.  My research involves the development of experimental techniques together with modeling of the experimental data to constrain the nature of both terrestrial and extraterrestrial environments through the study of synthetic analogs. 

The topics I am currently involved with:

Melt and fluid compositions in equilibrium with mantle material. Aqueous fluids play an important role in melting and metasomatism of the Earth’s mantle; I study the role of volatiles (H2O, CO2, etc.) in dehydration/hydration and melting processes in the mantle.

The evolution of meteorite groups. Samples delivered to the Earth as meteorites provide us with a unique opportunity to study the timing and the processes by which our solar system formed and evolved.  I combine both experimental and analytical methods to understand the formation conditions of different groups of meteorites.

 

Curriculum Vitae

 

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Boaz  Lazar

Boaz Lazar

Professor
Room 5 South
972-2-65-86535

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Research interests: 

My research has been focused on geochemical and biogeochemical processes at and near natural interfaces such as between water (saline/fresh) and rocks (or sediments or particles) and water-atmosphere boundaries. The research covers a wide-scale variety of geological environments. I have studied fluid inclusions within crystals, microgradients between seawater and electrode surfaces, stromatolites (microbial mats), coral reefs, porewaters within corals and sediments, floods and the open sea water column. A brief description of the research activities:Sr isotopes in ground waters as tracers of the calcite-calcite and calcite-dolomite transformations; Fluid inclusions in halite and the reconstruction of the chemical evolution of the oceans during the geological history; Diagenesis of reef corals and the distribution of trace elements (proxies for paleo-oceanographic conditions) between coralline aragonite and seawater; The fate of manganese in the soil-aquifer treatment of a sewage reclamation system; Isotopic effect of CO2 influx across brine-atmosphere interface induced by intense photosynthesis; 14C fluxes into marine sediments, across freshwater seawater interface, flood water and radiocarbon budgets; Carbon, oxygen and nutrients variations in coral reefs emphasizing the role of bioeroders, the decrease in reef calcification due to eutrophication, and suggesting that reefs will stop to grow on atmospheric CO2 doubling; Nutrients budget of the northern Gulf of Aqaba, Red Sea that enable to determine the role of fish farming in the eutrophication of that oligotrophic basin; Using the disequilibrium in the U-Th series, the cosmogenic isotopes 14C and 10Be for identifying atmospheric exchange, flood intensity, fluxes into porewater and water dating and analyzing the open system effect on dating corals by the U-Th method and studying water fluxes and adsorption/desorption kinetics. 4)
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Oded  Navon

Oded Navon

Professor
Room 202 North
972-2-65-8 5549

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Research interest: I am fascinated by volcanoes, diamonds and pink granites*.  Perhaps this is why I am interested in the role of water and other volatiles in magmatic processes.  Volatiles are involved in most igneous processes.  They are central in formation of melts, play a major role in transporting trace elements and radio-isotopes between mantle reservoirs or between mantle and crust, and are the driving force of explosive volcanic eruptions.  In my studies, diamonds provide a window to the nature of deep mantle fluids.  The geochemistry of Cenozoic alkali basalts, late-Proterozoic igneous rocks and lower crustal xenoliths from Israel is interpreted as reflecting progressive melting of hydrated lithosphere and is used to follow the transport of trace element between mantle and crust.  Hydrothermal experimental setup is combined with computer simulations in a study of melt-fluid separation and interaction during volcanic eruptions.

 

* I must admit that I also love colorful sandstones, but I do not study these rocks or their coloration.

Curriculum Vitae 

 

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