“From the Benthos to the Cosmos’
My research interests are focused on applications of isotope geochemistry in paleoclimatology, paleoceanography, extraction chromatography and cosmochemistry.
After joining the Division of Marine Geology & Geophysics (MGG) in March of 2009, one of my main objectives has been establishing the Neptune Isotope Laboratory (NIL) in collaboration with the Division of Marine and Atmospheric Chemistry at the Rosenstiel School. Along with a clean-room enclosure, we now have several class-100 vertical and horizontal laminar flow hoods, two high-purity water systems, sub-boiling acid distillation units and two, class-100 trace metal workstations for low-blank sample processing and wet chemistry. The lab is also equipped with a ThermoFisher Neptune Plus, high performance Multi-Collector Inductively Coupled Plasma Mass Spectrometer (MC-ICP-MS) and a New Wave Excimer 193 nm Laser Ablation (LA) system.
The NIL facility has been fully operational since January of 2012 and we are now capable of making the following routine measurements, and continue adding new isotope systematics:
- High-precision analysis of Li, B, Ca, Mg and, Fe isotopes.
- High precision analysis of Hf and the Rare Earth Element (REE) isotopes.
- High-precision analysis of Sr isotopes using wet chemistry and LA-MC-ICP-MS.
- Bulk elemental analysis of the REE, Sc and Y using MC-ICP-MS.
- Closed-system U-Th geochronology of carbonate rocks, including corals and speleothems.
Paleoclimatology and Paleoceanography: Prior to joining the University of Miami, I studied climate variability in northern Indian Ocean over the last glacial-interglacial period using a multi-proxy approach. A novel component of my research involved combining organic and inorganic geochemical tracers to document oceanic and atmospheric teleconnections between the climate of the North Atlantic and northern Indian Ocean over the last 120 Ka.
Since 2009, I have extend my research to terrestrial, lacustrine and shallow marine environments, with the aim to generate high-resolution records of climate variability using records from ombrotrophic (rain-fed) peat mires, lakes, cave deposits (speleothems, flow stones etc.) and shallow-water corals in West Asia, the Middle East and the Persian Gulf. With a rich history of human activity, this region provides a unique background for investigating how abrupt climate change has influenced human civilizations during the Holocene and the Anthropocene.
Extraction chromatography and Cosmochemistry: As a post-doctoral research associate at the Origins Lab and the Chicago Center for Cosmochemistry, I worked on several projects that involved developing new analytical techniques in extraction chromatography and multi-collection isotope mass spectrometry, with special focus on planetary and meterotics studies. We explored new techniques in purification of borate flux for high-efficiency, low-blank fusion of (extra) terrestrial materials and elemental separation using wet chemistry for high-precision isotope analysis. In 2011, the results of one of my projects with Dr. Nicolas Dauphas, the director of the Origins Lab, lead to a new constraint on the age of planet Mars and its accretion history (You can read more about this work here).
Currently, I am working on classifying meteorite pieces recently recovered in Iran during an observed entry (these meteorites are known as “fall”s), and the bulk REE patterns in more than 30 meteorites using a novel analytical and MC-ICP-MS technique we developed at the Origins Lab.
Funded projects:
Collaborative Research: High-resolution, Multi-proxy Reconstruction of Holocene Climate Variability in West Asia (NSF/PI)
Since the beginning of the Neolithic Era ca. 9500 B.P., some of the first and most outstanding human civilizations rose across the Fertile Crescent, extending between northern Persian Gulf in Iran and the eastern Mediterranean Sea. Evidence is mounting from paleoclimate proxy records around the globe that human societies have been impacted by abrupt climate shifts throughout the Holocene. Very few studies, however, have been conducted in West Asia that document climate variability at inter-annual to centennial time scales, which are most relevant to the flourishing and diminishing of human societies. We propose a novel study that will measure major and trace elements and organic biomarkers at inter-annual to centennial resolution in two ombrotrophic (rain-fed) peat cores from NW Iran, spanning the entire Holocene to:
- Establish the first high-resolution inter-annual terrestrial record of atmospheric dust from mid-latitudes in West Asia, and develop centennial records of moisture variability.
- Examine the role of solar irradiance as a potential forcing mechanism for changes in atmospheric patterns over West Asia.
- Investigate how climate change may have affected major civilizations in the region during the last 11 thousand years.
High-Resolution Records of Rapid Climate Change in Speleothem Records From the Bahamas (NSF/Co-PI)
This is an integrated geochemical and modeling study to test the hypothesis that aridification in Northern Africa and cooling in the North Atlantic associated with Heinrich events are recorded in the chemical composition of stalagmites from the Bahamas during periods of lower sea level. The sub-tropical Atlantic is an area generally without high-resolution climate records and therefore this work offers a special opportunity to ascertain whether and how Heinrich and Dansgaard/Oeschger events are actually recorded and how they relate to high-latitude records. Our approach will combine geochemical analysis of speleothems with regional modeling in order to gain a better understanding of the signatures and physical mechanisms of rapid climate change in the tropical/sub-tropical Atlantic.
A key component of this project is establishing a precise and accurate chronology for the cave deposits from the Bahamas using U-Th geochronology with MC-ICP-MS. Developing this technique is underway at the Neptune Isotope Lab.
Marine Testing of Absorbent Materials (ORNL/Rosenstiel School PI)
The world oceans can be a significant source of many elements that are crucial for maintaining our modern lifestyle. As part of this project, the ORNL and the Rosenstiel School have paired to test absorbent materials that may someday help explore the world oceans as the largest mines on Earth.
Other active projects:
- Reconstruction of paleo-pH in the corals of the Persian Gulf based on Boron isotopes.
- High-resolution records of climate change in speleothems from Iran: A multi-proxy approach to studying climate variability during the late Pleistocene and the Holocene in West Asia.
- Application of LA-MC-ICP-MS in tracking the source and provenance of archaeological artifacts.
