Science

IGL Research Topics

Project Snowball Earth
Reconstruction of marine environmental conditions during a snowball event at 680 Ma in Lantain, Anhui, southern China

There were two major snowball earth events that occurred near the Precambrian/Cambrian boundary and have reported some interesting macro-fossils preserved in the black shales. The evolution of Earth and the origin of life are closely connected. The surface environmental changes may have impacted to modify the genetic and molecular systems of life on Earth. On the other hand, biochemical interactions may influence importantly the composition of the atmosphere and oceans. The profound changes at the Ediacaran to Cambrian transition record these interactions, along with dramatic climatic and bio-spheric events, and are preserved in stratigraphic archives on the newly discovered site at Lantian in South China, for instance at the new Snowball Earth event site at Anhui (Yuan et al., 2011, Nature). A formation of a multidisciplinary international team to integrate the expertise of paleo-biology, sedimentology, geochemistry, and geochronology, the data generated will shed light on the Snowball Earth event and later diversification of early animals. After Yuan et al. (2011) identified the oldest well-preserved plant and animal fossils at Lantian, various interesting and critical discussions on life origin, snowball earth and marine characters before Cambrian have received surged new attention. During a pre-summit project at NCKU, we have visited and sampled value specimens from the Lantian site for preliminary ocean acidification hypothesis evaluation, as well as for redox and bio-tracers. The extreme environments associated with the Snowball Earth have offered rare opportunities to study greenhouse and ocean acidification under >350 times CO2 conditions. Based on our analytical platform and the newly jointed facilities, we propose to resolve the following questions on the Snowball Earth and life evolution during this project. The first target is to obtain the most precise age of the Snowball Earth event. Our SEM examinations have discovered suitable minerals of authigenic zircon, xenotime, monazite, barite, and carbonate for U-Pb or U-Th dating. Secondly, we will focus attention to evaluate various environmental proxies, such as B isotope (pH), S isotopes in sulfide and sulfate (bio-geochemical cycle), Mo and V isotopes (redox), stable Sr, radiogenic Sr and Ca isotopes (continental weathering), and stable C, N, O isotopes (C sources). Thirdly, we will put strong efforts to assemblage novel tools for high-resolution 3-D images of the newly discovered Pre-Cambrian micro-fossils of morphological and internal structures using confocal laser scanning microscopy (CLSM), and 3-D Raman- and fluorescence-imagery (cooperated with J. William Schopf at UCLA), synchrotron-coupled TXM, multi-photon fluorescence, and nano-scale SIMS, FTIR, FIB TEM. This proposal aims to reconstruct marine environments during the Snowball Earth events at 680 Ma, as well as the associated micro-fossils unearthed from the Lantian site. An international analytical platform will be assembled to make the best used of available facilities of TIMS, MC-ICPMS, LA-ICPMS, SEM, TEM, Nano-SIMS, at CMNST, IESAS, NMNS, and UCLA to tackle important sciences related to life evolution under extreme conditions and isotope environmental proxies during the Snowball Earth events.

Continental Environmental Changes

The linkage of global climatic change and continental weathering is a complex cause-consequence feedback system. The dissolved constituents in river waters are predominantly controlled by atmospheric precipitation, weathering of ambient rocks, water/sediment interaction in watersheds, anthropogenic pollution, biological activities, and redox conditions. To quantify the relationship between the continental weathering processes and climatic/environmental changes, we use geochemical and isotopic methodologies to investigate the biogeochemical characteristics of surface water, suspended particles and sediments.

- Dissolved constituents and Sr isotopes in river waters from a mountainous island - The Danshuei drainage system in northern Taiwan.
- Weathering sources in the Gaoping (Kaoping) river catchments, southwestern Taiwan: Insights from major elements, Sr isotopes, and rare earth elements.
- Seasonal variability of dissolved major and trace elements in the Gaoping (Kaoping) River Estuary, Southwestern Taiwan.
- Tracing freshwater plume migration in the estuary after a typhoon event using Sr isotopic ratios.
- Source variability of sediments in the Shihmen Reservoir, Northern Taiwan: Sr isotopic evidence.
- Riverine lithium isotope systematic during continental weathering from an active orogenic belt, Taiwan.

Oceanic Environmental Changes

The best way to predict the trend of future climate is by learning the lesson from the past climatic variability cycles. The characteristics of the porous coral (Porites.) with long life (several centuries) and relatively fast growth rate (about 1 cm/year) provides a high resolution and reliable message about the past oceanic conditions. Our coral research team relies on numbers of chemical and isotopic proxies to reconstruct the past oceanic environment affected by both natural and anthropogenic activities.

- A Feasibility Evaluation of Using Coral Chemical Compositions as Climate Proxies: A Tank Study.
- Ocean Acidification Records in the Western Pacific: Boron Isotopic Composition of Coral.
- Temporal distributions of anthropogenic Al, Zn and Pb in Hong Kong Porites Coral during the last two centuries.
- Record of the Anthropogenic impact and the Natural System Interaction from Porites Coral in Taiwan.
- Cd/Ca, Ba/Ca and Pb/Ca Records of Porites Coral from Lanyu Island, Northwestern Pacific: Contribution of Natural and Anthropogenic Sources to Seawater Trace Metal Variability.

Atmospheric Environmental Changes

Pollutants derived from long-range transport and local emission impact significantly heavy metal compositions in rainwater and aerosols. Dissolved chemical compositions in rainwater have provided valuable information on pollutant sources in the atmosphere and short-term environmental changes. To identify their sources and relative contributions in rainwater, we investigated the chemical and isotopic composition of rainwater collected during rainfall and typhoon events.

- Sources of Cu, Zn, Cd and Pb in rainwater at a subtropical islet offshore northern Taiwan.
- Seasonal variation in long-range transported dust to a subtropical islet offshore northern Taiwan: Chemical composition and Sr isotopic evidence in rainwater.
- Sources of major ions and heavy metals in rainwater associated with typhoon events in southwestern Taiwan.

Interior Geochemistry

The discharges of fluid in the vent-seep subsurface environment are efficient media to transport materials to the hydrosphere and affect the chemical mass balance in the ocean. Tracing fluid transport and evolution plays a major role and is of major interest to a variety of research works. To clarify the mechanism, IGL analyzed the vent fluids' chemical compositions and multi- non-traditional stable isotopes.

- Origin, Migration and Evolution of Submarine Hydrothermal Vent Fluids in Milos Island, Aegean Sea, Greece.

Environmental Science & ECO Researches

Toxic elemental contamination is threatening water supplies in many developing countries. The common treatment techniques for removing heavy metals from contaminated waters include precipitation, oxidation, coagulation, adsorption ion-exchange, and membrane filtration. The adsorption method is considered more advantageous over others because of its removal effectiveness, treatment cost, and ease in equipment handling. Commercial adsorbents are effective, however, the high cost makes it a tough competition in the market. IGL aims at investigating new synthesis materials and recycled sorbents from the sludge in the printed circuit board (PCB) industry on toxic elemental removal and improves the remediation strategy.

Biogeochemistry & Food Sciences

Coffee and tea are important commodities and popular beverages. However, cheap counterfeit products of poorer quality have begun to enter the market, affecting the taste but also potentially posing a threat to human health if contaminated. Therefore, food authenticity and traceability have become key issues. IGL aims to evaluate the feasibility of using chemical and isotopic compositions of coffee beans and tea left to identify their geographic origins.

- Geographic determination of coffee beans using multi-element analysis and isotope ratios of boron and strontium.
- Determination of the geographical origin of domestic tea in Taiwan using multi-element patterns and isotopic compositions of boron and strontium.