Lead


Lay summary
During the first year of the SNF research program, we propose to study the modern environment where dolomitic stromatolite structures are forming, as well as the geochemical signals that are produced in the stromatolites and microbial mats, and compare these with the geological record. As previously stated in the proposal, the project is divided into 3 parts, as follows: Part I. (a) To apply high-resolution microscopy techniques and spectrometry analysis at a nanoscale to stromatolites cultivated in the laboratory. Part II. To define a new paleothermometer for dolomite based on the ordering of 13C and 18O isotopes into bonds with each other in the carbonate mineral lattice (the so-called "clumped isotope" technique). Part III. To detect organic signatures in ancient microbialites applying Raman Spectroscopy. During the first year of the project, we are concentratling our research efforts on Part II. We are collecting field data, which will be very important to use in the calibration of the new paleothermometer for dolomite based on "clumped isotope" geochemistry. We began our sampling campaign in November, 2009 with the collection of water and sediment from the three lagoons in Brazil, where the mineral dolomite is precipitating. In addition, dolomite samples from Cretaceous formations were collected. The PhD student on the NSF project, Ms. Anelize Bahniuk, spent 3 months in the isotope laboratory of Prof. John Eiler at Caltech, Ca, USA, taking a trainee course to learn the "clumped isotope" technique and conduct preliminary measurements.To have a better control on the lagoonal environment, we will have a second field campaign during May 2010 in the study area to install the second meteorological station and Tinytag Aquatic temperature sensors into the sediment to collected data during the next three years. Two more field campaigns are scheduled for July and September 2010 to complete the dry season water and sediment sampling for this first phase of the project.In summary, the following activities are planned during the current year:-November 2009, collected samples for first measurements -January to April 2010, PhD student, Ms. Anelize Bahniuk, learned the "clumped isotopes" technique and analysed modern and ancient samples at Caltech, USA.-May 2010, continued sampling and installation of meteorological station and temperature sensor in the study area.-July and September 2010 sampling campaigns during the dry season.In between sampling campaigns, the analytical work will be undertaken for all three parts of the project.