Study of modern microbialites

Study of modern microbialites: Toward a better interpretation of the geological record

PI: Prof. Nina Zeyen

Collaborators: Prof. Johanna Marin-Carbonne (UNIL)

Funding: DIP

Description: 
This project is centered on the investigation of modern and ancient microbialites, organo-sedimentary rocks formed by the trapping and binding of detrital sediments and/or the precipitation of authigenic minerals by benthic microbial communities. The primary objective is to characterize a modern lacustrine system hosting modern microbialites and to identify the mineralogical, chemical and physical transformations occurring during early diagenesis with the end goal to better interpret the environments of formation and the biogenicity of ancient microbialites. 

Project 1: Analysis of Modern Microbialites and Sediments from a Volcanic Lake
This part of the project involves the study of modern microbialites and sediment cores from the Lake Specchio di Venere, Italy. These modern microbialites serve as analogs to ancient microbialites that thrived in Archean volcanic lakes. The main goal is to thoroughly characterize modern microbialites, biofilms, sediments, water chemistry, gases, and the carbon budget associated with these formations. This project aims to tease apart the respective roles of environmental conditions versus microbial activity in the formation of microbialites as well as to characterize the fate of the (mineral) phases and organic molecules during early diagenesis of the microbialites and the sediments. 

Project 2: Examination of Ancient Microbialites and comparison with modern analogues
Authigenic and poorly crystalline Mg-silicate clays (kerolite or stevensite) are widely observed within modern microbialites, where these phases are intimately associated with organic molecules composing microbial cells or remnants of extracellular polymeric substances. In this segment, we investigate microbialites from two different geological periods: the Green River microbialites, dating back to 53-49 million years ago in the USA, and the 2.72 billion years old Tumbiana stromatolites located in Australia. A comparative analysis with modern microbialites is conducted to track the presence of Mg-silicates and organic signatures within these ancient formations. The overarching aim of this research is to gain insights into the diagenetic transformations of microbialites over geological time, shedding light on their intricate mineralogical and chemical transformations spanning billions of years.

The overarching aim of this research is to gain insights into the geological evolution of microbialites over time, shedding light on their intricate transformations spanning billions of years.

Job opportunities:

• One PhD (Bhagyashree Mishra): Study of modern microbialites/sediments from the Lake Specchio di Venere
• One master student (Sumedh Dandale): Study of ancient microbialites to track the product of transformation of Mg-silicates