Precambrian-Cambrian phosphate deposits, ocean chemistry and the evolution of life
The Precambrian-Cambrian boundary comprises an episode of major environmental changes, which are believed to be relevant for the most prominent bioradiation in Earth’s history: from an ocean in which algae and microbes were the dominant form of life, to one in which siginificant skelton-forming higher life spread.
Concomitant with these changes is the onset of biomineralization and widespread phosphogenesis (i.e. authigenic phosphate deposition), the latter phenomena not yet fully understood. Our research therefore focuses on the facial, mineralogical and geochemical analyses of well-preserved Precambrian-Cambrian phosphate deposits from Central and South Asia (e.g. China, Kazakhstan, India).
Contact: Dorothee Hippler
Experimental formation and transformation of Ca-phosphates
Calcium phosphate phases have a wide range of occurrences and uses from products of biomineralization and post-sedimentation in natural surroundings, add-ons in composites for tailored properties e.g. of cements and water treatment agents, to innovative medical-related products e.g. for remineralisation of teeth. In aqueous environments amorphous calcium phosphate (ACP) is known to precipitate as intermediate phase, which subsequently converts into hydroxyapatite (HAP). The aim of this research project is to gain an improved understanding on the transformation process and the potential use of proxies (e.g. trace elements, REE, stable isotopes) to recover individual environmental conditions and reaction paths via Ca-phosphate formation and ACP-HAP transformation experiments.
Contact: Jessica Stammeier