Students Day: Three Msc/PhD Students and Postdocs present their work

1 - Dr. Xiaoxiao Zhao, Institute of Earth Sciences, Heidelberg University

Nitrous oxide emissions during the Paleocene-Eocene Thermal Maximum: an overlooked source of warming?

Abstract

The Paleocene–Eocene Thermal Maximum (PETM, ~56 Ma) was a rapid global warming event caused by massive carbon release in Earth’s history. This event led to profound changes in the marine environment, including ocean acidification, deoxygenation, and the extinction of benthic foraminifera, and reshaped marine biogeochemical cycles such as the nitrogen cycle. However, the amount of carbon required to explain the observed temperature rise remains under debate, introducing uncertainties in our understanding of Earth system climate sensitivity. In this talk, I will present evidence from the marine nitrogen cycle perspective, suggesting that enhanced nitrous oxide emissions driven by nitrogen cycle perturbations may represent an overlooked contributor to the observed warming during the PETM.

2 - Dr. Giulia Mingardi, Institute of Earth Sciences, Heidelberg University

Effect of differential stress on phase transitions: preliminary results from in-situ experiments on quartz-coesite

Abstract

Quartz-coesite is a key phase transition for constraining the pressure–temperature conditions recorded by ultrahigh-pressure metamorphic rocks, traditionally interpreted under the assumption of hydrostatic burial pressure. However, deviatoric stresses arising from sample heterogeneities (grain boundaries, inclusions, layering) can locally modify phase stability, and the mechanisms controlling this stress partitioning remain poorly constrained because the local stress state has never been measured dynamically during deformation. To address this, we conducted in-situ high-pressure, high-temperature deformation experiments on layered and host-inclusion quartz samples using the large-volume press at beamline ID06 (ESRF), monitoring lattice strain by synchrotron X-ray diffraction across the quartz–coesite boundary. Here we present preliminary data from these ID06 experiments, characterizing the evolution of differential stress before and after coesite nucleation. 

3 - Ana Clara Jardim Ferreira, MSc, Institute of Earth Sciences, Heidelberg University

Magmatism of the Northwest Region of the Florianópolis Batholith, Dom Feliciano Belt, southern Brazil

Abstract

The Florianópolis Batholith (BF) is an extensive granitic batholith from the Dom Feliciano Belt, southern Brazil. The belt corresponds to the southern sector of the Mantiqueira Province, an extensive Neoproterozoic orogen that outcrops from the northeastern coast of Brazil to Uruguay. The BF is composed of granitic suites of syenogranitic to tonalitic composition generated between the Cryogenian and Ediacaran periods. Since granitic rocks can be generated in diverse tectonic environments and record important aspects of the processes acting during their evolution, and their petrogenetic characterization allows inferences about formation conditions, magmatic sources, and associated geodynamic contexts, this work seeks to characterize the magmatism of the northwestern portion of the BF, aiming to understand its petrogenetic evolution and contribute to the advancement of knowledge about the geodynamics involved in its generation. To this end, a dataset composed of field and petrographic data, whole-rock geochemistry, whole-rock Sr, Nd, and Pb isotopes, zircon and titanite U-Pb geochronology, zircon Lu-Hf, zircon ICP-MS, zircon oxygen isotopes and Al-in-hornblende thermobarometry, is being assembled in order to characterize a set of nearly 15 igneous bodies from the region and describe their internal processes and relationships with one another. The results are expected to contribute to a better understanding of the magmatic and tectonic evolution of the Florianópolis Batholith and, together, the tectonic dynamics acting in the development of the Dom Feliciano Belt.