Climate change, lakes, and life during the rise of dinosaurs

Methods

Summary

This project will reconstruct climate and ecosystem changes during the Carnian Pluvial Episode (~230 million years ago) by studying ancient lake deposits preserved in western Argentina.

Our approach combines fieldwork, fossil analysis, geochemistry, and high-precision geochronology. During field expeditions, we will measure detailed stratigraphic sections and collect rock samples from carefully documented layers. These samples may contain visible fossils and microscopic fossils, such as pollen and spores, which provide key evidence of past ecosystems and environmental conditions.

In the laboratory, samples will be processed to recover fossils and analyze their mineralogical and chemical composition. We will study clay minerals and sediment textures to reconstruct environmental conditions and measure stable isotopes of carbon and oxygen to detect changes in temperature and hydrology. Volcanic ash layers will be analyzed to extract zircon crystals, allowing precise radiometric dating of the sediments and establishing a reliable timeline.

By integrating fossil, sedimentological, geochemical, and geochronological data, we will reconstruct the evolution of ancient lake systems and determine how ecosystems responded to climate disruption during this critical interval in Earth’s history.

This work builds on our team’s extensive experience in fieldwork, fossil analysis, and climate reconstruction, and uses established, reproducible analytical methods and international laboratory collaborations.

Challenges

Fieldwork in remote areas presents logistical and environmental challenges, including difficult terrain, limited accessibility, and weather conditions that may restrict access to key outcrops. To address this, our team works in well-planned expeditions with established permits, prior site knowledge, and extensive experience in these basins.

Another challenge is the variability in fossil preservation and geochemical signals, as not all rock layers preserve climate information equally. We address this by collecting multiple samples across different stratigraphic levels and applying multiple independent analytical methods. This multi-proxy approach increases reliability and reduces uncertainty.

Analytical challenges, such as sample preparation and laboratory processing, are mitigated through established protocols and collaboration with specialized laboratories in Argentina and internationally, thereby ensuring high-quality, reproducible results.

Our team has successfully applied these methods in previous projects, reducing both technical and logistical risk.

Pre Analysis Plan

Our central hypothesis is that lake deposits in western Argentina preserve measurable environmental and biological signals associated with the Carnian Pluvial Episode.

We will analyze sedimentological, paleontological, geochemical, and geochronological data to reconstruct environmental conditions and ecosystem responses.

Sedimentological and stratigraphic data will be used to identify depositional environments and environmental changes through time. Fossil data, including macrofossils and microfossils such as pollen and spores, will be analyzed to reconstruct biodiversity, ecosystem composition, and biological responses.

Geochemical data, including stable isotopes of carbon and oxygen, will be used to infer changes in hydrology, water balance, and environmental conditions. Clay mineral assemblages will be analyzed to infer paleoclimate conditions, as different minerals form under different environmental regimes.

Radiometric dating of zircon crystals from volcanic ash layers will provide precise chronological constraints, allowing us to correlate environmental changes across sites.

Statistical analyses will be used to evaluate patterns, correlations, and variability in the data, integrating multiple independent proxies to produce a robust reconstruction of climate and ecosystem evolution.

By combining these independent datasets, we will test whether environmental and biological changes observed in these lake systems are consistent with the timing and characteristics of the Carnian Pluvial Episode.