Thermochronometry, cosmogenic nuclides, and isotope studies

We analyse the detrital thermochronologic record of sediments from modern rivers and from Plio-Pleistocene siliciclastic rocks in eastern and western Taiwan.

Zircons from the foredeep sediments of eastern Taiwan record the onset of rapid exhumation in the Central Range after 2 Ma (Kirstein et al., 2009, Basin Research).

Erosion rates from multiple proxies (fission tracks in zircons, 10Be in quartz, geomorphic indices) of rivers of the eastern Central Range indicate a state of quasi-equilibrium over the last 1 Ma (manuscript in revision).

Detrital zircons from Plio-Pleistocene sediments of the western foredeep of Taiwan record changes of the river network that was likely characterized by short, steep and transverse rivers during the Pliocene while in the Pleistocene it developed longer and longitudinal reaches with rivers cutting into the zone of non-reset zircon fission-track ages (work in progress).

The Eastern Cordillera of Colombia is a fold and thrust belt formed during the Cenozoic by inversion of a Mesozoic rift. The culmination of the Eastern Cordiallera is the Cocuy Sierra that reaches 5000 m of elevation, located ~600 km east of the trench where the Nazca slab subducts almost horizontally under South America. Based on our new thermochronologic, structural and morphologig data, we aim to costrain the growth and exhumation of the Eastern Cordiallera sector including the Cocuy Sierra.

A project in collaboration with Dr. Claudio Faccenna, Dr. Paola Molin, and PhD student Gaia Siravo at Roma Tre University.

The topography in the High Atlas of Morocco reaches elevations of 4 km despite little shortening across the chain (~20%) and a normal crustal thickness of 33-36 km. Previous apatite fission-track and zircon (U-Th)/He ages indicate Miocene exhumation from depths not greater than 3-5 km. In order to provide constraints on rates and magnitude of exhumation over a larger area of the High Atlas, we apply a very low-T thermchronometer (apatite (U-Th-Sm)/He).

A project in collaboration with Dr. Claudio Faccenna and PhD student Riccardo Lanari, Roma Tre University.

Geodynamic processes associated with timing of river incision and river network reorganization on the Tibetan plateau margins remain controversial. In particular, hydrographic network modifications in SE Tibet have been interpreted as related with regional-scale uplift or fault motion. The paleocourse of the Yangtze River and the timing of the establishment of its modern course are highly debated, leading to conflicting models of the plateau evolution.

To address this problem, I combine diverse methods to assess the relief and palaeoenvironment evolution of SE Tibet, at the Cenozoic timescale. I use topography analysis, field investigation, (U-Th)/He and ⁴He/³He thermochronometry (to quantify exhumation) and paleoenvironmental information derived from the detrital record.