Research interests

I am currently working on further developing and advancing hematite (U-Th)/He dating applied to fault thermochronometry. Thanks to its unique closure temperature range (50-250 °C) and its dependence to grain size,  hematite (U-Th)/He dating has the potential to extract richer fault thermochronological records than conventional methodologies and allows to gain new insight into the timing of fundamental fault processes:

• Temperature driven deformation mechanisms and fault strength evolution

• Timing of fault fluid flow and fault mineralization

• Timing of fault related exhumation

• Timing of seismic slip

In my work I couple hematite (U-Th)/He dating with hematite textual and grain size analysis of natural and experimentally derived hematite coated fault surfaces.

 

Furthermore, during the course of my studies I have developed several other research interests that integrate different methodologies.

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SUBJECTS

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Structural geology

Understanding short- (at the seismic cycle scale) and long- (at the scale of fault system development) term processes governing faults nucleation propagation and development at different crustal depths.

The study of the spatiotemporal evolution of fault related exhumation, topographic growth and associated syntectonic deposition during the enucleation and propagation of continental fault systems.

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Continental tectonics

Study of the spatiotemporal evolution of intraplate strike-slip fault system aimed at the tectonic and geodynamic regional reconstruction and at the identification and comprehension of the driving processes that govern their localization, distribution and kinematics configuration.

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Regional reconstructions

Synthesis of geophysical, structural and stratigraphyc data aimed at the regional geodynamic and tectonic reconstruction.

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METHODOLOGIES

Structural, tectonostratigraphic and geomorphologic field investigation

Morphometric and geostatistical analysis in a GIS environment

Quantitative structural analysis

Application of geochronological methods: optically stimulated luminescence dating (OSL);

Application thermochronometric methods: Apatite Fission Track (AFT) dating, apatite (U-Th)/He (AHe) dating and hematite (U-Th)/He (HeHe) dating.

Thermocronological modelling

 

STUDY AREA

Central Iran,

South and Central America: Colombia (Llianos, Magdalena Valley and Colombia basins), Nicaragua (Nicaraguan Rise and Sandino Basin),

North America: Mexico (the Trans Mexican Volcanic Belt), 

 

ON-GOING PROJECTS

Thermomechanical evolution of brittle faults via coupled hematite (U-Th)/He thermochronometry of natural and experimentally-derived fault surfaces.

Hematite mineralization is ubiquitous in damage zones and fault cores as striated or “mirrored” (high gloss, lighreflective) hematite coated slip-surfaces. These faults archive important components of the thermal, physical, and chemical conditions of faulting and/or paleofluid flow. Working in collaboration with Dr. Alexis Ault (Utah State University, NSF CAREER) and Dr. Greg Hirth (Brown University), I couple hematite (U-Th)/He dating with hematite nano- to microtextual analysis of natural and experimentally derived hematite-coated fault surfaces. Hematite friction experiments, using a rotary shear apparatus, document the evolution of friction, temperature, microstructure, and He loss over a variety of slip displacements and rates. These experiments provide critical new insight on the thermomechanical evolution of hematite-coated fault surfaces and how brittle faulting affects the hematite (U-Th)/He system via grain size reduction and thermal resetting (He loss). Ultimately, this research extends the utility of hematite (U-Th)/He dating as a useful tool for structural geologists, tectonicists, and geochronologists.

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Thermochronological evolution of the Deadman Fault, Sangre de Cristo Mountains, Colorado

 A component of my postdoctoral research involves working in collaboration with Dr. Alexis Ault (USU) and Dr. Jonathan Caine (USGS) on the thermal evolution of the Deadman fault system in south-central Colorado. Building on skillsets I developed during my PhD research, this work combines structural mapping, bedrock apatite and zircon (U-Th)/He thermochronometry, and fault rock hematite (U-Th)/He dating with thermal modeling to constrain a protracted temperature-time history of this terrane during the Ancestral Rockies and Laramide orogenies as well as Rio Grande rifting. For example, I use a new protocol for selecting zircon crystals for (U-Th)/He thermochronometry (Ault et al., 2018, Chemical Geology) to generate a range of intrasample effective U concentration (eU) that leverages visual grain metamictization, a proxy for radiation damage accumulation. By using this approach to characterize zircon He date-eU relationships and implementing a zircon radiation damage accumulation and annealing model in thermal history simulations, I am able to better constrain the long-term thermal history of the Paleoproterozoic basement.  In addition, hematite (U-Th)/He dating of the fault rocks aims to discriminate between Laramide and rift faulting events.

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Dating faulting in the Transantarctic Mountains 

This project implements a multidisciplinary approach focused on dating fault slip to document spatiotemporal patterns of Cenozoic brittle deformation in the Transantarctic Mountains (TAM) in Antarctica. The project is financed by the Italian Antarctic Research Program and is coordinated by the PI Dr. Valerio Olivetti (University of Padova). I am acquiring and interpreting hematite (U-Th)/He data of hematite-coated fault surfaces exposed within multiple fault systems. Although the general structural architecture of the fault system along the TAM is well defined, outstanding issues persist on the initiation and evolution of the different specific fault systems. This project aims to refine and improve existing tectonic models for the Ross Sea region.

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PAST PROJECTS

Evolution of intraplate strike-slip faulting in Central Iran.

Central Iran provides an ideal test site to study the morphotectonic response to nucleation and propagation of intraplate faulting. My PhD research, supervised by Dr. Federico Rossetti (Roma Tre University) and co-supervised by Dr. Marta Della Seta (Sapienza University of Rome), was motivated by three fundamental questions: (1) How does the spatio-temporal propagation and long-term evolution of intraplate strike-slip systems influence topographic growth, erosion/exhumation, and syn-tectonic sedimentation (source-to-sink history) and how do these processes influence the propagation of intraplate strike-slip faults? (2) How does this evolution reflect the intraplate response to the far-field plate boundary processes and forces? (3) Is deformation and the source-to-sink evolution punctuated or continuous? In order to address these questions, I integrated structural tectonostratigraphic and geomorphological field investigations with low-temperature thermochronometry to reconstruct the spatio-temporal evolution of the Kuh-e-Faghan Fault, in northeaster Central Iran (Calzolari et al., 2016a; 2016b; 2018). My PhD research combined multidisciplinary field- and laboratory-based dataset on a previously unstudied strike-slip fault system in that bear important new implications on the tectonic and kinematic evolution of the region of central Iran in the aftermath of Arabia-Eurasia collision.

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