Geological Engineering Commons^™

Long-Term Shoreline Evolution And Anthropogenic Impact: Evidence From 76 Years Of Coastal Change In Mazagón, Spain, M. Fernández-Hernández, M. Pastor, L. Iglesias, R. Castedo, K. S. Sajinkumar

Michigan Tech Publications

The Mazagón coast (Huelva, southwestern Spain) illustrates the strong imprint of anthropogenic interventions on shoreline dynamics. This study evaluates its evolution between 1946 and 2022 by digitizing historical shorelines from aerial photographs and quantifying changes through three complementary indicators: Net Shoreline Movement (NSM), End Point Rate (EPR), and Linear Regression Rate (LRR). Statistical analyses (ANOVA and Tukey’s test) were performed to assess differences between pre- and post-construction phases of the Juan Carlos I breakwater. The results indicate a prevailing erosive trend, with mean retreat rates of − 1.4 m/yr and localized shoreline losses exceeding 100 m. Prior to the breakwater, …

Iron Ore Tailings Reprocessing By Electrostatic Separation Plus Two-Stage Froth Flotation, Vincent Bailey Arohunmolase, Akintunde Stephen Samakinde, Palas Kamlakar Borkar, Daniel Amponsah-Berko, Timothy Eisele

Michigan Tech Publications

The reprocessing of tailings is crucial for recovering valuable iron and reducing the environmental impact associated with tailings disposal. The raw iron ore tailings used in this study had an initial iron oxide content of 24.05 wt% Fe2O3, as determined by ICP-OES analysis. This study investigates the practicality of tailings reprocessing to enhance iron oxide content by integrating electrostatic separation with a two-stage froth flotation process consisting of direct anionic flotation using oleic acid followed by reverse cationic flotation using amine collectors. The primary goal is to efficiently recover valuable iron from tailings, thereby reducing waste and promoting sustainable resource …

A Model Intercomparison Study To Investigate Mixing Characteristics In Non-Precipitating Stratocumulus Clouds, Fan Yang, Kyoung Ock Choi, Kamal Kant Chandrakar, Fabian Hoffmann, Pei Hou, Steve Krueger, Chunsong Lu, Mikhail Ovchinnikov, Yangze Ren, Shin Ichiro Shima, Peng Wu, Chongzhi Yin, Zeen Zhu, Seong Soo Yum

Michigan Tech Publications

Recent aircraft observations of marine stratocumulus clouds consistently showed that cloud microphysical relationships vary with altitude, indicating inhomogeneous mixing characteristics near cloud top and homogeneous mixing characteristics in mid-levels of clouds. Here, we conduct model intercomparison of an idealized, non-precipitating stratocumulus cloud to evaluate model consistency and examine whether simulations can reproduce the observed mixing characteristics. The results show that eleven large-eddy simulations with various dynamics and microphysics schemes show good agreement on the thermodynamical, microphysical, and dynamical properties of the stratocumulus-topped boundary layer in a steady state. The inter-model spread in steady-state liquid water path is significantly reduced compared …

Geospatial Analysis Of Primary Healthcare Accessibility And Qualitative Assessment Of Affordability In Rural Communities Of Twifo Ati-Morkwaa District, Ghana, Peter Ansah Boakye, Daniel Buor, Francis Tei-Nartey

Michigan Tech Publications

Regardless of the efforts of the government and the private sector to improve health facilities in Ghana, a significant number of rural communities still experience inadequate access to primary healthcare. This study used the mixed-methods approach to provide an overview of the geographic distribution of healthcare facilities and the accessibility and affordability of primary healthcare within the Twifo Ati-Morkwaa District. Accessibility was assessed using Euclidean buffer analysis around primary healthcare facilities, while affordability was examined qualitatively using in-depth interviews and focus group discussions with community members, community leaders and health workers. Focus group discussions and interviews were conducted using the …

Remote Sensing Of Dynamic Ground Motion Via A Moiré-Based Apparatus, Adrian Ali Moazzam, Nontawat Srisapan, Gregory Waite, Durdu Guney, Roohollah Askari

Michigan Tech Publications

Highlights: What are the main findings? A Moiré-based optical apparatus enables long-range, non-contact ground displacement measurement in hazardous environments. Controlled indoor and outdoor experiments demonstrate reliable detection of dynamic and seismic-like ground motions with sub-millimeter resolution. What are the implications of the main findings? System performance is evaluated under atmospheric turbulence and wind, revealing key limits and mitigation strategies for field deployment. The proposed approach provides a low-cost, scalable complement to traditional seismic and geodetic monitoring techniques. Ground-based remote sensing of seismic and geophysical displacements remains a major challenge due to environmental hazards, signal attenuation, and practical deployment limitations of …

Volcanic Plume Height During The 2021 Tajogaite Eruption (La Palma) From Two Complementary Monitoring Methods-Implications For Satellite-Based Products, África Barreto, Francisco Quirós, Omaira E. García, Jorge Pereda-De-Pablo, Daniel González-Fernández, Andrés Bedoya-Velásquez, Simon Carn, Et. Al.

Michigan Tech Publications

Volcanic emissions from the Tajogaite volcano, located on the Cumbre Vieja edifice on the island of La Palma (Canary Islands, Spain), caused significant public health and aviation disruptions throughout the eruption (19 September–13 December 2021, officially declared over on 25 December). Nonetheless, it is considered the most significant volcanic event in Europe over the past 75 years due to the substantial amount of SO2 released into the atmosphere. The Instituto Geográfico Nacional (IGN), the authority responsible for volcano surveillance in Spain, implemented extensive operational monitoring to track volcanic activity and to provide a robust estimation of the volcanic plume height …

Solar Backscatter Ultraviolet (Buv) Retrievals Of Mid-Stratospheric Aerosols From The 2022 Hunga Eruption, Robert J.D. Spurr, Matt Christi, Nickolay A. Krotkov, Won Ei Choi, Simon Carn, Can Li, Et Al.

Michigan Tech Publications

On 15 January 2022, a highly explosive eruption of the submarine Hunga volcano (Kingdom of Tonga) generated the largest stratospheric hydration event ever observed and the largest aerosol perturbation since the 1991 Pinatubo eruption. Here, we develop a novel method for satellite retrieval of stratospheric aerosol optical depth (AOD) and layer peak height (zp) using solar backscattered ultraviolet (BUV) radiation; this is made possible by the exceptional mid-stratospheric altitude of the Hunga aerosols. We analyze BUV observations of the Hunga stratospheric aerosol cloud on 17 January 2022 (47 h after the eruption), using BUV band 1 measurements from the TROPOspheric …

High-Resolution Lidar Observations Of Sedimentation-Induced Size Sorting Of Droplets Near A Laboratory Cloud Top, Fan Yang, Yong Meng Sua, Zipei Zheng, Jesse Anderson, Hamed F. Sadi, Jae Min Yeom, Suryadev Pratap Singh, Pei Hou, Will Cantrell, Ernie Lewis, Alex Kostinski, Raymond Shaw

Michigan Tech Publications

No abstract provided.

Coaxial Electrospinning As A Promising Technique For Fabricating Advanced Materials For Energy Storage Applications, Yakubu Adekunle Alli, Abayomi Bamisaye, Akinsanmi S. Ige, Rabi Elabor, Oluwatobi Ife-Adediran, Adanlawo Olayinka Samson, Samuel Oluwadadepo Oni, Alfred Yeboah, Owolabi Mutolib Bankole, Dele Peter Fapojuwo, Adeniyi Sunday Ogunlaja

Michigan Tech Publications

As the demand for efficient, high-performance energy storage systems intensifies, the need for innovative materials that can enhance energy density, power output, and cycle stability has become paramount. Coaxial electrospinning, a versatile nanofabrication technique, has emerged as a powerful method for producing advanced core-shell nanofibers with tailored properties specifically designed for energy storage applications. This review delves into the principles of coaxial electrospinning, highlighting its advantages over conventional fabrication techniques in creating multifunctional materials for batteries and supercapacitors. By manipulating the core and shell compositions, coaxial nanofibers offer superior ion/electron transport, mechanical stability, and electrochemical performance. The review discusses the …

The Hunga Volcanic Eruption Atmospheric Impacts Report, Simon Carn

Michigan Tech Publications

No abstract provided.

Feasibility Study On Large-Scale Geologic Carbon Sequestration In Southern Colorado, Yanrui Ning, Ali Tura, David Herman, Jay Bridgeman, Dana Clark

Michigan Tech Publications

This study evaluates the feasibility of storing over 50 million metric tons of CO2 within a 30-year period in southern Colorado. The target for injection is the 7000 ft (2134 m)-deep Lyons saline aquifer formation, with the overlying alternating layers of anhydrite and shale serving as seals. Geological static models were constructed using seismic, well log and core data, followed by fluid flow modeling to understand the CO2 injection strategy, saturation distribution and plume size. The results indicate that approximately 60 million metric tons of CO2 can be injected with 2 wells into the formation over 30 years, with 85 …

Quantifying The Decay Timescale Of Volcanic Sulfur Dioxide In The Stratosphere, Paul A. Nicknish, Kane Stone, Susan Solomon, Simon Carn

Michigan Tech Publications

The injection of sulfur dioxide (SO2) into the stratosphere and its subsequent oxidation to form sulfate aerosols after large volcanic eruptions can have profound effects on Earth's climate. The removal of volcanic SO2 in the stratosphere is thought to be driven by its gas-phase oxidation by the hydroxyl radical (OH); once oxidized, it goes on to form sulfate aerosols. However, it has also been suggested that heterogeneous oxidation on ash could also be important or even dominant, which would imply the faster removal of SO2 and thus the faster formation of aerosols, at least in ash-rich plumes. Additionally, recent work …

Insights Into The Construction Of The Oruanui Magma Reservoir From A Comparison Of Zircon Hosted In Plagioclase And Whole-Rock, Tyler D. Schlieder, Kari M. Cooper, Adam J.R. Kent, Darren Gravley, Chad Deering, Seth Rubin, Adelicia Johnson

Michigan Tech Publications

Silicic magmatic systems play a critical role in the evolution of continental crust, and their eruptions could pose significant hazard to modern civilization. However, the processes of silicic magma storage and assembly prior to eruption are not well understood. We report new ²³⁸U-²³⁰Th ages and trace-element data for both rims and interiors of zircons separated from whole-rock (WR) samples and from bulk plagioclase separates from the 25.4 ka Oruanui eruption, Taupo Volcanic Zone, New Zealand. These data provide petrologic context and a more complete record of zircon crystallization than previous analyses of whole-rock hosted zircon interiors. In …

Origin Of The World-Class Eagle, Eagle East, And Tamarack Ni-Cu-Pge Deposits, Robert Nowak, Chad Deering, Espree Essig

Michigan Tech Publications

The 1.1 Ga Mesoproterozoic Midcontinent rift hosts the Eagle, Eagle East, and Tamarack Ni-Cu-PGE deposits and Embayment Prospect. These deposits are hosted by ultramafic igneous rocks and have some of the highest Ni-Cu grades on Earth. We use new bulk-rock data and published datasets (bulk-rock, mineral chemistry, and isotopic analyses) to examine major, minor, and trace element trends of both Midcontinent rift-related alkaline and tholeiitic intrusions. In addition, we compare the geochemical data to local kimberlite-hosted lower-crustal xenoliths and local igneous (Archean) and sedimentary (Paleoproterozoic) country rocks. We found the peridotite magma compositions dominantly consist of primitive mantle compositions with …

Analysis Of A Saline Dust Storm From The Aralkum Desert – Part 2: Atmospheric Flow Precursors In The Euro-Atlantic Region, Xin Xi

Michigan Tech Publications

Wind-blown dust emissions from the man-made Aralkum Desert pose significant environment and human health risks across Central Asia. Yet, little is known about the atmospheric circulation patterns favoring dust outbreaks from the region. This study examines the role of upstream atmospheric blocking and recurrent transient Rossby wave packets (RWPs) in initiating a severe dust storm from the Aralkum Desert in May 2018. Results show that the dust event was triggered by an unusual early-summer cold air outbreak and attendant postfrontal northerly winds reaching 24–31 m/s. The compound cold air and dust outbreaks were preceded by repeated meridional flow amplification linked …

Hourly Sulfur Dioxide Observations Over North America: First Retrieval Results From Tempo, Can Li, Nickolay A. Krotkov, Joanna Joiner, Simon Carn, Vitali Fioletov, Chris Mclinden, Debora Griffin, Xiong Liu, Heesung Chong

Michigan Tech Publications

We present the first sulfur dioxide (SO2) retrievals from Tropospheric Emissions: Monitoring of Pollution (TEMPO), the first geostationary atmospheric composition sensor to cover North America, along with some potential applications of TEMPO SO2 data. We show that high resolution (∼10 km²) TEMPO measurements can be used to produce good quality SO2 retrievals with relatively small noise and biases. We demonstrate that hourly TEMPO data are useful for monitoring volcanic hazards, by providing frequent updates on the plume location and additional information on the plume height or winds. With the large number of measurements from TEMPO, it is also …

The Relative Importance Of Wind And Hydroclimate Drivers In Modulating Wind-Blown Dust Emissions In Earth System Models, Xinzhu Li, Longlei Li, Yan Feng, Xin Xi

Michigan Tech Publications

Windblown dust emissions are subject to large uncertainties in Earth system models (ESMs), yet model discrepancies in dust variability and its physical drivers remain poorly understood. This study evaluates the consistency of 21 ESMs in simulating the climatological distribution and interannual variability of global dust emissions and applies dominance analysis to quantify the relative influence of near-surface wind speed and five hydroclimate variables (precipitation, soil moisture, specific humidity, air temperature, leaf area index) across different climate zones. In hyperarid regions, the models exhibit poor agreement in dust variability, with only 10 % of pairwise comparisons showing significant positive correlations. Most …

Analysis Of A Saline Dust Storm From The Aralkum Desert - Part 1: Consistency Between Multisensor Satellite Aerosol Products, Xin Xi, Jun Wang, Zhendong Lu, Andrew M. Sayer, Jaehwa Lee, Robert C. Levy, Yujie Wang, Alexei Lyapustin, Hongqing Liu, Istvan Laszlo, Changwoo Ahn, Omar Torres, Sabur Abdullaev, James Limbacher, Ralph A. Kahn

Michigan Tech Publications

The Aralkum Desert presents a challenging environment for satellite aerosol observations due to its very bright, heterogeneous, and dynamic surfaces and the lack of in situ constraints on region-specific aerosol properties. We survey current global satellite algorithms capable of detecting the presence, column burden, and elevation of airborne dust over the Aral Sea basin. Discrepancies and potential biases in retrieved UV aerosol index (UVAI), mid-visible and thermal infrared optical depth (AOD), and layer height due to different assumptions on surface and aerosol properties are assessed. The results indicate that (1) UVAI products consistently delineate dust plume extent but show large …

Remote Sensing Of Seismic Signals Via Enhanced Moiré-Based Apparatus Integrated With Active Convolved Illumination, Adrian A. Moazzam, Anindya Ghoshroy, Durdu Güney, Roohollah Askari

Michigan Tech Publications

The remote sensing of seismic waves in challenging and hazardous environments, such as active volcanic regions, remains a critical yet unresolved challenge. Conventional methods, including laser Doppler interferometry, InSAR, and stereo vision, are often hindered by atmospheric turbulence or necessitate access to observation sites, significantly limiting their applicability. To overcome these constraints, this study introduces a Moiré-based apparatus augmented with active convolved illumination (ACI). The system leverages the displacement-magnifying properties of Moiré patterns to achieve high precision in detecting subtle ground movements. Additionally, ACI effectively mitigates atmospheric fluctuations, reducing the distortion and alteration of measurement signals caused by these fluctuations. …

A Controlled-Source Physical Model For Long Period Seismic Events, Sananda Ray, Gregory P. Waite, Radwin Askari

Michigan Tech Publications

Long-period seismic events (LPs) are observed within active volcanoes, hydrothermal systems and hydraulic fracturing. The prevailing model for LP seismic events suggests that they result from pressure disturbances in fluid-filled cracks that generate slow, dispersive waves known as Krauklis waves. These waves oscillate within the crack, causing it to act as a seismic resonator whose far-field radiations are known as LP events. Since these events are generated from fluid-filled cracks, they have been used to analyse fluid transport and fracturing in geological settings. Additionally, they are deemed precursors to volcanic eruptions. However, other mechanisms have been proposed to explain LP …

Fracture Initiation Pressure As A Measure Of Cemented Paste Backfill Strength, James A. Frimpong, Basel Ahmad Shabab, Rohit Pandey, Snehamoy Chatterjee, Gabriel Walton, Alexander S. Brand

Michigan Tech Publications

This laboratory-scale study presents the development and validation of a hydraulic fracturing technique to directly measure the tensile strength of cemented paste backfill (CPB), providing an alternative to traditional strength testing methods. Fracture initiation pressure (FIP) was used as the primary measure of CPB strength. Experimental results were compared with traditional benchmark measures such as uniaxial compressive strength (UCS), Brazilian tensile strength (BTS), and critical Mode-I fracture toughness (KIc). Regression analysis of experimental results revealed a strong linear relationship between FIP and these benchmark strength measures, indicating that FIP can be used as a reliable predictor of CPB strength. However, …

Microphysics Regimes Due To Haze–Cloud Interactions: Cloud Oscillation And Cloud Collapse, Fan Yang, Hamed F. Sadi, Raymond Shaw, Fabian Hoffmann, Pei Hou, Aaron Wang, Mikhail Ovchinnikov

Michigan Tech Publications

It is known that aqueous haze particles can be activated into cloud droplets in a supersaturated environment. However, haze–cloud interactions have not been fully explored, partly because haze particles are not represented in most cloud-resolving models. Here, we conduct a series of large-eddy simulations (LESs) of a cloud in a convection chamber using a haze-capable Eulerian-based bin microphysics scheme to explore haze–cloud interactions over a wide range of aerosol injection rates. Results show that the cloud is in a slow microphysics regime at low aerosol injection rates, where the cloud responds slowly to an environmental change and droplet deactivation is …

Coastal Environments: Lidar Mapping Of Copper Tailings Impacts, Particle Retention Of Copper, Leaching, And Toxicity, W. Charles Kerfoot, Gary Swain, Robert Regis, Varsha K. Raman, Colin N. Brooks, Chris Cook, Et. Al.

Michigan Tech Publications

Tailings generated by mining account for the largest world-wide waste from industrial activities. As an element, copper is relatively uncommon, with low concentrations in sediments and waters, yet is very elevated around mining operations. On the Keweenaw Peninsula of Michigan, USA, jutting out into Lake Superior, 140 mines extracted native copper from the Portage Lake Volcanic Series, part of an intercontinental rift system. Between 1901 and 1932, two mills at Gay (Mohawk, Wolverine) sluiced 22.7 million metric tonnes (MMT) of copper-rich tailings (stamp sands) into Grand (Big) Traverse Bay. About 10 MMT formed a beach that has migrated 7 km …

Magmatic Volatiles Control The Sub-Plinian Basaltic Eruptions At Ambae Volcano, Vanuatu, Philipson Bani, Alessandro Aiuppa, Diego Coppola, Simon Carn, Dominique Cluzel, Estelle Rose-Koga, Et Al.

Michigan Tech Publications

The 2017–2018 eruption of Ambae volcano provided a rare opportunity to investigate gas emissions during a sub-Plinian basaltic eruption. Here we document the gas emissions during this eruption using satellite observation, alongside gas measurements and geochemical analyses. Our results indicate that the volcano released 3.3 teragrams of sulfur dioxide, 7.7 of carbon dioxide, 134 of water vapour, 0.2 of hydrogen sulfide, and 0,001 of dihydrogen, ranking Ambae among the world’s top volcanic gas emitters. Despite these substantial emissions, the relatively modest volume of 0.47 cubic kilometer of magma that fueled the eruption indicates a volatile-rich magma source. This enrichment is …

Estimating Unconfined Compressive Strength (Ucs) Of Rocks From Measurement While Drilling (Mwd) Data, Can Erdem

Dissertations, Master's Theses and Master's Reports

Measurement-while-drilling (MWD) technology enables the real-time monitoring of drilling parameters during the drilling process. MWD data can provide valuable insight into the mechanical behavior of intact rocks and rock masses, which is essential for geotechnical applications such as foundation design and underground construction. The aim of this study is to correlate real-time drilling parameters, recorded using a laboratory-developed MWD system, with the unconfined compressive strength (UCS) of rocks. A custom laboratory MWD system was designed to simultaneously record four key drilling parameters: thrust (axial force, crowd), torque, penetration rate, and rotational speed. The custom-built MWD system was used to continuously …

Iron Ore Tailings Reprocessing By Electrostatic Separation Plus Two Stages Froth Flotation, Vincent Bailey Arohunmolase

Dissertations, Master's Theses and Master's Reports

The reprocessing of tailings is crucial for recovering valuable iron and reducing the environmental impact associated with tailings disposal. This study investigates the practicality of reprocessing tailings to enhance iron oxide content, combining electrostatic separation with a two-stage froth flotation process using oleic acid (direct flotation) and amine (reverse flotation). The primary goal is to efficiently recover valuable iron from tailings, thereby reducing waste and promoting sustainable resource utilization. The process aims to upgrade the iron oxide content to around 93-99% Fe₂O₃, making the recovered material suitable for the production of direct-reduced iron.

Electrostatic separation was …

Characterization Of Non-Gaussianity In The Snow Distributions Of Various Landscapes, Noriaki Ohara, Andrew D. Parsekian, Benjamin M. Jones, Rodrigo C. Rangel, Kenneth M Hinkel, Rui A.P. Perdigão

Michigan Tech Publications

Seasonal snowpack is an important predictor of the water resources available in the following spring and early-summer melt season. Total basin snow water equivalent (SWE) estimation usually requires a form of statistical analysis that is implicitly built upon the Gaussian framework. However, it is important to characterize the non-Gaussian properties of snow distribution for accurate large-scale SWE estimation based on remotely sensed or sparse ground-based observations. This study quantified non-Gaussianity using sample negentropy; the Kullback-Leibler divergence from the Gaussian distribution for field-observed snow depth data from the North Slope, Alaska; and three representative SWE distributions in the western USA from …

Version 1 Noaa-20/Omps Nadir Mapper Total Column So2 Product: Continuation Of Nasa Long-Term Global Data Record, Can Li, Nickolay A. Krotkov, Joanna Joiner, Vitali Fioletov, Chris Mclinden, Debora Griffin, Peter J.T. Leonard, Simon Carn, Colin Seftor, Alexander Vasilkov

Michigan Tech Publications

For nearly 2 decades, the Ozone Monitoring Instrument (OMI) aboard the NASA Aura spacecraft (launched in 2004) and the Ozone Mapping and Profiler Suite (OMPS) aboard the NASA/NOAA Suomi National Polar-orbiting Partnership (SNPP) satellite (launched in 2011) have been providing global monitoring of SO2 column densities from both anthropogenic and volcanic activities. Here, we describe the version-1 NOAA-20 (N20)/OMPS SO2 product (10.5067/OMPS/OMPS_N20_NMSO2_PCA_L2_Step1.1, Li et al., 2023), aimed at extending the long-term climate data record. To achieve this goal, we apply a principal component analysis (PCA) retrieval technique, also used for the OMI and SNPP/OMPS SO2 products, to N20/OMPS. For volcanic …

Addressing The Effect Of Intra-Seasonal Variations In Developing Rainfall Thresholds For Landslides: An Antecedent Rainfall-Based Approach, Vishnu Chakrapani Lekha, Thomas Oommen, Snehamoy Chatterjee, Kochappi Sathyan Sajinkumar

Michigan Tech Publications

We developed a rainfall threshold model with the objective of limiting the effects of uncertainties typically associated with them, such as a lack of robust landslide database, the selection of the contributing rain gauge, seasonal variations in rainfall patterns, and the effect of extreme rainfall conditions. With the aid of gauge-corrected satellite precipitation data and a landslide database compiled from various sources, separate rainfall thresholds were developed for two waves of the monsoon season in the Western Ghats, India. The daily vs. antecedent rainfall distributions for different scenarios of antecedent rainfall were analyzed for landslide occurrence. The different scenarios considered …

Magnetization And Age Of Ca. 544 Ma Syenite, Eastern Canada: Evidence For Renewal Of The Geodynamo, Tinghong Zhou, Mauricio Ibañez-Mejia, Richard K. Bono, Rory D. Cottrell, Wouter Bleeker, Kenneth P. Kodama, Wentao Huang, Eric G. Blackman, Francis Nimmo, Aleksey Smirnov, John A. Tarduno

Michigan Tech Publications

The ca. 565 Ma Ediacaran geodynamo was highly unusual, producing an ultralow field 10 times weaker than present-day value of 8 x 1022 A m2. A ∼5 times rise in field strength is seen in time-averaged single crystal paleointensity data of ca. 532 Ma Early Cambrian anorthosites of Oklahoma (USA). The field increase could record the onset of inner core nucleation predicted by thermal evolution and numerical dynamo models. Here, we examine the renewal of the geodynamo through zircon U-Pb geochronology and single crystal paleointensity studies of plagioclase from the Chatham-Grenville syenite intrusion in the Grenville Province (Canada). U-Pb data …