Ryan McKenzie

Sedimentary Geology & Earth Systems Evolution Group

RESEARCH


Volcanism, mountain building, weathering, and erosion play first-order roles in dictating the chemical composition of the oceans and atmosphere. Thus, we strive to understand the integrative relationship between lithospheric processes, climate change, and biological evolution throughout Earth history.  


Our work primarily consists of field-based projects that assess regional tectonic– sedimentary contiental records in the context of global-scale changes in Earth's surface environment. As geological generalists, we take multidisciplinary, multiproxy approaches to decipher the stratigraphic archive. This includes detrital mineral geochemistry and geochronology, thermochronometry, chemostratigraphy, biostratigraphy, and/or whatever gets the job done!


CURRENT THEMES—The stuff that keeps us up at night...


$$$ FUNDING $$$



Hong Kong (in HK dollars and [US dollars])

**There are no overhead expenses in Hong Kong! **


2022-2025. Collaborator. RGC-Collaborative Research Fund (CRF): “Characterization of ancient lake basins on Mars using advanced topographic modelling and innovative spectroscopic techniques”. $5,809,600 HKD [~$745,261 USD]. Principal Coordinator J. Michalski.


2021-2023. Lead PI. URC-PDF/RAP Scheme. Provides matching funds for postdoctoral support. Approximate value ~$400,000 HKD [~$51,500 USD].


2020-2022. Lead PI. Teaching Innovation Award: “Digital scanning of petrographic thin sections for online teaching and learning” $100,000 HKD [$12,825 USD].


2020-2023. Co-PI. "Reconstructing the history of seawater sulfate and its role in the Phanerozoic Earth system" $665,512 HKD [$85,858 USD]. Co-PI Sean Crowe.


2019-2022. Co-PI. HKU Budget Resource Committee (BRC) award for $10.5 million HKD [~$1.4 million USD] for new MC-ICPMS and laser system.


2019-2022. Lead PI. RGC-GRF-Earth Sciences: "Zircon geochemical characterization of East Asian volcanic arc dynamics".   $558,272 HKD [$71,600 USD]


2019. HKU Excellence Fund.  $1,000,000 HKD [$128,253 USD]

2019-2021. Lead PI.  HKU Seed Grant: "Developing New LA-Split-Stream-ICPMS Techniques". $66,570 HKD [$8,484 USD]


2019-2020. Lead PI. Hung Hing Ying Physical Sciences Research Fund:  "Statistical Evaluation of Volcanic Carbon Fluxes on the end-Permian Mass Extinction".  $30,000 HKD [$3,823 USD].


2018-2021. Lead PI. RGC-GRF-Earth Sciences:  "Multi-proxy investigation of Cambrian mass extinction events".  $505,298 HKD [$64,382 USD].


2018–2019  Lead PI.  HKU Seed Grant: "Calibrating zircon trace element data as a proxy for crustal processes“. $95,190 HKD [$12,126 USD].


2018  PI.  URC Small Equipment Grant: "Acquisition of a Quadrupole ICPMS". $ 1,024,422 HKD [$130,508 USD]. Co-PI Christelle Not.


2017–2020  Lead PI. RGC (Early Career)-Earth Sciences: “Multi-proxy geochemical and geo-/thermochronologic investigation of continental crust evolution through Earth history”. $600,557 HKD [$76,873 USD].


2017–2018 Lead PI.  HKU Seed Grant: “Source-to-sink evaluation of bedrock weathering”. $150,000 HKD [$19,200 USD].


United States (in US dollars and [HK Dollars])


2015–2018 Lead PI. NSF-Tectonics: “Exhumation History of the Indian Lesser Himalaya: Discriminating Tectonic Models with Implications for the Neogene Isotopic Composition of Seawater”. Co-PIs D. Stockli & B. Horton. $361,773 USD [$2,824,994 HKD]. Collaborator A. Webb.


2014–2016 Co-PI. NSF-Tectonics: “Rapid Miocene thrust propagation and wholesale basin partitioning along the central and southern Andes, Argentina.” Co-PI: B. Horton. $298,481 USD [$2,330,702 HKD].


2014 Co-PI. Jackson School Seed Grant: “Convergent-margin deformation and arc magmatism as triggers of early Paleozoic global extinctions and biodiversification”. Co-PI B. Horton. $25,000 USD [$196,213 HKD].


2011–2014 Graduate student coauthor. NSF-Sedimentary Geology & Paleobiology. Collaborative Research: Testing Himalayan tectonic and erosional history via chronostratigraphic correlation between the Lesser Himalaya and Indian craton. PI N. Hughes. $180,189 [$1,414,217 HKD]. Collaborators P. Myrow, S. Xiao, and G. Jiang. Total awarded for project = $365,633 [$2,869,678 HKD].



Volcanism, Mountain Building, and Climate


Tectonic processes play important roles in governing atmospheric chemistry by providing CO2 through volcanic outgassing and removing CO2 via chemical weathering and organic matter burial.


Our research aims to understand:


—Regional-scale mountain building processes in various tectonic settings, e.g., the Andes, the Himalaya, and  Southeast Asia


—How changes in plate tectonic processes, global-scale volcanism, and mountain building influence climate on multi-million year time scales.


—The utility of proxies for tracking volcanism and weathering in Earth history.


For example, we used a ~750 million year record of detrital zircon age data as a proxy for regional continental arc volcanism to argue that changes in waxing and waning of arc magmatism, and young zircon production, has been primarily responsible for Earth's icehouse-greenhouse transitions (McKenzie et al., 2016, figured left). We are now expanding and improving upon these records to further explore the apparent volcanism-climate linkage, as well as test other models for global climatic shifts...




Crustal Evolution


Like the long-term carbon cycle, many biogeochemical processes are linked to tectonic processes. This means that the onset of lateral plate tectonics and evolution of the continental crust may have first-order implications for the evolution of Earth's atmosphere, oceans, and biosphere. Thus, it is important to know how the continents formed and when plate tectonics, as we know it, initiated.


We are broadly focused on:


—Constraining the compositional evolution of continental crust through Earth history


—Understanding the formation and long-term stability of continental interiors


The transition from mafic to felsic upper crust profoundly influenced the carbon and oxygen cycles (e.g., Lee et al., 2016).  By expanding global sedimentary geochemical datasets we explore this compositional change, particularly around the Archean-Proterozoic transition, and how the continents evolved through time. Further, we study the thermal history and stability of stable continental interiors to better understand long-term crustal recycling and erosion...



Animal Biodiversity & Mass Extinctions


Earth has experienced numerous diversification and mass-extinction events. The causes for these swings in diversity, in many cases, remains enigmatic. We are interested in how the biosphere interacts with shifts in Earth's surface environment, particularly during the early evolution of animals.  The 'Cambrian dead interval', a noted period of pronounced environmental stress characterized by numerous mass extinctions, intervenes two of the most dramatic diversification events in Earth history: The Cambrian 'explosion' and the Great Ordovician Biodiversification Event.


We are interested in:


—Drivers responsible for climatic shifts associated with these swings in biodiversity, such as the transition from Cryogenian icehouse, which included the 'snowball Earth' events, into the Cambrian greenhouse.


Environmental conditions during Cambrian trilobite mass extinctions events.




FIELD LOCALITIES—How we earn the flyer miles!


Lee et al., 2016

Paleoproterozoic Cave Temple Arenite, Dharwad craton, India

McKenzie et al., 2014

Hughes et al., 2011

India

Argentina

Southern Africa

North America

Southeast Asia

1.6 Ga Chorhat Sandstone, Lower Vindhyan

2.7 Ga (Glacial? ) Diamictite, Dharwad Craton

Chenab Valley, Himachal Pradesh, Himalaya

Aravalli-Delhi Belt, Rajasthan

Manatiales Basin, Frontal Cordillera

Malargue

Refugio Laguna Brava

Rio Agua Negra, Frontal Cordillera

China & South Korea

Mt. Bromo, Indonesia

Belt Supergroup Montana

Core Repository, Thunder Bay Canada

Glacier Nat. Park, Montana

Death Valley, California

Shandong Province, China

South Korea

2.6 Ga Precipitate Fans, Zimbabwe

2.6 Ga Banded Iron Formations, Zimbabwe

Shan Plateau, Myanmar

Irrawaddy River sampling, Myanmar

McKenzie et al., 2016

Maluku Islands, Indonesia

River Sampling

Maluku Islands, Indonesia