Michael A. Antonelli

Michael A. Antonelli
ETH Zurich | ETH Zürich · Department of Earth Sciences

Ph.D.

About

36
Publications
7,647
Reads
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430
Citations
Citations since 2017
23 Research Items
359 Citations
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2017201820192020202120222023020406080100
2017201820192020202120222023020406080100
2017201820192020202120222023020406080100
Introduction
Michael A. Antonelli earned his PhD at the University of California, Berkeley (Dec. 2018) and specializes in isotope geochemistry.
Additional affiliations
February 2019 - February 2020
Institut de Physique du Globe de Paris
Position
  • PostDoc Position
August 2013 - December 2018
University of California, Berkeley
Position
  • Research/Teaching Assistant
August 2011 - June 2013
University of Maryland, College Park
Position
  • Research Assistant
Education
August 2013 - December 2018
University of California, Berkeley
Field of study
  • Earth and Planetary Science
August 2011 - June 2013
September 2006 - April 2011
University of Alberta
Field of study
  • Honors Geology

Publications

Publications (36)
Article
Full-text available
Heat flow studies suggest that the lower crust has low concentrations of heat-producing elements. This could be due to either (i) greater fractions of basaltic rock at depth or (ii) metamorphic depletion of radioactive elements from rocks with more evolved (andesitic to granodioritic) compositions. However, seismic data suggest that lower crust is...
Article
Full-text available
Significance Timescale estimates for crystal growth in volcanic systems, which are generally much shorter than absolute crystal ages, are thought to be shortest in mafic (vs. silicic) systems. However, this result may be influenced by assumptions for growth rates and/or methodological biases. We show that Ca isotopes can be used to constrain crysta...
Article
Full-text available
Continents are unique to Earth and played a role in coevolution of the atmosphere, hydrosphere, and biosphere. Debate exists, however, regarding continent formation and the onset of subduction-driven plate tectonics. We present Ca isotope and trace-element data from modern and ancient (4.0 to 2.8 Ga) granitoids and phase equilibrium models indicati...
Article
Radiogenic 40Ca is preferentially concentrated in the continental crust through the decay of radioactive 40K and may have the potential to be used as a tracer for Ca fluxes to the ocean through time. Numerous published flux estimates suggest that rivers are the dominant source of Ca to the oceans. This conflicts, however, with conclusions drawn fro...
Article
Full-text available
Since the onset of plate tectonics, continents have evolved through a balance between crustal growth, reworking, and recycling at convergent plate margins. The term “reworking” involves the re-insertion of crustal material into pre-existing crustal volumes, while crustal growth and recycling respectively represent gains from and losses to the mantl...
Article
Igneous and metamorphic rocks exhibit greater isotopic heterogeneity than expected from equilibrium. Large nonequilibrium isotope effects can arise from diffusion and chemical reactions, such as crystal growth and dissolution. The effects are time-dependent and can, therefore, be used to probe timescales of igneous and metamorphic processes that ar...
Article
Biometals play a critical role in both the healthy and diseased brain’s functioning. They accumulate in the normal aging brain, and are inherent to neurodegenerative disorders and their associated pathologies. A prominent example of this is the brain accumulation of metals such as Ca, Fe and Cu (and more ambiguously, Zn) associated with Alzheimer’s...
Article
This chapter explores the growing body of stable and radiogenic Ca isotope measurements in high temperature terrestrial materials and covers the emerging applications for Ca isotope variability in igneous and metamorphic rocks and minerals. Calcium isotope fractionation at high temperature has been found to lead to larger effects than initially the...
Poster
Full-text available
Ancient carbonates indicate 87/86Sr in seawater has varied in the geologic past, and this is a proxy that helps constrain changes in weathering/alteration rates, and fluxes from different source material, that drive secular variability in seawater chemistry. Seawater circulating through ocean crust results in fluid-mineral (cation) exchange over a...
Conference Paper
Full-text available
The loss of heat-producing elements during high-temperature metamorphism of the lower crust plays an important role in stabilizing continents over geologic time. A large portion of the lower crust consists of granulite-facies metamorphic rocks, which are thought to represent residues from high-temperature partial melting of igneous and sedimentary...
Conference Paper
Full-text available
The sources and sinks of seawater Ca are of interest for understanding paleoseawater chemistry and the global carbon cycle. Radioactive 40K is concentrated in continental crust, and continental crustal rocks show enrichments in radiogenic 40Ca [1]. The composition of the oceans reflects competition between continental and seafloor weathering inputs...
Article
Full-text available
Significance Circulation of seawater through midocean ridges results in large-scale chemical transfer between the solid Earth and oceans. Driven by magmatic heat, seawater undergoes hydrothermal reactions that affect the concentrations of Mg, Ca, SO 4 , and Sr in the oceans over millions of years. Changes in the composition of seawater during the p...
Conference Paper
Full-text available
Modern mid-ocean ridge (MOR) hydrothermal systems have been extensively studied for decades. The evolution of seawater-derived fluids as they flow through heated MOR rocks is well understood when the fluids start out with modern seawater chemical composition [1]. However, for much of the past 500 million years, seawater has had higher Ca/SO4 and lo...
Conference Paper
Full-text available
Reports of δ 44 Ca in igneous and metamorphic mineral assemblages indicate that Ca isotope fractionation can be large, even at high temperatures [1-3]. However, the use of Ca isotopes for thermometry or as a crystal growth rate proxy [4] requires understanding of kinetic and equilibrium factors that control fractionation behaviour. We present densi...
Conference Paper
Low temperature (<100°C) water-rock reactions in oceanic crust have a potentially large influence on seawater chemical compositions and atmospheric pCO2. Quantification of the conditions (e.g., temperature) of oceanic crust alteration is needed to evaluate its importance for global silicate weathering fluxes. The isotopic and chemical compositions...
Conference Paper
Full-text available
Mid-ocean ridge hydrothermal circulation is a key component in the long-term regulation of global climate and chemical fluxes to the oceans [1]. Models reconstructing past weathering rates and CO2 concentrations often assume that seawater-basalt hydrothermal exchange worked the same in the past as it does today, yet geochemical proxies [2] suggest...
Conference Paper
Full-text available
African wild dogs (Lycaon pictus) are social coursing predators that hunt in packs and rely on mammalian prey and water intake from bodies of water. They are also listed on the IUCN list of endangered species. The role of prey-derived water in their survival, especially during drought, though seemingly important, is largely unknown. Our goal in thi...
Article
Full-text available
Significance This investigation focuses on the sulfur isotopic compositions of magmatically differentiated meteorites, the oldest igneous rocks in our solar system. We present evidence of anomalous ³³ S depletions in a group of differentiated iron meteorites, along with ³³ S enrichments in several other groups. The complementary positive and negati...
Conference Paper
Ocean plates transport surface materials, including oceanic crust and sediment, into the mantle at subduction zones. However, the fate of the subducted package--oceanic crust and sediment--in the mantle is poorly understood. A long-standing hypothesis maintains that subducted materials reside in the mantle for an extended, but unknown, period of ti...
Article
Full-text available
Basaltic lavas erupted at some oceanic intraplate hotspot volcanoes are thought to sample ancient subducted crustal materials. However, the residence time of these subducted materials in the mantle is uncertain and model-dependent, and compelling evidence for their return to the surface in regions of mantle upwelling beneath hotspots is lacking. He...
Conference Paper
Full-text available
Oceanic crust and sediments are introduced to the mantle at subduction zones, but the fate of this subducted material within the mantle, as well as the antiquity of this process, is unknown. The mantle is compositionally and isotopically heterogeneous, and it is thought that much of this heterogeneity derives from incorporation of diverse subducted...
Conference Paper
Full-text available
This abstract presents the multiple sulfur-isotopic compositions of 61 different iron meteorites from 8 different chemical groups, and their implications.
Conference Paper
We report the multiple sulfur isotopic compositions of fourteen iron meteorites from three different groups. We find that there are systematic differences in the sulfur isotopic composition of magmatic versus non magmatic iron meteorites.

Questions

Questions (3)
Question
I used to be able to check the accepted values for geochemical reference materials (e.g. AGV-2, DNC-1, W2a etc.) on the USGS website, but now the website no longer displays any of the necessary information.
Does anyone know what the problem is and if it will be resolved? This has been going on since the beginning of the year, approximately.
If someone has the accepted values for AGV-2 and DNC-1 this would be especially appreciated!
Thanks for the help,
Michael
Question
I'm wondering how galactic chemical evolution can still be correct if the age of the universe is infinite, as has been recently proposed by Ali and Das (2015). http://arxiv.org/abs/1404.3093v3
If there was no big bang, how can we explain that the universe has such low metallicity? and how can we explain the age of the universe as determined from U decay??
Question
This could potentially be relevant to sorting out issues of whether or not new human species are actually species? Some, I hear, have contested the status of the humanoid found in Flores... Could there be any stable isotope tools to probe this question?

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Projects

Projects (4)
Archived project
A collection of other projects in which I am involved
Archived project
Project
To understand the various equilibrium and kinetic effects that fractionate Ca isotopes at high-Temperature.