Nick Dygert

Nick Dygert
University of Tennessee | UTK · Earth and Planetary Sciences

PhD, Brown University

About

85
Publications
10,010
Reads
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468
Citations
Introduction
I use experiments, numerical models and studies of natural samples to understand the formation and evolution of planetary interiors and crusts. My focus is the Earth and Moon.
Additional affiliations
January 2015 - October 2016
University of Texas at Austin
Position
  • Distinguished Postdoctoral Fellow
December 2014 - present
University of Texas at Austin
Position
  • PostDoc Position
September 2014 - December 2014
Brown University
Position
  • Mineralogy Lab
Education
September 2009 - December 2014
Brown University
Field of study
  • Geology
September 2003 - May 2007
University of Rochester
Field of study
  • Geochemistry

Publications

Publications (85)
Article
The ratio of 3He and 22Ne varies throughout the mantle. This observation is surprising because 3He and 22Ne are not produced in the mantle, are highly incompatible during mantle melting, and are not recycled back into the mantle by subduction of oceanic sediment or basaltic crust. Our new compilation yields average 3He/22Ne ratios of 7.5 ± 1.2 and...
Article
Full-text available
Removal of mantle lithosphere by Rayleigh‐Taylor (R‐T) instabilities is invoked to explain the formation of high plateaus and mountain ranges. Here we report geochemical and microstructural observations from mantle xenoliths from Lunar Crater volcanic field, central Nevada, which we interpret to directly sample a R‐T instability beneath the Basin a...
Article
Full-text available
Ordinary chondrites (OCs) are variably thermally metamorphosed meteorites thought to originate from at least three different parent bodies (H, L, and LL) in the Main Belt of asteroids. The thermal evolutions of OC parent bodies are frequently explained by the onion shell model; however, a competing hypothesis is the fragmentation-reassembly model....
Article
Full-text available
Mercury has a compositionally diverse surface that was produced by different periods of igneous activity suggesting heterogeneous mantle sources. Understanding the structure of Mercury's mantle formed during the planet's magma ocean stage could help in developing a petrologic model for Mercury, and thus, understanding its dynamic history in the con...
Article
Full-text available
We investigate the cooling histories of peridotites and gabbros from localities that expose oceanic lithosphere formed beneath two fast seafloor spreading centers: Hess Deep as recovered from IODP Expedition 345 and ODP Leg 147, and the Oman Ophiolite as sampled by the Oman Drilling Project, ICDP Expedition 5057 (OmanDP). At these locations, relict...
Article
Enstatite‐rich meteorites, including the aubrites, formed under conditions of very low oxygen fugacity (ƒO2: iron‐wüstite buffer −2 to −6) and thus offer the ability to study reduced magmatism present on multiple bodies in our solar system. Elemental partitioning among metals, sulfides, and silicates is poorly constrained at low ƒO2; however, studi...
Article
Full-text available
The transition from the gabbroic oceanic crust to the residual mantle harzburgites of the Oman ophiolite has been drilled at Holes CM1A and CM2B (Wadi Tayin massif) during Phase 2 of the International Continental Scientific Drilling Program (ICDP) Oman Drilling Project (OmanDP) (Nov. 2017-Jan. 2018). In order to unravel the formation processes of u...
Conference Paper
Full-text available
Introduction: Silicate inclusions in primitive achondrite winonaites and IAB iron meteorites record a complex history of heating, brecciation, fragmentation, and metamorphism. Stony winonaites and IAB irons are thought to come from the same parent asteroid because of their similar silicate mineralogy, mineral chemistry, and oxygen isotopic composit...
Conference Paper
Full-text available
Introduction: Application of REE-in-two-pyroxene thermometry, two-pyroxene solvus thermometry and Ca-in-olivine thermometry to meteorites from H, L, LL chondrite and acapulcoite-lodranite parent bodies reveals fast (~1°C /y) cooling from peak or near-peak temperatures (temperature denoted as T below) [1,2]. Our previous work [1,3] shows that fast c...
Conference Paper
Full-text available
We investigate the rheological and microstructural properties of aggregates of ilmenite and olivine deformed in shear in a Griggs apparatus. The experiments constrain the effective viscosity of an ilmenite-bearing lunar mantle as a function of ilmenite content and shear strain. Ilmenite exhibits viscous anisotropy, deforming by basal slip in shear,...
Article
Full-text available
Recent observations of rapid cooling rates at high temperatures in several ordinary chondrite and primitive achondrite meteorite groups suggest the fragmentation of their parent bodies near peak temperatures. We use analytic models for conductive cooling of collisional fragments to show that the actively cooling part of a fragment experiences simil...
Conference Paper
Over dispersed zircon LA-ICP-MS U-Pb dates in single samples of igneous rock present challenges for age interpretation as the distribution of dates cannot be assumed to represent a single zircon population and formation event. Additionally, assessing the role of lead loss in young zircons is difficult due to the near-linear slope of the 1:1 concord...
Article
Full-text available
The lunar surface is ancient and well-preserved, recording Solar System history and planetary evolution processes. Ancient basin-scale impacts excavated lunar mantle rocks, which are expected to remain present on the surface. Sampling these rocks would provide insight into fundamental planetary processes, including differentiation and magmatic evol...
Article
Interactions of hydrous fluids and melts with dry mantle rocks are known to result in metasomatic alteration of the lithospheric mantle. This work investigates such interactions that occurred beneath the Hangay Dome, Mongolia, in 22 mantle xenoliths, which were recovered from Cenozoic basalts at the Tsagan, Zala, Horgo, and Shavaryn-Tsaram localiti...
Conference Paper
Full-text available
Introduction: New major and trace element data illuminate the magmatic and thermal evolution of the acapul-coite-lodranite parent body (ALPB). We observe major and trace element disequilibrium in the acapulcoite and transitional groups that provide evidence for melt infiltration and melt-rock reaction processes. In lodranites, which represent sourc...
Article
Full-text available
The viscosity of ilmenite is an important parameter that is thought to have influenced the thermal and chemical evolution of the lunar cumulate mantle. We conduct deformation experiments on two different ilmenite compositions, ilmenite100 (FeTiO3) and ilmenite40 ((Fe0.4Mg0.6)TiO3), to investigate the influence of pressure and Mg‐content on the rheo...
Article
Full-text available
The evolution and compositional structure of the lunar mantle has been extensively modeled but insufficiently constrained by observations. Here, we identify and characterize mantle materials exposed by the Moon's largest impact basin to better understand the composition, stratigraphy, and evolution of the upper mantle. The vast South Pole‐Aitken Ba...
Conference Paper
Full-text available
The emplacement and formation of the lower crust at fast-spreading mid-ocean ridges is modeled by two proposed end-member scenarios: the gabbro glacier model, which assumes a mass of crystalline mush in a large crustal magma chamber, or the sheeted sill model, in which crust accretes by solidification of a series of sills continuously emplaced with...
Conference Paper
Full-text available
Ordinary chondrites (OCs) are variably thermally metamorphosed meteorites thought to originate from three different asteroid parent bodies (H, L, and LL). Their thermal evolutions are frequently explained by the onion shell model; however, a competing hypothesis is the fragmentation-reassembly model. The onion shell model proposes an internally hea...
Article
Full-text available
We report partition coefficients for Sr, Sc, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Y, and Th for plagioclase, pigeonite, and olivine experimentally grown from a lunar basaltic liquid at 1 bar and two different oxygen fugacities (fO2; fayalite-magnetite-quartz (FMQ) and the iron-wüstite (IW) oxygen buffers) at temperatures (Ts) of...
Conference Paper
Full-text available
Introduction: Primitive achondrites include several groups of stony meteorites that are residues of low-degrees of partial melting, hence they have experienced higher temperatures (temps) than chondritic meteorites. Cosmochemical, oxygen isotope, and cosmic ray exposure age data for several primitive achondrite groups (and associated silicate-beari...
Poster
Geochemical investigation of lithospheric xenoliths to determine thermal or magmatic history of heating in the West Antarctic Rift System.
Conference Paper
Full-text available
During the early evolution of the Moon, the lunar mantle is proposed to have undergone an event known as cumulate mantle overturn, where an initially shallow layer of ilmenite sank into an underlying olivine cumulate layer due to a large density and viscosity contrast [1]. It is unclear how the addition of low viscosity ilmenite to the lunar mantle...
Article
Full-text available
Seismic observations show a reduced compressional‐wave gradient at the base of the outer core relative to the preliminary reference Earth model and seismic wave asymmetry between the east‐west hemispheres at the top of the inner core. Here we propose a model for the inner core boundary (ICB), where a slurry layer forms through fractional crystalliz...
Conference Paper
Full-text available
Ordinary chondrites (OCs) are thought to originate from three different parent bodies (H, L, LL). Their thermal evolutions are typically explained via two competing models; the classic onion shell model or the fragmentation-reassembly model. The onion shell model predicts that OC petrologic types (i.e., 3 to 6) develop with increasing temperature a...
Conference Paper
Full-text available
Using the global experimental plagioclase-melt partitioning dataset, new lunar-relevant partitioning experiments and predictive plagioclase-melt partitioning models developed by [1], [2] parameterized an Eu-in-plagioclase-melt oxybarometer for igneous rocks. The oxybarometer successfully reproduces the calibration dataset spanning 15 orders of magn...
Conference Paper
Full-text available
The West Antarctic Rift System produced extensive volcanism along the Transantarctic mountain range that delivered crustal and mantle xenoliths to the surface. Previous studies of Antarctic xenoliths largely focused on evaluating major and trace element variations to determine the compositions of mantle reservoirs beneath the rift system, which cou...
Article
Full-text available
Lunar cumulate mantle overturn has been proposed to explain the abundances of TiO2 and heat‐producing elements (U, Th, and K) in the source region of lunar basalts. Ilmenite‐bearing cumulates (IBCs) that were formed near the end of lunar magma ocean solidification are the driving force for overturn. IBCs are enriched with dense TiO2 and FeO content...
Preprint
Full-text available
Seismic observations show a reduced compressional-wave gradient at the base of the outer core relative to the preliminary reference Earth model and seismic wave asymmetry between the east-west hemispheres at the top of the inner core. Here, we propose a model for the inner core boundary (ICB), where a slurry layer forms through fractional crystalli...
Conference Paper
Full-text available
Cumulate mantle overturn is thought to be a consequence of crystallization of the lunar magma ocean (LMO). In the model, dense ilmenite-bearing cumulates (IBC) that solidified from the last dregs of the of the crystallizing LMO flow into underlying low density early (mafic) magma ocean cumulates as viscous solids [1,2]. The overturn model has been...
Conference Paper
Full-text available
We present new measurements of a Mercurian magma ocean analogue and use them to evaluate the efficiency of crystal fractionation from its magma ocean. Our analysis provides insights into Mercury’s dynamic history and the present-day composition of the crust.
Conference Paper
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Introduction: Thermal evolution models of asteroids are ground-truthed by estimates of temperatures (hereafter temps) and cooling rates from meteorite cosmochemical data [e.g., 1]. However, traditional geothermometers used to constrain the thermal evolution of meteorite parent bodies typically record blocking temps during cooling rather than peak o...
Poster
The transition from the crust to the mantle of Oman ophiolite was drilled at Holes CM1A and CM2B (Wadi Tayin Massif) during Phase 2 of the Oman Drilling Project (Nov. 2017-Jan. 2018). The 400m-long Hole CM1A core crosses from the lower crust, through the crust-mantle transition zone, into residual upper mantle peridotites. The 300m-long Hole CM2B c...
Conference Paper
Full-text available
We present results of a thermometric investigation of samples from the upper mantle and lower crust at Hess Deep, a rift along the fast-spreading East Pacific Rise (EPR), which place constraints on crustal accretion beneath seafloor spreading centers. We measured major and trace elements in three crustal gabbros (plagioclase (plag) An# 80-85, clino...
Article
Full-text available
The Spongtang ophiolite (Ladakh, NW India) constrains the nature of oceanic lithosphere before Indo-Asia collision and key stages in the development of the Himalayas. We report whole-rock ⁴⁰ Ar/ ³⁹ Ar and in situ zircon ²³⁸ U– ²⁰⁶ Pb ages from its crustal and upper and lower mantle sequences. Major and trace elements from harzburgite minerals sugge...
Conference Paper
Full-text available
Introduction: Models of the thermal evolution of meteorite parent asteroids are predicated on geothermometric estimates of temperatures and cooling rates achieved on those bodies [e.g., 1]. However, geothermometers used to constrain the thermal evolution of asteroids typically record blocking temperatures during cooling rather than peak or magmatic...
Article
Much of the lunar crust is monomineralic, comprising >98% plagioclase. The prevailing model argues the crust accumulated as plagioclase floated to the surface of a solidifying lunar magma ocean (LMO). Whether >98% pure anorthosites can form in a flotation scenario is debated. An important determinant of the efficiency of plagioclase fractionation i...
Article
Lunar cumulate mantle overturn and the subsequent upwelling of overturned mantle cumulates provide a potential framework for understanding the first-order thermochemical evolution of the Moon. Upwelling of ilmenite-bearing cumulates (IBCs) after the overturn has a dominant influence on the dynamics and long-term thermal evolution of the lunar mantl...
Conference Paper
Full-text available
The current paradigm argues the Moon formed after a giant impact that produced a deep lunar magma ocean (LMO). After a period of turbulent convection, the LMO experienced fractional crystallization, causing the initially peridotitic liquid to evolve to a plagioclase-saturated ferrobasalt. The lunar crust, much of which comprises 93-98% pure anortho...
Conference Paper
Full-text available
Ne are not produced in the mantle or fractionated by partial melting, and neither isotope is recycled back into the mantle by subduction of oceanic basalt or sediment. Thus, it is a surprise that large 3He/22Ne variations exist within the mantle and that the mantle has a net elevated 3He/22Ne ratio compared to volatile-rich planetary precursor mate...
Article
Full-text available
The consequences of hydrous basaltic melts and peridotite interaction were examined experimentally in Au–Pd, Pt, and graphite capsules using the reaction couple method. Reactions between a hydrous basaltic andesite (4 wt% H2O) and dunite or lherzolite in an Au–Pd capsule at 1 GPa and 1200 °C produce a melt-bearing orthopyroxenite–dunite sequence. R...
Article
Full-text available
Tabular dunite bodies are thought to represent remnants of high-porosity pathways for efficient melt extraction from the mantle. They form by melt–rock reaction, an important physical process that affects the compositions of dunite-hosted basaltic melts and the mantle they originate from. To better understand melt–rock interactions in dunite channe...
Article
We present results from new deformation experiments and a dislocation creep flow law for synthetic ilmenite. The flow law predicts an effective viscosity more than three orders of magnitude lower than dry olivine at mantle stresses and temperatures. Using the flow law, we predict that lunar ilmenite-bearing cumulates (IBC) will be weakened by the p...