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Paul Byrne

Associate Professor of Planetary Science

Jordan Hall 3135


Paul is an Assistant Professor in the Department of Marine, Earth, and Atmospheric Sciences and a Faculty Fellow with the Center for Geospatial Analytics. As a planetary geologist, Paul is interested in how and why planets look the way they do. With remotely sensed data, laboratory and numerical modeling, and fieldwork in analog sites around the world, he seeks to understand how volcanic, tectonic, and impact processes have shaped planetary surfaces. At NC State, he has established the Planetary Research Group to explore what our world can tell us of other planetary bodies—and vice versa.


Date: 09/01/19 - 8/31/22
Amount: $87,946.00
Funding Agencies: National Aeronautics & Space Administration (NASA)

Thrust faults observed across Mars formed as a result of compressive stresses and are a record of Mars’ tectonic evolution. I propose to use image and topographic data to investigate the geometries and timing of major thrust faults on Mars using structural analyses along with superposition and cross-cutting relationships. I am requesting support for a two-objective, two-year project. The first Objective, in Year 1, is to use image and topographic data to investigate the geometry of 33 thrust fault-related landforms on Mars, for which I will determine key structural properties that will enable a detailed assessment of each structure and for the set as a whole. The second Objective, in Year 2, will involve the characterization of superposition relations between the uplifts, associated incised valleys, and impact craters. The application of crater statistics in the study areas will allow for first-order constrains of the timing of widespread thrust faulting resulting from global contraction. Together, these results will provide new insight into the mechanics and timing of large-scale crustal shortening on Mars.

Date: 08/01/18 - 7/31/22
Amount: $181,268.00
Funding Agencies: National Aeronautics & Space Administration (NASA)

All of Saturn’s major icy moons exhibit substantial tectonic deformation. Various mechanisms have been invoked to explain this deformation, including non-synchronous rotation, tidal recession, despinning, polar wandering, and global expansion due to interior phase change. Yet the structural outcomes of these processes, and the extent to which they may have shaped the surfaces of these tectonic moons, either in isolation or in concert, remains to be fully understood. Moreover, at least three Saturnian icy satellites are tectonically deformed in broadly the same way, despite likely differences in internal structure, mechanical properties, and geological evolution. The icy moons of Dione, Rhea, and Tethys each feature extensive, relatively pristine rift systems (chasmata) at or bordering their trailing hemispheres. This similarity in deformation suggests that one or more causative mechanisms may apply equally to all three bodies. In this three-year project, we will use image and topographic global base maps developed from Cassini Imaging Science Subsystem (ISS) data to characterize the chasmata on these three moons. We will also appraise the nature and style of a similar tectonic system on Titania, Uranus’ largest moon, as a basis for comparison with our Saturnian surveys. We will then compare our structural maps with predicted stress and strain patterns generated by the SatStress and COMSOL Multiphysics programs for a number of mechanisms that may account for chasma formation.

Date: 07/01/20 - 6/30/22
Amount: $74,019.00
Funding Agencies: National Aeronautics & Space Administration (NASA)

This proposal is responsive to the Early Career Fellowship Start-Up Program for Named Fellows call in ROSES 2019. Here, I detail a request for ECF funds in support of the development of an analog modeling laboratory here at NC State, to position my research group at the forefront of physical modeling of planetary surface processes in the United States. I request ECF support over two project years for the renovation of laboratory space, for the purchasing of lab equipment and materials, and for publications, travel, and a portion of my summer salary.

Date: 05/16/17 - 5/15/22
Amount: $383,681.00
Funding Agencies: National Aeronautics & Space Administration (NASA)

The first reconnaissance of Mercury was carried out by the Mariner 10 spacecraft in the 1970s. Three flybys of the innermost planet yielded images of just under half of the globe, at a variety of viewing geometries and resolutions. These images were used as the basis for a series of Mercury quadrangle maps; however, the map authors did not follow a uniform set of mapping conventions or units, making it difficult to compare the geology of different parts of the imaged hemisphere or to interpret boundaries between the maps. The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft orbited Mercury from 2011 to 2015 and imaged the planet in its entirety. A global monochrome base map is now available in the Planetary Data System (PDS) at largely uniform viewing geometry and a resolution of ~250 m/pixel. This vastly improved data product represents the basis of the first geological map of Mercury, which has been prepared by members of the MESSENGER science team. The map has been drafted at the 1:15M scale within a geographical information system (GIS). The monochrome PDS-archived base map (and similar base map products with alternate viewing geometries) is supplemented with ancillary topography and color data where necessary to aid in the identification of specific units. Datasets from other published and ongoing local and regional mapping efforts have been incorporated wherever possible, including a global map of crater and basin rims, ghost craters, smooth plains, and tectonic structures. The locations of features not resolvable at this map scale, such as pyroclastic vents and hollows, are represented by point features to assist future analyses. Impact features >90 km in diameter have been classified with a revised version of the previously established five-age classification scheme, and their ejecta deposits have been mapped; below this diameter, these deposits are generally too small to be resolved at the map scale. The production of this first global geological map of Mercury has necessitated the development of standardized unit descriptions. These descriptions facilitate the comparison of units distributed discontinuously across the planet surface and thereby enable the formulation of the first global stratigraphic column for Mercury. Though the current version of the map will be submitted to a peer-reviewed planetary journal for publication around the time the PDART Step-2 proposals are due, the standards for maps published through the USGS afford more detailed community feedback and result in a product that will provide a robust basis for future mappers and missions both nationally and internationally. In this three-year project, then, we propose to revise this geological map according to the rigorous U.S. Geological Survey mapping guidelines, with the ultimate goal to publish it as a USGS Scientific Investigations Map (SIM) series product. In project Year 1, we will import the existing individual map elements (e.g., unit boundaries, crater outlines, tectonic structures, etc.) into the USGS-provided project GIS. We will also conduct additional mapping not incorporated into the previous version of the map. We will: 1) investigate whether there is cause to subdivide the major surface unit (“Intercrater Plains”) on Mercury into additional subunits; 2) subdivide additional basin units; and 3) revise boundaries of another major unit, “Smooth Plains,” on the basis of crater density and the new PDS-available global color dataset. In Year 2, we will continue to prepare the geological map to USGS SIM mapping standards, which will include the finalization of the correlation and description of map units, and the preparation of final electronic datasets and map components. In Year 3, we will respond to the USGS reviews of our map, as well as providing NASA-required technical reviews of other USGS maps.

Date: 06/03/20 - 12/30/21
Amount: $147,512.00
Funding Agencies: National Aeronautics & Space Administration (NASA)

We propose to undertake an updated fault analysis of the 20% of Venus’ surface described by a recent topographic model derived from stereo-matching imaging techniques. This topographic model, the spatial resolution of which is an order of magnitude better than the Magellan GTDR, has already been used in crater morphology studies, yet the data remain under-utilized for structural studies. Our study will focus specifically on those features currently described as “ridge belts” and “dorsae” in order to assess the behavior of a specific, globally distributed tectonic feature. This approach will allow us to characterize surficial strains and thus infer timing and directionality of driving stresses, rheological behavior of the host rock, and likely crustal stratigraphy, all from as geographically broad a perspective as these recent data currently permit. Conventional interpretations of Venus’ global network of ridge belts—extensive, low-amplitude curvilinear rises with widths of tens of kilometers and profile elevations on the order of hundreds of meters—are ambiguous at best. Based upon Magellan, Venera, and terrestrial backscatter radar and radar altimetry (the latter mainly from Magellan), these interpretations are restricted by the kilometer-scale horizontal resolution of Venus’ global topography model. As a result, these belts have historically been interpreted based upon (non-topographic) backscatter images and elevation profiles comprising a few data points. A preliminary analysis of these features using the higher resolution topography products shows that there is a substantial amount of morphological information not captured in the Magellan GTDR. Specifically, ridge profiles are characterized by asymmetric but high-angle slopes and have broad distal rises and smaller proximal depressions. This morphology is strongly indicative of low-angle thrust faults that are commonly observed on the Moon, Earth, Mars, and Mercury. The improved view of the planet Venus provided by these recently available stereo topographic data permits well-established approaches of fault analysis, including geometric, analytic, and numeric modeling, to be applied to these structures for the first time.

Date: 11/04/19 - 8/01/21
Amount: $16,030.00
Funding Agencies: National Aeronautics & Space Administration (NASA)

The NASA MESSENGER mission revolutionized our understanding of the planet Mercury, and the dual-spacecraft ESA–JAXA BepiColombo mission promises further breakthroughs in Mercury science. Yet there is only so much that can be accomplished from orbit. In situ measurements from Mercury’s surface are required to address the fundamental science questions raised by MESSENGER’s pioneering exploration of Mercury. It stands to reason that we should begin to consider the benefits of a landed mission at Mercury as the logical next step in Mercury exploration. Now is the time to prepare for a Mercury lander, to ensure the continued exploration of the innermost planet after BepiColombo. A landed mission to Mercury would provide revolutionary data about the innermost planet, addressing fundamental open science questions about planetary and solar system formation, evolution, and processes. This proposal is thus relevant to the Planetary Mission Concept Program and its goal to develop input to the 2023 Decadal Survey for missions that address NASA's planetary science objectives to ascertain the origin and evolution of our Solar System.

Date: 09/01/17 - 2/28/21
Amount: $133,387.00
Funding Agencies: National Aeronautics & Space Administration (NASA)

Pit craters are widespread on planetary surfaces, but despite their prevalence it is unclear if they are tectonic or volcanic landforms, or even both. With this proposal, I request funding from NASA’s Earth and Space Science Research Fellowship to support my Ph.D. research into the processes that drive pit crater formation on solid-surface bodies. I will examine a case study region on Mars, Noctis Labyrinthus, which hosts a great number of intersecting faults and pit craters. With a combination of photogeological mapping, field work, and physical laboratory modelling, I will test two primary formation mechanisms for pit crater formation, dike intrusion and dilational faulting. The results of this project will provide new insight not only into the enigmatic Noctis Labyrinthus region on Mars, but on the process(es) responsible for this common type of geological landform we observe across the Solar System.

Date: 09/01/17 - 2/28/21
Amount: $213,998.00
Funding Agencies: National Aeronautics & Space Administration (NASA)

The Moon’s Mare Crisium features an annulus of elevated topography whose inner edge is bounded by wrinkle ridges. The thrust faults underlying these ridges penetrate ~20 km into the lunar lithosphere. GRAIL free-air gravity and derived crustal thickness data show that the mascon below Mare Crisium is structurally bound by these faults. Finite-element models indicate that the combination of downward movement of Crisium’s superisostatic mantle plug and the upward motion of the surrounding sub-isostatic collar of thickened crust is responsible for this mechanical arrangement. Crisium is not the only lunar mare with this distinctive topographic and tectonic signature. In this two-year project, we will use LRO and GRAIL data to investigate whether deep-seated, mascon-bounding thrust faults underlie six other mare-filled lunar basins: maria Humorum, Imbrium, Moscoviense, Nectaris, Orientale, and Serenitatis. This project consists of four Tasks. In the first, we will characterize the spatial distribution and relationship with topography of tectonic shortening landforms within these six lunar maria through GIS-based mapping with PDS-hosted LRO photogeological and topographic data. In Task 2, we will then determine displacement distributions along those thrust faults that bound portions of elevated terrain by taking a series of topographic measurements along each of their overlying wrinkle ridges. We will estimate in Task 3 the depths to which a subset of these thrust faults penetrate within the six lunar mascon basins. This Task will employ COULOMB elastic-dislocation modeling of 5–9 case-study faults in each basin (for a total of 43), to elucidate subsurface fault architecture by matching model solutions for surface displacement with LOLA-derived topographic profiles. Combined then with the displacement profiles of all elevated topography-bounding faults from Task 2, we will ascertain in Task 4 how thrust faults spatially relate to the mascon within each basin, through comparison of fault architecture with the geometry of each mascon using GRAIL-derived crust–mantle boundary maps. Establishing whether the fault architecture in Crisium applies to other lunar mascons is important for understanding mascon formation and development on terrestrial worlds in general. This project will increase our understanding of the formation and development of lunar mascons, an enigmatic crustal structure that has also been identified on Mars and on Mercury. By combining photogeological, topographic, and gravity data from LRO and GRAIL, this study will enhance the scientific return of those missions—and is therefore directly relevant to LDAP.

Date: 08/01/16 - 7/31/19
Amount: $67,299.00
Funding Agencies: National Aeronautics & Space Administration (NASA)

The lithospheres of Mercury, the Moon, Mars, and Venus show evidence of tectonic compression, manifest as two primary types of landform: lobate scarps and wrinkle ridges. The geological processes and properties that govern how each structure type forms are yet to be entirely understood, however: for example, there is substantial uncertainty regarding the subsurface architecture of the thrust faults assumed to underlie wrinkle ridges, and the depths to which they penetrate. Given the abundant distribution of wrinkle ridges throughout the inner Solar System, we propose to conduct a two-year study of the formation and subsurface geometry of these contractional landforms, using a combination of photogeological mapping and numerical modeling techniques. And because of the recent availability of high-resolution imaging and topographic data from NASA’s MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft in orbit about Mercury, we have chosen to focus our study on ridges on the innermost planet. In this project, we will quantify the morphometry of a number of exemplar wrinkle ridges in Mercury’s northern hemisphere, and will use these data as constraints for elastic dislocation models of the faults that underlie the ridges. By characterizing the subsurface architecture of wrinkle ridge faults, we will test whether these structures penetrate to only shallow depths, or if they extend tens of kilometers into Mercury’s lithosphere. The results of this study will enable new estimates of how much shortening strains Mercury’s wrinkle ridges have accommodated, and may provide insight into the mechanical stratigraphy of the units in which they occur. Moreover, given the prevalence of these landforms on other terrestrial bodies, this project will improve our understanding of tectonic deformation on worlds throughout the inner Solar System.

Date: 10/01/15 - 9/30/18
Amount: $38,143.00
Funding Agencies: National Aeronautics & Space Administration (NASA)

Large-scale tectonic landforms on Mars are a window into its subsurface structure and its thermal history. Among these large tectonic landforms are thrust-fault-related lobate scarps. The faults underlying these scarps are thought to deeply penetrate the brittle portion of the lithosphere, indicating that it was subjected to high and long-lasting compressive tectonic stresses throughout Martian geologic history. However, the current understanding of Martian thrust faulting is limited because fault geometries and offsets have been determined for only a handful of examples, which are assumed to be representative of the entire planet. It is exactly these parameters that, when quantified in more detail, would allow better characterization of global compressional tectonics, geometric and bulk rock-physical properties of the lithosphere, and the mechanics of faulting on Mars. We therefore propose (1) a detailed HRSC and CTX image mapping campaign of nine large systems of lobate scarps, complemented by a systematic characterization of the MOLA topography across the scarps as the basis for (2) a fault displacement analysis and (3) a numerical modeling suite. The detailed mapping will inform our understanding of Martian thrust fault growth behavior. The displacement analysis will result in scaling statistics with which we will further describe the three-dimensional characteristics of thrust fault growth behavior, allowing us to constrain the depth to which faults extend and to infer bulk physical properties of the rock the faults penetrate. Finally, the numerical modeling work will contribute to our understanding of fault plane geometry at depth, in turn providing insight into the mechanics of thrust faulting on, and compressional tectonics of, Mars. This study will address crucial aspects of the nature and evolution of the tectonic processes that have created and modified the Martian crust, and will link surface observations to the structure and evolution of the interior of Mars.

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