M.S. - Earth and Planetary Sciences

Permanent URI for this collection

https://hdl.handle.net/10125/66122

Browse

Recent Submissions

Now showing 1 - 10 of 22
  • Thumbnail Image
    Item
  • Thumbnail Image
    Item
    CHARACTERIZING THE TEMPERATURE AND HYDROLOGICAL DYNAMICS OF THE MĀNOA STREAM
    (2024) Pantaleo, Hailey Rose; Dulai, Henrietta; Earth and Planetary Sciences
  • Thumbnail Image
    Item
    Building an Understanding of Human-Water Resource Relationships through Community Engagement in Haʻikū and Huelo, HI
    (2024) Bees, Brandon Thomas; Shuler, Christopher; Earth and Planetary Sciences
  • Thumbnail Image
    Item
    Drainage Failure and Associated Urban Impacts Under Combined Sea-Level Rise and Precipitation Scenarios
    (2024) Obara, Chloe; Fletcher, Charles H.; Earth and Planetary Sciences
  • Thumbnail Image
    Item
  • Thumbnail Image
    Item
    Rate of Beach Loss Greatest with Near-term Sea Level Rise
    (2020) Tavares, Kammie; Fletcher, Chip; Earth and Planetary Sciences
  • Thumbnail Image
    Item
    Receiver Function Imaging of Kīlauea Using Broadband and Nodal Seismometers
    (2023) Wight, Jade Carrillo; Janiszewski, Helen; Earth and Planetary Sciences
  • Thumbnail Image
    Item
    Evaluation of microcontaminants as tracers for groundwater nutrient sources within mixed-use watersheds along the South Kohala coast of the Island of Hawaii
    (University of Hawaii at Manoa, 2022) McKenzie, Casey D.; Dulai, Henrietta; Earth and Planetary Sciences
    Anthropogenic nutrient loading of coastal environments is a known contributor to marine ecosystem health decline in Hawai‘i, and submarine groundwater discharge (SGD) has been shown to serve as a pathway to fuel nutrient delivery to coastal zones. Anthropogenic sources that may supply nitrogen (N) to groundwater include agricultural practices, resorts and golf courses that utilize fertilizers in landscaping applications, an abundance of homes outfitted with cesspools, and input from wastewater infrastructure. SGD provides a means of conveying land-derived nutrients to the coastal ocean and hence facilitates N-transport to coastal zones. Analysis of SGD enabled the exploration of the spatial distribution of groundwater composition and its relation to land-use. Previous research identified the presence of SGD in the study area, and we targeted and sampled 45 coastal springs and 20 upland wells along a 14 km long coastline in South Kohala, Hawai‘i. A wide range in nutrient concentrations was observed in SGD and well samples, with N loads well above 100 μM (1000-fold above marine levels). Some, but not all, δ15N-NO3- signatures suggest that N observed in SGD is of wastewater origin. We utilized known microcontaminants as novel tracers for identifying which land-use categories are hydrologically and chemically connected to SGD and, therefore, may be nutrient sources to the coastline. Microcontaminants of interest included pharmaceuticals commonly present in cesspool waste, restricted use pesticides and herbicides utilized in landscaping practices, and common detergents used in commercial industry that utilize public sewage infrastructure. To determine groundwater flow paths, δ18O-H2O allowed calculation of estimated recharge elevations to estimate upstream end members of flow lines. Spatial analysis of land uses and practices (LUP) along flow lines was utilized to quantify LUP overlying groundwater flow. δ18O-H2O of groundwater also contributed evidence of where groundwater flow paths from Kohala, Mauna Kea and Mauna Loa volcanoes may potentially converge along the South Kohala coastline. When comparing flow path analysis to developed scoring methods, upstream contribution of microcontaminants to groundwater pathways confirmed that microcontaminants could serve as land-use tracers throughout the length of the flow path. Microcontaminant scoring geochemically connected up-stream land uses to coastal SGD seeps along hydrological flow paths. Spatial analysis of microcontaminant distribution in SGD and LUP scoring revealed that caffeine, carbamazepine, sulfamethoxazole has strong correlation with presence of OSDS, confirming their suitability as wastewater specific tracers.
  • Thumbnail Image
    Item
    Revisiting the Census and Age of the Beta Pictoris Moving Group in the Gaia Era
    (University of Hawaii at Manoa, 2022) Lee, Rena Aerey; Gaidos, Eric; Earth and Planetary Sciences
    Determining the precise ages of young (~10 to few hundred Myr) kinematic ("moving") groups is important for placing star, protoplanetary disk, and planet observations on an evolutionary timeline. The nearby ~25 Myr-old Beta Pictoris Moving Group (BPMG) is an important benchmark for studying stars and planetary systems at the end of the primordial disk phase. Gaia DR3 astrometry combined with ground-based observations and more sophisticated stellar models permit a systematic re-evaluation of its membership and age. We combined Gaia astrometry with previous and new radial velocities to evaluate moving-group membership in a Bayesian framework. To minimize the effect of unresolved stellar multiplicity on age estimates, we identified and excluded multi-star systems using Gaia astrometry, ground-based adaptive optics imaging, and multi-epoch radial velocities, as well as the literature identifications. We estimated age using isochrone and lithium-depletion-boundary fitting with models that account for the effect of magnetic activity and spots on young, rapidly rotating stars. We report an age of 33(+9/-11) Myr to the BPMG based on isochrone fitting to the single-star and resolved-binary sample, which is older than, but within the uncertainties of, literature values.
  • Thumbnail Image
    Item
    Mantle vs. Crust: Untangling influences on ocean island basalt stable O and H isotopic composition via tandem olivine-glass analyses at Kamaʻehuakanaloa Volcano, Hawaiʻi
    (University of Hawaii at Manoa, 2022) Cunningham, Molly Jean; Pietruszka, Aaron J.; Earth and Planetary Sciences
    The stable O and H isotopic composition of ocean island basalts reflect the interplay of deep and shallow magmatic processes such as melting of a heterogeneous mantle source and crustal contamination. For Hawaiian volcanoes, it has been debated whether lavas retain their source-derived isotopic compositions, or if these signatures are overprinted by assimilation of hydrothermally altered materials. New δD and δ18O analyses of glass and olivine from the youngest Hawaiian volcano, Kamaʻehuakanaloa (Kamaʻehu; formerly Lōʻihi), clarify the extent to which magmatic contamination influences O and H isotope ratios of erupted lavas. We find that in most samples, assimilation of seawater-derived fluids is minor: this process has elevated δD, Cl/K2O, and H2O in some glasses, but most samples retain mantle-like δD (-60 to -90‰) until eruption. In contrast, Kamaʻehu lavas demonstrate variation in olivine δ18O (δ18Ool = ~4.5 to 5.4‰) and glass δ18O (δ18Ogl = ~5.0 to 6.2‰) that is greater than that expected from melting of simple peridotitic mantle. We find that different regions of the volcanic edifice erupt lavas that are compositionally distinct in their δ18O: North Rift Zone lavas are relatively 18O-enriched (δ18Ogl = ~5.6‰); South Rift Zone lavas are relatively 18O-depleted (δ18Ogl = ~5.3‰); and lavas from the summit region have intermediate δ18O values (δ18Ogl = ~5.4‰). We resolve these observations into an isotopically consistent model of the Kamaʻehu magmatic plumbing system. Over time, differences in the temperature of circulating hydrothermal fluids may have altered basalt in the volcanic edifice to high δ18O in the NRZ and low δ18O in the SRZ. Magmas with initial mantle-derived δ18O (δ18Oliq = ~5.4‰) ascend into the shallow volcanic plumbing system and assimilate this hydrothermally altered rock, causing individual magmas to shift toward the δ18O value of local assimilants. The degree of this contamination may be greatest in the rift zones and least in the summit due to a higher rate of magma supply to the summit reservoir system. δ18Ool tracks with regional differences in δ18Ogl, indicating that the assimilation process begins before or during olivine fractionation. Finally, olivine entrainment and lack of homogenization prior to eruption preserve isotopic heterogeneity on small spatial scales in erupted lavas. Variations in δ18O for Hawaiian lavas thus may be controlled by processes operating within the shallow volcanic plumbing system, overprinting variation derived from melting of a heterogeneous mantle source. To determine the true, mantle-derived O isotopic signature of a volcano, systematic analyses of many samples are required.