[Eoas-seminar] MS Defense - Ariana Lovings

[eoas-seminar at lists.fsu.edu]

Good afternoon,

Please join us for Ariana Lovings MS Defense on April 20th, 2026 at Noon in EOAS 2061.


Name: Ariana Lovings

Date: April 20th, 2026

Time: 12:00 PM – 2:00 PM

Location: EOAS 2061

Zoom: https://fsu.zoom.us/j/94058698150<https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.google.com%2Furl%3Fq%3Dhttps%3A%2F%2Fnam04.safelinks.protection.outlook.com%2F%3Furl%253Dhttps%25253A%25252F%25252Ffsu.zoom.us%25252Fj%25252F94058698150%2526data%253D05%25257C02%25257Caa25bq%252540fsu.edu%25257C108be46ab493462b093d08de7951f682%25257Ca36450ebdb0642a78d1b026719f701e3%25257C0%25257C0%25257C639081590086786753%25257CUnknown%25257CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%25253D%25253D%25257C0%25257C%25257C%25257C%2526sdata%253DUMmgbrboVYn0QRMXdsDC71fRI97lgpXl43fXm%25252B9QpeE%25253D%2526reserved%253D0%26sa%3DD%26source%3Dcalendar%26usd%3D2%26usg%3DAOvVaw2TMkHklEfV5WFU7slNIe5w&data=05%7C02%7Ceoas-seminar%40lists.fsu.edu%7C9532f7c0921547e5a8e208de9b23a8bd%7Ca36450ebdb0642a78d1b026719f701e3%7C0%7C0%7C639118774628486015%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=UDFqO4fIQ2q%2FUEdo5DUpEEjxRrgVRIJg9Os9ehCboaw%3D&reserved=0>


Title: Geochemical Evidence for Widespread Off-Axis Hydrothermal Circulation: tracking Diffusive Exchange in Sediment Porewater Chemistry


Abstract: Off-axis hydrothermal flow is a widespread but under recognized process occurring within basaltic basement beneath deep-sea sediments. While high-temperature ridge-axis systems have been extensively characterized, the geochemical expression and quantitative contribution of off-axis systems to global ocean biogeochemical cycles remain poorly constrained. This study develops a geochemical framework for identifying off-axis hydrothermal influence using sediment porewater data from scientific ocean drilling programs. Four regions with confirmed off-axis circulation were examined through a literature review to establish reference geochemical patterns. Concentration differences between sediment and basalt layers drive porewater gradient reversals of Sr²⁺, Ca²⁺, Mg²⁺, SO₄²⁻, and NH₄⁺ near the sediment–basement interface, which serve as proxies for this circulation. To assess the broader occurrence of these proxies, the first-ever integrated sediment porewater dataset from IODP expeditions (“SED-PIE”) was compiled by aggregating porewater data from all DSDP, ODP, and IODP expeditions. A web-scraping, AI-assisted Python script was developed to systematically screen both expedition reports and the new SED-PIE dataset for off-axis hydrothermal circulation proxies. This approach identified 35 new sites with geochemical signatures of off-axis flow, suggesting that this flow may be more widespread than previously documented. Because individual concentration profiles can be superimposed by diagenesis or other chemical reactions, ⁸⁷Sr/⁸⁶Sr isotope ratios were also evaluated as a potentially more specific diagnostic tool. At IODP Sites U1540 and U1541, located on the western flank of the East Pacific Rise ~130-180 nmi from the spreading axis, porewater concentration profiles show some features suggestive of off-axis hydrothermal circulation but not all proxies agree. The strontium isotope ratios also clearly exhibit curvature toward modern seawater values near the sediment–basement interface, consistent with diffusive exchange with basalt-derived fluids. These results suggest that while traditional tracers may provide mixed evidence for off-axis circulation, Sr isotopes may serve as a more sensitive proxy for off-axis hydrothermal circulation. The site identification in this study focuses on geochemical and isotopic porewater profiles, but other physical proxies are essential for understanding subsurface hydrologic pathways and quantifying off-axis hydrothermal fluxes. Therefore, a limited heat flow dataset for newly identified sites is presented. This study introduces a robust method of identifying sites of off-axis hydrothermal circulation and provides some data which can be used to later quantify flux in these regions.

Best,
Adea


Adea Arrison
Sr. Academic Program Specialist
Department of Earth, Ocean & Atmospheric Science
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