- Title Information
- Title
- Subduction and rift processes: Their effects on mantle heterogeneities and magmatism at the Antarctic Peninsula and surrounding mid-ocean ridges
- Type of Resource (primo)
- dissertations
- Name:
Personal
- Name Part
- Anderson, Danny W.
- Role
- Role Term:
Text
- creator
- Name:
Personal
- Name Part
- Saal, Alberto
- Role
- Role Term:
Text
- Advisor
- Name:
Personal
- Name Part
- Cooper, Reid
- Role
- Role Term:
Text
- Reader
- Name:
Personal
- Name Part
- Hirth, Greg
- Role
- Role Term:
Text
- Reader
- Name:
Personal
- Name Part
- Huber, Christian
- Role
- Role Term:
Text
- Reader
- Name:
Personal
- Name Part
- Parman, Stephen
- Role
- Role Term:
Text
- Reader
- Name:
Personal
- Name Part
- Panter, Kurt
- Role
- Role Term:
Text
- Reader
- Name:
Corporate
- Name Part
- Brown University. Department of Earth, Environmental, and Planetary Sciences
- Role
- Role Term:
Text
- sponsor
- Origin Information
- Copyright Date
- 2024
- Physical Description
- Extent
- 12, 220 p.
- digitalOrigin
- born digital
- Note:
thesis
- Thesis (Ph. D.)--Brown University, 2024
- Genre (aat)
- theses
- Abstract
- Magmatism at the northern Antarctic Peninsula offers an exceptional opportunity to study the evolution of the Earth’s upper mantle in a region with an extensive history of subduction and rifting. The peninsula’s abundant, well-sampled magmatism provides a valuable window into the distribution and movement of the local mantle’s major compositional heterogeneities. Despite having erupted in close spatial and temporal proximity, these lavas are quite geochemically diverse, suggesting complex origins. This thesis addresses the major outstanding questions surrounding this geochemical diversity, linking it to the greater tectonic history of the region through a combination of analytical and computational approaches. We integrate published datasets for lavas from West Antarctica with new data in this thesis. These data include major element, trace element, volatile element, and radiogenic isotope data collected on a considerable suite of submarine and subaerial lavas from the area, in addition to trace element and radiogenic isotope data for present-day sediments from the subducting plate. At the modern back-arc, we find spatial correlations reflecting the present geometry of the slab. Sub-slab asthenosphere, flowing toroidally into the mantle wedge at the slab’s edges, has diluted the subduction flux and focused the most subduction-modified mantle towards the back-arc’s center. At the volcanic front, we find evidence the mantle wedge transitioned from being fluxed by predominantly sediments to predominantly fluids between ~140 and ~30 Ma as volcanism migrated northeastwards. We also find that as spreading slowed at the nearby ridges, melts increasingly sampled the less abundant but more fusible and volatile-rich enriched portions of the mantle. The similarities between melts from these ridges and those from the East Pacific Rise suggest a large-scale movement of Pacific mantle into the region beneath the peninsula. There is also evidence of subduction-modified mantle beneath the West Scotia Ridge, which we conclude was left behind ~30 Ma by the South Sandwich subduction zone, which has since migrated >1000 km away. Finally, we suggest that the widespread Cenozoic alkaline magmatism found across the peninsula could reasonably be produced by recent melting of the lithospheric mantle, metasomatized by mixed rift- and subduction-derived melts within the past ~100 Myr.
- Subject (fast)
(authorityURI="http://id.worldcat.org/fast", valueURI="http://id.worldcat.org/fast/00940343")
- Topic
- Geochemistry
- Subject (fast)
(authorityURI="http://id.worldcat.org/fast", valueURI="http://id.worldcat.org/fast/00980223")
- Topic
- Isotope geology
- Subject
- Topic
- mantle metasomatism
- Subject (fast)
(authorityURI="http://id.worldcat.org/fast", valueURI="http://id.worldcat.org/fast/01136435")
- Topic
- Subduction zones
- Subject (fast)
(authorityURI="http://id.worldcat.org/fast", valueURI="http://id.worldcat.org/fast/00827893")
- Topic
- Basalt
- Subject (fast)
(authorityURI="http://id.worldcat.org/fast", valueURI="http://id.worldcat.org/fast/01097843")
- Topic
- Rifts (Geology)
- Subject (fast)
(authorityURI="http://id.worldcat.org/fast", valueURI="http://id.worldcat.org/fast/00805384")
- Topic
- Alkalic igneous rocks
- Subject (fast)
(authorityURI="http://id.worldcat.org/fast", valueURI="http://id.worldcat.org/fast/01239991")
- Topic
- Antarctica--Antarctic Peninsula
- Subject (fast)
(authorityURI="http://id.worldcat.org/fast", valueURI="http://id.worldcat.org/fast/01020295")
- Topic
- Mid-ocean ridges
- Subject (fast)
(authorityURI="http://id.worldcat.org/fast", valueURI="http://id.worldcat.org/fast/00825090")
- Topic
- Back-arc basins
- Language
- Language Term (ISO639-2B)
- English
- Record Information
- Record Content Source (marcorg)
- RPB
- Record Creation Date
(encoding="iso8601")
- 20240501