Unraveling the Iceland Plume Track Through Greenland’s Mantle Transition Zone
Description:
Over the last ~100 Ma, Greenland passed over the present-day Iceland hotspot. However, the path of the plume track across Greenland is debated and obscured by the Greenland ice sheet. The passage of Greenland over the Iceland hotspot provides an opportunity to investigate how mantle transition zone structure recovers from hotspot interaction over time. We analyze information from converted Ps phases to infer the characteristics of the mantle transition zone below Greenland using data from broadband stations, including the first analyses of recent deployments of seismometers on the Greenland ice sheet. We calculate receiver functions in a 2-100 s period band using time domain deconvolution, after separating the P and SV components using a free-surface transform where free-surface velocities were obtained from P and S waveforms. High-quality receiver functions are identified and are migrated to depth using a recent 3-D tomographic model (Lei et al., 2020). Depth-migrated receiver functions are stacked in 30° back-azimuthal bins at each station and the observed depths of the positive phases corresponding to the 410 and 660 km discontinuities are used to calculate transition zone thicknesses. The thickness measured for a given bin is assigned to all mid-transition zone piercing points for that bin. Thicknesses are smoothed laterally with a 1° radius spherical cap to generate a map of transition zone thicknesses. We find a corridor of thin mantle transition zone across Greenland and Iceland, consistent with some models of the Iceland plume track and the distribution of coastal paleogene basalt provinces. We also observe areas of thick transition zone beneath mid-latitude eastern Greenland, possibly related to remnant subducted lithosphere in the transition zone, and an additional thin transition zone region in northeast Greenland.
Session: Earth’s Structure From the Crust to the Core [Poster]
Type: Poster
Date: 4/18/2023
Presentation Time: 08:00 AM (local time)
Presenting Author: Anant Hariharan
Student Presenter: Yes
Invited Presentation:
Authors
Anant Hariharan Presenting Author anant_hariharan@brown.edu Brown University |
Erica Nathan Corresponding Author erica_nathan@brown.edu Brown University |
Karen Fischer karen_fischer@brown.edu Brown University |
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Unraveling the Iceland Plume Track Through Greenland’s Mantle Transition Zone
Category
Earth’s Structure From the Crust to the Core