EGU2020-2222
https://doi.org/10.5194/egusphere-egu2020-2222
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Coastal to Abyssal Vertical Sediment Accumulation Rates Predicted via Machine-Learning: Towards Sediment Characterization on a Global Scale

Giancarlo Restreppo1, Warren Wood2, and Benjamin Phrampus2
Giancarlo Restreppo et al.
  • 1NRC Postdoctoral Associate, U.S. Naval Research Laboratory, Geology and Geophysics, Stennis Space Center, MS, United States of America (giancarlo.restreppo.ctr@nrlssc.navy.mil)
  • 2U.S. Naval Research Laboratory, Geology and Geophysics, Stennis Space Center, MS, United States of America

Observed vertical sediment accumulation rates (SARs; n = 1166) were gathered from ~55 years of peer reviewed literature.  Original methods of rate calculation include long-term isotope geochronology (14C, 210Pb, and 137Cs), pollen analysis, horizon markers, and box coring. These observations are used to create a database of contemporary vertical SARs. Rates were converted to cm yr-1, paired with the observation’s longitude and latitude, and placed into a machine-learning based Geospatial Predictive Seafloor Model (GPSM). GPSM finds correlations between the data and established global “predictors” (quantities known or estimable everywhere; e.g. distance from coast line, river mouths, etc.).  The result, using a k-nearest neighbor (k-NN) algorithm, is a 5-arc-minute global map of predicted vertical SARs.  The map generated provides a global reference for vertical sedimentation from coastal to abyssal depths.  Areas of highest sedimentation, ~3-8 cm yr-1, are generally river mouth proximal coastal zones and continental shelves on passive tectonic margins (e.g. the Gulf of Mexico, eastern United States, eastern continental Asia, the Pacific Islands north of Australia), with rates falling exponentially towards the deepest parts of the oceans.  Coastal zones on active tectonic margins display vertical sedimentation of ~1 cm yr-1, which is limited to near shore when compared to passive margins.  Abyssal depth rates are functionally zero at the time scale examined (~10-4 cm yr-1), and increase one order of magnitude near the Mid-Atlantic ridge and at the conjunction of the Pacific, Nazca, and Cocos tectonic plates.  Predicted sedimentation patterns are then compared to established quantities of fluvial sediment discharge to the oceans, calculated by Milliman and Farnsworth in River Discharge to the Coastal Ocean: A Global Synthesis (2011).

How to cite: Restreppo, G., Wood, W., and Phrampus, B.: Coastal to Abyssal Vertical Sediment Accumulation Rates Predicted via Machine-Learning: Towards Sediment Characterization on a Global Scale, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-2222, https://doi.org/10.5194/egusphere-egu2020-2222, 2020

Comments on the presentation

AC: Author Comment | CC: Community Comment | Report abuse

Presentation version 1 – uploaded on 28 Apr 2020 , no comments