| NSF Org: |
OCE Division Of Ocean Sciences |
| Recipient: |
|
| Initial Amendment Date: | March 26, 2021 |
| Latest Amendment Date: | March 29, 2021 |
| Award Number: | 2128781 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Dennis Geist
OCE Division Of Ocean Sciences GEO Directorate for Geosciences |
| Start Date: | April 1, 2021 |
| End Date: | August 31, 2021 (Estimated) |
| Total Intended Award Amount: | $215,042.00 |
| Total Awarded Amount to Date: | $26,093.00 |
| Funds Obligated to Date: |
|
| History of Investigator: |
|
| Recipient Sponsored Research Office: |
8622 DISCOVERY WAY # 116 LA JOLLA CA US 92093-1500 (858)534-1293 |
| Sponsor Congressional District: |
|
| Primary Place of Performance: |
8602 La Jolla Shores Dr La Jolla CA US 92093-0210 |
| Primary Place of
Performance Congressional District: |
|
| Unique Entity Identifier (UEI): |
|
| Parent UEI: |
|
| NSF Program(s): | Marine Geology and Geophysics |
| Primary Program Source: |
|
| Program Reference Code(s): | |
| Program Element Code(s): |
|
| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
A long-standing question in the study of mid-ocean ridges focuses on how they initiate and evolve. Our research cruise to the Galapagos Triple Junction in the eastern equatorial Pacific Ocean will characterize the transition from initial rifting to seafloor spreading, and the associated development of ridge axis segmentation. In this region, the western tip of the Cocos-Nazca Rift is breaking into ~0.5 Ma crust accreted on the east flank of the East Pacific Rise, and each stage in the transition from rifting to magmatic seafloor spreading can be studied. In order to examine along-axis changes as a function of distance from the rift tip, we will collect geophysical data on morphology, gravity and magnetic variations, rock samples for chemical analyses, and water column data for identifying hydrothermal activity. Our findings on oceanic rifting will complement on-going studies of these processes in continental rift settings.
Our study area extends eastward from the site of initial rifting of the Cocos-Nazca spreading center to nucleation of magmatic spreading at the Hess Deep rift, to full magmatic spreading, thus exhibiting progressive stages in the initiation and development of rifting and segmentation. Multibeam bathymetry, gravity, and magnetic data will be collected to reconstruct the tectonic evolution from initial rifting through seafloor spreading, and in particular, changes in segment and offset characteristics as they develop. Chemical analysis of rock samples collected along the spreading axes and along flow lines will shed light on the evolution of mantle melting and melt delivery systems and their relationship to the tectonic segmentation. Graduate and undergraduate students (Duke and MIT/WHOI), will participate in the cruise and on-shore research, gaining valuable seagoing experience and learning to conduct collaborative research. In addition, we will develop activities based upon this work for use in a yearly science-immersion program for minority, middle school girls.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
Note:
When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external
site maintained by the publisher. Some full text articles may not yet be available without a
charge during the embargo (administrative interval).
Some links on this page may take you to non-federal websites. Their policies may differ from
this site.
PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
A fundamental question in the study of mid‐ocean ridges is how spreading centers initiate and change through time. At the Galapagos triple junction in the equatorial Pacific, the oceanic crust is being broken apart to form rift basins, which develop into individual mid‐ocean ridge spreading segments. During this project, bathymetry, magnetic, and gravity data were collected during an expediton to the Galapagos triple junction on RV Sally Ride in 2018, to help understand the stages in the transition from rift basins to a magmatic seafloor spreading center. From inception, the developing spreading center is composed of individual segments that are offset from each other. Currently, rifting progresses to magmatic spreading over three segments, which opened at slow spreading rates. Older spreading segments originated at faster‐spreading rates. Data indicate that the change from rifting to full magmatic spreading was more rapid in these older segments. Near the spreading axis, gravity data show that temperatures increase beneath segments as they mature, suggesting that magma supply is developing beneath the segments. Propagation ofthe western ends ofsegments is common. Understanding how seafloor spreading initiates and forms a segmented mid‐ocean ridge provides information on how mantle melting is established beneath a rift zone and how tectonic plate boundaries evolve.
Last Modified: 01/13/2022
Modified by: Ross Parnell-Turner
Please report errors in award information by writing to: awardsearch@nsf.gov.
