Geologic Origin of Deep Crustal and Uppermost Mantle Structures at the Continent-Ocean Transition Offshore Nova Scotia from Modeling of Wide-Angle S-Wave Arrivals (part of the PAGEO research program)

This work will produce S-wave velocity models for two of the existing refraction profiles from the Scotian margin. The objective is to better constrain the crustal origin of the continent-ocean transition (COT) using both the P and S-wave velocity models.

In the first 3 months, preprocessing the horizontal components of all Ocean Bottom Seismometer (OBS) recordings from offshore Nova Scotia will be performed. The subsequent 3 months are dedicated to evaluating the prepared S-wave data from all five OBS profiles collected in the Scotian offshore in order to select two profiles most suitable for S-wave velocity modelling. The two selected profiles will be those with the best combination of S-wave data quality and most suitable profile location for constraining the continent-ocean transition (COT). Should the S-wave data quality be the same across all 5 OBS profiles, preference will be given to SMART-2 because of its central position at the Scotian margin, which provides maximum benefit for correlating with the MCS reflection results, and its proximity to the Dalhousie University, Nova Scotia. 15 months will be dedicated to development of the S-wave velocity models and their interpretation, followed by resolution tests and error analysis in the last 6 months of the project. The project objective is to provide strong constraints on the geologic origin of the crustal and uppermost mantle rocks at the COT offshore Nova Scotia.

Outcomes

• Final Technical Reports synthesizing all results including the final S-wave velocity models, error analyses, and resolution tests, and describing their use to build a coherent interpretation with insights on calibrating Moho picks of other projects and drilling targets.
• Final S-wave velocity models in RayInvr v.in format, SEGY format, and GMT grid file.
• A manuscript will be submitted for publication. Plots of the final models and OBS data will be included together with a well justified interpretation of the velocity models. Focus will be on both the S-wave analysis technique and the new constraints on the crustal origins of the COT and upper mantle.