W-9: Mapping the Moho: Integrations and Implications

SEG 2012 Annual Meeting Technical Program

Date: Thursday, 8 November 2012
Time: 1:30 pm – 5:00 pm
Location: Mandalay Bay Convention Center, Room: Breakers B
Organizers: Tim Grow and Dr. Rao Yalamanchili
Through the support of the SEG Gravity and Magnetics Committee
 

Description
 

The Mohorovicic discontinuity has been the subject of numerous geophysical investigations and debate since its discovery in 1909. It is defined geologically as the crust – mantle boundary, it is defined geophysically, using refraction data, as the interface associated with a velocity increase from less than 7 km/sec. to greater than 7.8 km/sec.

The Moho is also associated with the base of gravity models in exploration and it is often associated with the Curie Isotherm, thus can affect the interpretation of magnetic models also.  The depth to the Moho can vary dramatically even over abbreviated distances. The Moho can, in some areas, be imaged with reflection data and is routinely modeled with gravity data. Given the relative paucity of refraction coverage worldwide many models of the Moho are largely dependent on the integration of reflection, gravity and any other available geologic information. 

The exploration interest in studying the Moho is that it is often the base of crustal models, that the thickness of crust controls heat flow, and that there can be significant gravity anomalies observed from density changes just above the moho (Lower Crustal Bodies).

Determination of the Moho and models that incorporate the Moho will be the focus of this workshop. Invited papers will cover the topics of crustal models over both oceanic and continental domains, methods of determining the moho, Isostasy, and the Curie Depth. Papers will include the assumptions and error margins of the various models, and should emphasize impact of the crustal models on exploration efforts.

Schedule

Nominal times:

1:30 pm:  Introduction

1:45 pm: Gravity-Derived Moho: Definitions, Methods and Examples—Rao Yalamanchili, Xiong Li, Vsevolod Egorov, Gordon Shields, Janine Weber, and Mehmet Kaldirim, Fugro Gravity & Magnetic Services, Houston, Texas

2:10 pm:  Integrated Mapping of the Curie Isotherm on a Global Scale—Chris Green, Derek Fairhead, and Ahmed Salem, GETECH and U of Leeds; Kumar Hemant, Indian Institute of Technology; Stefan Maus, NGDC; Ed Biegert, Steve Bergman, and Mike Burianyk, Shell International Exploration and Production

2:35 pm:  Deep gravity: Long wavelengths and Measured Moho—Susan J. Webb, School of Geosciences, U of the Witwatersrand, Wits, South Africa

2:50 pm:  Break

3:05 pm:  Crustal thickness beneath the Red Sea derived from satellite gravity data—J. Derek Fairhead,  Ahmed Salem, and Chris Green, GETECH Leeds and U of Leeds, Leeds, UK; Lorenzo Cascone, Lee Moorhead, and Simon Campbell, GETECH Leeds, UK

3:30 pm:  The link between the Moho depth of the NE Atlantic margin and magnetic and gravity fields and satellite gravity gradients—Jörg Ebbing, Geological Survey of Norway, Trondheim & Department of Petroleum Technology and Applied Geophysics, Norwegian U of Science and Technology, Trondheim

3:55 pm:  A Workflow for Estimating the Moho—Adrienne E. Block, E-Gerald Hensel, and Elizabeth (Betty) Johnson, Chevron Energy Technology Company