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The Wise Report

The Wise Report Henry M. Wise, P.G. August 22, 2010 Lynn Clark, member of the Texas Board of Professional Geoscientists wrote to me a response to the previous Wise Report. He states: I attended the Legislative Committee also, and I offer my personal observations to augment Mr. Mikel's more

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HGS Int'l Explorationists Dinner: Understanding the Deep Crust

Sponsored by DIGs

Monday 22-Mar-10 5:30 PM to 8:30 PM CDT
We were unable to register you for this event as the event deadline has passed or the maximum number of seats available has been reached.
Total Seats: 100
Reserved: 50

Westchase Hilton

9999 Westheimer
Houston Texas 77042-3802
Google Maps | Hotels Near | Yahoo! Maps | Weather Forecast
Phone: (713) 974-1000
Fax: (713) 974-6866

Speaker Dr. Walter D. Mooney

Position: Research Geophysicist
Company: United States Gelogical Survey

Event Description

From the Bay of Bengal and Beyond!

Using seismic techniques to understand the earth's crust beneath sedimentary basins.
 
Dr. Walter D. Mooney
United States Geological Survey
 
 
Understanding how sedimentary basins evolve is an exciting but difficult task. Seismic reflection data do a marvelous job of imaging the internal structure of sedimentary basins. There is no better technique. However, we often want more than just a detailed image of the basin. Of particular interest are the physical properties within the basin and below it, within the crystalline crust. For example, seismic P- and S-wave velocities are closely tied to lithology, and hence crustal type (oceanic versus continental). Consequently, seismic reflection studies are complemented by seismic velocity studies. Such velocity information is very effective in determining basin geometry, and can be used to determine Poisson’s ratio, an important parameter for determining the kind of source rocks, crustal type, as well issues related to the Law of the Seas convention.
 
           
One good way to obtain reliable deep seismic velocities is to shoot wide-offset seismic refraction profiles. Actually, this technique is a classical one that every student encounters in their first course about the Earth’s crust. Indeed, seismic refraction profiles formed the basis for the early exploration of hydrocarbon resources. Today, high resolution seismic refraction profiles are recorded one land and at sea using a wide variety of techniques.
 

 In this talk I will present a global synthesis of what we have learned from deep crustal seismic velocity profiles, from the Gulf Coast to the Bay of Bengal, and beyond. A very extensive literature search has been undertaken to track down as many of the seismic refraction publications as possible. The resulting database contains over 10,000 one-dimen­sional P-wave and S-wave profiles, making it the largest such catalog in existence. These data, especially when examined as complete crustal cross sections,  reveal a number of surprising results, such as the discovery of highly thinned continental crust extending 100’s of km offshore; serpentinized peridotite (rather than basalt) right at the sea floor, and evidence that deep, highly metamorphosed sediments that mimic crystalline basement rocks, thus confounding traditional basin interpretations. Indeed, many of these results challenge conventional views of “how the Earth works”. That’s just what makes this investigation so exciting!
 

           

Comments

 
 In their regional exploration studies, DIGs and GrizGeo have been incorporating depth to basement data compiled from multiple sources as constraints on the more detailed depths derived from inversion of gravity and magnetics. Our poster shows global and basin-level basement and sediment thickness mapping in Southeast Asia and across the Atlantic margin basins. Initial basement control includes points from the CRUST2.0 model with values at 2 arc-degrees (roughly 222 km) from global refraction and earthquake surface wave data, merged with NGDC data from reflection seismic profiling. This material augmented with published maps, geological and seismic profiles constrains the gravity and magnetics inversion.  Depth to basement is then produced on grids as fine as 4 km (normally 20 km) and globally accurate within 20% of depth; typically within 10% of depth.
 
 
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 Event Contact

 Event Coordinator
HGS Office Justin Vandenbrink
(713) 463-9476 (281) 448-6188
(281) 679-5504 FAX (281) 448-6189 FAX
http:\\www.hgs.org
   

HGS Int'l Explorationists Dinner: Understanding the Deep Crust

Sponsored by DIGs

Monday 22-Mar-10 5:30 PM to 8:30 PM CDT

Speaker Dr. Walter D. Mooney

Position: Research Geophysicist
Company: United States Gelogical Survey

Biography

 

Walter D. Mooney, Ph.D. is a senior research geophysicist with the US Geological Survey in Menlo Park, California, where he has worked since 1978. He has studied the structure, composition, and evolution of the Earth’s crust for more than thirty years. His work has taken him to locations throughout the world, with much of his recent work in China, Indonesia, and Africa. His undergraduate degree was from Cornell University (physics) and his Ph.D. (geophysics) from the University of Wisconsin-Madison. He is the recipient of the George P. Woollard Award from the Geological Society of America (GSA), and is a Fellow of the GSA, American Geophysical Union (AGU), and Geological Society of London. He was a visiting professor in the Department of Earth Sciences at Rice University in 2003, and has authored or coauthored over 150 publications. He collects British sports cars, some of which are actually running.


HGS Int'l Explorationists Dinner: Understanding the Deep Crust

Sponsored by DIGs

Monday 22-Mar-10 5:30 PM to 8:30 PM CDT

Westchase Hilton

9999 Westheimer
Houston Texas 77042-3802
Google Maps | Hotels Near | Yahoo! Maps | Weather Forecast
Phone: (713) 974-1000
Fax: (713) 974-6866

HGS Int'l Explorationists Dinner: Understanding the Deep Crust

Sponsored by DIGs

Monday 22-Mar-10 5:30 PM to 8:30 PM CDT
 
Before 19-Mar-10
After 19-Mar-10
Member:
$28.00
$35.00
Non-Member:
$35.00
$35.00
Student Member:
$0.00
Student Non-Member:
$0.00
$0.00
Emeritus/Life/Hon:
$14.00
$17.50

 


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