SEMINAR: SEMINAR Today: MGG Student Seminar - March 29th 12-1 "Stromatolites in Hamelin Pool: Why do we care" Parke and "Using InSAR for monitoring earthquake cycle" Greene: CIMAS conference room

[David Weinstein <dweinstein@rsmas.miami.edu>]

On Mar 28, 2011 4:05 PM, "David Weinstein" <dweinstein@rsmas.miami.edu> wrote:

Stromatolites in Hamelin Pool: Why do we care?

Erica Parke

Stromatolites, organosedimentary structures produced by large mats of filamentous cyanobacteria, dominated the fossil record for over 80% of Earth’s history.  The world’s most spectacular, diverse, and extensive living stromatolite system lines the shoreline of Hamelin Pool in the Shark Bay area of Western Australia.  The Shark Bay stromatolites are the first known modern microbial buildups to have sizes and shapes analogous to Precambrian stromatolites.  Hamelin Pool is a shallow hypersaline embayment with an area of around 1270 km².  Tidal flow is restricted by the Faure Sill, a sea grass and carbonate sand bank.  The arid climate of the region combined with the restricted tidal flow into and out of Hamelin Pool causes the elevated salinities.  The bay was formed by marine incursion into a pre-existing eolian-dune landscape. The bathymetric configuration imposed by Cenozoic tectonism in Shark Bay and it’s dune systems is reflected in the elongated bays and inlets.  The shoreline of Hamelin Pool is lined with stromatolites and flat-lying microbial mats, extending for a total length of nearly 135 km.  Although Shark Bay stromatolites have captured the world’s attention for over 50 years, very few detailed geospatial and microstructural studies have been completed on the microbial reefs and associated sediments throughout Hamelin Pool.  Without these studies there is little ability to model these systems.  The purpose of this talk is to discuss why a greater understanding of facies distribution patterns, microfabrics, and physical properties of stromatolites in modern depositional environments such as Hamelin Pool are important.  Knowing more about this environment will lead to improved prediction capability for mineral and hydrocarbon exploration in carbonate rocks from Precambrian to recent.            

 

Using InSAR for monitoring earthquake cycle

Fernando Greene

Interferometric synthetic aperture radar (InSAR) provides the image capability for measuring ground surface deformation and inferring land surface changes. Measuring spatial and temporal patterns of surface deformation before, during and after earthquakes is useful for understanding rupture dynamics and estimating seismic risks. Although radar images before and after the earthquake are needed, satellites can acquire them over remote sites with areas measuring thousands of square kilometers and achieve spatial resolution of tens of meters. Some examples of its application in different areas of the world will be presented, denoting some of the limitations when measuring subtle large-scale tectonic processes such as inter-seismic and post-seismic deformation. I will focus in the Central Nevada Seismic Belt, where a recent study reported a broad area of uplift (~ 2-3 mm/yr) explained by postseismic mantle relaxation after a sequence of four earthquakes (M ~ 7) that occurred in the first half of the 20th century. New time-series results suggest that the uplift velocity decreased for the last 7 years, which is consistent with models of postseismic relaxation.

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Marine Geology and Geophysics
Rosenstiel School of Marine and Atmospheric Science
University of Miami
4600 Rickenbacker Causeway
Miami Fl 33149
http://www.rsmas.miami.edu/users/dweinstein/

---------- Forwarded message ----------
From: Estelle Chaussard <echaussard@rsmas.miami.edu>
Date: Tue, Mar 22, 2011 at 10:04 AM
Subject: SEMINAR: MGG Student Seminar - TODAY -Marichesini and Yang
To: SEMINAR@rsmas.miami.edu

MGG Student Seminar
Today
12:00pm CIMAS Conference Room

Pierpaolo Marchesini
What is the influence of fractures on fluid flow? 4D GPR gives a new prospective in characterizing fluid transport in carbonate rocks.

Abstract:Carbonate rocks hold more than 60% of the world’s oil, 40% of the world’s
gas reserves and are the most common of all bedrock aquifers.
Post-depositional mechanisms processes like diagenesis, compaction,
fracturing, shearing result in large variations in the reservoir quality
of carbonates. In particular, fractures represent major fluid conduits
often controlling control much or all of their permeability. Yet,
characterization of the parameters controlling fluid flow in fractured
carbonates relies largely on 0.01-0.1 m scale sample measurements,
upscaling, and modeling. For the first time we conducted a 1-10 m scale
infiltration experiment using time-lapse Ground Penetrating Radar (4D GPR)
to monitor fluid flow and quantify water content changes with centimeter
precision in a reservoir analog. Initial results help delineating
flooding/drainage boundaries, determining the influence of faults and
deformation bands on fluid flow propagation rates and show a switch over
time from a gravity-driven to a capillary-driven transport mechanism.

Qian Yang
Investigation of the Health of Greenland’s Ice Sheet

Abstract:There is widespread concern about the health of Greenland Ice Sheet because of its close relationship with global warming and sea level rise.
There is a lot of work going on now to try to understand the ice sheet dynamics:  is it healthy, will it melt quickly or not?
Observations (gravity, elevation and marginal outlet glacier velocity) over the past decades show a rapid acceleration of ice mass loss of the
Greenland’s ice sheet. In this talk, some background knowledge about the Greenland’s ice sheet will be given. Also, I’ll present how to use GPS data
 to study the mass loss of the Greenland, and how to correct atmospheric pressure loading and to avoid post-glacier rebound effect.