Science Spotlight

Station ANTS

Researcher: D. Sarah Stamps
Virginia Tech

GPS station ANTS is located in northern Madagascar.

Name: Ants
Country: Madagascar
Elevation: 29.0 m
Lat/Long:  -12.3153 / 49.3275

Plate Boundary Formation in Madagascar

Almost a billion years ago Madagascar was two separate parts. East Madagascar was attached to a continent called East Gondwanaland and West Madagascar was attached to a continent called West Gondwanaland. Over time the two continents joined forming the landmass we know as Madagascar (Figure 1). The place where they joined - in central Madagascar - is known as a suture. Sutures are weaker than the surrounding land and can become a place where continents break apart.

Currently, the suture in central Madagascar has lots of small earthquakes (Figure 2). The suture also has a volcano and hot springs, which means there is hot material beneath the island. This hot material can also cause weakening in the suture. Since the suture has active tectonic processes, I hypothesize that central Madagascar is forming a new plate boundary. To test this hypothesis I work with scientists in Madagascar to install GPS instruments and measure how Madagascar is moving (Figure 3).

Figure 1.The approximate locations of East and West Madagascar (in blue) 700-800 million years ago (DeWitt, 2003).

Figure 3. The blue circles are where we are making GPS measurements. The site ANTS is in the north. The site in the middle of Madagascar is a continuous GPS site that was installed in 2008. The other sites are benchmarks that we installed and measured in 2010. We re-measured them in 2012.


Figure 2. Orange dots represent small earthquakes in Madagascar that have been detected since 1970. The transparent orange region is the location of the suture.

Last modified: 2019-12-26  16:24:58  America/Denver  


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