
We bid farewell to Cecilia and Khaled at the border, and after two hours of immigration and customs paperwork we started our drive from near sea-level to 6000ft. The drive to our hotel took almost 5 hours because we geologists can't resist stopping when we see a good outcrop!
This border between Bangladesh and India adds another challenge to our work. We often meet border security guards who do not want us to go close to the border. This can be very frustrating if we see a good outcrop that we cannot access. We can see Bangladesh from our hotel, although it's often covered in clouds (see photo). This border also makes building in Bangladesh difficult because almost all the hard rock is on the Indian side of the border, and must be transported across the border by truck, unloaded and reloaded onto a Bangladeshi truck -- all by hand!
Right now we're studying the central portion of the Dauki Fault, focusing on the area just south of the letter n in Shillong Plateau on the map above. Measuring strike and dip using our compasses, we can make a map to to understand the shape of this really large fold in the Earth's crust. The fold is cored by very old rocks from more than 2.5 billion years ago - that's almost half the age of the Earth! Along the southern margin we have progressively younger rocks that were deposited before the rivers brought sand and mud to build up Bangladesh. At the time of the Dinosaurs, this was a beach! On top of that we have limestone with lots of fossils including sea urchins and shells. By understanding the relationships between these rocks and mapping the faults we find, we hope to learn more about how the crust is deforming.
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