Saturday, Apr 23, 2016, 4:00 pm - 6:00 pm
575 Osgood Street
North Andover, MA
Lecture 15: Ha Long Bay – Dramatic Karst Landscapes
In the last few lectures, we’ve talked about caves and sinkholes, but we might think of what happens at Ha Long Bay on the northern coast of Vietnam as something like caves and sinkholes taken to their extreme. Geologically speaking, caves and sinkholes are early stages of karst geography. In some areas that have sinkholes and are subject to a great deal of rain over a long period of time, the sinkholes merge together, leaving numerous caves and underground rivers beneath the surface. Much of the surface itself collapses, and only the toughest, most weathering-resistant features remain standing. The result is a landscape such as what we find in Ha Long Bay.
Lecture 16: Bryce Canyon – Creative Carvings of Erosion
In the past few lectures, we’ve seen some geologic wonders that occur in karst regions, where weathering and erosion from rain wear away both at the surface and in the interior of layers of limestone. In this lecture, we’ll look at other forms of erosion caused by rainwater, specifically in Bryce Canyon in the state of Utah. To some degree, everything on the surface of the Earth shows the effects of erosion. Most geologic features on Earth’s surface, such as mountains, form slowly over millions of years, and they erode as they form, but even those features that form quickly, such as volcanoes, still show the effects of weathering and erosion almost as quickly as they are built.
RSVP's are closed for this event.