Assignment 5: KTE Key Term Exploration

KTE - Key Term Exploration #4a
Anne Ainsworth, Geol 110 Online Fall

Key Term: Dendrochronology

Dendrochronology
The science of tree rings is known as dendrochronology. It is also referred to as tree-ring dating and this absolute dating technique uses annual growth rings of trees to determine the age of the tree, how fast it grew and what the climatic conditions were like during the lifetime of the tree. Dendrochronology is also used to calibrate radiocarbon dates.

http://www-saps.plantsci.cam.ac.uk/treerings/index.htm

The picture at right illustrates how a tree grows.

As the trunk grows thicker every year, it adds a Inner Bark

new growth ring. New growth takes place in the cambium Hardwood

which is the outer layer of the tree. Bark

Cambrium

Sapwood

The picture below was taken November, 1988 of my sister-in-law and Mother at the North Grove of Calaveras Big Trees National Park. In another picture, we are standing on a sequoia tree stump that was cut in the 1850s. The tree rings are clearly visible on the stump. Some of these trees weigh 2,600 tons and the oldest in the grove, based on ring count is 3,200 years old. The giant sequoias, Sequoiadendron giaganteum, were first seen by a European in the Calaveras Grove - explorer J.K. Leonard in 1833. As an aside, my brother, who attended the University of Utah had a professor, Donald Currey, who as a graduate student, cut down one of the oldest, if not the oldest tree on earth. It was a bristlecone pine, named Prometheus by Dr. Edmund Schulman, who first researched the age of the bristlecones in 1954. Prometheus’ age was estimated at over 4,862 years old. When we visited the Ancient Bristlecone Pine Forest on the White Mountains, some 15 years ago, we were awed by their strange beauty (although problems with the altitude by some of our party caused us to turn back before completing the entire loop). The oldest trees are unmarked so no one disturbs them.

KTE - Key Term Exploration #4b
Anne Ainsworth, Geol 110 Online Fall Key Term: Law of Superposition

The Law of Superposition. The law of superposition, a concept proposed by Nicolas Steno in the 17^th century, states that undisturbed rock strata that are younger will be deposited on top of strata that are older, given normal conditions of deposition. The picture above shows the many layers or formations that make up the Grand Canyon. The oldest layers are on the bottom, near the river and the youngest layers on top. (above illustration from: http://www.bobspixels.com/kaibab.org/geology/gc_layer.htm)

Buttes-of-the-Cross – Green River Utah. From October 1 – 8, 1998 we kayaked down the Green River from the town of Green River to the takeout on the Colorado River at Spanish Bottom and took pictures of the many geologically beautiful formations. However, we took slides and I couldn’t get them converted to pictures in time for this KTE. Below is a picture taken from the web (http://www.pbase.com/camboman/image/43615347) of Buttes-of-the-Cross, which is located on the western edge of Canyonlands National Park. From afar, as we neared the formation, Buttes-of-the-Cross looked like one butte in the shape of a cross. However, as you get closer, you can see that it is actually two buttes. On John Wesley Powell’s 1869 trip down the Green River, the formation was originally named Butte-of-the-Cross until the expedition came closer and realized it was actually two buttes. The mesas consists of a complete Triassic stratigraphic section, in ascending order: Moenkopi Formation (cliff), Chinle Formation (slope), Wingate Formation (cliff), Kayenta Formation (Cliff), and Navajo Sandstone. http://3dparks.wr.usgs.gov/3Dcanyons2/html/desolation.htm