A blood transfusion is a safe, common procedure in which blood is given to you through an intravenous (IV) line in one of your blood vessels. Blood transfusions are done to replace blood lost during surgery or due to a serious injury. A transfusion also may be done if your body can't make blood properly because of an illness. During a blood transfusion, a small needle is used to insert an IV line into one of your blood vessels. Through this line, you receive healthy blood. The procedure usually takes 1 to 4 hours, depending on how much blood you need. Blood transfusions are very common.
1 The roots of the ancient mountain range that now lies at the bottom of the Grand Canyon were formed about 1.7 billion years ago. 2  There is then an unconformity of about 450 million year in which the rocks are missing. 3  At 1.25 billion years ago the first sedimentary layer, the Bass Formation, was laid down.
The geology of the Grand Canyon area includes one of the most complete and studied sequences of rock on Earth. The nearly 40 major sedimentary rock layers exposed in the Grand Canyon and in the Grand Canyon National Park area range in age from about 200 million to nearly 2 billion years old.Most were deposited in warm, shallow seas and near ancient, long-gone sea shores in western North America.ach meter walked on the trail represents one million years of Grand Canyon's geologic history. Bronze markers on the trail mark your location in time. The trail begins at Yavapai Geology Museum at 2 billion years ago, and ends at Verkamp's Visitor Center.