Total annual layer (summer + winter) thickness for 36 varves is plotted on the graph to the right. A data file and the lines posted on the image were all created by a computer program designed to sequentially measure varve sequences.
Blockage of the bile ducts may cause symptoms such as abdominal pain, nausea and vomiting. If the bile duct remains blocked bile is unable to drain properly, jaundice (yellow discoloration of the eyes and skin) can develop and an infection known as cholangitis may also occur.ccasionally the gallstones can also block the flow of digestive enzymes from the pancreas because both the bile ducts and pancreas ducts drain through the same small opening (called the Ampulla of Vater) which is held tight by a small circular muscle (called the Sphincter of Oddi).
The most common cause of an obstruction in the biliary tree is a bile duct stone (choledocholithiasis). This includes a stone or stones lodged in the common hepatic, cystic or common bile ducts. The causes, symptoms and treatment is discussed further under Bile Duct Stones.