text: A sound called the Bergie Seltzer is made when these structures degrade.
full_question: A sound called the Bergie Seltzer is made when these structures degrade. A letter and number is assigned to every one of these structures, based on the longitude of their origin. The two basic forms of these formations are tabular and non-tabular. A loud cracking noise often precedes when these structures are formed in a process called (*) calving. These mobile structures can cause seabed gouging when oceanic currents move them towards shallower waters. For 10 points, name these geological features, of which only 10% of their size can be seen above sea level due to the properties of water’s density in different phases.
first_sentence: A sound called the Bergie Seltzer is made when these structures degrade.