How are peninsulas formed?

Question

How are peninsulas formed?

Answer 1

peninsulas are formed when waves start hitting a section of rock on the coastline that is not as easilly eroded as the rock around it. Over time it starts to stick out as a headland and if that process continues for enough years, the waves hitting the headland will start to curve around the sides and begin eroding the softer rock behind. If this continues long enough, that softer rock behind will slowly disappear and you may end up with an offshore rock attached to the land by a sandy beach

Answer 2

Each peninsula is different, and it will depend on geological and weather processes that enable to create them.  Some peninsulas were created by collision of continental plate with islands which is the case of the Iberian, Aegean, and Italian peninsulas.  Other peninsulas appeared by tearing of the Earth’s crust and filling the break with sea water.  This is the case of the Baja California and Arabian peninsulas.  Other peninsulas were created by volcanism and eventual merging of volcanic islands into larger land mass like Aleutian.  Also you will notice that many small peninsulas are in the areas further from the tropics and that is because of the extensive glaciations.  Glaciers are heavy and they depressed many underlying crust and created bow like shapes on it (like Great Lakes and Baltics).  Other times, glaciers pushed sand in front of it, and after retreat, we have Cape Code peninsula.  The last type of peninsula was created by orogeny and uplift of land by underground geological process.  Since no uplift is spread equally the lower land got flooded since it was sinking, and higher ground was pushed higher…This is the case of Kamchatka and Florida peninsulas.  In Florida, also large amount of mineral deposits from Atlantic (such as sea shells) helped to create this land.  Over millions of years, compressed minerals were slowly uplifted above sea level.

In summary:

Collisions, split, volcano, glacier, uplift, and deposits.  Many peninsulas were created by combination of the several geological processes that I had mentioned.  This process took millions of years.