Recently in the news due to the crash of Air Asia Flight 8501, the Java Sea is the southern section of a vast shallow sea that extends southward from Thailand, Cambodia and Vietnam to the southern islands of Indonesia. Averaging just 150 feet in depth, the Java Sea was an inland plain during the Pleistocene Ice Age.
Indeed, the archipelagos of Malaysia, Indonesia and the Philippines occupy a broad peninsula of the Eurasian Plate, extending southward from what is now the Southeast Asia mainland. Subduction volcanoes rim the peninsula, where the edges of the Australian, Pacific and Philippine Plates are being shoved beneath the Eurasian Plate. As the climate began to warm near the end of the Pleistocene, some 15,000 years ago, continental and cordilleran glaciers began to melt and sea levels rose; of course, this process continues today, intensified by our use of fossil fuels. Moving up coastal river valleys, the ocean waters spilled across lowlands of the Eurasian Peninsula, producing archipelagos of high ground.
Transient shallow seas, such as the Java Sea, have left sedimentary strata across the Continents; marine limestones, dolomites, shales and siltstones cover most of the ancient Precambrian basement rock, as do sandstones deposited as beaches along the shallow seas. Seemingly a permanent feature of Earth's landscape from the perspective of our brief human life span, the Java Sea will expand and contract as sea levels rise and fall; its sediments, now scoured to retrieve aircraft debris and human remains, may, in the distant future, be uplifted and sculpted into mesas, plateaus or mountain ranges.
