Palau

Palau (7° 30' N, 133° 30' E) Palau, Micronesia (Also known as Belau) is situated among the Western Caroline Islands on the western Pacific rim. The Palau archipelago consists of more than 350 islets most of which are remnants of a tectonically uplifted coral reef . The curved island chain runs for 150 km from North to South is 25km across at its widest point . The nearest large landmasses are New Guinea to the South and the Philippines to the West, both approximately 800km from Palau.

Geography

Area

• total: 458 sq km
• land: 458 sq km
• water: 0 sq km
• coastline: 1,519 km
• lowest point: Pacific Ocean 0 m
• highest point: Mount Ngerchelchuus 242 m

Palau has a total landmass of 458km2, Babeldaob is the largest island in this archipelago and covers an area of 363km2 , which is more than 80% of the landmass of the entire archipelago. The remainder of the landmass consists of three volcanic islands (Koror, Ngerekebesang and Ngemelachel), an atoll (Kayangel), platform like reef islands (Peleliu, Anguar and parts of Koror) and several hundred uplifted coralline limestone islands or “Rock islands” . In the Western pacific trench system, the Cenozoic subduction zone has lead to the Western Pacific basin being rimmed by trenches, back arc basins and island arcs . The islands constituting Palau are apart of one of these island arcs systems. The 350 islands and islets of the Palau archipelago constitute the southernmost exposure of the Kyushu Palau Ridge . Most of the islands are gaurded by a barrier reef with the exception for Kayangel Island in the North, and Anguar island as well as South West Island group to the South . Palau is tectonically active with Babeldaob and Koror still rising relative to sea level.

Babeldaob

Babeldaob is the largest island and primarily formed as a volcanic island. The volcanic substrates consist of breccias and interbedded tuffs formed during the Eocene and Oligocene , Mason et al 1956]. Within this volcanic substrate there are three distinguishable geologic units; the Babelthaup formation, the Aimeliik formation and the Ngeremlengui formation. These stratigraphic units record 12 million years of arc history . The erupted material consists of basalt, andesite and dacite. Although eruption was submarine, the islands were formed by subsequent uplift. The erosion of the volcanic units during the Miocene to Pliocene lead to the formation of clay deposits in the low coastal waters, this clay formation is known as the Airai clay . The interior uplands of Babeldaob are formed by three low ridge systems and have a maximum elevation of 242m above sea level is reached . The low ridge system is heavily eroded and has well rounded peaks, giving Babeldaob an undulating terrain .

Early studies of the geology of Babeldaob were thought to indicate tectonic upliftment and it was suggested by Snyder and Butler that no submersed habitation sites were likely on Babeldaob. However, the recent recognition of Holocene subsidence brings to light the possibility that the integrity and visibility of cultural deposits maybe compromised by wave erosion and tidal fluctuations.

Rock Islands

The rock islands are made of what is colloquially known as “Palau Limestone” which is actually raised coralline reef structures that formed in the warm waters that characterized the western Pacific during the early Miocene to late Pliocene, the calcareous detritus of these ancient reefs are cemented by calcite . These karstic (cave forming), limestone islands are defined by narrow elongated and precipitous ridges. The islands have poorly developed soils and no surface drainage .

The rock islands typically have a distinctive mushroom shape and can range from 10m to 200m in height . The distinct shape is a result of the limestone being undercut at sea level by a solution notch which forms an overhang. These overhangs can range from 0.5 meters to 6meters in height . The topography of the rock islands is caused by the freshwater dissolving the limestone, often forming features such as fissures, sinkholes, caves and speleothems will form .

Climate and Vegetation

The maritime tropical climate of the Palau islands is characterized by low seasonal variation. Palau has a mean annual temperature of 27oC and the range in variation from the coolest months (January and February) to the warmest month (April) is less than 4oC . Daily rains and short but torrential storms provide 3.8m of rain annually . The annual humidity on the islands is as high as 82%.

The Rock Islands are typically covered with a dense mass of tropical rain forest . The larger volcanic islands have vegetation varying from tropical rain forest (Approximately 75% of the Palau islands are forested) to savanna, and broad belts of coastal mangrove swampland . Within the forests thereis a great diversity of plant life. The upland forests are known for their hardwoods, palms and pandanus. The food producing forests associations are known for resources such as coconut, breadfruit, mango, banana and betelnut. Several species of taro, cassava, pineapple and tobacco are also grown in garden areas by indigenous Palauens. Swamp and Mangrove forests are found on coastal lowlands where the terrain is level and these forests that prevent the eroding soil from washing into the lagoonal areas. A large portion (16%) of Babeldaob is covered in savanna/grassland environments. While much of the Savannah environment may be the result of human activity, a large portion of it is almost certainly due to the poor soils on the volcanic island . A variety of other habitats are also present on Palau including patch, fringing, and barrier reefs, reef walls, mud flats, sand and rubble flats, sea grass flats, mangrove forests, estuaries, freshwater streams, lakes, both fresh and marine, and the Rock islands .

Terrestrial Fauna

Prior to human habitation, there were no mammals or terrestrial reptiles on Palau probably due to its extreme isolation and distance from other large landmasses . Early settlers probably imported pigs, rats and possibly fruit bats . Today, there are typical domestic animals kept by islanders.

WWII combat

Palau was the scene of significant combat during WWII. Task force 58’s operation DESECRATE ONE on March 30-31, 1944, more than 60 Japanese ships were sunk . The attack involved U.S. carrier based aircraft attacking Japanese shipping and land based targets situated throughout the Rock Islands and on the main islands.

Peleliu

One of the bloodiest land battles of the U.S. led Pacific campaign began on Sept. 15th, 1944 when the 1st marine Division landed on the beaches of Peleliu island near the southern end of the archipelago with the intent of taking what was considered a strategic airfield. The 15 square mile island was reportedly defended by upwards of 13,000 well entrenched Japanese troops and the invading U.S. Marines fielded as many as 20,000 troops . Following more than 70 days of fighting, a Japanese commander surrendered. By that time more than 1,500 U.S. servicemen had been killed and more than 10,000 Japanese servicemen had died .

Diving

Palau is world-renowned for its diving. Situated just of the Palau trench, deep water up-welling creates an ideal environment for a rich and abundant marine life. Famous dive localities include Blue Corner, Blue Hole and diving the many WWII wrecks.

Other interesting facts

In 1686, the Spanish explorer Francisco Lezcano named Yap Island (now in the Federated States of Micronesia) "La Carolina" after King Charles II of Spain. The name was later generalized to include all the islands.