Pillow Lava and Foraminifera Fossil Parang Ireng Beach

Pantai Parangireng yang terletak sekitar 850 m selatan Pantai Pancur, dan termasuk dalam wilayah Taman Nasional Alas Purwo bagian barat, menyingkapkan lava bersusunan andesit basal yang berwarna hitam. Warna batuan ini rupanya mendasari penamaan pantai (ireng, bahasa Jawa=hitam). Lava yang sebagian besar terfragmenkan ini menunjukkan ciri bantal, yang menggambarkan bahwa aliran lava dari sumbernya masuk ke dalam lingkungan air (laut). Pasir di Pantai Parangireng justru dikuasai oleh pasir berwarna putih. Butiran pasir berukuran sangat kasar itu merupakan fosil foraminifera Schlumbergerella florensis yang dijumpai dalam jumlah sangat banyak. Sebarannya di pinggir pantai mencapai beberapa km, dengan lebar antara 10-25 m, dan tebal lebih dari 1 m. Disini juga kurang lebih hal yang sama dengan daerah pancur, namun fitur batu gampingnya tidak terlihat.

Parangireng Beach, which is located about 850 m south of Pancur Beach, and is included in the western part of the Alas Purwo National Park, reveals lava composed of black basalt andesite. The color of these rocks apparently underlies the naming of the beach (ireng, Javanese is black). This mostly fragmented lava shows pillow characteristics, which illustrates that the lava flows from the source into the aquatic environment (sea). The sand on Parangireng Beach is actually controlled by white sand. The sand grains are very coarse, which are fossils of foraminifera Schlumbergerella florensis, which are found in abundance. The distribution on the beach reaches several km, with a width of between 10-25 m, and a thickness of more than 1 m. Here too, more or less the same thing as the pancur area, but the limestone features are not visible. The volcanic activity in southern Java which is now only traces of it is the forerunner of the activities of the current Ijen Caldera Complex.

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