The Rare Rocks and Fossils

Batuan Langka dan Fosil

In Ciletuh geoarea, geological heritage site exists in the form of rare rocks and fossils. The rare rocks consist of ophiolite rocks and metamorphic rocks older than 60 million years old and sedimentary rock composed of melange and nummullites fossil of Eocene age. Ophiolite rocks derived from oceanic crust consist of: peridotite, layered gabbro, gabbro dike, plagiogranit, pillow lava that covered by deep sediments of chert. While the metamorphic rock is a rock resulting from the subduction proccess between the continental crust and oceanic crust due to high pressures and/or high temperatures. This rock consists of: mica schist, green schist, amphibolite and serpentinite. The sedimentary rocks consists of quartz sandstone at the top and melange at the bottom. This sedimentary rock is then known as Ciletuh Formation.

Greenschist (Foto Rinaldi)
Fosil numumulites (Foto Mega FR)
Batuan sedimen laut dalam (Chert-Rijang) di komplek Melange dekat Pulau Kunti (Foto Mega FR)
Batubatik oksidasi (Foto Mega FR)
Lava Bantal FOTO: RON AGUSTA
Lava Bantal FOTO: RON AGUSTA

The most ideal location to see the different types of these rocks are in Gunung Badak up to the south coast of Kunti island, Batu Naga Complex near Batununggul beach, Sodong Parat near the Cikepuh beach , as well as the area of Gunung Beas, Tegal Pamindangan, Tegal Sabuk, Keusik Luhur, Cikepuh River, CikopoRiver and Citirem. In the area of Gunung Badak, it can be clearly seen the peridotite, gabbro, serpentinite, pillow lava, melange, and nummullites fossil. While in the Batu Naga complex, it can be found the type locality of Ciletuh Formation that partially fractured due to the influence of tectonics. These fractures are filled by quartz and carbonate to form a specific pattern and then undergone oxidation process so that exhibit various color from brownish to yellow until dark red which resulting beautiful pattern (motif). This sedimentary rock is called as Batu Batik by local people. Gunung Beas area, is the most ideal place to visit and study about the peridotite rocks which originated from the top layer of the Earth’s mantle. This place also has a distinctive morphologic shape of the rocky hill where only grass plants that live on it, because the very thin layer of soil cover and rich in ferrous (Fe) and magnesium (Mg) elements in the soil. While Cikepuh River area and Sodong Parat are best outcrops to study about gabbro and plagiogranite that originally came from oceanic crust, and metamorphic rocks of amphibolite and serpentine that formed due to the subduction.

Peridotit Serpentinit (Foto Rinaldi)
Peridotit Serpentinit (Foto Rinaldi)