East Coast Geopark
The distribution range of Baishuimu is in the coastal areas of Taiwan. It can also be seen on the beaches or coral reefs along the coast of Lanyu and Green Island. The fruit can be spread by seawater. In addition to its salt and drought tolerance characteristics, the leaves are densely covered with hairs It also grows fast, with dense white flowers becoming the focus of attention.
Wave marks are generated after being affected by ocean waves or currents. When the vortex is weakened into advection, there will be slight friction at the bottom, resulting in smaller wave-like undulations, forming a gentle and steep sedimentary structure, which can be used to indicate the ancient flow direction. It can be seen from the photos that the joint generation time is later than the wave mark, and the structures such as joints are generated after the rock layer is lifted and compressed.
The tofu rock landscape formed after the rock formation was cut by two sets of parallel joints. The seawater continues to erode along the joint surface, and the fracture surface will expand. The tofu rocks of Xiaoyeliu are not square or rhombic, but many of them are rectangular and look like tofu. They are called "tofu rocks".
Coral reef rocks were originally located on the sea floor. They would appear above sea level only when the plates were squeezed and the crustal uplifted. The sandstones on the lower side were relatively resistant to corrosion. Coral reefs are lined up on sandstone, which also indicates that the sea level once rose, allowing coral reefs to grow on sandstone.
The reason for the formation of mushroom-shaped rocks is that the corrosion resistance of the upper and lower layers of the rock is different, leaving harder upper nodules after being eroded. With continuous erosion and uplift, the sandstones that are more susceptible to erosion in the lower layers will gradually become narrow necks.
The nodules in the center of the rock are harder than the surroundings, so the surroundings are more likely to be eroded and recessed. At the same time, the depressions are grayish in color. It can be judged that the rocks are eroded by wind and seawater at the same time, and gray salt crystals are left after the seawater evaporates.
Coastal shellfish such as barnacles have stayed. Due to the secretion of organic acids, the surface of the rocks is often uneven, forming many round depressions. The formation of a circular cavity is that when the waves are sprayed on the coast with the wind, it will remain in the concave of the rock surface to form stagnant water. The cavity is gradually enlarged by weathering. When many round cavities are gathered on the same rock surface, they are like honeycombs and are called honeycomb rocks.
In the photo, it can be seen that ginger rock and the underlying rock layer have obvious upper and lower layers, indicating that the lithology is different. Only part of the honeycomb rocks of ginger stone developed on it, forming a strange rocky landscape. It can be explained that the rock formation composition and cementation are different due to different erosion.
Sandstone stratification is clear. Wave marks and iron oxide traces in the rock layer can be seen in order from the bottom to the top, which is helpful for understanding the sedimentary environment at the time. It can also be seen that the same sandstone layer has different erosion resistance . It can also be seen from the photos that the rock blocks are broken due to the joints.