Introduction to the guided tour of the coastal landscape area in Nanshantou,Qingqi

 

潮汐變化、潮間帶差異導覽

 

Algae tour

 

The onion skin weathering of the basalt rock

 

植物痕跡化石

 

  Diverse geological features of great and lesser Kinmen produce rich landscape and ecology. Taiwan, including Matsu and Penghu, have established six "geological parks", However, Taiwan, Penghu, Kinmen and Matsu still lack of Kinmen, so It is hoped that with the efforts of the county government, Kinmen National Park Headquarters, and the Kinmen Environmental Conservation Association, Kinmen will also establish a geopark as soon as possible to protect the island ’s natural geological environment and become an important tourist attraction and environmental education place.

In 1999, in order to protect the earth ’s heritage, UNESCO promoted the World Geopark, It aims at the conservation of geological landscape, It also incorporates multiple values such as community participation, sightseeing and recreation, and environmental education. In 2011, Taiwan Forestry Bureau promoted the establishment of 6 geoparks. In addition to Liji Taitung ,Yanchao Kaohsiung ,Caolin Yunlin, and the northern coast (Yehliu pedestal rock), there are Penghu and Matsu

If you want to get close to the rich ecological and geological landscape of the Kinmen coastline, the time of rising tide and ebb tide is a problem you must pay attention to!

 

Under the influence of the rotation of the earth and the gravity of the sun and the moon, the sea level will rise and fall, The rise of seawater is called "Rising tide", and the highest point of rise is called "Full tide"otherwise, it is called "Ebb tide", ”Dry tide”, The highest and lowest difference in tide is called "Tidal range", but the Tidal range is not fixed.

 

Normally, there will be two rising tide and ebb tide in a day; but because the cycle of rising and ebbing is about 12 hours and 25 minutes,extra 25 minutes, because of the two cycles, the daily rising and ebb tide time is delayed by about 50 minute.

For example: today's full tide is 12 o'clock, and tomorrow's full tide is 12:50. At the same time, the result of each delay also causes a full or dry tide sometimes only once a day.

 

There is a proverb about tides in Kinmen:

“The noon full  1th and 15th ,the morning and night full 8th and 23th”

 

It simply explains the changes in the tide of Kinmen. Remember it and understand the basics of it. The date it refers to is the "Lunar Calendar", and the term full refers to the "full tide."

 

But now there is a simpler way. As long as the mobile phone clicks on the mobile version of the Jincheng Tide Forecast of the Central Weather Bureau, you can see the forecast time within 30 days at most.

 

If you use a computer, please go to the website of the Central Weather Bureau, click "Fishery Meteorology" on the left column, then look at the tide forecast, click the area - Sea surface in Kinmen, you can know the current tide status of Kinmen, if you want to arrange a trip, you can click "Tide forecast for the next 30 days" / Kinmen, there is information for reference

Basalt coast landscape

Qingqi is located in the southwest of Lieyu and is the largest traditional tribe on the island, and its residents are mainly engaged in agriculture and fishing. From the front right of Shangqi National Elementary  School, you can reach the waterfront through the controlled outpost. Looking along the north coast, there is a Granite-gneiss in the beach.

Weathered basalt

The surface presents different colors such as yellow, red and brown, It is very colorful. Basalt is a dark green rock. When it is weathered, the iron in the rock is released and oxidized to ferric iron. And iron oxide has different colors because of different water content

The onion skin weathering of the basalt rock

Basalt is composed of fairly uniform particles, It is subject to thermal expansion and contraction, or due to weathering, the minerals in the rock are hydration and expanded, and the rock is easy to form concentric layers and exfoliate. This causes so-called onion skin weathering, which is easily observed on the rocky walls of the coast.

Basalt stomata and amygdaloidal structure

The magma sprayed out of the surface, and the gas in the magma escaped, and then formed stomata after cooling. If the stomata are filled with minerals of secondary carbonates, they are amygdaloidal structure.

Basalt weathering and formation of shingle beach

After the magma sprayed out of the surface, rapid cooling caused the rock to shrink and form joints. Weathering can easily proceed along joints and quickly. Due to the seashore, weathering and seawater erosion are quite severe, and the sedimentary rock under the basalt is weak in lithology, so easily eroded by seawater, and basalt easily collapses. The collapsed basalt blocks piled up on the beach or formed shingle beach.

Plant ichnofossil and strata

Middle section of Qingqi Coast, Clay-bearing sandstone formation below basalt lava flow In the sandstone layer, there are a lot of fossils The fossils are the creatures that originally lived in the intertidal zone, the residual structure of living and feeding, and the traces left behind as the rocks accumulate. Due to the weathering and erosion of the surface of the basalt's lava above the sandy layer, Its groundwater has high iron content, In the original fossil cavities, due to the adsorption of muddy sediments, the iron is gradually precipitated, which causes limonitization fossils. When the upper lava eroded away, the fossils were finally exposed.

Columnar basalt in Nanshantou

Traveling south along the Qingqi coast, you can reach the southernmost tip of Nanshantou, The cliffs made of columnar basalts here are majestic and rich in landscape beauty. Basalt resists the strong southwest monsoon, protects the southern coast of Lieyu, and is an excellent natural barrier.

The basalts in different regions are more or less different in color because of their different compositions. For example, the basalt of Bali is pure black, and the basalt of Nanshantou is gray-black. Zhangzhou Volcanic Geopark also has basalt, but its appearance is different from the basalt of Nanshantou and has its own characteristics.

 

Rocks are mainly divided into three categories: igneous rocks, metamorphic rocks, and sedimentary rocks. Igneous rocks are formed by magma cooling. Sedimentary rock is the rock formed after the weathered sand particles slowly accumulate and clump. Metamorphic rocks are rocks transformed from igneous rocks and sedimentary rocks which after high temperature and high pressure.

Igneous rocks are divided into volcanic rocks and plutonic rock. Volcanic rocks are formed by the cooling of magma after being ejected from the surface, and plutonic rock are formed by the slow cooling of magma under the ground. The basalts in Qingqi and Nanshantou are caused by the magma erupted by ancient volcanoes 13 million years ago,so the basalts in Nanshantou are volcanic rocks in igneous rocks.

 

Lieyu Geopark is expected to have 6 locations in Donggang, Qingqi Port, Nanshantou, Shaxibao, Maogongshi and Qilin Mountain. Each location has its own characteristics. Among these locations, although Qilin Mountain is also basalt, because it is located at the highest of Lieyu , it has a superior geographical position and unique characteristics, so it is also classified as a geopark.

The grid outside the columnar basalt are joints, after the joint formation, the onion-skin weathering slowly occurs due to the weathering, so the onion-skin weathering occurs in the joint grids. The joints are caused by magma cooling and shrinking. Onion-skin weathering is caused by the infiltration of air and water after the formation of rocks. So the onion-skin weathering occurs after joint formation.

 

The upper part of Basalt in Nanshantou is red, the reason why the lower part is gray-black color is because the upper minister has been exposed to outside The weathering starts first from the upper part, and therefore the upper part begins to oxidize and weather into red. The lower part of the basalt is protected by the upper part and is less weathered, so it can maintain the original gray-black color.

 

The basalt in Nanshantou will slowly collapse due to weathering and ocean erosion. Laying sand on the bottom of the basalt may slow down the ocean erosion, but onion-skin weathering cannot be avoided, just let it be.

There are also sandstone and limonite in the seaside of Nanshantou. The sandstone (Kinmen layer) of Nanshantou was originally under the basalt, and it was gradually exposed due to the erosion of the basalt above. The black strips on the sandstone are fossils which inferred to carbonization of ancient plants. The fossils of the roots and trunks of petrochemical ancient  plants are suspected at the edge of limonite, it has carbonization inside. These fossils are very fragile, so visitors must be very careful when passing by.