🛶 🌗 #Granite #weathering Journey
Artwork Introduction
At posted coordination stands the sculpture, called Ship Moon. Ship Moon is a public art piece created by Japanese artist Uehara Kazuaki in 2002. The sculpture stands quietly along the Tamsui riverside, resembling a ship that symbolizes the connection between water culture and Tamsui’s historical heritage. One side of the artwork is finely polished, while the other side retains the natural rough texture of the stone, presenting a contrast between human craftsmanship and the power of nature.
The material used for Ship Moon is Mikage Stone (御影石), a type of granite commonly used for construction and sculpture.
This geocache will guide geocachers to learn about granite and its minerals, as well as explore the process of natural weathering through the artwork.
Granite Introduction
Granite is an intrusive igneous rock, formed by the slow cooling of magma deep beneath the Earth’s surface. It is commonly found in mountain ranges and coastal landscapes. In the Ship Moon sculpture, the following minerals can be observed:
Plagioclase Feldspar, White, the main component with larger grains
Quartz, Gray or Transparent, semi-transparent with high hardness
Potassium Feldspar, Pink or Brown, may be mixed within the rock
Biotite, Black, often reflective in small and flaky grains
Granite Weathering in Nature
Although granite is hard and durable, it still undergoes weathering in natural environments. When rainwater infiltrates cracks in the rock, minerals gradually transform into clay. Iron-rich minerals like biotite oxidize, leaving behind yellow or reddish weathering marks. Weathering roughens the rock surface, loosens grains, and eventually forms fine sand or clay particles.
The location where the sculpture Ship Moon is located is near the estuary. It is close to the sea and is prone to wind and rain. High temperatures and exposure to sunlight in summer. These environmental conditions make the granite susceptible to weathering.
Types of Weathering
1. Physical Weathering
• Thermal Expansion: Daily temperature fluctuations cause the rock to expand and contract, forming cracks over time.
• Frost Wedging: Water infiltrates cracks, freezes, and expands, breaking the rock apart.
• Pressure Release: As erosion reduces pressure on the rock’s surface, it causes layers to peel off.
2. Chemical Weathering
• Oxidation: Iron-rich minerals react with air, forming yellow rust stains.
• Hydrolysis: Feldspar reacts with water, transforming into clay minerals that weaken the rock.
• Dissolution: Acidic rainwater gradually dissolves quartz or carbonate minerals.
Logging Tasks
1. In your observation, which minerals might be responsible for the main color of the sculpture?
2. Examine the sculpture closely and identify any visible minerals. Describe which minerals you found.
3. Find the connection line (yellow area) on the sculpture. Do you think the yellow color in the area is the original mineral or the result of weathering? If it is the original mineral, explain which mineral it might be. If it is weathered, determine which type of weathering may have caused it.
Please, do not post your answers in the log. Log this EarthCache as “Found it” and send your suggested answers via the message system. I hope you enjoy this EarthCache. Favorite Points Appreciated.
🛶 🌗 #Granite #weathering Journey 舟月與花崗岩的風化之旅
作品介紹
公布點為一座名為《舟月》（Ship Moon）的雕塑。它是日本藝術家上原一明（Uehara Kazuaki）於2002年創作的公共藝術作品。雕塑靜立於淡水河岸，外型像一艘船，象徵水域文化與淡水的歷史連結。作品表面一側經過細緻打磨，另一側保留岩石自然破裂的粗糙樣貌，呈現人為雕琢與自然力量的對比。
舟月使用的石材為御影石，也就是花崗岩。御影石是日本常用的建築與雕塑石材，因為耐久且質感細膩，廣泛用於公共設施與景觀藝術。
這個地質寶將帶領尋寶玩家從藝術作品認識花崗岩與礦物，並探索自然風化的過程。
花崗岩介紹
花崗岩是一種深成火成岩，由岩漿在地底緩慢冷卻而成，常見於山脈與岩岸地形。舟月雕塑的花崗岩可以觀察到以下礦物：
斜長石 (Plagioclase Feldspar),白色,最主要的成分，顆粒較大
石英 (Quartz),灰色、透明,呈半透明狀，硬度較高
鉀長石 (Potassium feldspar),粉紅色或棕色,可能混合於岩石中
黑雲母 (Biotite),黑色,片狀小顆粒，常反光
花崗岩在自然中的風化
花崗岩雖然堅硬，但在自然環境中仍然會經歷風化。當雨水滲透岩石裂縫，礦物會逐漸轉變成黏土，黑雲母中的鐵質礦物也會氧化，留下黃色或紅色的風化痕跡。風化作用會讓岩石表面變粗糙，顆粒鬆散，最終形成細小的沙粒或黏土。
雕塑舟月所在的位置為淡水，此地臨海多風雨，夏季高溫、陽光曝曬，這些環境條件讓花崗岩容易受到風化的影響。
風化類型
1. 物理風化
熱膨脹風化：日夜溫差讓岩石膨脹與收縮，久而久之產生裂縫。
冰楔風化：水滲入裂縫後結冰膨脹，使岩石裂開。
壓力釋放風化：表面岩石隨著侵蝕減少壓力，導致剝落。
2. 化學風化
氧化作用：鐵質礦物與空氣反應，形成黃色鏽跡。
水解作用：長石與水作用，變成黏土礦物，讓岩石變鬆散。
溶解作用：雨水中的酸性成分會逐漸溶解石英或碳酸鹽礦物。
登錄任務
1. 請觀察雕塑的主要顏色，可能受到哪種礦物的影響?
2. 請靠近欣賞雕塑，盡可能在雕塑表面找到花崗岩中的礦物，說明你找到哪些礦物。
3. 請在雕塑找到連接區域(黃色位置)。你覺得此區域的淡黃色是原本礦物的顏色，或是受到風化的影響？如果是礦物原色，請說明是哪種礦物，如果有受到風化影響，請判斷它屬於哪些風化類型。
請不要在log中公布你的答案。登錄此地質寶為「found it」並透過 geocaching.com 訊息發送給我您建議的答案。希望你喜歡這個地質寶，歡迎給予FP。