Introduction
Goddess of Nine Oakes Village（Vila de Nossa Senhora） is located on a coastal hillside on the southeast side of Taipa Island, Macao, on the west bank of the Pearl River Estuary, adjacent to the South China Sea. It is one of the most remote natural areas in Macao. Its eastern side faces the open sea and is directly affected by the tides and monsoons of the South China Sea. The coastline is mainly composed of bedrock, forming typical marine erosion landforms. For more information about Goddess of Nine Oakes Village, please visit https://www.geocaching.com/geocache/GCAKME2.
Geological structure of Kau Tau
The coastline beside Goddess of Nine Oakes Village is one of the few original bedrock coastlines in Macao. The other coasts of Macao are mostly sandy or sandy-mud coasts, composed of Quaternary sediments. They are prone to be reshaped by waves, forming gentle beaches, lacking the steep form of bedrock coasts. The bedrock along the coast of Kau Tau is mainly composed of granite from the Yanshanian period (formed during the Jurassic to Early Cretaceous, approximately 135 million to 200 million years ago), which is a product of the magmatic activity along the South China coast. This type of granite is hard in texture and has a relatively strong resistance to weathering, but it has well-developed joints (fissures), providing an entry point for wave erosion.
Joint
The extension direction of joints directly determines the erosion path and landform type:
1. Vertical joints dominate the formation of sea stacks: If there are dense vertical joints on both sides of a headland (a rock mass protruding into the sea), waves erode along the joints in both directions to form sea caves facing each other. When the caves penetrate the headland, the top rock mass collapses, leaving isolated rock columns, which are sea stacks.
2. Horizontal joints shape Marine erosion platforms: Horizontal joints cause rock layers to peel off in a plate-like manner. The waves carry gravel and repeatedly grind the horizontal fissure surface to make it flat and smooth, gradually forming a sea-eroded platform that slopes towards the sea. When the tide goes out, a large area of it is exposed.
Question
1. Are the local joints horizontal or vertical? Therefore which do you see, a sea cave or a sea platform? Please give some reasons.
2. Which colors mainly constitute the granite in the location?
3. Why do the nearby granite rocks show different colors?
4. Upload a photo near the coordinate location. The photo can include yourself, Trackables/handheld GPS/Geocaching related software, or any item that can indicate you are a geocacher. (Optimal）
介紹
九澳聖母村位於澳門路環島東南側的海岸山岡上，地處珠江口西岸，毗鄰南海，是澳門最偏遠的自然區域之一。其東側面向開闊海域，受南海潮汐與季風直接影響，海岸線以基岩爲主，形成了典型的海蝕地貌。更多有關九澳聖母村的信息請移步九澳聖母村。
九澳地質構造
九澳圣母村旁的海岸是澳门少有的原生基岩海岸。澳門的其他海岸多爲砂質或砂泥質海岸，由第四紀沉積物構成，易受波浪改造形成平緩沙灘，缺乏基岩海岸的陡峭形態。九澳海岸的基岩主要爲燕山期花崗岩（形成於侏羅紀至白堊紀早期，約1.35億至2億年前），屬於華南沿海岩漿活動的產物。這類花崗岩質地堅硬，抗風化能力較強，但節理（裂隙）發育明顯，爲海浪侵蝕提供了突破口。
節理
節理的延伸方向直接決定侵蝕路徑與地貌類型：
1.垂直節理主導海蝕柱形成：岬角（向海突出的巖體）兩側若存在密集的垂直節理，海浪沿節理雙向侵蝕形成相向的海蝕洞。當洞穴貫穿岬角時，頂部巖體塌落，殘留孤立巖柱即海蝕柱。
2.水平節理塑造海蝕平臺：水平節理使岩層呈板狀剝離。海浪攜帶礫石反覆研磨水平裂隙面使其平坦光滑，逐漸形成向海傾斜的海蝕平臺，退潮時大面積裸露。
問題
1.當地的節理爲水平節理還是垂直節理？因此你可以看到海蝕洞還是海蝕平臺？请说明原因。
2.所在位置的花崗岩主要由什麼顏色構成？
3.爲什麼距離較近的花崗岩會呈現出不同的顏色？
4.在座標位置附近上傳一張照片，照片中可以包含本人，Trackables/手持 GPS/Geocaching 相關軟件，或任何可以表明你是尋寶者的物品。(選做)