金門烈嶼海岸地質地形調查
一、研究緣起
金門烈嶼海岸地景地形甚富變化，藉本研究之深入調查了解金門烈嶼海岸地質地景形成之原因、地史，海岸侵蝕現狀和可能面對的問題，加以調查和規劃將有利於保護並提供金門國家公園作為海岸地景保育和海岸保護的參考 。
二、研究方法及過程
本研究以以野外調查、岩象學分析、X光繞射礦物分析、XRF元素分析等方法描述烈嶼海岸地形、地質，著重烈嶼重要之地景貓公石，並探討其成因。
三、重要發現
(一) 烈嶼黃厝至埔頭一帶海岸分布的貓公石成因與古寧頭海岸的貓公石成因相同，都是由上覆紅土層中的鐵，向下淋溶到風化的火成岩或源自火成岩的長石質砂岩風化後的高嶺土質砂岩，再沈澱形成鐵網紋（plinthite），再進一步受海水沖刷移除高嶺土，由鐵網紋硬化為岩質鐵網紋（petroplinthite）。
(二) 黃厝、埔頭一帶的貓公石主要發育在火成岩風化而成的高嶺土層中，與古寧頭一帶的貓公石發育在火成岩先經過侵蝕、搬運形成的長石質砂岩再風化而成的高嶺土層中，二者經歷的過程有所不同。
(三) 烈嶼海岸地形發育的主要控制因素為岩性，堅硬的岩石形成海岬，軟弱的岩石形成海灣；海浪侵蝕方向性差異不明顯。
(四) 東崗附近海岸出露的金門層，有發育良好的暴雨所形成的沈積構造，為前人所未報告者。此處金門層露頭與前人所描述的金門層頗為不同，在金門本島亦未見金門層有類似沈積構造。
四、主要建議事項
根據研究發現，本研究針對烈嶼的鄉土教學與地景保育，提出下列具體建議。以下分別從立即可行的建議、及長期性建議加以列舉。
立即可行之建議
建議一
埔頭海岸貓公石步道
主辦機關：金門國家公園
協辦機關：金門縣政府
埔頭－黃厝間海岸的平台狀貓公石是烈嶼的特色，但目前多數遊客多數只在埔頭貓公石海岸入口短暫停留觀賞崩落的塊狀貓公石而忽略了平台狀貓公石。似乎可考慮在自行車道旁現有的貓公石海岸入口（埔頭）和貓公石觀賞平台（埔頭－黃厝）之間設置步道，鼓勵遊客沿海岸步行一段，再回到自行車道。
建議二
東崗海岸步道
主辦機關：金門國家公園
協辦機關：金門縣政府
東崗－青歧間海岸的金門層露頭，出露了發育良好的暴雨形成的沈積構造，不僅在金門地區唯一可見者，在台灣也不多見。這是實施科普教育與鄉土教學的良好地點。此地接近東崗岬角，可由自行車道上近東崗之涼亭步行前往。目前多數遊客與金門本地學生還不知道這個地點。建議在自行車道涼亭處設置指引標誌，並在崖壁旁設置解說牌，說明其形成的地質背景。
長期性建議
海岸保護與地景保育
主辦機關：金門國家公園
協辦機關：金門縣政府
烈嶼海岸的各處海岬主要為堅硬的火成岩或變質岩，唯一的例外是埔頭－黃厝間的貓公石海岸，可見貓公石抵抗海浪侵蝕的能力和火成岩、變質岩接近。從海岸保護與地景保育的觀點，均應妥善保護埔頭－黃厝間的貓公石，而不需要防波堤或消波塊。
Abstract
1. Purpose
The Lieyu, Kinmen has very diverse coastal landforms and landscape. This project studied the coastal landscape and coastal geology of Lieyu and their origin and geohistory to make available resources of public education for tourism. The project also investigate potential problem in coastal protection in order to provide the Kinmen National Park a reference in landscape conservation and coast protection.
2. Methods
This project performed field investigation and sampling, petrographical study, XRD mineralogy study and XRF elemental analysis to document the coastal landform, coastal geology with a focus on the famous “Mau-gong-shi” (petroplinthite) and discuss their origins.
3. Important results
(1) The origin of “Mau-gong-shi” at Huangcuo and Putou of Lieyu is similar to that of Guningtou. Both were formed by iron leached from the overlying red soil and re-precipitated in the kaolinitic bed below the red soil, then developed into plinthite. The kaolinitic bed resulted from weathering of granitic rocks or arkosic sandstones derived from granitic rocks. Kaolinite in plinthite may further be washed away by waves and evolved into petroplinthite.
(2) The “Mau-gong-shi” of Lieyu differs from that of Guningtou in geohistory of the host rock. At Guningtou, the kaolinitic bed resulted from weathering of arkosic sandstones that were derived from grduitic rocks, while at Huangcuo and Putou, the kaolinitic bed resulted from weathering of granitic rocks.
(3) The main control of coastal development of Lieyu is lithology. Hard igneous or metamorphic rocks developed into headlands while sedimentary or weathered igneous rocks developed into bays. The wave influence is not significant.
(4) The Kinmen Formation outcrops along coast near Dong-gang reveals well developed sedimentary structures of storm deposition. This has not been reported before. The sedimentary characteristics of Kinmen Formation at this site are different significantly from other outcrops.
4. Suggested strategies
This project comes to the immediate and long-term strategies.
For immediate strategies:
(1) Build a walking trail along the coast from the entrance to “Mau-gong-shi” at the bicycle trail near Putou to a sight-seeing platform is located at the bicycle trail about halfway toward Huangcuo. This walking trail will allow visitors to walk along the best part of the “Mau-gong-shi” coast, yet confine them stay in the trail and not to damage the landscape. Panels should be installed next to the trail to explain the origin of “Mau-gong-shi”.
(2) Put a sign at a pavilion along the bicycle trail near Dong-gang to guide the visitors to see the beautiful outcrops of storm beds in the Kinmen Formation. Panels should be installed at to the site to explain the origin of the sedimentary structures.
For long-term strategies:
Preserve the “Mau-gong-shi” (plinthite and petroplinthite) along the coast from Putou to Huangcuo. Those iron-cemented formation serve as natural wave-breaker and has successfully protected the northeast coast of Lieyu for thousands years. Artificial levee or wave breaker is not necessary in this area as far as coast protection is concerned, and will only destroy the beautiful landscape at the site.
金門烈嶼海岸地景地形甚富變化，藉本研究之深入調查了解金門烈嶼海岸地質地景形成之原因、地史，海岸侵蝕現狀和可能面對的問題，加以調查和規劃將有利於保護並提供金門國家公園作為海岸地景保育和海岸保護的參考 。
二、研究方法及過程
本研究以以野外調查、岩象學分析、X光繞射礦物分析、XRF元素分析等方法描述烈嶼海岸地形、地質，著重烈嶼重要之地景貓公石，並探討其成因。
三、重要發現
(一) 烈嶼黃厝至埔頭一帶海岸分布的貓公石成因與古寧頭海岸的貓公石成因相同，都是由上覆紅土層中的鐵，向下淋溶到風化的火成岩或源自火成岩的長石質砂岩風化後的高嶺土質砂岩，再沈澱形成鐵網紋（plinthite），再進一步受海水沖刷移除高嶺土，由鐵網紋硬化為岩質鐵網紋（petroplinthite）。
(二) 黃厝、埔頭一帶的貓公石主要發育在火成岩風化而成的高嶺土層中，與古寧頭一帶的貓公石發育在火成岩先經過侵蝕、搬運形成的長石質砂岩再風化而成的高嶺土層中，二者經歷的過程有所不同。
(三) 烈嶼海岸地形發育的主要控制因素為岩性，堅硬的岩石形成海岬，軟弱的岩石形成海灣；海浪侵蝕方向性差異不明顯。
(四) 東崗附近海岸出露的金門層，有發育良好的暴雨所形成的沈積構造，為前人所未報告者。此處金門層露頭與前人所描述的金門層頗為不同，在金門本島亦未見金門層有類似沈積構造。
四、主要建議事項
根據研究發現，本研究針對烈嶼的鄉土教學與地景保育，提出下列具體建議。以下分別從立即可行的建議、及長期性建議加以列舉。
立即可行之建議
建議一
埔頭海岸貓公石步道
主辦機關：金門國家公園
協辦機關：金門縣政府
埔頭－黃厝間海岸的平台狀貓公石是烈嶼的特色，但目前多數遊客多數只在埔頭貓公石海岸入口短暫停留觀賞崩落的塊狀貓公石而忽略了平台狀貓公石。似乎可考慮在自行車道旁現有的貓公石海岸入口（埔頭）和貓公石觀賞平台（埔頭－黃厝）之間設置步道，鼓勵遊客沿海岸步行一段，再回到自行車道。
建議二
東崗海岸步道
主辦機關：金門國家公園
協辦機關：金門縣政府
東崗－青歧間海岸的金門層露頭，出露了發育良好的暴雨形成的沈積構造，不僅在金門地區唯一可見者，在台灣也不多見。這是實施科普教育與鄉土教學的良好地點。此地接近東崗岬角，可由自行車道上近東崗之涼亭步行前往。目前多數遊客與金門本地學生還不知道這個地點。建議在自行車道涼亭處設置指引標誌，並在崖壁旁設置解說牌，說明其形成的地質背景。
長期性建議
海岸保護與地景保育
主辦機關：金門國家公園
協辦機關：金門縣政府
烈嶼海岸的各處海岬主要為堅硬的火成岩或變質岩，唯一的例外是埔頭－黃厝間的貓公石海岸，可見貓公石抵抗海浪侵蝕的能力和火成岩、變質岩接近。從海岸保護與地景保育的觀點，均應妥善保護埔頭－黃厝間的貓公石，而不需要防波堤或消波塊。
Abstract
1. Purpose
The Lieyu, Kinmen has very diverse coastal landforms and landscape. This project studied the coastal landscape and coastal geology of Lieyu and their origin and geohistory to make available resources of public education for tourism. The project also investigate potential problem in coastal protection in order to provide the Kinmen National Park a reference in landscape conservation and coast protection.
2. Methods
This project performed field investigation and sampling, petrographical study, XRD mineralogy study and XRF elemental analysis to document the coastal landform, coastal geology with a focus on the famous “Mau-gong-shi” (petroplinthite) and discuss their origins.
3. Important results
(1) The origin of “Mau-gong-shi” at Huangcuo and Putou of Lieyu is similar to that of Guningtou. Both were formed by iron leached from the overlying red soil and re-precipitated in the kaolinitic bed below the red soil, then developed into plinthite. The kaolinitic bed resulted from weathering of granitic rocks or arkosic sandstones derived from granitic rocks. Kaolinite in plinthite may further be washed away by waves and evolved into petroplinthite.
(2) The “Mau-gong-shi” of Lieyu differs from that of Guningtou in geohistory of the host rock. At Guningtou, the kaolinitic bed resulted from weathering of arkosic sandstones that were derived from grduitic rocks, while at Huangcuo and Putou, the kaolinitic bed resulted from weathering of granitic rocks.
(3) The main control of coastal development of Lieyu is lithology. Hard igneous or metamorphic rocks developed into headlands while sedimentary or weathered igneous rocks developed into bays. The wave influence is not significant.
(4) The Kinmen Formation outcrops along coast near Dong-gang reveals well developed sedimentary structures of storm deposition. This has not been reported before. The sedimentary characteristics of Kinmen Formation at this site are different significantly from other outcrops.
4. Suggested strategies
This project comes to the immediate and long-term strategies.
For immediate strategies:
(1) Build a walking trail along the coast from the entrance to “Mau-gong-shi” at the bicycle trail near Putou to a sight-seeing platform is located at the bicycle trail about halfway toward Huangcuo. This walking trail will allow visitors to walk along the best part of the “Mau-gong-shi” coast, yet confine them stay in the trail and not to damage the landscape. Panels should be installed next to the trail to explain the origin of “Mau-gong-shi”.
(2) Put a sign at a pavilion along the bicycle trail near Dong-gang to guide the visitors to see the beautiful outcrops of storm beds in the Kinmen Formation. Panels should be installed at to the site to explain the origin of the sedimentary structures.
For long-term strategies:
Preserve the “Mau-gong-shi” (plinthite and petroplinthite) along the coast from Putou to Huangcuo. Those iron-cemented formation serve as natural wave-breaker and has successfully protected the northeast coast of Lieyu for thousands years. Artificial levee or wave breaker is not necessary in this area as far as coast protection is concerned, and will only destroy the beautiful landscape at the site.