Entrance fee to Fugang Geopark. 富岡地質公園有入場費用。
Logging Task 登錄任務
When you arrive at the posted coordination, you will see a wall of rocks. 抵達地質寶公布點後，眼前會有一片岩壁。
Flame Structure 火焰構造
1. Find the flame structure in the rocks (Spot A, B, or C). Describe the size of the flame structure. Do the flame structures here have the same direction as other flame structures in the listing page? 請找到火焰構造是位在哪裡 (A、B、C)？描述這裡的火焰構造大小。這裡的火焰構造跟寶頁中火焰構造的方向相同嗎？
Bouma Sequence 波馬序列
2. Observe the profile of this wall of rocks and describe the size of grain at spot A, B, C. (Hint: Sand has bigger grain than mud. Mud has a deeper colour.) Does the turbidite here have a normal Bouma Sequence? 觀察這處岩石的剖面，描述 A、B、C三處的沉積岩顆粒大小(提示:砂的顆粒比泥的顆粒大，泥的顏色比較深)。請問富岡濁流岩是否有一般/正常的波馬序列順序?
3. From the answers of logging task 1 and 2, what geological incident happened here? Explain your answer. 依據登錄任務1和2的回答，過去可能發生過什麼樣的地質事件?解釋你的答案。
4. Find another flame structure at Fugang Geopark. Photo the flame structure with you, your identifying items, or your GPS device. 請找到富岡地質公園中其他的火焰構造，請與你找到的其他火焰構造拍照，內容包含火焰構造與你、你的代表物、或你的GPS裝置。
Log this cache "Found it" and send me your suggested answers either via my profile, or via geocaching.com (Message Center) messaging, and I will contact you if there is a problem. Please, do not post your answers in the log, except logging task 4. 線上登錄這個地質寶，請將答案寄到Geocaching.com的信箱，若有什麼問題，會再回覆給你。除了登錄任務第4題，請不要在線上log中公佈你的答案，感謝。
富岡，舞動火焰 #火焰構造
富岡地質公園有多樣的地質，可以觀察到單面山、節理、蜂窩岩、風化紋、交錯層、砂岩頁岩與珊瑚礁的差異侵蝕，這個地質寶將以微觀角度來認識荷重鑄型/火焰構造，來觀察這區域岩石的沈積過程有哪些獨特的地方。
這個地質寶要做什麼？ 辨識火焰構造與濁流岩。
富岡地區的岩石為濁流岩，這些岩石上還附有隆起珊瑚礁岩。層層疊疊的地層記錄著不斷發生的沉積作用，富岡的濁流岩還有明顯的交錯層，把水流動的樣子都記錄在岩石中，仔細觀察富岡濁流岩時，還可以發現到岩石上有火焰一般的形狀，這是一種荷重鑄型，又稱火焰構造，紀錄著獨特的沈積活動。
濁流(turbidite)為夾帶泥沙的混濁水流，有較高的密度，會沈入水底快速向下流動。濁流停積下來所形成的沈積岩為濁流岩。濁流岩是一套下粗而上細的沈積岩層序，其產狀又被稱為「波馬序列」(Bouma Sequence)。
荷重鑄型/火焰構造的形成機制為後期較重的沈積物，下陷到早期較軟的沉積物中。火焰構造為沉積物尚未膠結成沈積岩，脫水作用使砂下沉，砂的重量使泥向上湧出，而後膠結成沈積岩，形成火焰構造。富岡砂岩因為是砂頁岩互層，沙子比泥的顆粒為大、也比較重，因此是砂下陷到泥中，這個獨特的沉積情境讓火焰結構有形成的機會。
然而，富岡岩石的秘密還不僅如此，有些特殊的地質事件潛藏在這些岩石中。現在，請到富岡地質公園尋找火焰結構與波馬序列，推敲看看有什麼料在裡面。
Dancing Fire@Fugang #Flamestructure
Fugang Geopark has diverse rock formations, like cuesta, joints, honeycomb rock, weathering textures, cross bedding, differential erosion of sand rock, shale, and coastal reef. Beside these easy-to-observe rock formations, there are tiny things in the rocks. That’s Load Cast/Flame structure in rocks. This earthcache will investigate Fugang geopark from a micro perspective. Let’s discover the uniqueness of Fugang.
What to do with this earthcache?
Recognize the flame structure and turbidite.
Rocks in Fugang are turbidites and there are lifted coral reefs on it. Rock layers and obvious cross bedding recorded the movement of current and the ongoing deposition process of sediments. Some shapes of fire were curved in tubidites if you looked closely. These shapes are flame structure (load cast), recording an unique activity of deposition.
A turbidite is the geologic deposit of a turbidity current, which is a type of amalgamation of fluidal and sediment gravity flow responsible for distributing vast amounts of clastic sediment into the deep ocean. The Bouma sequence specifically describes the ideal vertical succession of structures deposited by low-density turbidity currents.
A flame structure is a type of soft-sediment deformation that forms in unconsolidated sediments. The overlying bed must be of a higher density than the underlying bed. The weight of an overlying bed forces an underlying bed to push up through the overlying bed, generally when both strata are saturated with water. The resulting pattern may resemble flames.
Rocks in Fugang have a unique deposition process in period of time, in which the sand and mud grains were cross-lying deposited. The size of sand is bigger and heavier than the size of mud. The deposition condition gaved the circumstance for forming flame structures.
However, the secret in rocks at Fugang is far more than this. Some special geological incidents happened on these rocks. Now, explore Fugang Geopark to discover the flame structure and the result of Bouma Sequence to find out what the tea here is.
Reference
億萬年尺度的臺灣:從地質公園追出島嶼身世
Shaking conditions required for flame structure formation in a water-immersed granular medium