Travelogue: 向南美出發 Day 6

2018年7月26日星期四

向南美出發 Day 6

向南美出發 Day 6

CREDIT: GEOLOGYHUB

Rainbow mountain (又稱Vinicunca/Winicunca)

The Ausangate Mountain of the Peruvian Andes also known as the rainbow mountain is one of the most breathtaking geological features in the world. The mountain is awash with colours from red to turquoise(青綠色) to green to gold and is even thought to be holy. To local citizens who bring offerings to the geological wonder it is a place of daily worship.

How did this mountain form?

The Andes, the range to which the rainbow mountain belongs, formed along the western edge of the South American continent due to subduction. The Nazca plate subducted under the South American plate resulting in mountain building and the uplift of the mountain range. This also initiated volcanism and the introduction of rare mineralogy to the Andes.

Uplift and tectonically driven crustal shortening has tilted the sedimentary layers on exposing colourfully stripped stratigraphic intervals. The reason these Peruvian mountains exhibit such varied colours is due to weathering and their unique mineralogy.

The different colouration is due to different environmental conditions and mineralogy when the sediment was originally deposited and subsequently diagenetically altered. Red colouration of sedimentary layers often indicates iron oxide rust as a trace mineral. Introduction of goethite or oxidized limonite will introduce brownish colouration to sandstones. The bright yellow colouration could be due to iron sulphide as trace minerals. The varying shades of green colour depend on chlorite (綠泥石/亞氯酸鹽)in different diagenetic states and concentrations.

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今早三時起床，為了去彩虹山。

車要接齊人，所以等了很久，車去到七點才吃早餐。冷氣從車底滲入，有一張毛毯給我們。差不多零度，地上的植物都結霜，樹上也有。

坐了很久才從山中zigzag 型的在走，時而攀上高峰，時而下降。車子爬過幾座山，終於到達目的地。那裡有廁所，有小販，也有賣coca leaves.

起步是早上11:45分左右，高度都四千多米，一開步都行到氣喘。而我們的目標是5000公里以外的彩虹山，vincunca。沿路周圍雪山和褶曲山的風光明媚，實在是breath taking 的山色，加上附近穿秘魯傳統服飾人士，其實很美，但我無力跑來跑去拍照。如果走到累可以騎馬。大概10 sol 一百米。我們在最後可騎馬的地方騎馬，因為最後一段實在是很崎嶇。

彩虹山有5200 米高，我這個平原人士和亞洲人士，體力和耐力實在無法追到其他人。我的高原反應是一路走，有少許頭痛。上山的最後一段是喘氣喘得很厲害，呼吸很大聲。而下了第一段山的斜路後，非常頭赤，在繼續下山實在是很疲累，一坐下就不想起來。最後行出來已是下午2:30。