Page 12 - 雕鐫海之角

本區的鼻頭角及三貂角為突出於海面之岬角，以地層
The following is an introduction of the main
年代及岩層變質度來區分東北角地區，可將其分成古第三紀 stratum in this district:

地層輕度變質地層（雪山山脈地層）、變質過渡帶（澳底地 The Sheishan Mountains formation
塊）及新第三紀未變質地層（西部麓山帶地層）三大區塊。 The Sheishan mountains formation is a four- layered
分別以龍洞斷層及屈尺斷層為界，龍洞斷層以北屬麓山帶地 sandstones with thick white large grains of quartz sandstone
層，屈尺斷層以南為雪山山脈地層，而介於屈尺斷層與龍洞 and quartz gravel. There are also argillaceous sandstones
with thin layers of dark grey hard shale, representing the
斷層間的澳底地塊，為上述兩個地質區的變質過渡帶。
relatively deep sea deposits on the continental shelf or the
以下為本區主要地層的介紹：
continent slope. The rocks rest on the Aoti formation a thick
雪山山脈地層 floor of sandstone, shale, and a thin layer of sand shale also
由四稜砂岩、乾溝層、大桶山層及澳底層所構成。四 with several layers of thin coal seams. These represet the
deposits rom the shallow sea to the seashore.
稜砂岩主要由厚層的白色粗粒石英砂岩及石英質礫石組成；
Sedimentary Formations
乾溝層與大桶山層則由暗灰色硬頁岩夾薄層的泥質砂岩所組
The sedimentary sandstone contains many rock
成，代表大陸棚或大陸斜坡等較深海之沉積；澳底層是由厚
formations, including the Mushan, Daliao, Shihdi, Nangang,
層砂岩、頁岩、砂頁岩薄互層組成，其上部並夾數層薄煤
Nanjhuang, and the Gueijhulin formations. The Mushan, Shihdi
層，代表淺海至濱海相的沉積，由於受到變質作用，所以岩 and Nangang formations are mainly thick sandstones, sandy-
層皆比一般同類的沉積岩來得堅硬。 shales white sandstones and coal seam. It is formed from
marine sediment closed to the seashore. The Daliao, Nangang
麓山帶地層

and Gueijhulin formations include thick layers of argillaceous
由中新世之木山層、大寮層、石底層、南港層、南莊層
sandstone, shales, including marine fossil layers. Representing
及桂竹林層所構成。其中木山層、石底層及南莊層主要由厚 the shallow marine deposit of the continental shelf. These
層砂岩、砂頁互層、白砂岩及夾煤層所組成，為濱海相沉積 Miocene Epoch seashore and shallow marine strata appear to
物；而大寮層、南港層、桂竹林層則由厚層泥質砂岩、厚層 repeat at intervals, showing that the strata of this period went
through cyclical deposition during numerous transgressions
頁岩組成，並含多量海相化石，代表大陸棚淺海相沉積，這
and regressions.
些中新世濱海相及淺海相的地層間隔且循環出現，表示本區
Aoti Massif Formation
於此時期之地層，經歷多次海進海退之沉積循環。
The area between the Longdong fault and the chiuchi
澳底地塊地層 fault is called the Aoti massif.
位於屈尺斷層與龍洞斷層之間的地區稱之為澳底地塊， The formation belongs to the foothill mountain belt
地層上屬於麓山帶地質區與雪山山脈地質區，前人研究將此 geological district and Sheishan Mountain geological district.
The Aoti massif formation presents a continuous metamorphic
區分成另一套地層，並做成此三區之地層對比。就岩性及變
質度而言，澳底地塊因受不同程度之造山運動擠壓應力，成
為連續漸變帶。

地質圖書 Geopark at Northeast and Yilan Coast National Scenic Area