台湾岛的年龄
发布时间：2018-09-19 20:20
【摘要】：台湾岛为华夏陆块东缘自中生代晚期以来的年轻活动造山带,在东海-南海陆架地质背景上,台湾岛具有多重特殊性:除缺失始新世晚期层序外,始新世-更新世间有连续陆相至浅海相层序出露;记录"中国海"的发展及东海-南海陆架沧海桑田变迁;快速的隆升速率及重要的海洋沉积物贡献源;活跃的地震活动;既有被动又有活动大陆边缘层序;从台湾-吕宋间海域到岛上同时进行俯冲-碰撞-仰冲-张裂构造活动,因此有完整的威尔逊构造旋回地质纪录."台湾岛什么时候出露?"及"台湾岛怎么形成?"是大家关心台湾岛地质的基本问题.如果把东海陆架一半水深(60m)的海水拿掉,150km宽的台湾海峡就是台湾岛跟大陆相连的脐带;如果把台湾岛恢复到未造山前的原始形貌,台湾岛就是东海连结到南海间的脐带.但是为什么在东海及南海的陆架上只有台湾岛有比较大范围的出露?显然是有一个特定的地质作用在这个特殊的脐带位置发生,那就是早中新世19~18Ma开始的南海俯冲及随后6.5Ma开始的北吕宋火山岛弧与俯冲的欧亚大陆发生了斜向碰撞.台湾岛在晚中新世(~6.5Ma)时开始出露,最早出露部位就在中央山脉.中央山脉为中生代白垩纪的活动大陆边缘,随后拼合为欧亚大陆一部分,经新生代古近纪断陷构造(50~39Ma)、渐新世-中期中新世南海张裂(33~16Ma)、早中新世(19~18Ma)至今欧亚大陆-南海岩石圈沿马尼拉海沟向东俯冲于西进的花东海盆-菲律宾海板块之下,形成中新世增生楔,及6.5Ma至今由北向南迁移的斜向弧陆碰撞,导致中央山脉隆升出露海平面之上,形成原始台湾岛.由此原始台湾岛,台湾河流系统开始发生,并将侵蚀物经河流向西供输到原始台湾海峡前陆盆地,同时也向东供应到北吕宋海槽弧前盆地.随着弧陆碰撞的持续进行,南海东北部陆架上层序被推覆并出露在中央山脉西侧,台湾岛出露的面积也随之变大;1Ma的吕宋火山岛弧北段更向西仰冲,形成海岸山脉,拼贴在中央山脉东侧;最后又因1Ma冲绳海槽弧后张裂,中央山脉东北部又发生断陷,产生宜兰平原,形成今日台湾岛的形貌.
[Abstract]:Taiwan Island is a young active orogenic belt in the eastern part of the Cathaysian block since the late Mesozoic. In the geological background of the East China Sea and the South China Sea shelf, Taiwan Island has many particularities: except for the missing sequence of the late Eocene. The Eocene-Pleistocene world has successive continental facies to shallow sea facies sequence outcrop; records the development of "China Sea" and the vicissitudes of the East China Sea-South China Sea shelf; rapid uplift rate and important marine sediment contribution source; active seismicity; There are both passive and active continental margin sequences, and subduction, collision, upwelling and extensional tectonic activity from the Taiwan-Luzon sea area to the island at the same time, so there is a complete geological record of the Wilson tectonic cycle. " When will the island of Taiwan be exposed? " And "how did Taiwan Island come into being?" It is a basic concern for the geology of Taiwan Island. If the Taiwan Strait, which is 150 km wide, is removed from the half-depth (60 m) of the East China Sea shelf, it is the umbilical cord connecting the island to the mainland, and if the island is restored to its original appearance before the orogeny, it is the umbilical cord between the East China Sea and the South China Sea. But why is there a relatively large area of exposure on the shelf of the East China Sea and the South China Sea only on the Taiwan Island? It is obvious that a particular geological process occurred in this particular umbilical cord, that is, the South China Sea subduction from the early Miocene 19~18Ma and the collision between the North Luzon volcanic Island arc and the subducted Eurasian continent, which followed by 6.5Ma. The island began to emerge during the late Miocene (6.5 Ma), the earliest part of which was in the Central Mountains. The Central Mountains are the active continental margin of the Mesozoic Cretaceous period, and subsequently joined together as part of the Eurasian continent. Through the Cenozoic Paleogene faulted tectonics (50~39Ma), the Oligocene Miocene South China Sea (33~16Ma), and the early Miocene (19~18Ma) Eurasian and South China Sea lithosphere subducted eastward along the Manila trench beneath the westward Huadonghai-Philippine Sea Plate. The formation of the Miocene accretive wedge and the oblique arc land collision in which 6.5Ma migrated from north to south resulted in the uplift of the Central Mountains above the sea level and the formation of the primitive Taiwan Island. Therefore, the Taiwan river system began to occur in the primitive Taiwan Island, and the erosion was transported westward through the river to the primitive Taiwan Strait Foreland basin, and also to the north Luzon trough arc basin to the east. With the continuation of the arc-land collision, the upper shelf sequence of the northeastern South China Sea was pushed over and exposed to the western side of the central mountain range, and the area of the outcrop of Taiwan Island became larger and the northern segment of the Luzon volcanic Island more westward, forming a coastal mountain range. The collage is on the eastern side of the central mountain range, and finally, because of the 1Ma Okinawa trough arc behind the rift, the northeast of the central mountain has a fault depression, producing the Ilan Plain, forming the appearance of the island of Taiwan today.
【作者单位】： 同济大学海洋与地球科学学院;中国科学院广州地球化学研究所边缘海重点实验室;成功大学地球科学系;
【基金】：国家自然科学基金项目(批准号:U1505231,41472093,91528301,91128211) 广州海洋地质调查局项目(编号:20161972)资助
【分类号】：P736
本文编号：2251227
[Abstract]:Taiwan Island is a young active orogenic belt in the eastern part of the Cathaysian block since the late Mesozoic. In the geological background of the East China Sea and the South China Sea shelf, Taiwan Island has many particularities: except for the missing sequence of the late Eocene. The Eocene-Pleistocene world has successive continental facies to shallow sea facies sequence outcrop; records the development of "China Sea" and the vicissitudes of the East China Sea-South China Sea shelf; rapid uplift rate and important marine sediment contribution source; active seismicity; There are both passive and active continental margin sequences, and subduction, collision, upwelling and extensional tectonic activity from the Taiwan-Luzon sea area to the island at the same time, so there is a complete geological record of the Wilson tectonic cycle. " When will the island of Taiwan be exposed? " And "how did Taiwan Island come into being?" It is a basic concern for the geology of Taiwan Island. If the Taiwan Strait, which is 150 km wide, is removed from the half-depth (60 m) of the East China Sea shelf, it is the umbilical cord connecting the island to the mainland, and if the island is restored to its original appearance before the orogeny, it is the umbilical cord between the East China Sea and the South China Sea. But why is there a relatively large area of exposure on the shelf of the East China Sea and the South China Sea only on the Taiwan Island? It is obvious that a particular geological process occurred in this particular umbilical cord, that is, the South China Sea subduction from the early Miocene 19~18Ma and the collision between the North Luzon volcanic Island arc and the subducted Eurasian continent, which followed by 6.5Ma. The island began to emerge during the late Miocene (6.5 Ma), the earliest part of which was in the Central Mountains. The Central Mountains are the active continental margin of the Mesozoic Cretaceous period, and subsequently joined together as part of the Eurasian continent. Through the Cenozoic Paleogene faulted tectonics (50~39Ma), the Oligocene Miocene South China Sea (33~16Ma), and the early Miocene (19~18Ma) Eurasian and South China Sea lithosphere subducted eastward along the Manila trench beneath the westward Huadonghai-Philippine Sea Plate. The formation of the Miocene accretive wedge and the oblique arc land collision in which 6.5Ma migrated from north to south resulted in the uplift of the Central Mountains above the sea level and the formation of the primitive Taiwan Island. Therefore, the Taiwan river system began to occur in the primitive Taiwan Island, and the erosion was transported westward through the river to the primitive Taiwan Strait Foreland basin, and also to the north Luzon trough arc basin to the east. With the continuation of the arc-land collision, the upper shelf sequence of the northeastern South China Sea was pushed over and exposed to the western side of the central mountain range, and the area of the outcrop of Taiwan Island became larger and the northern segment of the Luzon volcanic Island more westward, forming a coastal mountain range. The collage is on the eastern side of the central mountain range, and finally, because of the 1Ma Okinawa trough arc behind the rift, the northeast of the central mountain has a fault depression, producing the Ilan Plain, forming the appearance of the island of Taiwan today.
【作者单位】： 同济大学海洋与地球科学学院;中国科学院广州地球化学研究所边缘海重点实验室;成功大学地球科学系;
【基金】：国家自然科学基金项目(批准号:U1505231,41472093,91528301,91128211) 广州海洋地质调查局项目(编号:20161972)资助
【分类号】：P736
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