研究台灣上新統至更新統的岩相和古環境分析，有助於瞭解造山帶及前陸盆地的演變。本研究於台灣中部麓山帶，濁水溪剖面和湖山水庫剖面兩個研究區域，調查晚期上新世的錦水頁岩與更新世的卓蘭層、頭嵙山層，總地層厚度約為2,500公尺。利用野外地質調查與岩相分析，瞭解前陸盆地沉積環境演變及沉積體系變化。 本研究共劃分出18種岩相、11個沉積次環境以及3種生痕化石相。依據沉積相特徵，古環境屬於以潮汐為主之三角洲系統的淺海環境，包括開放性淺海的前三角洲、以潮汐為主的三角洲前緣，及陸相曲流河等3組環境。前陸盆地的沉積序列，以錦水頁岩沉積環境最深，為開放性淺海的前三角洲；卓蘭層時，沉積環境為前三角洲及三角洲前緣交替出現，且環境逐漸變淺；至頭嵙山層沉積環境最淺，轉變為陸相曲流河環境。整體層序呈向上變粗、變淺的序列，反映前陸盆地及造山帶向西遷移、沉積物向外加積逐漸填滿盆地的過程。 卓蘭層上部至頭嵙山層環境逐漸變淺為陸相環境，古土壤層出現於三角洲平原及河流系統之氾濫平原。卓蘭層有數層大型球枕狀構造，推測是由古地震所造成之同沉積變形構造。另外，卓蘭層上部的潮坪及古土壤層中常見脊椎動物化石。 ;Stratigraphic and lithofacies analyses of the Pliocene-Pleistocene foreland deposits enable us to understand the stratigraphic development of the foreland basin in western Taiwan. In this study, we performed lithofacies analyses in two areas in the Western Foothills of central Taiwan, the Jhuoshuei River and the Hushan Reservoir. The studied lithostratigraphic units are the Chinshui Shale, the Cholan Formation, and the Toukoshan Formation, in an ascending order, with a total stratigraphic thickness more than 2,500 m. Nineteen lithofacies and eleven lithofacies associations are identified, pertaining to tide-dominated deltaic systems bordering a shallow marine setting in the foreland basin. The vertical facies change shows a coarsening-and-shallowing-upward succession, indicating the gradually filling up of the foreland basin by sediment progradation. The progradation is interpreted to result from westward migrating orogenic belt and an increase in sediment supply. A few paleosol horizons are developed in deltaic plains and floodplains in the Cholan Formation and the Tokoushan Formation. In addition, a few layers of thickly-bedded sandstones, featuring ball-and-pillow structures, are interpreted as resulted from earthquake shaking. Vertebrate fossils are identified in the upper Cholan Formation deposited in coastal to fluvial settings.
