This study illustrates the influences of sea-level on the depositional process during the last 1000 years of the southwestern delta, Bangladesh. Sediments of eight litho-sections from landward in upper delta plain to seaward in lower delta plain along the Rupsa-Pasur river were studied. Sedimentary facies, total organic carbon, total nitrogen, δ¹³C value, diatom assemblages, and radiocarbon dating of deposits were carried out to determine the paleoenvironments that were influenced by the relative sea-level (RSL) change over time. During the 850–1300 AD, RSL was reached up to +80 cm higher than the present level where tidal-influenced bioturbated light yellow to gray mud deposited in the upper delta plain area. RSL was dropped up to −110 cm during 1300–1850 AD, organic-rich bluish-gray mud, mangrove peat, and terrestrial influenced yellowish-gray mud were deposited successively in the lower delta plain area, and the terrace was formed at landward due to the lowering of the base level. RSL started to rise after the period 1850 AD where tidal-influenced sediments gradually increased and deposited in the upper part at seaward and terrestrial flood sediment deposited over the erosional surface at the landward part. The estimated average sedimentation rate (1.96–2.89 mm/year) is not enough to offset the effect of subsidence and present sea-level rise over the study area. The rising trend of the sea creates inundation in the lower delta plain area, also hinders upstream water flow. For that, terrestrial flood sediments settle over the erosional surface in landward, and tidal-influenced sediment gradually onlap upon it from seaward.

这项研究说明了孟加拉国西南三角洲最近1000年中海平面对沉积过程的影响。研究了沿Rupsa-Pasur河从上三角洲平原的陆路到下三角洲平原的海路的八个岩石剖面的沉积物。沉积相，总的有机碳，总氮，δ ¹³进行了C值，硅藻组合和沉积物的放射性碳测年，以确定受相对海平面（RSL）随时间变化影响的古环境。在850-1300 AD期间，RSL比当前水平高出+80 cm，当时潮汐影响的生物扰动的浅黄色至灰色泥浆沉积在上三角洲平原地区。在公元1300–1850年，RSL下降至−110 cm，富含有机蓝灰色泥浆，红树林泥炭和陆生影响的微黄灰色泥浆依次沉积在下三角平原地区，阶地在陆缘形成。降低基础水平。在公元1850年之后，RSL开始上升，潮汐影响的沉积物逐渐增加并沉积在海面的上部，陆生洪水沉积物沉积在陆面的侵蚀面上方。估计的平均沉积速率（1.96-2.89 mm /年）不足以抵消沉降作用和研究区域当前海平面上升的影响。海洋的上升趋势在较低的三角洲平原地区造成洪水泛滥，也阻碍了上游水流。为此，陆地洪水沉积物沉积在陆上的侵蚀面之上，潮汐影响的沉积物从海面逐渐重叠在其上。海洋的上升趋势在较低的三角洲平原地区造成洪水泛滥，也阻碍了上游水流。为此，陆地洪水沉积物沉积在陆上的侵蚀面之上，潮汐影响的沉积物从海面逐渐重叠在其上。海洋的上升趋势在较低的三角洲平原地区造成洪水泛滥，也阻碍了上游水流。为此，陆地洪水沉积物沉积在陆上的侵蚀面之上，潮汐影响的沉积物从海面逐渐重叠在其上。