ABSTRACT

We report 130 vertebrate fossils preserved as bony elements and the co-occurring assemblage of fish teeth and spines from the lower strata of the Pisco Formation exposed along the western side of the lower Ica Valley (East Pisco Basin, Peru). Geological mapping at 1:10,000 scale reveals that all these fossils originate from the Langhian–Serravallian P0 allomember. In the study area, P0 is up to ∼40 m thick and features a sandy lower portion, reflecting shoreface deposition, that fines upwards into a package of offshore silts. Marine vertebrates only occur in the lower sandy layers and include whales, dolphins, reptiles, birds, and bony and cartilaginous fishes. The reconstructed paleoenvironment is consistent with a warm-water, marginal-marine setting with a strong connection to the open ocean. This work helps to elucidate the rich yet still poorly understood middle Miocene portions of the Pisco Formation, and highlights the need to conserve this outstanding Fossil-Lagerstätte.

摘要

我们报告了130个脊椎动物化石，这些化石被保存为骨元素，并且从沿下伊卡河谷西侧（秘鲁东皮斯科盆地）暴露出来的皮斯科形成的较低地层的鱼齿和刺共生。以1：10,000比例尺绘制的地质图显示，所有这些化石均起源于Langhian-Serravallian P0异形体。在研究区中，P0的厚度最大为40m，下部为沙质，反映出海岸面沉积，向上细化为一堆离岸淤泥。海洋脊椎动物仅出现在沙质下层，包括鲸鱼，海豚，爬行动物，鸟类以及骨性和软骨鱼类。重建后的古环境与温水，边缘海洋环境保持一致，并与广阔的海洋紧密相连。