Time filter

Source Type

Loma Linda, CA, United States

Esperante R.,Geoscience Research Institute | Poma O.,Union Peruvian University
Spanish Journal of Paleontology | Year: 2015

Two mysticete fossil whales from the upper Miocene of the Pisco Formation in Peru are described that show healed bone-fractures in ribs. One specimen is preserved in a tuffaceous, diatomaceous siltstone and the other specimen is preserved in siltstone. Both specimens are well preserved, mostly articulated and almost complete. Shark teeth were found associated with one of the skeletons, but both specimens lack any trace evidence for the activity of macro-scavengers. We suggest that the cause of bone fracture may have been collision with rocky shores, other whales, or large predators. The fact that the rib fractures healed indicates that the whales did not die due to the bone fractures. Sedimentologic and paleontological evidence indicate that they were rapidly buried in the marine platform with well-oxygenated water. © 2015, Sociedad Española de Paleontolog a. Source

Muniz F.,Area de Educacion y Cultura | De Gibert J.M.,University of Barcelona | Esperante R.,Geoscience Research Institute
Palaios | Year: 2010

Whale corpses on the modern seafloor host particular communities that benefit from the large amounts of available labile organic matter. The study of these communities has revealed the presence of the siboglinid annelid Osedax that feeds on bone tissue by means of a symbiotic relationship with heterotrophic bacteria. Here we report the presence of tubular borings in a fragment of the neurocranium of a fossil baleen whale found in lower Pliocene rocks of southeastern Spain. They are formally described as Trypanites ionasi isp. n. The fossil borings can be assigned to annelid or sipunculid worms and may constitute the first evidence of an Osedax-like osteophagous behavior in the fossil record of cetaceans. Nevertheless, the definitive assignment to Osedax is not possible until we have more information on the morphology of modern siboglinid borings. © 2010 SEPM (Society for Sedimentary Geology). Source

Xiao Y.-J.,Peking University | Xiao Y.-J.,Geoscience Research Institute | Li J.-H.,Peking University
Natural Gas Geoscience | Year: 2014

Lishu Depression is an oil-rich depression whose source rocks and reservoirs both are early-Cretaceous formations mainly. Oil and gas was discovered in bedrock buried hill of pre-Mesozoic in recent years and a good exploration prospects is shown in the study area. Based on the analysis of the reservoir-forming factors of buried hill reservoirs in this area, the dark mudstone of Shahezi Formation and Yingcheng Formation of lower Cretaceous with lacustrine facies were considered to be the chief source rock. Gneisses, schist and granites of lower Proterozoic were the main reservoir with fractures as the main reservoir space. Two groups of source rocks exposed directly to the buried hill trap and formed a favorable trap- source configuration. Dark mudstone of lower Cretaceous with lacustrine facies provided a favorable cap rock condition. Four kinds of accumulation modes were summarized which are single side oil-source of Huoshiling Formation, single side oil-source of Shahezi Formation, single side oil-source of Shahezi-Yingcheng Formation and double side oil-source of Shahezi-Yingcheng Formation according to the buried hill reservoir pool-forming feature of Bawu area in Lishu Depression. Single side two oil-sources accumulation mode was the mainly pool-forming type. 16721926 ©, 2014, Science Press. All right reserved. Source

Brand L.,Loma Linda University | Urbina M.,Museo de Historia Natural | Chadwick A.,Southwestern Adventist University | DeVries T.J.,University of Washington | Esperante R.,Geoscience Research Institute
Journal of South American Earth Sciences | Year: 2011

The Miocene/Pliocene Pisco Formation of Peru contains a rich marine vertebrate fossil record, providing a unique opportunity for the study of paleoecology and evolution, along with the sedimentological context of the fossils. The lack of a high-resolution stratigraphic framework has hampered such study. In this paper we develop the needed stratigraphy for the areas in the Pisco Formation where most of the vertebrate paleontological research is occurring. In the Ica Valley and in the vicinity of Lomas, series of lithologically or paleontologically unique marker beds were identified. These were walked out and documented with GPS technology. Measured sections connecting these marker beds provide a stratigraphic framework for the areas studied. GPS locations, maps of the marker beds on aerial photographs, and outcrop photographs allow field determination of the stratigraphic positions of study areas. © 2011 Elsevier Ltd. Source

Esperante R.,Geoscience Research Institute | Brand L.R.,Loma Linda University | Chadwick A.V.,Southwestern Adventist University | Poma O.,Union Peruvian University
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2015

The Pisco Formation in Peru contains abundant fossil cetaceans in middle Miocene to lower Pliocene sandstone, siltstone, and tuffaceous and diatomaceous mudstone. Fossil whales are especially abundant in the uppermost diatomaceous units. Most specimens are well articulated or partially disarticulated but associated. Degree of preservation is exceptionally high and uniform among articulated and disarticulated specimens and on the lower and upper surfaces of the bones. Some specimens have baleen preserved in anatomical position. Bones show no evidence of bioerosion by macro- or micro-invertebrates, except for a very limited amount of microbial borings. Diatomaceous layers seem to lack bioturbation. However, bioturbation did occur in a few tuffaceous silty and sandy layers of the lower part of the formation. Shark teeth are found associated with many of the specimens; however, despite abundance of whale skeletons, shark tooth marks are extremely rare. Several lines of evidence indicate that sediments and whales were deposited in a shallow-to-deep shelf environment (an embayment), and not in a beach environment. The thick diatomaceous successions record conditions of strong ocean upwelling indicated by the abundant occurrence of the diatom species Thalassionema nitzschioides. The exceptional preservation of diatom frustules suggests that they reached the seafloor very rapidly and were not successively reworked. The hundreds of whale specimens found, their excellent preservation, and their high degree of articulation make the Pisco Formation fossil whales the best representative assemblage of fossil Mysticeti known so far. The abundance of whale skeletons and other vertebrates in the diatomaceous beds, their excellent preservation, including evidence that soft tissue (baleen) was still present at burial, and the degree of articulation, point to frequent mortalities followed by rapid sedimentation that prevented decay of the skeletons and colonization by invertebrates. Sedimentation rates appear much higher than rates inferred from some other modern and ancient settings where whale skeletons have been found. © 2014 Elsevier B.V. Source

Discover hidden collaborations