Geochemistry and Early Diagenesis of Mammal-Bearing Concretions from the Sucker Creek Formation (Miocene) of Southeastern Oregon

Downing, Kevin F.; Park, Lisa Ellyn

doi:10.2307/3515278

Cited by 30 publications

(25 citation statements)

References 33 publications

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“…It seems, then, that the Malalmuerzo Neolithic materials have re-precipitated. The observed development of bentonic clays around concretions during pedogenesis has already been reported (Downing and Park, 1998). Such observation confirms the mechanism proposed previously as hydroxyapatite re-crystallizes without filling fluids.…”

Section: Discussionsupporting

confidence: 86%

“…Instead, in the darker zones, where bone lamellae are found, the Ca/P molar ratio is the expected one (Table 2). Thus, some alumino-silicates are present as patches on the surface; some voids may be filled by calcite, quartz, hematite and zeolite (Downing and Park, 1998). This observation is in agreement with the X-ray diffraction patterns where calcite was identified, but the alumino-silicate must be a non-crystalline material as no other diffraction peaks were found.…”

Section: Neolithic Samplessupporting

confidence: 86%

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Boiled versus unboiled: a study on Neolithic and contemporary human bones

Bosch

Aguilera

Moreno‐Castilla

et al. 2011

Journal of Archaeological Science

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Section: Discussionsupporting

confidence: 86%

Section: Neolithic Samplessupporting

confidence: 86%

Boiled versus unboiled: a study on Neolithic and contemporary human bones

Bosch

Aguilera

Moreno‐Castilla

et al. 2011

Journal of Archaeological Science

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“…Precipitation and mineral replacement are two of the complex diagenetic processes, which occur during infilling of openings in the bones (Downing and Park, 1998;Williams and Marlow, 1987;Pate et al, 1989;Piepenbrink, 1989;Wings, 2004). The dinosaur bones analyzed here show similar processes of mineralization and compaction (as summarized in table 3).…”

Section: Taphonomic Pathwaysmentioning

confidence: 69%

Bone microstructure and diagenesis of saurischian dinosaurs from the Upper Cretaceous (Neuquén Group), Argentina

Previtera

2017

andgeo

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ABSTRACT. The Neuquén Basin in northwestern Patagonia, Argentina, holds the most important record of Cretaceous dinosaurs in South America.The Neuquén Group (Upper Cretaceous) is the richest dinosaur-bearing unit of the basin. It comprises the Río Limay, the Río Neuquén and the Río Colorado subgroups. In this study, dinosaur remains from the Río Neuquén and the Río Colorado subgroups outcropping in Mendoza are examined. In this group, isolated, disarticulated or partially articulated sauropods and theropods are abundant. However, little is known about the diagenetic history of fossil assemblages. In southern Mendoza, three fossiliferous sites were found in the areas of Paso de las Bardas (Quebrada Norte) and Cerro Guillermo (CG1, CG2). This study aims to add to the knowledge of diagenetic processes involving dinosaur remains from the Neuquén Group, as well as their relation to the depositional environment. Histologic features and diagenetic processes of dinosaur bones were analyzed through thin sections in order to interpret the degree of taphonomic alteration. The fossil-diagenetic processes inferred include substitution, fracturing, plastic deformation and different permineralization events. Combined analyses through X-ray diffractometry (XRD) and petrographic studies reveal the substitution of hydroxyapatite by francolite. The presence of fluorine -in one of the cases-suggests a link between the elemental composition and depositional environments: floodplain and fluvial channel. Permineralization stages include infilling of vascular canals, trabeculae and fractures with iron oxides and iron carbonate minerals during the burial history. This contribution represents an integral approach to the study of Cretaceous dinosaurs for assessing the diagenetic changes in the bone microstructure and the differential preservation of fossil remains in fluvial environments.

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“…There is no indication that the vertebrate carcasses were transported by currents on these hydromorphic floodplains. Decay of the carcasses both pre-and post-burial under anoxic poorly drained conditions led to the precipitation of iron minerals, most notably hematite, in the La Peña Member (Bao et al, 1998;Downing and Park, 1998).…”

Section: Discussionmentioning

confidence: 99%

“…The fossils preserved in the proximal facies exhibit variable weathering stages and varying states of disarticulation and association. The hydromorphic and potentially somewhat acidic conditions associated with prolonged wet seasons apparently led to the partial dissolution of some bones (Behrensmeyer, 1975) and prompted permineralization with iron complexes (Bao et al, 1998;Downing and Park, 1998).…”

Section: Discussionmentioning

confidence: 99%

Vertebrate taphonomy of the Ischigualasto Formation

Colombi

Rogers

Alcober

2012

Journal of Vertebrate Paleontology

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ABSTRACT-Trends of preservation are established on the basis of 385 fossil occurrences in the Ischigualasto Formation. The distribution and preservational quality of vertebrate fossils are related to sedimentary facies and stratigraphic position and follow trends in basin evolution and paleoclimate. Fossils in the Ischigualasto Formation are mainly concentrated along the margins of the basin. Floodplain deposits preserve ca. 88% of fossils, which range from unidentifiable fragments to articulated skeletons. The remaining fossil occurrences (ca. 12%) come from coarser-grained fluvial channel deposits and exhibit variable preservational quality, including some well-preserved cynodont skulls. Fossils in the basal La Peña Member (ca. 4% of occurrences) are generally highly weathered and disarticulated with hematitic permineralization. The majority of collected specimens (ca. 65% of occurrences) come from the overlying Cancha de Bochas Member and range from isolated bones to articulated skeletons. Calcite, rather than hematite, is the predominant agent of permineralization. The succeeding Valle de la Luna Member (ca. 30% of occurrences) preserves an association between vertebrate fossils and plant remains. Fossil preservation suggests prolonged exposure prior to burial under wetter conditions with superficial and penetrating precipitation of hematite. The uppermost Quebrada de la Sal Member of the Ischigualasto Formation is nearly barren of fossil remains.RESUMEN-Se establecieron las tendencias en la preservación de restos de paleovertebrados a lo largo de la Formación Ischigualasto en base a 385 fósiles. La distribución y la calidad de preservación de los fósiles de vertebrados en esta unidad está relacionada con las facies sedimentarias y la posición estratigráfica de los mismos, variando según la evolución de la cuenca y del paleoclima. Los fósiles en la Formación Ischigualasto están principalmente concentrados en los márgenes de la cuenca. Paleoambientalmente, los depósitos de llanura de inundación preservan alrededor del 88% de los fósiles de la unidad, los cuales van desde fragmentos inidentificables hasta esqueletos articulados. Las restantes ocurrencias de fósiles (alrededor del 12%) provienen de depósitos de canal de grano grueso y también exhiben variables calidades de preservación, incluyendo algunos pequeños cráneos de cinodontes en excelente estado de preservación. Estratigráficamente, los fósiles en el miembro basal La Peña (alrededor del 4% de los hallazgos) están generalmente muy meteorizados, desarticulados y permineralizados con hematita. La mayoría de los especímenes colectados (alrededor del 65% de los hallazgos) provienen del suprayacente Miembro Cancha de Bochas, los cuales van desde huesos aislados hasta esqueletos articulados completos. Estos restos están permineralizados principalmente con calcita en lugar de hematita. En el siguiente, Miembro Valle de la Luna (alrededor del 30% de los hallazgos), se preserva una peculiar asociación de restos fósiles de vertebrados y plantas. La preservación ...

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Geochemistry and Early Diagenesis of Mammal-Bearing Concretions from the Sucker Creek Formation (Miocene) of Southeastern Oregon

Cited by 30 publications

References 33 publications

Boiled versus unboiled: a study on Neolithic and contemporary human bones

Boiled versus unboiled: a study on Neolithic and contemporary human bones

Bone microstructure and diagenesis of saurischian dinosaurs from the Upper Cretaceous (Neuquén Group), Argentina

Vertebrate taphonomy of the Ischigualasto Formation

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