Maryland's Cliffs of Calvert: A fossiliferous record of mid-Miocene inner shelf and coastal environments

Vogt, Peter R.; Eshelman, Ralph E.

doi:10.1130/0-8137-5405-4.9

Cited by 10 publications

(8 citation statements)

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“…Sediments are both diatomaceous and tuffaceous, and most fossil occurrences appear to be rapidly buried falls (Esperante et al, 2002, 2008; Brand et al, 2004, 2011) or strandings (Pyenson et al, 2014) in embayments. Along passive margins, Calvert Cliffs, Maryland, preserves a rich cetacean fauna, but the accumulation is attritional over millions of years (Vogt & Eshelman, 1987; Gottfried et al, 1994). In Africa, the Cretaceous upwelling area along Morocco is the antitropical equivalent of that which occurred at the same time along the Bentiaba coast and it has produced a rich and varied marine fauna (Bardet et al, 2010; Bardet, 2012).…”

Section: Discussionmentioning

confidence: 99%

Geological setting and paleoecology of the Upper Cretaceous Bench 19 Marine Vertebrate Bonebed at Bentiaba, Angola

Strganac

Jacobs

Polcyn

et al. 2014

Netherlands Journal of Geosciences

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The Bench 19 Bonebed at Bentiaba, Angola, is a unique concentration of marine vertebrates preserving six species of mosasaurs in sediments best correlated by magnetostratigraphy to chron C32n.1n between 71.4 and 71.64 Ma. The bonebed formed at a paleolatitude near 24°S, with an Atlantic width at that latitude approximating 2700 km, roughly half that of the current width. The locality lies on an uncharacteristically narrow continental shelf near transform faults that controlled the coastal outline of Africa in the formation of the South Atlantic Ocean. Biostratigraphic change through the Bentiaba section indicates that the accumulation occurred in an ecological time dimension within the 240 ky bin delimited by chron 32n.1n. The fauna occurs in a 10 m sand unit in the Mocuio Formation with bones and partial skeletons concentrated in, but not limited to, the basal 1-2 m. The sediment entombing the fossils is an immature feldspathic sand shown by detrital zircon ages to be derived from nearby granitic shield rocks. Specimens do not appear to have a strong preferred orientation and they are not concentrated in a strand line. Stable oxygen isotope analysis of associated bivalve shells indicates a water temperature of 18.5°C. The bonebed is clearly mixed with scattered dinosaur and pterosaur elements in a marine assemblage. Gut contents, scavenging marks and associated shed shark teeth in the Bench 19Fauna indicate biological association and attrition due to feeding activities. The ecological diversity of mosasaur species is shown by tooth and body-size disparity and by d 13 C analysis of tooth enamel, which indicate a variety of foraging areas and dietary niches. The Bench 19 Fauna was formed in arid latitudes along a coastal desert similar to that of modern Namibia on a narrow, tectonically controlled continental shelf, in shallow waters below wave base. The area was used as a foraging ground for diverse species, including molluscivorus Globidens phosphaticus, small species expected near the coast, abundant Prognathodon kianda, which fed on other mosasaurs at Bench 19, and species that may have been transient and opportunistic feeders in the area.

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Section: Discussionmentioning

confidence: 99%

Geological setting and paleoecology of the Upper Cretaceous Bench 19 Marine Vertebrate Bonebed at Bentiaba, Angola

Strganac

Jacobs

Polcyn

et al. 2014

Netherlands Journal of Geosciences

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“…1994, Kidwell and Kelly 1998). The geological and paleoenvironmental settings within these Miocene formations in Maryland and Virginia have been described by Shattuck (1904), Kidwell (1984, 1989), Vogt and Eshelman (1987), Ward and Powars (1989), Ward (1992), Gottfried et al . (1994), Kidwell and Kelly (1998), and Ward and Andrews (2008).…”

Section: Geological and Paleoenvironmental Settingmentioning

confidence: 72%

“…The sediments comprising Bed 13 of the Calvert Formation are approximately 15 millionyr old, whereas the Choptank Formation along Calvert Cliffs ranges in age from approximately 11 to 13 million yr (Gottfried et al 1994, Kidwell andKelly 1998). The geological and paleoenvironmental settings within these Miocene formations in Maryland and Virginia have been described by Shattuck (1904), Kidwell (1984Kidwell ( , 1989, Vogt and Eshelman (1987), Ward and Powars (1989), Ward (1992), Gottfried et al (1994), Kidwell and Kelly (1998), and Ward and Andrews (2008). The entirely extinct cetacean fauna within the Chesapeake Group comprises a diverse assemblage of approximately 30 species of both odontocetes and mysticetes (Shattuck 1904, Gottfried et al 1994, Godfrey and Barnes 2008.…”

Section: Geological and Paleoenvironmental Settingmentioning

confidence: 76%

Enigmatic osteology in Miocene odontocete rostra suggests periostitis

Gerholdt

Godfrey

2010

Marine Mammal Science

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Eight Miocene odontocete partial rostra (six specimens from the Chesapeake Group of Maryland, one from the Chesapeake Group of Virginia, and another from the Hawthorn Group of Florida) exhibit periostitis, of unknown etiology, characterized by proliferative bone growth. Periostitis is an inflammation of the periosteum secondary to a predisposing event such as a fracture or infection. Computed tomography reveals that the lesions are limited to the premaxillae and that they became progressively swollen and gnarled as evidenced by the onion‐like layering within the deformity. The level of maturity and degree of organization of the periostitis indicates that it likely developed over a period of months or years in these individuals. Given this length of time, these pathologies seem not to have been life‐threatening despite the gross size and shape of most of these periosteal reactions. The fossils range in age from about 11 to 15 million yr and all eight rostra appear to be derived from the same, but as yet unnamed or unrecognized species of odontocete. The family from which these odontocetes derive remains unknown. Un‐deformed rostra attributed to this species have not been identified, which opens the possibility that “abnormal” was the new normal for this species of odontocete.

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“…The Calvert fauna in Maryland and Virginia includes: very abundant and diverse marine invertebrates, particularly mollusks; abundant sharks and rays; relatively common bony fishes , crocodiles, and sea turtles; seabirds; a significant assemblage of marine mammals; and occasional terrestrial mammals. Vogt and Eshelman (1987), Ward (1992), and Gottfried et al (1994) provide recent summaries of the stratigraphy and depositional environment of the Miocene portion of the Chesapeake Group.…”

Section: Class Chondrichthyesmentioning

confidence: 97%

Miocene Basking Sharks (Lamniformes: Cetorhinidae) from the Chesapeake Group of Maryland and Virginia

Gottfried

1995

Journal of Vertebrate Paleontology

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Maryland's Cliffs of Calvert: A fossiliferous record of mid-Miocene inner shelf and coastal environments

Cited by 10 publications

References 0 publications

Geological setting and paleoecology of the Upper Cretaceous Bench 19 Marine Vertebrate Bonebed at Bentiaba, Angola

Geological setting and paleoecology of the Upper Cretaceous Bench 19 Marine Vertebrate Bonebed at Bentiaba, Angola

Enigmatic osteology in Miocene odontocete rostra suggests periostitis

Miocene Basking Sharks (Lamniformes: Cetorhinidae) from the Chesapeake Group of Maryland and Virginia

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