Marine Invertebrate Fossils as Horizon Markers in the Pennsylvanian Rocks of Illinois

It is increasingly clear that present-day dynamic topography on Earth, which is generated and maintained by mantle convective processes, varies on timescales and length scales on the order of 1−10 m.y. and 103 km, respectively. A significant implication of this behavior is that Phanerozoic stratigraphic records should contain indirect evidence of these processes. Here, we describe and analyze a well-exposed example of an ancient landscape from the Grand Canyon region of western North America that appears to preserve a transient response to mantle processes. The Surprise Canyon Formation lies close to the Mississippian-Pennsylvanian boundary and crops out as a series of discontinuous lenses and patches that are interpreted as remnants of a westward-draining network of paleovalleys and paleochannels within a coastal embayment. This drainage network is incised into the marine Redwall Limestone whose irregular and karstified upper surface contains many caves and collapse structures. The Surprise Canyon Formation itself consists of coarse imbricated conglomerates, terrestrial plant impressions including Lepidodendron, and marine invertebrate fossils. It is overlain by marine, fluvial, and aeolian deposits of the Supai Group. These stratal relationships are indicative of a transient base-level fall whose amplitude and regional extent are recognized as being inconsistent with glacio-eustatic sea-level variation. We propose that this transient event is caused by emplacement and decay of a temperature anomaly within an asthenospheric channel located beneath the lithospheric plate. An analytical model is developed that accounts for the average regional uplift associated with landscape development and its rapid tectonic subsidence. This model suggests that emplacement and decay of a ∼50 °C temperature anomaly within a channel that is 150 ± 50 km thick can account for the observed vertical displacements. Our results are corroborated by detrital zircon studies that support wholesale drainage reorganization at this time and by stratigraphic evidence for spatially variable regional epeirogeny. They are also consistent with an emerging understanding of the temporal and spatial evolution of the lithosphere-asthenosphere boundary.

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New species of marine invertebrate fossils from the Bearpaw Formation of southern Alberta

10.4095/105044 ◽

1930 ◽

Author(s):

M Y Williams

Keyword(s):

New Species ◽

Marine Invertebrate ◽

Southern Alberta ◽

Invertebrate Fossils

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Jurassic animals and algae in the flooring of Our Lady of Sorrows Church in Poznań

Biological Letters ◽

10.1515/biolet-2015-0013 ◽

2015 ◽

Vol 52 (1-2) ◽

pp. 37-43

Author(s):

Mateusz Antczak

Keyword(s):

Marine Invertebrate ◽

Genus Level ◽

Holy Cross Mountains ◽

Jurassic Rocks ◽

Invertebrate Fossils ◽

Tectonic Movements

Abstract The flooring of Our Lady of Sorrows Church in Poznań is made of Jurassic rocks from the Świętokrzyskie Mountains (also known as Holy Cross Mountains) and contain abundant marine invertebrate fossils: sponges, bivalves, brachiopods, various families of cephalopods, etc. Some of them can be identified to the genus level. The fossils make it possible to describe the environment and ecosystem of the Jurassic sea and biostratigraphy of the sediment. There are also some significant inorganic structures, which suggest post-diagenetic tectonic movements.

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Sampling-standardized expansion and collapse of reef building in the Phanerozoic

Fossil Record ◽

10.5194/fr-11-7-2008 ◽

2008 ◽

Vol 11 (1) ◽

pp. 7-18 ◽

Cited By ~ 14

Author(s):

W. Kiessling

Keyword(s):

Fossil Record ◽

Late Jurassic ◽

Marine Invertebrate ◽

Late Triassic ◽

Late Devonian ◽

Reef Growth ◽

Temporal Scales ◽

Natural Processes ◽

Invertebrate Fossils

Tracing the variability of reef production over long temporal scales is important to approach natural processes favoring or suppressing reef growth. Raw compilations of reef abundance per unit of time do not necessarily depict biologically meaningful patterns, because the waxing and waning of reefs might just follow the quality of the fossil record, that is, the amount of paleontological information that is available in general. Here I standardize the published record of Phanerozoic reefs, as stored in the PaleoReefs database, to the published record of marine invertebrate fossils as stored in the Paleobiology Database. The sampling-standardized peaks in reef growth are essentially identical to those of previous studies, but significant peaks are rare. Times when unusual changes in ecological conditions are likely to control changes in metazoan reef proliferation were identified in the Late Devonian, Late Triassic, Late Jurassic and Neogene. <br><br> doi:<a href="http://dx.doi.org/10.1002/mmng.200700008" target="_blank">10.1002/mmng.200700008</a>

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Pennsylvanian brachiopods from the Geumcheon-Jangseong Formation, Pyeongan Supergroup, Taebaeksan Basin, Korea

Journal of Paleontology ◽

10.1666/09-105.1 ◽

2010 ◽

Vol 84 (3) ◽

pp. 417-443 ◽

Cited By ~ 6

Author(s):

Sangmin Lee ◽

Duck K. Choi ◽

G. R. Shi

Keyword(s):

New Species ◽

North China ◽

Marine Invertebrate ◽

Late Paleozoic ◽

Marine Environments ◽

Faunal Composition ◽

Taebaeksan Basin ◽

Close Affinity ◽

Two New Species ◽

Invertebrate Fossils

We provide the first detailed systematic taxonomy and paleoecological investigation of late Paleozoic brachiopod faunas from Korea. Specifically, we focus on the brachiopods from the Geumcheon-Jangseong Formation, the lower part of the Pyeongan Supergroup in the Taebaeksan Basin. The formation yields a variety of marine invertebrate fossils, including brachiopods, molluscs, echinoderms, corals, fusulinids, and conodonts. Diverse brachiopods are described from six siliciclastic horizons of the formation at three localities, including 23 species belonging to 20 genera with two new species: Rhipidomella parva n. sp. and Stenoscisma wooi n. sp. Three brachiopod assemblages of the late Moscovian (Pennsylvanian) age are recognized based on their species compositions and stratigraphic distributions, namely the Choristites, Rhipidomella, and Hustedia assemblages. The brachiopod faunal composition varies within each assemblage as well as between the Assemblages, most likely reflecting local paleoenvironmental and hence paleoecological differences. The Choristites Assemblage includes relatively large brachiopods represented by Derbyia, Choristites, and Stenoscisma and may have inhabited open marine to partly restricted marine environments, whereas the Rhipidomella and Hustedia Assemblages consist of a small number of small-sized brachiopods living in lagoonal environments. The Choristites Assemblage shows a close affinity with Moscovian brachiopod assemblages in the eastern Paleo-Tethys regions, especially the Brachythyrina lata-Choristites yanghukouensis-Echinoconchus elegans Assemblage of North China, whereas the Rhipidomella and Hustedia assemblages both exhibit strong endemism.

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