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Articles 1 - 30 of 49
Full-Text Articles in Paleontology
Effectiveness Of Four Water-Bearing Zones Of The Glacierized Basin In Meltwater Runoff Modeling, Umesh K. Haritashya
Effectiveness Of Four Water-Bearing Zones Of The Glacierized Basin In Meltwater Runoff Modeling, Umesh K. Haritashya
Umesh K. Haritashya
Meltwater runoff modeling from glacierized basins needs several input data, including total meltwater contributing area. This study utilizes optical remote sensing data to assess glacierized basins in the central Himalayas where snow and glaciers contribute substantially to the water resources. Result shows that there are four main water-bearing zones in the basin: (a) dry snow, (b) wet snow, (c) exposed glacial ice, and (d) debris-covered glacial ice, and it is possible to differentiate and map these zones and their spatio-temporal variations from satellite sensor data. These zones can then be incorporated in meltwater runoff modeling as separate entities because they …
Evolution Of Floral Zygomorphy In Androecium And Corolla In Solanaceae, Jingbo Zhang, Peter F. Stevens, Wenheng Zhang
Evolution Of Floral Zygomorphy In Androecium And Corolla In Solanaceae, Jingbo Zhang, Peter F. Stevens, Wenheng Zhang
Peter Stevens
Phylogenetic Patterns Of Rarity In A Regional Species Pool Of Tropical Woody Plants, M. Isabel Loza, Iván Jiménez, Peter M. Jørgensen, Gabriel Arellano, Manuel J. Macía, Vania W. Torrez, Robert E. Ricklefs
Phylogenetic Patterns Of Rarity In A Regional Species Pool Of Tropical Woody Plants, M. Isabel Loza, Iván Jiménez, Peter M. Jørgensen, Gabriel Arellano, Manuel J. Macía, Vania W. Torrez, Robert E. Ricklefs
Robert Ricklefs
Permian Foraminifera From British Honduras, Charles A. Ross
Permian Foraminifera From British Honduras, Charles A. Ross
Charles Ross
Fusulinids identified from the Macal Shale Group, Macal Series, south central British Honduras and Schwarerina gruperaensis Thompson and Miller, Schwagerina sp. A, Eoverbeekina aff. E. americana Thompson and Miller, Ozawainella? sp., and Staffella sp. One species of the Trochamminid genus Tetrataxis also occurs in these strata. These species suggest correlation with the lower part of the Chochal Limestone of Guatemala, the Grupera Formation of Chiapas, Mexico, and the Lenox Hills Formation (upper part of the standard Wolfcampian Series, Permian), Glass Mountains, Texas.
Early Permian Fusulinids From Macusani, Southern Peru, Charles A. Ross
Early Permian Fusulinids From Macusani, Southern Peru, Charles A. Ross
Charles Ross
Triticites patulus Dunbar and Newell and Schwagerina adamsi sp. nov. from the early Wolfcampian (Permian) part of the Copacabana Group near Macusani, southern Peru, show morphological features that add new data concerning the evolution of the genera Schwagerina and Pseudoschwagerina from lineages arising within the genus Triticites near the close of the Pennsylvanian.
Effects Of Changes In Moisture Source And The Upstream Rainout On Stable Isotopes In Precipitation – A Case Study In Nanjing, Eastern China, Y. Tang, H. Pang, W. Zhang, Y. Li, Shuang-Ye Wu, S. Hou
Effects Of Changes In Moisture Source And The Upstream Rainout On Stable Isotopes In Precipitation – A Case Study In Nanjing, Eastern China, Y. Tang, H. Pang, W. Zhang, Y. Li, Shuang-Ye Wu, S. Hou
Shuang-ye Wu
In the Asian monsoon region, variations in the stable isotopic composition of speleothems have often been attributed to the "amount effect". However, an increasing number of studies suggest that the "amount effect" in local precipitation is insignificant or even non-existent. To explore this issue further, we examined the variability of daily stable isotopic composition (δ18O) in precipitation from September 2011 to November 2014 in Nanjing, eastern China. We found that intra-seasonal variations of δ18O during summer were not significantly correlated with local rainfall amount but could be linked to changes in the moisture source location and rainout processes in the …
Reconstruction Of The Hirnantian (Late Ordovician) Palaeotopography In The Upper Yangtze Region, Linna Zhang, Junxuan Fan, Qing Chen, Shuang-Ye Wu
Reconstruction Of The Hirnantian (Late Ordovician) Palaeotopography In The Upper Yangtze Region, Linna Zhang, Junxuan Fan, Qing Chen, Shuang-Ye Wu
Shuang-ye Wu
Reconstruction of the Hirnantian (Late Ordovician) palaeotopography in South China is important for understanding the distribution pattern of the Hirnantian marine depositional environment. In this study, we reconstructed the Hirnantian palaeotopography in the Upper Yangtze region based on the rankings of the palaeo-water depths, which were inferred according to the lithofacies and biofacies characteristics of the sections. Data from 374 Hirnantian sections were collected and standardized through the online Geobiodiversity Database. The Ordinary Kriging interpolation method in the ArcGIS software was applied to create the continuous surface of the palaeo-water depths, i.e. the Hirnantian palaeotopography. Meanwhile, the line transect analysis …
Transition From Contraction To Extension In The Northeastern Basin And Range: New Evidence From The Copper Mountains, Nevada, Jeffrey M. Rahl, Allen J. Mcgrew, Kenneth A. Foland
Transition From Contraction To Extension In The Northeastern Basin And Range: New Evidence From The Copper Mountains, Nevada, Jeffrey M. Rahl, Allen J. Mcgrew, Kenneth A. Foland
Allen J. McGrew
New mapping, structural analysis, and 40Ar/39Ar dating reveal an unusually well‐constrained history of Late Eocene extension in the Copper Mountains of the northern Basin and Range province. In this area, the northeast‐trending Copper Creek normal fault juxtaposes a distinctive sequence of metacarbonate and granitoid rocks against a footwall of Upper Precambrian to Lower Cambrian quartzite and phyllite. Correlation of the hanging wall with footwall rocks to the northwest provides an approximate piercing point that requires 8–12 km displacement in an ESE direction. This displaced fault slice is itself bounded above by another normal fault (the Meadow Fork Fault), which brings …
Correspondence Of Historic Salinity Fluctuations In Florida Bay, Usa, To Atmospheric Variability And Anthropogenic Changes, Anna Wachnicka, Evelyn Gaiser, Laurel Collins
Correspondence Of Historic Salinity Fluctuations In Florida Bay, Usa, To Atmospheric Variability And Anthropogenic Changes, Anna Wachnicka, Evelyn Gaiser, Laurel Collins
Evelyn E. Gaiser
Florida Bay is a highly dynamic estuary that exhibits wide natural fluctuations in salinity due to changes in the balance of precipitation, evaporation and freshwater runoff from the mainland. Rapid and large-scale modification of freshwater flow and construction of transportation conduits throughout the Florida Keys during the late nineteenth and twentieth centuries reshaped water circulation and salinity patterns across the ecosystem. In order to determine long-term patterns in salinity variation across the Florida Bay estuary, we used a diatom-based salinity transfer function to infer salinity within 3.27 ppt root mean square error of prediction from diatom assemblages from four ~130 …
Prevailing Weather Conditions During Summer Seasons Around Gangotri Glacier, Pratap Singh, Umesh K. Haritashya, K. S. Ramasastri, Naresh Kumar
Prevailing Weather Conditions During Summer Seasons Around Gangotri Glacier, Pratap Singh, Umesh K. Haritashya, K. S. Ramasastri, Naresh Kumar
Umesh K. Haritashya
Meteorological data collected near the snout of the Gangotri Glacier suggest that the study area receives less rainfall. The average seasonal rainfall is observed to be about 260 mm. The rainfall distribution does not show any monsoon impact. Amount of seasonal rainfall is highly variable (131.4-368.8 mm) from year to year, but, in general, August had the maximum rainfall. A verage daily maximum and minimum temperatures were 14.7 and 4.1°C respectively, whereas average mean temperature was 9.4°C. July was recorded as the warmest month. During daytime, wind speed was four times higher than that at night-time. The average daytime and …
Multispectral Image Analysis Of Glaciers And Glacier Lakes In The Chugach Mountains, Alaska, Jeffrey Kargel, Matthew Beedle, Andrew Bush, Francisco Carreño, Elena Castellanos, Umesh Haritashya, Gregory Leonard, Javier Lillo, Ivan Lopez, Mark Pleasants, Edward Pollock, David Wolfe
Multispectral Image Analysis Of Glaciers And Glacier Lakes In The Chugach Mountains, Alaska, Jeffrey Kargel, Matthew Beedle, Andrew Bush, Francisco Carreño, Elena Castellanos, Umesh Haritashya, Gregory Leonard, Javier Lillo, Ivan Lopez, Mark Pleasants, Edward Pollock, David Wolfe
Umesh Haritashya
The Chugach Mountains contain the largest nonpolar alpine glaciers in the world and include a wide variety of glacier types: some are land terminating; some calve variously into tidewater, lakes, and rivers; some are heavily debris covered; some are surge-type, whereas others are neither debris covered nor surge type. Nearly all are retreating, thinning, or both, though some rare ones are advancing, and some are thickening at high elevations. To assist the further documentation of changes, we establish an inventory of glaciers in the eastern Chugach Mountains. Several case studies of diverse glacier types showcase remotesensing applications and are used …
Encyclopedia Of Snow, Ice And Glaciers, Vijay P. Singh, Pratap Singh, Umesh K. Haritashya
Encyclopedia Of Snow, Ice And Glaciers, Vijay P. Singh, Pratap Singh, Umesh K. Haritashya
Umesh K. Haritashya
The objective of this encyclopedia is to present the current state of scientific understanding of various aspects of earth’s cryosphere – snow, glaciers, ice caps, ice sheets, ice shelves, sea ice, river and lake ice, and permafrost – and their related interdisciplinary connections under one umbrella. Therefore, every effort has been made to provide a comprehensive coverage of cryosphere by including a broad array of topics, such as the atmospheric processes responsible for snow formation; snowfall observations; snow cover and snow surveys; transformation of snow to ice and changes in their properties; classification of ice and glaciers and their worldwide …
New Body Mass Estimates For Canis Dirus, The Extinct Pleistocene Dire Wolf, William Anyonge, Christopher Roman
New Body Mass Estimates For Canis Dirus, The Extinct Pleistocene Dire Wolf, William Anyonge, Christopher Roman
Christopher Roman
Quantitative study of the body mass of Canis dirus. Results indicate a mean body mass comparable to the extant gray wolf, suggesting larger individual animals probably exceed the body mass range of extant gray wolves.
Algal Stromatolites In The Willow River Member Of The Lower Ordovician Shakopee Formation Near Chatfield, Minnesota, Usa, Sophia May, Larry Davis, David Brown
Algal Stromatolites In The Willow River Member Of The Lower Ordovician Shakopee Formation Near Chatfield, Minnesota, Usa, Sophia May, Larry Davis, David Brown
David C. Brown
No abstract provided.
Microstratigraphic Analysis Of Burrow-Reworked Dinosaur Track Bed At Joanna's Track Site, Cretaceous Glen Rose Formation, Glen Rose, Texas, Michael Blair, Benjamin Dattilo, Anthony Martin, James Farlow
Microstratigraphic Analysis Of Burrow-Reworked Dinosaur Track Bed At Joanna's Track Site, Cretaceous Glen Rose Formation, Glen Rose, Texas, Michael Blair, Benjamin Dattilo, Anthony Martin, James Farlow
Benjamin F. Dattilo
Although dinosaur trackways are common in the Cretaceous Glen Rose Formation of Texas, the recently discovered Joanna track site illustrates a unique ichnological relationship where dinosaur tracks were disrupted by invertebrate burrows made long after burial. In an effort to document the precise sequence of events, we described the interval from 0.3 m below the track layer through 2.7 m above it in a vertical outcrop adjacent to the track site, focusing on the 70-cm of strata immediately above the track horizon. An 8-meter N-S cross-section of this 70-cm interval was power-washed, examined for trace fossils, body fossils, and lithology …
Early Ordovician Mitrates And A Possible Solute (Echinodermata) From The Western United States, Colin Sumrall, James Sprinkle, Thomas Guensburg, Benjamin Dattilo
Early Ordovician Mitrates And A Possible Solute (Echinodermata) From The Western United States, Colin Sumrall, James Sprinkle, Thomas Guensburg, Benjamin Dattilo
Benjamin F. Dattilo
Two new kirkocystid mitrate stylophorans (Echinodermata, Homalozoa) and a new possible solute (Echinodermata, Homalozoa) are described from the Early Ordovician of the western United States. The mitrates are among the earliest members of their clade to appear near the beginning of the Ordovician Radiation. Anatifopsis ninemilensis new species comes from the Ninemile Shale in central Nevada and the McKelligon Canyon Formation in west Texas. Anatifopsis fillmorensis new species comes from the middle Fillmore Formation in western Utah and a Ninemile Shale equivalent limestone bed in southern Nevada. The possible solute Drepanocystis dubius new genus new species from the lower Wah …
Stirred Not Shaken: Using Taphonomy To Reconstruct Paleoecological Succession And Taphonomic Feedback In A Cincinnatian (Ordovician, Ohio) Storm-Disturbed Shell Bed, Rebecca Freeman, Benjamin Dattilo, Aaron Morse, Michael Blair, Steve Felton, John Pojeta
Stirred Not Shaken: Using Taphonomy To Reconstruct Paleoecological Succession And Taphonomic Feedback In A Cincinnatian (Ordovician, Ohio) Storm-Disturbed Shell Bed, Rebecca Freeman, Benjamin Dattilo, Aaron Morse, Michael Blair, Steve Felton, John Pojeta
Benjamin F. Dattilo
Walker and Alberstadt’s 1975 idea that a single shell bed contains a record of ecological succession has seemingly been refuted through stratinomic studies. These studies suggest that fossils are destroyed and accumulations are reworked by storms to the point of obliterating any record of successional-scale changes in faunas. Therefore storm-disturbed shell beds are not considered ideal for reconstruction of paleoecological succession.
Nevertheless, a storm-winnowed shell bed from the Fairview Formation, Ohio preserves a wide variety of shells in a range of taphonomic conditions that reveal succession-like changes. Exceptionally-preserved lingulid brachiopods found as intact pyrite-lined spar-filled shells rule out the final …
Dinosaur Tracksites Of The Paluxy River Valley (Glen Rose Formation, Lower Cretaceous), Dinosaur Valley State Park, Somervell County, Texas., James O. Farlow, Mike O'Brien, Glenn J. Kuban, Benjamin F. Dattilo, K. T. Bates, Peter L. Falkingham, L. Pinuela, Amanda Rose, A. Freels, C. Kumagai, Courtney Libben, Justin Smith, J. Whitcraft
Dinosaur Tracksites Of The Paluxy River Valley (Glen Rose Formation, Lower Cretaceous), Dinosaur Valley State Park, Somervell County, Texas., James O. Farlow, Mike O'Brien, Glenn J. Kuban, Benjamin F. Dattilo, K. T. Bates, Peter L. Falkingham, L. Pinuela, Amanda Rose, A. Freels, C. Kumagai, Courtney Libben, Justin Smith, J. Whitcraft
Benjamin F. Dattilo
In 1940 R.T. Bird of the American Museum of Natural History collected segments of a sauropod and a theropod trackway from a site in the bed (Glen Rose Formation; Lower Cretaceous) of the Paluxy River, in what is now Dinosaur Valley State Park (Glen Rose, Texas, USA). However, Bird left undocumented thousands of other dinosaur footprints from this and other Paluxy tracksites. In 2008 and 2009 our international team carried out fieldwork to create detailed photomosaics of extant Paluxy tracksites, using GIS technology to combine these with historic maps and photographs. We also made photographs, tracings, LiDAR images, and measurements …
The Curse Of Rafinesquina: Negative Taphonomic Feedback Exerted By Strophomenid Shells On Storm-Buried Lingulids In The Cincinnatian (Katian, Ordovician) Series Of Ohio, Rebecca Freeman, Benjamin Dattilo, Aaron Morse, Michael Blair, Steve Felton, John Pojeta
The Curse Of Rafinesquina: Negative Taphonomic Feedback Exerted By Strophomenid Shells On Storm-Buried Lingulids In The Cincinnatian (Katian, Ordovician) Series Of Ohio, Rebecca Freeman, Benjamin Dattilo, Aaron Morse, Michael Blair, Steve Felton, John Pojeta
Benjamin F. Dattilo
Thousands of lingulid brachiopods were found clustered beneath hundreds of individual valves of the strophomenid brachiopod Rafinesquina in the Upper Ordovician of Ohio. This association suggested a relationship between the two brachiopods, but the nature of this relationship was unclear. We utilized serial thin sectioning to examine these brachiopods and to determine the origin of the bed in which they were found. Sedimentary structures, mixed taphonomies, and stratigraphic and paleogeographic setting suggest that the lingulids occupied a hiatal concentration that had previously been reworked, but not significantly transported, by tropical storms. The final burial event was a storm that exhumed …
Remarkable Preservation Of A New Genus And Species Of Limuline Horseshoe Crab From The Cretaceous Of Texas, U.S.A., Rodney Feldman, Carrie Schweitzer, Benjamin Dattilo, James Farlow
Remarkable Preservation Of A New Genus And Species Of Limuline Horseshoe Crab From The Cretaceous Of Texas, U.S.A., Rodney Feldman, Carrie Schweitzer, Benjamin Dattilo, James Farlow
Benjamin F. Dattilo
A single specimen, part and counterpart of a carapace, of a horseshoe crab from the Lower Cretaceous (Albian) Glen Rose Formation in north-central Texas, forms the basis for the definition of a new genus and species, Crenatolimulus paluxyensis. The discovery represents only the fifth limuline known from the Cretaceous. Its preservational style is remarkable in that the carapace exterior is faithfully replicated by a massive overgrowth of serpulid worms.
Conodont Biostratigraphy Across A Conformable Sauk–Tippecanoe Megasequence Boundary, Western Central Utah., Raymond Ethington, James Miller, Benjamin Dattilo, Rebecca Freeman
Conodont Biostratigraphy Across A Conformable Sauk–Tippecanoe Megasequence Boundary, Western Central Utah., Raymond Ethington, James Miller, Benjamin Dattilo, Rebecca Freeman
Benjamin F. Dattilo
The Sauk–Tippecanoe Megasequence boundary is a major unconformity in cratonic Laurentia and in the Appalachians. In contrast, the western margin of Laurentia in west-central Utah preserves a thick, continuously deposited record of the Whiterockian Regression at the top of the Sauk Megasequence (Middle Ordovician). Relevant strata include the Lehman Formation (limestone, shale), Watson Ranch Quartzite (sandstone, limestone, shale), and Crystal Peak Dolomite (dolomite, limestone).
Prominent facies changes occur in the Watson Ranch Quartzite, which is all sandstone near Ibex (southern Barn Hills), is sandstone with sandy carbonate and carbonate interbeds 12 miles SW near Crystal Peak (southern Confusion Range), and …
The “Passive Implanter” Strategy Of The Adult Ordovician Brachiopod, Platystrophia Ponderosa., Sadye Howald, Benjamin Dattilo
The “Passive Implanter” Strategy Of The Adult Ordovician Brachiopod, Platystrophia Ponderosa., Sadye Howald, Benjamin Dattilo
Benjamin F. Dattilo
Platystrophia ponderosa is found throughout the Maysvillian Strata of the Cincinnati Ordovician. This species thrived in a high energy environment with only muddy shell gravels, and no solid substrates for pedicle attachment. Our growth-series studies show juveniles of this species had large pedicle openings, thin shell, small size, nearly flat shape, and shallow sinus/sulcus. In contrast, the adults had relatively small pedicle openings obstructed by a large beak, secondary thickening of the pedicle valve making it considerably thicker than the brachial valve, large size (up to 4cm in diameter), spherical shape, and deep sinus/sulcus. The morphological characteristics of the adult …
A Quantitative Paleoecological Approach To High-Resolution Cyclic And Event Stratigraphy: The Upper Ordovician Miamitown Shale In The Type Cincinnatian, Benjamin Dattilo
A Quantitative Paleoecological Approach To High-Resolution Cyclic And Event Stratigraphy: The Upper Ordovician Miamitown Shale In The Type Cincinnatian, Benjamin Dattilo
Benjamin F. Dattilo
No abstract provided.
Middle Paleozoic Sequence Stratigraphy And Paleontology Of The Cincinnati Arch: Part 2 Northern Kentucky And Se Indiana, Carlton Brett, Benjamin Dattilo, Patrick Mclaughlin, Thomas Schramm, James Thomka, Bradley Cramer
Middle Paleozoic Sequence Stratigraphy And Paleontology Of The Cincinnati Arch: Part 2 Northern Kentucky And Se Indiana, Carlton Brett, Benjamin Dattilo, Patrick Mclaughlin, Thomas Schramm, James Thomka, Bradley Cramer
Benjamin F. Dattilo
No abstract provided.
How Many Track Horizons Are Exposed At Dinosaur Valley State Park? Stratigraphy Of The Cretaceous Glen Rose Formation Track Sites Of The Paluxy River, Glen Rose, Texas, Benjamin Dattilo, Sadye Howald, James Farlow, Anthony Martin
How Many Track Horizons Are Exposed At Dinosaur Valley State Park? Stratigraphy Of The Cretaceous Glen Rose Formation Track Sites Of The Paluxy River, Glen Rose, Texas, Benjamin Dattilo, Sadye Howald, James Farlow, Anthony Martin
Benjamin F. Dattilo
The dinosaur tracks of the Glen Rose Formation in the Paluxy River at Dinosaur Valley State Park are among the best preserved and most abundant in the world. While many track sites are easily correlated to the Main Tracksite, others, especially those at the extreme ends of the park, are differently preserved and not obviously correlated. To count track horizons, several stratigraphic sections were measured along the river from upstream at the McFall Ledge Site to 7.6 km downstream at the County Road 1001 crossing (3.1 km linear distance). These reveal 6 meters of strata separating two track-bearing horizons exposed …
The Mollusk-Rich Ordovician Miamitown Shale Mapped From Cincinnati To The Bluegrass: Probing Contemporaneous Peritidal Deposits To Decipher The Paleobathymetric Problem Of A Puzzling Pelite., Benjamin Dattilo, Thomas Schramm, Sasha Mosser, Lydia Mark, William Ward
The Mollusk-Rich Ordovician Miamitown Shale Mapped From Cincinnati To The Bluegrass: Probing Contemporaneous Peritidal Deposits To Decipher The Paleobathymetric Problem Of A Puzzling Pelite., Benjamin Dattilo, Thomas Schramm, Sasha Mosser, Lydia Mark, William Ward
Benjamin F. Dattilo
While most Upper Ordovician (Katian stage) strata in the Cincinnati region can be characterized as mixed carbonates and mudstones, there are a few carbonate-poor silty mudstone units including the Maysvillian Miamitown Shale and the Richmondian Waynesville Formation. These are characterized by molluscan faunas that contrast with the typical brachiopod-bryozoan fauna of the Cincinnatian, or, for that matter, of the Lower Paleozoic in general. The paucity of more widespread common taxa makes it difficult to use such assemblages in determining paleoenvironmental conditions, particularly water depth. Thus, combined with the lack of distinctive sedimentological indicators, it is difficult to say if these …
Sedimentology And Microstratigraphy Of A Cincinnatian Edrioasteroid Obrution Deposit., Aaron Morse, Benjamin Dattilo, David Meyer, Lydia Mark, Michael Harrison
Sedimentology And Microstratigraphy Of A Cincinnatian Edrioasteroid Obrution Deposit., Aaron Morse, Benjamin Dattilo, David Meyer, Lydia Mark, Michael Harrison
Benjamin F. Dattilo
The Manchester edrioasteroid pavement is a shell layer in mudrock from the Corryville Formation (U. Ordovician, Maysvillain). No previous studies have examined sediments that buried Cincinnatian edrioasteroid pavements. To address this problem, a 16 cm thick stratigraphic sample measuring 90 cm by 30 cm was collected with a plaster jacket, dried for 2 years, then encased in fiberglass for dry cutting into slabs 2-4 cm thick. These were hardened with epoxy and polished dry with sandpaper. A prepared slab was sent to Bruker AXS for analysis using the M4 Tornado µ-XRF.
Delicate colonies of bryozoans, embedded in mudrock were found …
The Orientation Of Strophomenid Brachiopods On Soft Substrates, Roy Plotnick, Benjamin Dattilo, Daniel Piquard, Jennifer Bauer, Joshua Corrie
The Orientation Of Strophomenid Brachiopods On Soft Substrates, Roy Plotnick, Benjamin Dattilo, Daniel Piquard, Jennifer Bauer, Joshua Corrie
Benjamin F. Dattilo
Strophomenid brachiopods have long been interpreted as ‘‘snowshoe’’ strategists, with their flattened concavoconvex valves providing resistance to foundering in very soft sediments. There has been a sharp difference of opinion in whether the shells were oriented with their convex or their concave surface in contact with the sediment. This study, along with independent evidence from sedimentology, ichnology, and morphology, indicates that the strophomenids lived with their shells concave down (convex up). Experiments indicate the force required to push shells into soft cohesive muds is much greater for the convex up than for the convex down orientation. Forces also increase with …
An Enigmatic Lobate Mat-Like Fossil(?) In The Kope Formation (Upper Ordovician), Kenton County, Kentucky, Ron Fine, Carlton Brett, Benjamin Dattilo, David Meyer
An Enigmatic Lobate Mat-Like Fossil(?) In The Kope Formation (Upper Ordovician), Kenton County, Kentucky, Ron Fine, Carlton Brett, Benjamin Dattilo, David Meyer
Benjamin F. Dattilo
A new, enigmatic, large fossil(?) object from a thin silty mudstone bed (up to 3 cm thick) underlain by siltstone was excavated from the lower Kope Formation (Economy Member, basal Pioneer Valley submember) near Covington, KY. The excavated object is roughly elliptical in outline, over 2 m long, with a parallel-fluted structure at one end that terminates in a complex of conjoined, flattened, ellipsoidal or spatulate concretion-like lobes at the other end. The lobes are about 10 cm and range to 45 cm long. Internally, some lobes show lamination, sometimes convoluted. The most perplexing feature of the lobe-like structures is …
Upper Ordovician Strata Of Southern Ohio-Indiana: Shales, Shell Beds, Storms, Sediment Starvation, And Cycles, Carlton Brett, Thomas Schramm, Benjamin Dattilo, Nathan Marshall
Upper Ordovician Strata Of Southern Ohio-Indiana: Shales, Shell Beds, Storms, Sediment Starvation, And Cycles, Carlton Brett, Thomas Schramm, Benjamin Dattilo, Nathan Marshall
Benjamin F. Dattilo
The Cincinnatian Series (ca. 450 to 442 Ma) of the Cincinnati Arch features some of the most spectacular Ordovician fossils in the world. The rich faunas of bryozoans, brachiopods, molluscs, echinoderms, and trilobites are preserved as discrete shell-rich limestones, cyclically interbedded with sparsely fossiliferous shales and mudstones that may yield exceptionally preserved trilobites and crinoids. Similar successions of shell beds interbedded with mudstones are common components of Paleozoic successions. In such successions, the genesis of the highly concentrated shell beds is often attributed to storm-winnowing, but is this the whole story? This trip will offer an overview of the classic …