WEATHERING PITS VERSUS TRAMPLE MARKS: A REINTERPRETATION OF THE “DINOSAUR DANCE FLOOR”: A JURASSIC NAVAJO SANDSTONE SURFACE IN THE VERMILION CLIFFS NATIONAL MONUMENT, ARIZONA

Palaios ◽  
2021 ◽  
Vol 36 (11) ◽  
pp. 331-338
Author(s):  
BRENT H. BREITHAUPT ◽  
MARJORIE A. CHAN ◽  
WINSTON M. SEILER ◽  
NEFFRA A. MATTHEWS
Keyword(s):  
Direct Evidence ◽  
Lower Jurassic ◽  
Dance Floor ◽  
Navajo Sandstone ◽  
National Monument ◽  
A Site

ABSTRACT Within the eolian Lower Jurassic Navajo Sandstone, exposed in the Coyote Buttes area of Vermilion Cliffs National Monument in Arizona, a site (informally known as the “Dinosaur Dance Floor”) is reinterpreted as an enigmatic, modified (possibly pedogenic) eolian surface that was exposed and further modified and accentuated by modern weathering and erosion. The resultant surface is covered with small, shallow potholes or weathering pits, with no direct evidence of dinosaur activity.

scholarly journals First reported actinopterygian from the Navajo Sandstone (Lower Jurassic, Glen Canyon Group) of southern Utah, USA

2017 ◽  
Vol 91 (3) ◽  
pp. 548-553
Author(s):  
Joseph A. Frederickson ◽  
Brian M. Davis
Keyword(s):  
North America ◽  
Middle Jurassic ◽  
Fossil Record ◽  
Lower Jurassic ◽  
Western North America ◽  
Dune System ◽  
Navajo Sandstone ◽  
National Monument ◽  
First Occurrence ◽  
Glen Canyon

AbstractWe report the first occurrence of an actinopterygian fish from the Lower Jurassic Navajo Sandstone, discovered in the Grand Staircase-Escalante National Monument in southern Utah, U.S.A. The site contains multiple individuals, preserved within an interdune deposit, possessing the elongate modified dorsal scales usually characterizing semionotiform fishes. The presence of moderately sized fish provides further evidence that interdune oases were occasionally persistent environmental habitats within the greater Navajo dune system, and that the paleobiota is still woefully undersampled. Additionally, this site could help fill a gap in the actinopterygian fossil record between the patchy Lower Jurassic and better-known Middle Jurassic documentation of western North America.

Diagnosis of spontaneous intracranial hypotension by using magnetic resonance myelography

2000 ◽  
Vol 92 (5) ◽  
pp. 873-876 ◽  
Author(s):  
Akira Matsumura ◽  
Izumi Anno ◽  
Hiroshi Kimura ◽  
Eiichi Ishikawa ◽  
Tadao Nose
Keyword(s):  
Magnetic Resonance ◽  
Intracranial Hypotension ◽  
Direct Evidence ◽  
Spontaneous Intracranial Hypotension ◽  
Content Type ◽  
Highly Sensitive ◽  
Csf Leakage ◽  
Leakage Site ◽  
A Site ◽  
Mr Myelography

✓ The authors describe a case of spontaneous intracranial hypotension in which the leakage site was determined by using magnetic resonance (MR) myelography. This technique demonstrated the route of cerebrospinal fluid (CSF) leakage, whereas other methods failed to show direct evidence of leakage. Magnetic resonance myelography is a noninvasive method that is highly sensitive in detecting CSF leakage. This is the first report in which a site of CSF leakage was detected using MR myelography.

Revising the stratigraphy at Mollies Nipple, Kane County, Utah, USA to better understand the origin of jarosite and alunite cements

2021 ◽  
Author(s):  
Jordan Walker ◽  
Sally Potter-McIntyre
Keyword(s):  
Special Interest ◽  
Depositional Environments ◽  
Navajo Sandstone ◽  
National Monument ◽  
Regional Correlation ◽  
Kane County

<p>Mollies Nipple—a butte located in the Grand Staircase-Escalante National Monument (GSENM)—is of special interest because of the presence of unusual alunite and jarosite cements within the caprock. These minerals precipitate in hyperacidic environments (pH1-2) and are not stable over ~pH5; yet they are abundant on Mars where they are used to interpret depositional and diagenetic environments. The caprock at Mollies Nipple is historically interpreted as Navajo Sandstone via photogeologic mapping; however, it is ~200 m above the mapped upper extent of the Navajo Sandstone in this region. The units overlying the Navajo Sandstone have complex stratigraphic relations in this region and the caprock could be the Carmel or Temple Cap Formations, or the Page Sandstone. This study aims to characterize Mollies Nipple through measured sections, mineralogical analyses, palynomorph analysis, and radiometric age dates from ash lenses present in the caprock. The results will better define the stratigraphy of Mollies Nipple and determine the regional correlation of the caprock. Ultimately, this work will contribute to the understanding of how alunite and jarosite were precipitated at Mollies Nipple; why these minerals are still present at Mollies Nipple, and potentially revise the understanding of Martian depositional environments.</p>

Working towards a universal formation model for spheroidal iron (oxyhydr)oxide concretions

2021 ◽  
Author(s):  
Desiree Baker ◽  
Sally Potter-McIntyre
Keyword(s):  
Host Rock ◽  
Redox Reactions ◽  
Mineralogical Composition ◽  
Recent Model ◽  
Universal Model ◽  
Formation Model ◽  
Navajo Sandstone ◽  
Diagenetic Facies ◽  
A Site ◽  
Diagenetic Reactions

<p>Three principal models exist for iron (oxyhydr)oxide concretion formation in the Navajo Sandstone in southern Utah, USA and the most recent model by Yoshida et al. (2018) suggests that calcite concretions are precursors to iron (oxyhydr)oxide concretions. This model could account for the existence of a gradient of carbonate and iron concretions found in both red diagenetic facies (with primary hematite grains coatings retained) and white diagenetic facies (primary hematite grain coatings removed during diagenesis). However, evidence for calcite precursor minerals and an understanding of the fluid chemistries involved in these diagenetic reactions is lacking. This research focuses on spheroidal concretions in the Navajo Sandstone at Coyote Gulch—a site that is down gradient, but upsection from Spencer Flat (the focus of previous work) and tests the hypothesis that calcite concretions are precursors to iron (oxyhydr)oxide concretions. Bulk mineralogy, bulk geochemistry, and petrography provide elemental and mineralogical composition of the concretions and show that the concretions are calcite cemented (~40 wt.%) and the host rock is predominately iron (oxyhydr)oxide cemented (~3 wt.%). The host rock surrounding embedded concretions shows secondary iron (oxyhydr)oxide precipitation and decreases in calcite in transects away from the concretion. These relationships suggest that the calcite concretions formed prior to the precipitation of secondary iron (oxyhydr)oxides and may have provided a localized buffering environment for the precipitation of iron (oxyhydr)oxides. This study also represents an opportunity to determine a universal model for carbonate and iron (oxyhydr)oxide spheroidal concretion formation, and to understand the influence of fluid interactions in the search for subsurface redox reactions to power metabolisms on Earth and Mars.</p>

The first Mid-Blancan occurrence of Agriotherium (Ursidae) In North America: A record from Hagerman Fossil Beds National Monument, Idaho

2009 ◽  
Vol 83 (4) ◽  
pp. 597-603 ◽  
Author(s):  
Joshua X. Samuels ◽  
Julie A. Meachen-Samuels ◽  
Philip A. Gensler
Keyword(s):  
North America ◽  
National Monument ◽  
Extant Genus ◽  
A Site ◽  
Land Mammal

Members of the subfamily Ursinae dispersed into North America from Africa and Asia during the Miocene, with the appearance of Ursavus (Schlosser, 1899), Indarctos (Pilgrim, 1913), and Agriotherium (Wagner, 1837) (Dalquest, 1986; Miller and Carranza-Castañeda, 1996; Hunt, 1998). However, none of these genera were thought to have survived past the Hemphillian Land Mammal Age in North America. It is thought that these genera were replaced, and possibly out-competed, by members of the extant genus Ursus (Linnaeus, 1758), or Plionarctos (Frick, 1926), as suggested by several sources (Bjork, 1970; Dalquest, 1986; Bell et al., 2004). It has also been suggested that the Ursavini (Agriotherium and Indarctos) may have given rise to the extant ursids and the Tremarctinae (Harrison, 1983; Miller and Carranza-Castañeda, 1996). Of the Ursavini, Agriotherium is consistently found in the Hemphillian Land Mammal Age, and so is used as an index fossil in that its absence is assumed to indicate that a site is Blancan rather than Hemphillian (Lundelius et al., 1987; Bell et al., 2004; Hunt, 2004).

scholarly journals A New Basal Sauropodomorph Dinosaur from the Lower Jurassic Navajo Sandstone of Southern Utah

PLoS ONE ◽  
2010 ◽  
Vol 5 (3) ◽  
pp. e9789 ◽  
Author(s):  
Joseph J. W. Sertich ◽  
Mark A. Loewen
Keyword(s):  
Lower Jurassic ◽  
Navajo Sandstone

Defining bounding surfaces within and between eolian and non-eolian deposits, Lower Jurassic Navajo Sandstone, Moab Area, Utah, U.S.A.: Implications for subdividing erg system strata

2021 ◽  
Vol 91 (12) ◽  
pp. 1275-1304
Author(s):  
Stephen T. Hasiotis ◽  
Marjorie A. Chan ◽  
Judith Totman Parrish
Keyword(s):  
Large Scale ◽  
Multiple Scales ◽  
Complex Surface ◽  
Lower Jurassic ◽  
Composite Surface ◽  
Independent Sequence ◽  
Navajo Sandstone ◽  
Basin Scale ◽  
Eolian Deposits ◽  
Bounding Surfaces

ABSTRACT A model-independent, sequence stratigraphic approach is used to define bounding surfaces in the Navajo Sandstone in order to identify an architectural hierarchy of genetically related sedimentary packages and the surfaces that bound them across multiple scales of both eolian and non-eolian components of an erg system. Seven bounding surfaces and eight depositional units are defined, from small to large scale. A lamina-deviation surface bounds wedge- and tabular-shaped sets of laminae and/or laminasets, separating those that have different angle orientations on the dune slipface. A bed-deviation surface bounds a succession of beds (crossbeds) that lie at different angles or orientations to bedding above, below, or adjacent to it. A bedset-deviation surface is curved, inclined, and/or wavy and irregular that bounds bedsets and their internal stratification patterns; that is, bed-deviation surfaces, and lamina-deviation surfaces. A simple surface is gently inclined with or without small, concave or convex segments that bound beds and bedsets. A composite surface is horizontal with or without concave, curved, or irregular portions of that surface. A complex surface is laterally extensive (∼ 1–10+ km) that regionally bounds and truncates underlying conterminous and interfingered eolian and non-eolian strata. An amalgamated surface is a regionally extensive (∼ 10 to 100s km) mappable unconformity, merged unconformities, and their laterally equivalent conformable surface that can exhibit local to regional pedogenic modification, lags, and significant (meters to 10s m) paleotopographic relief. The genetically related sedimentary packages typically bounded by like or higher-rank surfaces are defined as laminae, laminasets, bed, bedsets, and simple, composite, complex, and amalgamated units. Field relationships of strata and surfaces are key to reconstructing the interactions between eolian and non-eolian deposits and the processes they represent at the local, regional, and basin scale. This classification scheme can be applied to erg-system strata to fully integrate changes in diverse facies within and between contiguous deposits.

scholarly journals Secondary erythrocytosis due to a cerebellar hemangioblastoma: demonstration of erythropoietin mRNA in the tumor

Blood ◽  
1991 ◽  
Vol 78 (3) ◽  
pp. 599-601 ◽  
Author(s):  
M Trimble ◽  
J Caro ◽  
A Talalla ◽  
M Brain
Keyword(s):  
Direct Evidence ◽  
Northern Blotting ◽  
Cyst Fluid ◽  
Cerebellar Hemangioblastoma ◽  
A Site ◽  
First Time

Abstract Cerebellar hemangioblastoma is a rare cause of secondary erythrocytosis. Although the erythrocytosis is a result of erythropoietin (Ep) stimulation, direct evidence of Ep synthesis by the tumor has been lacking. In an erythrocytotic patient with a cerebellar hemangioblastoma we found elevated levels of Ep in the tumor cyst fluid and for the first time demonstrated Ep mRNA in the tumor by Northern blotting. This finding confirms cerebellar hemangioblastoma as a site of ectopic Ep production.

scholarly journals Secondary erythrocytosis due to a cerebellar hemangioblastoma: demonstration of erythropoietin mRNA in the tumor

Blood ◽  
1991 ◽  
Vol 78 (3) ◽  
pp. 599-601
Author(s):  
M Trimble ◽  
J Caro ◽  
A Talalla ◽  
M Brain
Keyword(s):  
Direct Evidence ◽  
Northern Blotting ◽  
Cyst Fluid ◽  
Cerebellar Hemangioblastoma ◽  
A Site ◽  
First Time

Cerebellar hemangioblastoma is a rare cause of secondary erythrocytosis. Although the erythrocytosis is a result of erythropoietin (Ep) stimulation, direct evidence of Ep synthesis by the tumor has been lacking. In an erythrocytotic patient with a cerebellar hemangioblastoma we found elevated levels of Ep in the tumor cyst fluid and for the first time demonstrated Ep mRNA in the tumor by Northern blotting. This finding confirms cerebellar hemangioblastoma as a site of ectopic Ep production.

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