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Geologic Map of Petrified Forest National Park, Arizona
This geologic dataset covers the area within the boundaries of Petrified Forest National Park (PEFO), located in northeastern Arizona (Figure 1) as defined prior to the expansion approved in December of 2004 (Figure 2); much of the land in the approved expansion has not yet been acquired by the National Park Service, and is inaccessible to the public. The map is based on unpublished mapping by Billingsley (1985b), Johns (1988), Woody (2003), published mapping by Martz and Parker (2010), and new mapping. The geology of the Little Colorado River Valley in eastern Arizona, including the PEFO area (Figures 1, 2), is characterized by widespread exposures of Triassic and Jurassic terrestrial sedimentary rocks. The Upper Triassic Chinle Formation constitutes the bulk of the non-Quaternary exposures within the Park (Figure 3). The Chinle Formation unconformably overlies the Lower- Middle Triassic Moenkopi Formation. Although this latter unit is not exposed within PEFO, widespread exposures are present to the west and south in the Little Colorado River Valley.Documents in the AZGS Document Repository collection are made available by the Arizona Geological Survey (AZGS) and the University Libraries at the University of Arizona. For more information about items in this collection, please contact [email protected]
The palynology of the Sonsela member (Late Triassic, Norian) at Petrified Forest National Park, Arizona, USA
Recent paleontological investigations and lithostratigraphic revisions reveal a marked biotic turnover zone within the continental deposits of the Sonsela member of the Chinle Formation (Late Triassic, Norian) at Petrified Forest National Park, USA. Within the Sonsela member we found three pollen assemblage biozones: Zone II (90.5–94 m above the Mesa Redondo member) contains a relatively diverse palynological assemblage, with a mix of pteridosperms, voltzialean and some Mesozoic conifers. Following a 2.3 m hiatus, Zone IIIa (96–97.5 m) is characterized by a decrease in pteridosperms and Mesozoic conifers and a drop in voltzialean conifer diversity. The alleged voltzialean conifer pollen Klausipollenites gouldii was dominant in this part of the assemblage and a significant rise in spores and cycad pollen was also evident. In Zone IIIb (97.5–98.5 m) diversity increases and several taxa, which were absent in Zone IIIa reappear, although K. gouldii remained the most abundant taxon. The transition between the palynological assemblages Zones II and IIIa coincide approximately (within a ~ 2.5 m interval) with a documented faunal turnover. The floristic assemblages suggest that the climate of the south-western United States during the Norian was most likely semi-arid and highly seasonal, despite being located at tropical latitudes, with aridification occurring towards the end-Triassic as the continent drifted northwards and global volcanism increased. The gymnosperm-dominated palynofloral assemblage as opposed to the fern- and horsetail-dominated macrofossil record of the Sonsela member of the Chinle Formation, conforms to a semi-arid upland environment alternated by riparian, swampy lowland
Emerging Trends in the Etiology, Prevention, and Treatment of Gastrointestinal Anastomotic Leakage
Anastomotic leaks represent one of the most alarming complications following any gastrointestinal anastomosis due to the substantial effects on post-operative morbidity and mortality of the patient with long-lasting effects on the functional and oncologic outcomes. There is a lack of consensus related to the definition of an anastomotic leak, with a variety of options for prevention and management. A number of patient-related and technical risk factors have been found to be associated with the development of an anastomotic leak and have inspired the development of various preventative measures and technologies. The International Multispecialty Anastomotic Leak Global Improvement Exchange group was convened to establish a consensus on the definition of an anastomotic leak as well as to discuss the various diagnostic, preventative, and management measures currently available. © 2016, The Society for Surgery of the Alimentary Tract