scholarly journals Regional stratigraphy and subsurface geology of Cenozoic deposits, Gulf Coastal Plain, south-central United States

1991 ◽  
Author(s):  
R.L. Hosman
Keyword(s):  
United States ◽  
Coastal Plain ◽  
Gulf Coastal Plain ◽  
Subsurface Geology ◽  
South Central ◽  
Central United States

scholarly journals Regional variations in the structure of the crust in the central United States from P-wave spectra

1973 ◽  
Vol 63 (5) ◽  
pp. 1663-1687
Author(s):  
Tuneto Kurita
Keyword(s):  
United States ◽  
Gulf Of Mexico ◽  
Crustal Structure ◽  
Coastal Plain ◽  
Lower Crust ◽  
P Wave ◽  
Ratio Method ◽  
Gulf Coastal Plain ◽  
Regional Variations ◽  
Central United States

abstract Regional variations in the crustal structure in the central United States have been inferred by the transfer ratio method from an analysis of long-period P waves recorded at SHA, OXF, FLO and MDS, the stations nearly along 89°W longitude. The crustal structure in this region is approximated by a stack of horizontal parallel layers except possibly in the area around FLO, where the structure is rather complicated. The crustal thickness is predominantly controlled by the thick silicic upper crust, whereas the mafic lower crust is about 10 km thick throughout this region. The P-wave velocity of the lower crust is about 6.9 to 7.0 km/sec except probably in the area around FLO, where 7.4 km/sec velocity is more likely. A sedimentary layer with a velocity of about 3.0 km/sec, having a thickness of about 3 km near the coast of the Gulf of Mexico, tapers out to the north within the Gulf Coastal Plain. Deep discontinuities in the crust may be replaced by transitional layers up to 10 km thick. The Moho is about 33 km deep near the coast of the Gulf of Mexico, deepens to about 41 km near an intersection of the Gulf coastal plain and the interior plain, reaches about 47 km or more in the midst of the interior plain, and rises to about 41 km toward an intersection of the interior plain and the superior upland. As for the midst of the interior plain, however, the depth of the Moho reduces by as much as 5 km, if the velocity in the lower crust is about 7.0 km/sec instead of about 7.4 km/sec. In any case, the general trend of the depth of the Moho may match with the topographic feature from the Gulf of Mexico to Lake Superior.

New mud turtles (Kinosternidae,Kinosternon) from the middle–late Miocene of the United States

2015 ◽  
Vol 89 (5) ◽  
pp. 821-844 ◽  
Author(s):  
Jason R. Bourque
Keyword(s):  
United States ◽  
Great Plains ◽  
Late Miocene ◽  
Coastal Plain ◽  
Middle Miocene ◽  
The United States ◽  
Gulf Coastal Plain ◽  
North Central ◽  
South Central ◽  
Kinosternon Subrubrum

AbstractKinosternonSpix, 1824, was widespread in xeric to savanna associated paleowetlands across North America during the middle–late Miocene and steadily diversified following its first occurrences in the Hemingfordian. In the middle Miocene,Kinosternon rinconn. sp. occurred in the late Barstovian Cerro Conejo Formation of north central New Mexico, perhaps concurrently withKinosternon pojoaqueBourque 2012a from the Tesuque Formation. Subsequent late Miocene kinosternine fossils indicate that at least three potentially contemporaneous species existed throughout the Clarendonian. These areKinosternon pannekollopsn. sp., from the Ogallala Formation of northern Texas;Kinosternon wakeeniense, n. sp., from the Ogallala Formation of northwestern Kansas and Ash Hollow Formation of south-central Nebraska; andKinosternon notolophusn. sp., from the Alachua and Statenville formations of northern Florida.Kinosternon rinconis phylogenetically nested between theKinosternon flavescens(Agassiz, 1857) group (=PlatythyraAgassiz, 1857) and more derivedKinosternonincluding theKinosternon subrubrum(Lacépède, 1788) group (=ThyrosternumAgassiz, 1857).Kinosternon pannekollopsis recovered on the stem of theK.subrubrumgroup and is the oldest and largest member of that lineage.Kinosternon notolophusis readily differentiated from other MioceneKinosternonin possessing a distinct dorsomedial keel on the nuchal and faint dorsolateral costal carination. TheK.subrubrumgroup probably originated in the late Miocene savannas of the Great Plains and dispersed eastward via the Gulf Coastal Plain. An unnamed kinosternine taxon existed in the coastal plains of the eastern and southeastern United States during the Middle Miocene Climatic Optimum (with fossils from ~18 to 15 Ma), and disappeared from the region coincident with the end of that megathermal event.

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