Stratigraphy of the Triassic Martin Bridge Formation, Wallowa terrane: Stratigraphy and depositional setting

2008 ◽  
Author(s):  
George D. Stanley ◽  
Christopher A. McRoberts ◽  
Michael T. Whalen
Keyword(s):  
Bridge Formation ◽  
Wallowa Terrane ◽  
Depositional Setting

Neoguadalupia oregonensis new species: Reappearance of a Permian sponge genus in the Upper Triassic Wallowa Terrane, Oregon

1998 ◽  
Vol 72 (2) ◽  
pp. 221-224 ◽  
Author(s):  
Baba Senowbari-Daryan ◽  
George D. Stanley
Keyword(s):  
New Species ◽  
North America ◽  
South China ◽  
Upper Triassic ◽  
Island Arc ◽  
Western North America ◽  
Generic Level ◽  
Bridge Formation ◽  
Wallowa Terrane

The sponge Neoguadalupia oregonensis new species is described from the Upper Triassic Martin Bridge Formation in the southern Wallowa Mountains, Oregon. It is the first authenticated Triassic occurrence of the genus Neoguadalupia, previously known from the Permian of South China and suspected to occur in Upper Triassic of Nevada. This discovery provides evidence at the generic level of survival of a Lazarus taxon in an island-arc terrane of western North America.

Triassic sponges (Sphinctozoa) from Hells Canyon, Oregon

1988 ◽  
Vol 62 (03) ◽  
pp. 419-423 ◽  
Author(s):  
Baba Senowbari-Daryan ◽  
George D. Stanley
Keyword(s):  
Endemic Species ◽  
Upper Triassic ◽  
Island Arc ◽  
Tropical Island ◽  
The Family ◽  
Wallowa Terrane ◽  
Unique Condition ◽  
Hells Canyon

Two Upper Triassic sphinctozoan sponges of the family Sebargasiidae were recovered from silicified residues collected in Hells Canyon, Oregon. These sponges areAmblysiphonellacf.A. steinmanni(Haas), known from the Tethys region, andColospongia whalenin. sp., an endemic species. The latter sponge was placed in the superfamily Porata by Seilacher (1962). The presence of well-preserved cribrate plates in this sponge, in addition to pores of the chamber walls, is a unique condition never before reported in any porate sphinctozoans. Aporate counterparts known primarily from the Triassic Alps have similar cribrate plates but lack the pores in the chamber walls. The sponges from Hells Canyon are associated with abundant bivalves and corals of marked Tethyan affinities and come from a displaced terrane known as the Wallowa Terrane. It was a tropical island arc, suspected to have paleogeographic relationships with Wrangellia; however, these sponges have not yet been found in any other Cordilleran terrane.

Introductory Remarks

1980 ◽  
Vol 38 ◽  
pp. 598-599
Author(s):  
H. Mohri
Keyword(s):  
Muscle Contraction ◽  
Experimental Evidence ◽  
Sea Urchin ◽  
Constant Length ◽  
Thin Filaments ◽  
Bridge Formation ◽  
Thick Filaments ◽  
Sliding Mechanism ◽  
Radial Spokes ◽  
Cilia And Flagella

In 1959, Afzelius observed the presence of two rows of arms projecting from each outer doublet microtubule of the so-called 9 + 2 pattern of cilia and flagella, and suggested a possibility that the outer doublet microtubules slide with respect to each other with the aid of these arms during ciliary and flagellar movement. The identification of the arms as an ATPase, dynein, by Gibbons (1963)strengthened this hypothesis, since the ATPase-bearing heads of myosin molecules projecting from the thick filaments pull the thin filaments by cross-bridge formation during muscle contraction. The first experimental evidence for the sliding mechanism in cilia and flagella was obtained by examining the tip patterns of molluscan gill cilia by Satir (1965) who observed constant length of the microtubules during ciliary bending. Further evidence for the sliding-tubule mechanism was given by Summers and Gibbons (1971), using trypsin-treated axonemal fragments of sea urchin spermatozoa. Upon the addition of ATP, the outer doublets telescoped out from these fragments and the total length reached up to seven or more times that of the original fragment. Thus, the arms on a certain doublet microtubule can walk along the adjacent doublet when the doublet microtubules are disconnected by digestion of the interdoublet links which connect them with each other, or the radial spokes which connect them with the central pair-central sheath complex as illustrated in Fig. 1. On the basis of these pioneer works, the sliding-tubule mechanism has been established as one of the basic mechanisms for ciliary and flagellar movement.

Conodonts, ammonoids, foraminifers, and depositional setting of the Serpukhovian and Bashkirian stages in the Kugarchi Section in the South Urals, Russia

2017 ◽  
Vol 14 (1-4) ◽  
pp. 319-347 ◽  
Author(s):  
Svetlana V. Nikolaeva ◽  
Elena I. Kulagina ◽  
Elena N. Gorozhanina ◽  
Alexander S. Alekseev ◽  
Vera A. Konovalova
Keyword(s):  
South Urals ◽  
The South ◽  
Depositional Setting

DEPOSITIONAL SETTING OF METALLIFEROUS, ORGANIC-RICH BLACK MUDROCK IN THE HEATH FORMATION (UPPER MISSISSIPPIAN), CENTRAL MONTANA

2016 ◽  
Author(s):  
Julie A. Dumoulin ◽  
◽  
Craig A. Johnson ◽  
Karen D. Kelley ◽  
Palma J. Jarboe ◽  
...  
Keyword(s):  
Central Montana ◽  
Depositional Setting
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