Transitional Zone


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Transitional Zone

 

a major global morphostructure located between the underwater continental margin and the ocean floor. Typical transitional zones are encountered along the northern and western margins of the Pacific Ocean, in parts of the Caribbean and Scotia seas, and in the northeastern part of the Indian Ocean. They consist of the basins of marginal seas, island arcs, and deep trenches. Such zones are characterized by the most varied types of relief, ranging from trenches with depths of 11 km to volcanic peaks with elevations to 5–7 km on the island arcs.

Transitional zones are marked by sharp differences between the values of the magnetic and gravitational fields and heat flow values (greater values on the island arcs and values below the norm in the trenches) and by rapid and sharp differentiation in vertical movement of the earth’s crust. Under the basins of the deep-water seas the crust is suboceanic, whereas under the island arcs it is subcontinental and sometimes continental. In the oceanic trenches, the crust may be subcontinental, suboceanic, or oceanic. The transitional zone is an area of volcanic activity, intense seismic activity, and mountain formation.

O. K. LEONT’EV

References in periodicals archive ?
The distinction of the Rakvere Stage in the same area is based on the appearance of the ostracode association with Pelecybolbina pelecyoides, characteristic of the pure micritic limestone of the Ragavere Formation in central Estonia, of the upper part of the claystone of the Priekule Member (Mossen Formation) within the Livonian Tongue area, and recorded in the upper part of the siliciclastic deposits of the Variku Formation in the transitional zone. In summary, the available information suggests the penecontemporaneity of the Variku and Mossen formations and refers to the Oandu and Rakvere age of some parts of the Variku Formation (Fig.
Caption: Figure 7: Taylor diagram showing the statistical summary for the transitional zone for the (a) dry year (2001) and (b) wet year (2008).
(a) The size of peripheral zone tumors (lesion number, n = 52) was smaller than that of the transitional zone tumors (n = 17) (0.68 [+ or -] 0.41 [cm.sup.2] versus 0.93 [+ or -] 0.59 [cm.sup.2]; p < 0.05).
The mean annual precipitation of the analyzed 50 years is 896 mm for the entire basin; this is in accordance with the proved conclusion that the Huaihe River is located in the transitional zone for the 800 mm precipitation contour in China [25].
Figures 2(a) and 2(b) show the data only in the transitional zone, and the horizontal coordinates of t = 0.113 sand t = 0.074 s are the critical values between transitional and turbulent zones as shown in Figures 2(c) and 2(d), respectively.
Electrocardiogram results used for differentiation of the origins of outflow tract ventricular arrhythmias (OTVAs) using three algorithms: transitional zone (TZ) index; [V.sub.2] transition ratio; and [V.sub.2] R wave duration and R/S wave amplitude indices.
As the body moves through space, light provides the surface of readability and works as a transitional zone or membrane, an interface between the object and the subject.
It grades from prismatic hornblende into actinolite in the transitional zone to chlorite in the underlying green schist facies (Miyashiro 1994).
Clinicopathological variables examined included patient age (year), serum PSA level (ng/mL), total prostate volume (cc), transitional zone volume (cc), PSA density (serum PSA level divided by prostate volume; ng/mL/cc), resected tissue weight (g), history of needle biopsy, and pathological diagnosis on TURP specimen.
The Marmara coast is a climatic transitional zone between the first two.
in their studies suggested that multiplanar reformations are helpful in the localization of the transitional zone. Jaffe et al.
Continuous encircling linear cryolesions (CryoICE, AtriCure, Ohio, USA) were applied at the transitional zone of the scar and viable tissue (Figure 2).