. Bulletin - United States National Museum. Science. STUDIES EST FORAMINIFERA 105 and Bermudez, and Globorotalia cocoaensis Cushman. There are also numerous upper Eocene benthonic species, e. g., Bulimina jacksonensis Cushman, that do not cross the Eocene-Oligocene boundary. Cassigeri- nella chipolensis (Cushman and Ponton) and the Globigerina ciperoensis Bolli group on the other hand appear for the first tune in the lower Oligocene Globi- gerina ampliapertura zone. Apparently normal contacts between the Cipero and Lengua formations have been observed at various localities, such as in trenches
. Bulletin - United States National Museum. Science. STUDIES EST FORAMINIFERA 105 and Bermudez, and Globorotalia cocoaensis Cushman. There are also numerous upper Eocene benthonic species, e. g., Bulimina jacksonensis Cushman, that do not cross the Eocene-Oligocene boundary. Cassigeri- nella chipolensis (Cushman and Ponton) and the Globigerina ciperoensis Bolli group on the other hand appear for the first tune in the lower Oligocene Globi- gerina ampliapertura zone. Apparently normal contacts between the Cipero and Lengua formations have been observed at various localities, such as in trenches in the Barrackpore area. The extinction of Globorotalia fohsi rohusta, the change to a more clayey lithology, and the presence in certain areas of pebble beds and slump-masses of considerable thickness are indications not only of environmental changes but also of tectonic and possibly of tm-bidity flow activities at the end of Cipero time. The structural complexities in the area of the type section and further to the north (see text-fig. 19) make extremely difficult a satisfactory interpretation of the existing tectonic conditions. The complex pattern as exposed along the Cipero type section is also character- istic for the whole Naparima area fm-ther to the east. With the introduction of the present zonation it has become more and more evident that many of the com- plications in the area are not of a tectonic nature but are probably caused by penecontemporaneous large scale slumping (Kugler, 1953).. Figure 19.—Type section of the Cipero formation, Trinidad, B. W. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original United States National Museum; Smithsonian Institution; United States. Dept. of the Interior. Washington : Smithsonian Institution Press, [etc. ]; for sale by the Supt. of Docs. , U. S. Govt Pr
Size: 1648px × 1515px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorun, bookcentury1800, bookdecade1870, booksubjectscience
