INTRODUCTION 



This interim report describes procedures used and findings 

 to date regarding the engineering behavior of a deep-sea calcareous 

 ooze, composed primarily of Globigerina foraminifera tests. 



The report describes the results of physical property, engineering 

 index parameter, one-dimensional consolidation, and triaxial shear 

 strength (undrained) testing. Examination of the drained shear strength 

 behavior, shear creep and secondary consolidation performance, and 

 the accompanying changes in sediment grain character is underway; 

 the results will be summarized in a subsequent report. 



BACKGROUND 



Sediment Description 



Calcareous oozes are seafloor sediments containing more than 

 30% calcium carbonate [ 1 ] . Such oozes cover approximately 

 36% of the seafloor and are generally restricted to water depths 

 less than 4,500 m (14,000 ft) [2]. The calcareous fraction of these 

 sediments, which may be as large as 97% of the whole by weight [3] , 

 is composed primarily of the skeletal remains of various plankton 

 animals and plants of which the foraminifera Globigerina predominates. 



The most widely distributed sizes of Globigerina tests are 0.05 

 to 0.25 mm [4], although Globigerina tests of 1 mm diameter are common 

 in the Caribbean samples of the subject study. The coarse-grained 

 sediment fraction of predominantly whole tests is mixed in varying 

 proportion with a finer -grained fraction composed of foraminifera 

 test fragments; other marine life remains, such as those of the 

 Coccolithophoridae and the nannoplankton (dwarf plankton) ; inorganic - 

 origin material, such as the clay minerals; and minor additional components 

 [1]. 



Objective 



It is the purpose of this study to examine the consolidation 

 and shear creep behavior of a calcareous deep-sea sediment, composed 

 in large part of Globigerina foraminifera; to evaluate that behavior 

 with respect to observed sediment grain character changes; and to 

 propose a generalized behavioral model for similar deep-sea sediments. 



