DESCMPTION OF SAMPLES 



17 



DESCRIPTION OF SAMPLES 



General Discussion 



A synoptic description of the deposit samples col- 

 lected in the Pacific on the seventh cruise of the Carne - 

 gie is given in table 1 (pp. 18-41). The samples are 

 numbered consecutively from 10 to 89 in column 1 of the 

 table. Column 2 lists the stations at which the samples 

 were collected. The latitude and longitude are given in 

 column 3, and the corrected depths in column 4. The 

 samples are then classified according to the system out- 

 lined in the section on classification, and the estimated 

 calcium carbonate contents, together with the bases of 

 the estimates, are given in the next column. The colors 

 of the samples and brief descriptions of the physical 

 characters are given in column 7. Column 8 lists the 

 samplers and containers used in the collection and pres- 

 ervation of the samples. Extracts from the field notes 

 mad? on shipboard at the time the samples were collect- 

 ed are given in column 9. Column 10 contains extracts 

 from the descriptions given by Murray and Renard 

 (1891), Murray and Lee (1909), Murray (1906), and 

 Flint (1905) of the nearest previous samples collected 

 by the Challenger. Albatross. Nero, and other ships in 

 the Pacific; and in the footnotes of the table brief de- 

 scriptions of the organic and inorganic components, and 

 of any characteristic or remarkable features of the sam- 

 ples are given. For mechanically analyzed samples, ex- 

 cept when otherwise indicated, these descriptions are 

 based only on microscopic examination of the sand 

 grades (particles larger than 0.05 mm in diameter). 

 For samples which were too small for mechanical anal- 

 ysis, a rough petrographic examination of a part of the 

 undifferentiated material was made. 



Of the total of eighty-nine samples obtained on this 

 cruise, two were lost in the destruction of the Carnegie 

 at Apia; and one other was not received in Washington. 

 Samples 1 to 9 were collected in the Atlantic Ocean, and 

 samples 88 and 89 represent shallow-water deposits 

 which were collected from Callao harbor and from the 

 beach at Easter Island, respectively. These eleven sam- 

 ples have not been taken into account in the following 

 discussions although some of them were analyzed chem- 

 ically and in other ways. The other seventy-five sam- 

 ples were collected from a very large area in the north 

 and the southeast Pacific, ranging from latitudes 45°24' 

 north to 40°24' south, and from longitudes 141°15' east 

 to 77°54' west. The average depth of all samples is 4223 

 meters, the extremes being 6008 and 1089 meters. 



Many of the primary types of deep-sea deposits are 

 present in the collection. There are thirty-two Globig- 

 erina oozes, ranging in depth from 4953 to 1089 meters, 

 with an average of 3368 meters, and having carbonate 

 contents ranging between 30 and 94 per cent (averaging 

 78 per cent). Five of these are siliceous Globigerina 

 oozes, eight are ferruginous, and one is volcanic, where- 

 as the remaining eighteen samples are not subdivided. 

 Of the eighteen, samples 18, 23, 26, 27, 29, 36, 44, and 

 85 are shown by chemical analysis to have silica sesqui- 

 oxide ratios between 2.21 and 4.33 and, hence, to be ar- 

 gillaceous or normal Globigerina oozes. The remaining 

 samples have not been chemically analyzed. 



There are 26 red clays, with a range in depth be- 

 tween 5787 and 3657 meters (averaging 4762 meters) 

 and having carbonate contents between less than 1 and 20 



per cent, the average being 3.83 per cent. Two of these, 

 samples 31 and 35, are siliceous red clays; the remain- 

 ing twenty-four samples are normal or calcareous red 

 clays. 



Besides these major types of pelagic deposits, dia- 

 tom ooze is represented by two samples from the north- 

 west Pacific, collected at depths of 5296 and 5198 meters, 

 both of which have carbonate contents of less than 1 per 

 cent; radiolarian ooze is represented by three samples, 

 two from the central Pacific and one volcanic radiolar- 

 ian ooze from the northwest Pacific, collected at depths 

 between 5396 and 4918 meters and having carbonate con- 

 tents of 2 per cent or less. One siliceous ooze from the 

 northwest Pacific is listed as either a volcanic diatom 

 or radiolarian ooze, since both groups of organic re- 

 mains are present in large amounts. 



Twelve samples are listed as terrigenous. Five of 

 these were collected off the coasts of North and South 

 America and are designated, because of their color and 

 the fact that the principal components are argillaceous 

 and detrital, simply as green and gray silty and clayey 

 (or coprolitic) muds. One sample from off the South 

 American coast is a green diatom mud, and there is one 

 volcanic Globigerina mud from southeast of Japan. The 

 chief components of the remaining five samples are vol- 

 canic; one of these is a volcanic gravel, collected about 

 a hundred miles west of Guayaquil; another, from off the 

 coast of Japan, is a gray siliceous volcanic mud; and the 

 remaining three are brown and gray volcanic muds, col- 

 lected southeast of Japan. 



It should be noted that three of the samples are as- 

 sumed not to be representative of the region in which 

 they occur. Sample 46 is listed as a Globigerina ooze, 

 even though it consists only of a few manganese nodules, 

 which are, however, partly covered with fresh, unbroken 

 pelagic foraminifera. Likewise, samples 75 and 78 are 

 designated as red clay, although they consist respective- 

 ly of coarse volcanic ash and volcanic cinders, coated 

 with manganese. 



Relatively big volcanic fragments or manganese nod- 

 ules were also present in samples 11, 15, 17, 24, 57, 58, 

 72, 79, 81, and 86. Considering the methods of collection 

 of the samples, the large number of such materials ob- 

 tained is a remarkable illustration of their widespread 

 abundance on the floor of the deep sea. At station 49 

 (sample 17) the condition of the wire and sounding in- 

 struments when hauled in, indicated a rocky, very irreg- 

 ular bottom, probably a submarine lava flow, the pres- 

 ence of which is confirmed by the fact that the large 

 broken pieces of basic volcanic glass collected at this 

 station were coated with manganese only on one side. 



Even a casual study of the descriptions given in table 

 1 shows that the assemblage of sand-sized minerals in 

 the pelagic samples of the region investigated is chiefly 

 volcanic, although small amounts of wind- and ice-borne 

 detrital minerals occasionally occur. Furthermore, 

 volcanic glass or pumice, or both, are recorded in about 

 two-thirds of all samples described. In several pelagic 

 samples also, relatively large euhedral crystals of horn- 

 blende, plagioclase feldspar, and hypersthene (the latter 

 only in the siliceous volcanic muds and oozes collected 

 northeast of Japan) were found, sometimes partly sur- 

 rounded by pumice. Small manganese grains are nearly 

 always present in the samples examined. Some of these. 



