Institution

More documents

Recommendations

Info

series of ridges associated with an early east-west trans- form fault. If so, the basement structures under the Greater Anti 11 es Outer Ri dge may represent a younger extension of this fault zone. During late Cretaceous time the rugged sea floor received pyroclastic sediments from the Greater Antilles, which were experiencing extensive geosynclinal volcanism (Weyl, 1968; Monroe, 1968). Some of the siltstones, clay- stones, cherts, and limestones dredged from the north slope of the present Puerto Rico Trench probably also were derived from the Greater Antilles, and they may have been interbedded with flows of tholeiitic magma (Chase and Hersey, 1968). The Cenomanian 1 imestones dredged from the north slope were probably deposi ted at depths greater than 3000 m (Todd and Low, 1964); their nonclastic texture indicates that they may have been deposited on an elevated area whi ch was not i nfl uenced by the downs lope sedi mentati on. Core data from DSDP Site 28 on the north slope of the Puerto Rico Trench indicate that the deposition of interbedded layers of chert, limestone, siltstonè, lutite, and mi crofoss i 1 ooze apparently conti nued under s i mi 1 ar conditions, but without the basait flows, until middle Eocene time, thus forming the present stratified layer. Pyroclastic debris was furnished by early to middle Eocene 221 volcanism in the Greater Antilles (Mattson and Pessagno,1971). It is likely that the acoustic stratification of the pre-mi ddl e Eocene sedi ment is due to i nterbeddi ng of these \ )
) . ) -~ sediment types and to layering formed by downslope sediment movement and turbidity currents, similar to the layering found on modern continental rises and abyssal plains. The absence of the strati fi ed 1 ayer under the Greater Antilles Outer Rid gee a s t of about 630 W long. (Figs. 3. 4 , 3.5) i ndi cates ei ther that there was no source of 1 and- derived material to the south or that an intervening deep (possibly a precursor of the Puerto Rico Trench) was present to cut off the supply of sediment from the Greater Antilles. MIDDLE TO LATE EOCENE The middle Eocene Datum A is the top of the stratified layer under the eastern Greater Antilles Outer Ridge, and it marks a distinct change from acoustically stratified to acoustically transparent sediment. It is suggested here that this acoustic dissimilarity also represents a change in depositional conditions and that Datum A marks the final stage of downslope sedimentation on the eastern sector of the Greater Antilles Outer Ridge. The formation of the Puerto Rico Trench may have proceeded far enough at this time to form a chasm along the southern portion of the eastern outer ridge, and it trapped sediments which were shed from the present region of Puerto Rico and the Virgin Islands (Fig. 8.2) (Tucholke and others, 1972). This timing for the formation of the Puerto Rico Trench is in genera 1 agreement wi th independent geol ogi c evi dence from Puerto Rico which dates initial trench formation as late 222 i ~
Page 1 and 2:
I "a f IMods Hole '" ~ o c.,,~tlOGR
Page 3 and 4:
) )
Page 5 and 6:
" \ / )
Page 7 and 8:
parent sediment on the eastern oute
Page 9 and 10:
esearch. 5 )
Page 11 and 12:
Res u 1 ts. . . . . . . . . . . . .
Page 13 and 14:
Figure 3.12 Echo-sounding profile (
Page 15 and 16:
Fi gure 6.14 6. 15 7. 1 7.2 7.3 7.4
Page 17 and 18:
\ I ) Table 4. 1 4.2 5.1 5.2 5.3 6.
Page 19 and 20:
CHAPTER I INTRODUCTION The area inv
Page 21 and 22:
) \ .1 Fi gure i. 1. Bathymetry of
Page 23 and 24:
~. ~ 71° 70° tI 68 fJ0 25° 7' 25
Page 25 and 26:
) ) This is expected since most of
Page 27:
GENERAL DES CRI PT I ON CHAPTE R I
Page 30 and 31:
j
Page 32 and 33:
egi onal contours. An area centered
Page 34 and 35:
this region. However, all of these
Page 36 and 37:
) ì /
Page 38 and 39:
') ) ) /
Page 41 and 42:
'"-, i~ 7t 70° 6f 68 67° 25° 72
Page 43:
Fig u r e 3. 2 . CON RA D 10 s e is
Page 46 and 47:
sequence corresponds to layered tur
Page 49:
) . .) Figure 3.3. Map showing domi
Page 52 and 53:
\ )
Page 55 and 56:
"- '''--.- 25° ................. .
Page 57 and 58:
) ) others, 1973), and the upper po
Page 59 and 60:
) Figure 3.5. CONRAD 8 seismic refl
Page 61 and 62:
. Q) 3W/L NOI.L~ l( . (Y CI s. :: 0
Page 63 and 64:
.) Figure 3.6. Idealized profile al
Page 65 and 66:
) ) a: 0 ~ ~ (J L. Z Q) a: ~ lU UJ
Page 67 and 68:
) ) Figure 3.7. CONRAD 10 seismic r
Page 69 and 70:
i- (Y (1 ~:: en or- LL 47
Page 71 and 72:
) ) THE TRANSPARENT LAYER The distr
Page 73 and 74:
Fi gure 3.8. CH A I N 34 s e ism i
Page 75 and 76:
co . (Y (l So :: O' "r- Li 51
Page 77 and 78:
) 53
Page 79 and 80:
) Figure 3.9. CONRAD 10 seismic ref
Page 81 and 82:
0' (V CJ s. :: O' ... LL 55
Page 83 and 84:
\ J ) Figure 3.10. Seismic reflecti
Page 85 and 86:
or- . (V Q) S- :: rn Li 58
Page 87 and 88:
ì ) Figure 3.11. CONRAD 10 seismic
Page 89 and 90:
l UJ .líliiiP',,:... ¡ '"'" ~ ' ~
Page 91 and 92:
) .I Figure 3.12. Echo-soundi ng pr
Page 93 and 94:
N CV OJ s. :: 01 l. 62
Page 95 and 96:
) ) Figure 3.13. CONRAD 10 seismic
Page 97 and 98:
(' r- (' (j $. :: en 'r- LL 64
Page 99 and 100:
) ) GENERAL LITHOLOGY CHAPTER iv TH
Page 101 and 102:
~ , ) Figure 4.1. General lithology
Page 103:
.'-/ '..-/ AIr 60-8 A II 60-8 An60~
Page 106 and 107:
) )
Page 108 and 109:
average of 80% lutite (~ 2 ~m) and
Page 110 and 111:
) )
Page 112 and 113:
.\ ! ') )
Page 114 and 115:
ì/ )
Page 116 and 117:
10 m2, with an average value of 1.3
Page 118 and 119:
) ) /
Page 120 and 121:
The laminated zones and overlying p
Page 122 and 123:
) )
Page 124 and 125:
\ j )
Page 127 and 128:
) ) Figure 4.7. Graph of carbonate
Page 129 and 130:
) ) z 0 N O~ E I i ,,_.' i." I ." .
Page 131:
) ì i Figure 4.8. Curves of carbon
Page 134 and 135:
currents have transported many Fora
Page 136 and 137:
increased dissolution (elevated lys
Page 138 and 139:
TABLE 4.1. MINERALOGY OF THE c 2 ~m
Page 140 and 141:
the following peaks and weighting f
Page 142 and 143:
.,1 ì / ) j
Page 144 and 145:
\ J )
Page 146 and 147:
) )
Page 148 and 149:
) )
Page 150 and 151:
Obvi ous ly, di 1 uti on of the nor
Page 152 and 153:
The m i n era log i c a 1 com po si
Page 154 and 155:
gray 1 uti t e s per s i s t n ear
Page 156 and 157:
) )
Page 158 and 159:
TABLE 5.1. AVERAGE RATES OF SEDIMEN
Page 160 and 161:
and thus the T-Z zonation (Fig. 5.1
Page 162 and 163:
) ) )
Page 164 and 165:
TABLE 5.2. AVERAGE RATES OF SEDIMEN
Page 166 and 167:
Cl z: c: l/ l. i- c: Cl z: o OJ IX
Page 168 and 169:
consolidated (A.J. Silva, pers. com
Page 170 and 171:
) ) _/
Page 172 and 173:
\ ) \ ì ../
Page 174 and 175:
in age, and the ash is probably ass
Page 176 and 177:
') .I \...../
Page 178 and 179:
122 must result from mixing with th
Page 180 and 181:
eas twa rd flow of NADW between 150
Page 182 and 183:
whi ch recorded currents for about
Page 184 and 185:
,) , ,
Page 186 and 187:
ottom photographs in February, 1972
Page 188 and 189:
Several important features were obs
Page 190 and 191:
. \ .' ì ,) ~)
Page 192 and 193:
. ) )
Page 194 and 195:
)j )
Page 196 and 197:
) )
Page 198 and 199:
, " ) ) ./
Page 200 and 201:
. \ ) )
Page 202 and 203:
'\ ) ) J
Page 204 and 205:
I )
Page 206 and 207:
141 turn north in the western part
Page 208 and 209:
" ) , \ -./)
Page 210 and 211:
. ) ) / )
Page 212 and 213:
145 bottle spacing. An example is t
Page 215 and 216:
~() ~ 3.0 ~ ~ ) ~ ~i. ) .. ~ 2.0 ~i
Page 217 and 218:
) ) Figure 6.6. Silicate ("g-atoms/
Page 219 and 220:
) ) ~ 2.2 ~ 2.0 t2 ~ tt ~" 1.8 .. ~
Page 221 and 222:
,) -) 152 structure persist at and
Page 223 and 224:
) ~) 154 Figure 6.7. Current patter
Page 225 and 226:
) ) 72° DEPTH IN CORR. METERS Fi g
Page 227 and 228:
) ) speeds of 2 cm/sec (the stall s
Page 229 and 230:
) I / Fi gure6. 8. 158 Progressi ve
Page 231 and 232:
" ) / ) 10 19 17 5 5616 M 5801 M N
Page 233:
) ) ~ 160 Figure 6.9. Polar histogr
Page 236 and 237:
. ì )
Page 239 and 240:
,) B(LOWER) START 22 B(UPPER) START
Page 241 and 242:
) ) Figure 6.11. Polar histogram of
Page 243 and 244:
) 2700 ) 00 1800 F; g u re 6. 11 C
Page 245 and 246:
, ) ) _/ Figure 6.12. 168 Progress
Page 247 and 248:
\ --~ E START 21 5 30 12 XI 21 xu )
Page 249 and 250:
) / i I .~J the flow recorded at cu
Page 251 and 252:
) Figure 6.13. Directions and relat
Page 253 and 254:
') ./ ) ,j 70° 68° 66° ~~oo · "
Page 255:
Fig u re 6. 14. i 75 Bottom photogr
Page 258 and 259:
S e c t ion 2 (F i g s. 6. 1, 6. 7)
Page 260 and 261:
) )
Page 262 and 263:
') / ) j
Page 264 and 265:
northwest flow along the west flank
Page 266 and 267: " ) /
Page 268 and 269: \ )
Page 270 and 271: filter (0.50 lJmpore size). After f
Page 273 and 274: . '! ) ) ,./ 2.2 ~ 2.i () '- 2.0 ~
Page 275 and 276: ) ) Figure 7.3. Light-scattering pr
Page 277 and 278: '\. './. V 23-7 V 23-6 V 25-74 V 25
Page 279 and 280: extensive erosion on the lower cont
Page 281 and 282: ) \/ (SEM) to determine composition
Page 283: \ ) ) Figure 7.4. 195 Scanning elec
Page 286 and 287: ) \ ./
Page 288 and 289: 'i j
Page 290 and 291: The less than 2 ~m (lutite) fractio
Page 292 and 293: 201 In a sample where additional cl
Page 294 and 295: TAB LE 7. 1. CALCULATE D CLAY MI NE
Page 296 and 297: :1 / , ì j
Page 298 and 299: I ) \ )
Page 300 and 301: cannot always be accepted at face v
Page 302 and 303: The apparent enrichment of chlorite
Page 304 and 305: , \! )
Page 306 and 307: in favor of the concept that the su
Page 308 and 309: on the north flank of the far easte
Page 310 and 311: that enough suspended matter has be
Page 312 and 313: The following pages describe a mode
Page 314 and 315: ) )
Page 318 and 319: Eocene to 01 i gocene (Monroe, 1968
Page 320 and 321: :') ¡i )
Page 322 and 323: \ i / ') ./
Page 324 and 325: (Table 8.1). The interbedded silts
Page 326 and 327: 229 Chase and Hersey, 1968). The th
Page 329 and 330: \ ! Figure 8.3. 231 Schematic diagr
Page 332 and 333: Downslope sedimentation covered the
Page 335 and 336: ) 235 Fi gure 8.4. Sketch showi ng
Page 337 and 338: '\ l ) ~z w u w a: o ~ wz w o u ~ w
Page 339 and 340: ) / the same event of current-contr
Page 341 and 342: ) Figure 8.5. Idealized representat
Page 343 and 344: ) \ ) d / 'I i II I Ii I i I i I I
Page 345 and 346: ) \ ) formed earlier depositional s
Page 347 and 348: ) ) homogenei ty of the sediments o
Page 349: ) ) 2 ) Sou t h S lop e - P u e rt
Page 352 and 353: 248 Biscaye, P.E. and S.L. Eittreim
Page 354 and 355: Ericson, D.B., M. Ewing, G. Wollin
Page 356 and 357: Hersey, J.B. (1965) Sediment pondin
Page 358 and 359: McCullough, J.R. and G.H. Tupper (1
Page 360 and 361: Swallow, J.C. and L.V. Worthington
Page 362 and 363: " ) )
Page 364 and 365: 259 approximation of the amount of
Page 366 and 367:
s ~ 0 ~ Q) o '- CO 0 U ~ it \f0 Q)
Page 368 and 369:
) )
Page 370 and 371:
Crui se All 11 All 11 AII 60 Leg 8
Page 372 and 373:
TABLE A2.1. BOTTOM PHOTOGRAPHS (Con
Page 374 and 375:
TABLE A2.1. BOTTOM PHOTOGRAPHS (Con
Page 376 and 377:
TAB LE A2. 1. BOTTOM PHOTOGRAPHS (C
Page 378 and 379:
CH 19 CH 19 CH 19 CH 34 CH 34 TABLE
Page 380 and 381:
KN25 KN 25 KN 25 KN 25 TABLE A2.1.
Page 382 and 383:
LL 8 LL 8 LL 8 LL 8 LL 8 SA C ru is
Page 384 and 385:
) )
Page 386 and 387:
s. .. M i. 0 1. " .. QJ ..- N .. C'
Page 388 and 389:
~.. c. 0' 0 .. Q)+l- ~ 0' 0' 0 ~ M
Page 390 and 391:
TABLE A3.1. SUSPENDED PARTICULATE M
Page 393 and 394:
) -) APPENDIX IV PHYSICAL PROPERTIE
Page 395:
) ) Figure A4.1. Plots of water con
Page 398 and 399:
) \ )
Page 400 and 401:
ì )
Page 402 and 403:
\ )
Page 404 and 405:
') /
Page 406 and 407:
\ ) ) . //
Page 409 and 410:
) ) C\' 0 § to ~ ~ ~ 0 ~ ~ ~ CI Q:
Page 411 and 412:
) /) 295 Figure A4.5. Plots of wate
Page 413 and 414:
'-. ~, 160 SHEAR STRENGTH 30 50 (g/
Page 415:
) ) Figure A4.6. Plots of water con
Page 418 and 419:
) . ) .
Page 420 and 421:
ì ) )
Page 422 and 423:
\ ) )
Page 424 and 425:
.J , .)
Page 426 and 427:
ì /"
Page 428 and 429:
D \ )
Page 430 and 431:
\ / ) /
Page 432 and 433:
) , )
Page 435 and 436:
) ) 307 Fi gure A4.11. Plots of wat
Page 437 and 438:
"-, ',, WATER CONTENT (% DRY WEIGHT
Page 439:
) j 309 Figure A4.12. Plots of wate
Page 442 and 443:
) ) ./
Page 445 and 446:
) 312 WATER CONTENT (%DRY WT) SHEAR
Page 447 and 448:
) J BIOGRAPHY Born: Ma rch 19, 1946
Page 449:
') \ ) ~UWDATORY DISTRIBUTION LIST
Page 452 and 453:
) J
Page 454:
UNCLASSI FIED 1/31/74 SECURITY CLAS
show all

Institution

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?