Core recovery: USNS Eltanin and
Reports of the Deep Sea Drilling Project, 28. U.S. Government Printing Office, Washington, D.C. 869p. McElhinny, M.W. 1973. Palaeomagnetism and Plate Tectonics. Cambridge University Press. McIntyre, D.J., and G.J. Wilson. 1966. Preliminary palynology of some antarctic Tertiary erratics. New Zealand Journal of Botany, 4: 315. Moore, T.C., Jr., and G.R. Heath. In press. Survival of deep-sea sedimentary sections. Earth and Planetary Science Letters. Ryan, W.B.F., M.B. Cita, M.D. Rawson, L.H. Burckle, and T. Saito. 1974. A paleomagnetic assignment of Neogene stage boundaries and the development of isochronous datum planes between the Mediterranean, the Pacific, and the Indian Oceans in order to investigate the response of the world ocean to the Mediterranean salinity crisis. Reviews of Italian Paleontology, 80: 631. Savin, SM., R.G. Douglas, and F.G. Stehli. 1975. Tertiary marine paleotemperatures. Geological Society of America. Bulletin, 86: 1499. Shackleton, N.J., and J.P. Kennett. 1975a. Late Cenozoic oxygen and carbon isotopic changes at DSDP site 284: implications for glacial history of the northern bemisphere and Antarctica. In: Initial Reports of the Deep Sea Drilling Project, 29. U.S. Government Printing Office, Washington, D.C. 801p. Shackleton, N.J., and J.P. Kennett. 1975b. Paleotemperature history of the Cenozoic and the initiation of antarctic glaciation: oxygen and carbon isotope analyses in DSDP sites 277, 279, and 281. In: Initial Reports of the Deep Sea Drilling Project, 29. U.S. Government Printing Office, Washington, D.C. 743p. Weissel, J.K., and D.E. Hayes. 1972. Magnetic anomalies in the southeast Indian Ocean. Antarctic Research Series, 19. American Geophysical Union, Washington. 165p. van Andel, T.H., G.R. Heath, and T.C. Moore, Jr. 1975. Cenozoic tectonics, sedimentation, and paleoceanography of the central equatorial Pacific. Geological Society of America. Memoir, 143.
Core recovery: USNS Eltanin and ARA Islas Orcadas DENNIS S. CASSIDY and SUSAN SHEPLEY
Antarctic Research Facility Department of Geology Florida State University Tallahassee, Florida 32306
This article presents a graphic summary of recovery, by cruise, of marine sediment cores retrieved aboard USNS Eltanin and ARA Islas Orcadas. Figure 1 shows core length for piston cores, and figure 2 that of trigger, Phieger, and camera-Phleger cores. Figure 1 also provides the total number of cores collected aboard each cruise and the average core length per cruise. These data serve no other purpose than to illustrate total core recovery per cruise, number of cores retrieved per October 1977
cruise, and average core length per cruise. Some persons have erroneously used such data to indicate success or failure of a cruise (or cruises) relative to other cruises. This cannot be done for several reasons. Many factors contribute to the success of a shipboard program, all of which must be considered to evaluate relative coring success. Among them are precruise coring objectives, cruise duration, steaming time between coring stations, ship breakdowns, type of coring equipment used, weather, coring time alloted per coring station, water depths at coring stations, lithologic character of the cored sediments, and whether or not multiple or duplicate coring attempts were made at the station. For example, figures 1 and 2 show that the greatest total sediment recovery for any two cruises was from Eltanin cruises 39 and 45, both for piston and trigger core recovery. At each coring station aboard these cruises, however, two piston core attempts were made, and the trigger wire for each was rigged with two trigger corers. The dominant objective of each cruise was core retrieval, and coring began soon after departure from port. Coring continued along a more or less straight line of clustered, closely spaced coring stations. Duplicate piston coring was not done on other cruises, although multiple trigger and Phleger cores were recovered during some cruises. The average core length per cruise is also a poor criterion, since objectives may have been to core on the crests or flanks of seamounts. In most of these cases, the overburden of recent sediments will have been winnowed away, laying bare the more indurated and older sediments that resist penetration. These sediments often have proved rare and hence more valuable than those in long cores of homogeneous composition retrieved repetitiously in deep, abyssal plains consisting of easily cored biogenic oozes. Cruise 54, for example, was successful in terms of the precruise objective, which was to recover the oldest sediments (Cretaceous) obtained by Eltanin (Kaharoeddin et al., 1973); this cruise, though, ranks but 45th in total meterage of piston core recovery among the 50 Eltanin/Islas Orcadas coring cruises. (Eltanin cruises lasted from 11 to 80 days.) Figure 1 indicates an increase in sediment recovery during the later cruises. If coring success, however, is to be measured in terms more indicative than the magnitude of total recovery, we suggest use of such additional factors as the average core length per cruise per unit of station time alloted to coring as a function of water depth and sediment type, together with the ratio of stratigraphically useful, undisturbed sediment length recovered to disturbed sediment recovery, the latter rendered useless by piston malfunctions, core liner implosions, etc. Ultimately, coring success is a function of the significance and value of the recovered materials to research objectives and the quality of research upon the sediments, regardless of total meterage recovered. This work was supported by National Science Foundation contract C-1059.
Reference Kaharoeddin, F.A., F.M. Weaver, and S.W. Wise, Jr. 1973. Cretaceous and Paleogene cores from the Kerguelen Plateau, southern ocean. AntarcticJournal of the U. S., VIII(5): 297-298. 75
Figure 1. Total recovery, in meters, of piston core sediments by cruise. Cruises 1 to 55 are Eltanin cruises; 0775, 1176 and
1277 are Islas Orcadas
700
700
cruises. Circled numbers within top of meterage bars are total number of piston cores recovered aboard cruise. Average core length per cruise is shown.
600
500
0 400
z 400 0
0
0
200
11111L11012100
Figure 2. Total recovery, in meters, of trigger, Phleger and camera9 100 Phleger core sediments by ° cruise. Cruise numbering is the same as that ex plained for figure 1. No So auxiliary cores were attempted aboard Eltanin cruises 1, 2, and 3.
00
50
60
60
40
(0 40
cr 0 (0 20 cr 0
I 2 3 4 5 6 7 8 9 10 II 12 13 14 IS 16 I? IS 19 20 21 22 23 24 25 26 27 32 33 3435 36 32 30 3356 53 40 45 '(1 '2950 9) 06 9.5 09 '('(4!
CRUISE NUMBER
Note: Recovery totals for figures 1 and 2 are for all cores recovered, regardless of whether or not cores were received by the Florida State facility or by other institutions. Cruises 1 and 2 of Eltanin were trial cruises in the North Atlantic; no coring took place aboard Eltanin cruises 28, 29, 30, 31, 40, 41, 46, and 50. 76
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Core recovery: USNS Eltanin and ARA Islas Orcadas DENNIS S. CASSIDY and SUSAN SHEPLEY
Antarctic Research Facility Department of Geology Florida State University Tallahassee, Florida 32306
This article presents a graphic summary of recovery, by cruise, of marine sediment cores retrieved aboard USNS Eltanin and ARA Islas Orcadas. Figure 1 shows core length for piston cores, and figure 2 that of trigger, Phieger, and camera-Phleger cores. Figure 1 also provides the total number of cores collected aboard each cruise and the average core length per cruise. These data serve no other purpose than to illustrate total core recovery per cruise, number of cores retrieved per October 1977
cruise, and average core length per cruise. Some persons have erroneously used such data to indicate success or failure of a cruise (or cruises) relative to other cruises. This cannot be done for several reasons. Many factors contribute to the success of a shipboard program, all of which must be considered to evaluate relative coring success. Among them are precruise coring objectives, cruise duration, steaming time between coring stations, ship breakdowns, type of coring equipment used, weather, coring time alloted per coring station, water depths at coring stations, lithologic character of the cored sediments, and whether or not multiple or duplicate coring attempts were made at the station. For example, figures 1 and 2 show that the greatest total sediment recovery for any two cruises was from Eltanin cruises 39 and 45, both for piston and trigger core recovery. At each coring station aboard these cruises, however, two piston core attempts were made, and the trigger wire for each was rigged with two trigger corers. The dominant objective of each cruise was core retrieval, and coring began soon after departure from port. Coring continued along a more or less straight line of clustered, closely spaced coring stations. Duplicate piston coring was not done on other cruises, although multiple trigger and Phleger cores were recovered during some cruises. The average core length per cruise is also a poor criterion, since objectives may have been to core on the crests or flanks of seamounts. In most of these cases, the overburden of recent sediments will have been winnowed away, laying bare the more indurated and older sediments that resist penetration. These sediments often have proved rare and hence more valuable than those in long cores of homogeneous composition retrieved repetitiously in deep, abyssal plains consisting of easily cored biogenic oozes. Cruise 54, for example, was successful in terms of the precruise objective, which was to recover the oldest sediments (Cretaceous) obtained by Eltanin (Kaharoeddin et al., 1973); this cruise, though, ranks but 45th in total meterage of piston core recovery among the 50 Eltanin/Islas Orcadas coring cruises. (Eltanin cruises lasted from 11 to 80 days.) Figure 1 indicates an increase in sediment recovery during the later cruises. If coring success, however, is to be measured in terms more indicative than the magnitude of total recovery, we suggest use of such additional factors as the average core length per cruise per unit of station time alloted to coring as a function of water depth and sediment type, together with the ratio of stratigraphically useful, undisturbed sediment length recovered to disturbed sediment recovery, the latter rendered useless by piston malfunctions, core liner implosions, etc. Ultimately, coring success is a function of the significance and value of the recovered materials to research objectives and the quality of research upon the sediments, regardless of total meterage recovered. This work was supported by National Science Foundation contract C-1059.
Reference Kaharoeddin, F.A., F.M. Weaver, and S.W. Wise, Jr. 1973. Cretaceous and Paleogene cores from the Kerguelen Plateau, southern ocean. AntarcticJournal of the U. S., VIII(5): 297-298. 75
Figure 1. Total recovery, in meters, of piston core sediments by cruise. Cruises 1 to 55 are Eltanin cruises; 0775, 1176 and
1277 are Islas Orcadas
700
700
cruises. Circled numbers within top of meterage bars are total number of piston cores recovered aboard cruise. Average core length per cruise is shown.
600
500
0 400
z 400 0
0
0
200
11111L11012100
Figure 2. Total recovery, in meters, of trigger, Phleger and camera9 100 Phleger core sediments by ° cruise. Cruise numbering is the same as that ex plained for figure 1. No So auxiliary cores were attempted aboard Eltanin cruises 1, 2, and 3.
00
50
60
60
40
(0 40
cr 0 (0 20 cr 0
I 2 3 4 5 6 7 8 9 10 II 12 13 14 IS 16 I? IS 19 20 21 22 23 24 25 26 27 32 33 3435 36 32 30 3356 53 40 45 '(1 '2950 9) 06 9.5 09 '('(4!
CRUISE NUMBER
Note: Recovery totals for figures 1 and 2 are for all cores recovered, regardless of whether or not cores were received by the Florida State facility or by other institutions. Cruises 1 and 2 of Eltanin were trial cruises in the North Atlantic; no coring took place aboard Eltanin cruises 28, 29, 30, 31, 40, 41, 46, and 50. 76
ANTARCTIC JOURNAL
