LA
rESDAY, DECEMBER 2, 1975
NYTtrn
DEC 2 1975
C
35
Glomar Challenger Off to Drill Sea's FloOr
By WALTER SULLIVAN
Inaugurating an international
effort to probe the deepest layer of the oceanic crust, the
drill ship Glomar Challenger
Projected Atlantic
Drill Sites
• Deep Sea Drill Site
O Shelf Test Site
Numerals indicate sea floor age in
millions of years
• •
5/3
seismic evidence to contain 'a
"pond" of sediment a few
hundred feet deep. Beneath that
are believed to be some 1,300
feet of "pillow" basalts and
other lava forms typical of unleft San Juan, P.R., yesterday
derwater eruptions.
headed for the mid-Atlantic.
These are thought to have
There, in 14,500 feet of wa0
spread over the sea floor as
ter a short distance east of
that zone was forming along
rc ;53 81.
the ridge midway between Afri•
: •
,
the middle-ocean ridge millions
,,
ca and North America, she will
ATLANTIC ; pc! C;.■CEAN:
of years agb. Beneath is a
attempt to bore at least 6,600
00
: : . z: ■
rather similar layer 5,000 feet
feet into, the ocean floor rock.
13:5 • ....."..._
thick. Only when those layers
: ..•--81
to_ 4.ta.....e
In the past, the deepest such
0"
-.-G,.,,53,81
have been pierced can samples
rock penetration has been only
• 1
of the underlying "third layer"
1,909 feet altough the ship has
0 / i
13.5
.-I
be retrieved.
00
been able to drill as much
.',
The latter is two and a half
as 4,630 feet where there was
135
Q
a
miles thick and is thought to
a great accumulation of sedrepresent the basement of the
iment.
oceanic crust that is being carThe project, known as IPOD for
53,
1'35
ried away from the midocean
International Phase of Ocean
'41,.,18/3g..•
•
ridge. Composition shouldthelp
0EA `11014.
81
Drilling, succeeds the Deep Sea
explain how a large part of
Drilling Project carried out
the earth's surface has been—
over the last seven years by
and is still being—formed.
the same ship. The new effort
In another project, approved
differs in being more internaThe New York Times/Dec. 2, 1975
a month ago by the United
tional in scope and seeking far,
,States Geological Survey, a
deeper penetrations into the
extent the crust changes with the plume, flowing beneath the deep test hole is to be bored
sea floor.
crust, becomes increasingly di- into the Baltimore Canyon of
Its goals bear on some of age.
the outer continental shelf 80
the most basic problems in Holes equal distances east luted by other material.
earth science. These include and west of the ridge will The •north-south chain of miles off New Jersey and anholes, whose drilling is to begin other one into Georges Bank
the manner in which the deepsea floor, which covers more penetrate sea floor formed late next summer, would test off Cape Cod. In each case,
than half the earth's surface, roughly 80 million years ago, whether this holds true at great an alternative drill site also has
has evolved, the nature of the according to magnetic evidence depth and at great distance been approved.
force that is steadily widening on the bottom. These will as- from Iceland.
Shallow-Water Drilling
the Atlantic Ocean and the sess the extent to which the The IPOD budget for the In contrast to deep-sea drillformative
process
was
symmetnext
three
years
is
planned
manner in which ore deposits
the water depths in no
of oceanic origin were formed. rical on opposite sides of at $50 million. Britain, Japan ing,
the ocean.
and the Soviet Union have each cases reach 300 feet. The peneDrill Sites Chosen
The north-south line of drill agreed to contribute a million trations are to range from 16,If all goes well it is hoped holes will lie along the zone dollars yearly. West Germany 000 to 22,000 feet into sedimenthat the first hole can be drilled of sea floor formed nine to is expected to renew its annual tary basins that it is hoped,
in about a month. After a re- 10 million years ago. One theo- commitment of such a sum are rich in oil.
turn to port, the Glomar Chal- ry to account for the spreading and France is also expected The drilling is to be done.
lenger would then drill addi- apart of the Atlantic is that to join. The balance of the by the Ocean Production Comtional holes along a line per- a massive plume of molten rock cost is borne by the United pany, operating for the Continental Offshore Stratigraphic
pendicular to the Mid-Atlantic rising from deep within the States.
Ridge and along a line parallel earth under Iceland is forcing While the area directly on Test group, an oil industry conapart the two sides of the the ridge is the youngest, there sortium. The results can then;
to it.
The first line would probe ocean. '
is insufficient sediment there be used by participants in bidthe crust at increasing distan- In support of this, some to "spud in" the drill pipe. ding for leases of offshore drill
ces from the ridge, where the scientists point to a systematic It will not bite into the rock sites next May and August.
entire Atlantic sea floor is be-' change in composition of rock unless it has first penetrated The information must be
lieved to have been formed as dredged along the Mid-Atlantic enough sediment to hold it made public 60 days efter issuance of the first lease within
the Americas separated from Ridge at increasing distances steady.
Europe and Africa. In this way from Iceland. They believe this The first drill site has been 50 miles of the drill site or,
it should become clear to what is because molten rock from chosen because it appears from in amy case, within five years.
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