Cohee, G.V., Glaessner, M.F., and Hedbert, H., 1981. Contributions to the Geologic Time Scale. Papers given at the Geological Time Scale Symposium 106.6, 25th IGC, Sydney, Australia, August 1976.
Collinson, D.W., 1983. Methods in Rock Magnetism and Palaeomagnetism, Techniques and Instrumentation: London, New York (Chapman and Hall).
Habicht, J.K.A., 1980. Paleoclimate, Paleomagnetism, and Continental Drift. Amer. Assoc. Petrol. Geol., Stud. Geol., 9.
Harland, W.B., Cox, A.V., Llewellyn, P.G., Pickton, C.A.G., Smith, A.G., and Walters, R., 1982. A Geologic Time Scale: Cambridge (Cambridge University Press).
Harrison, C.G. (Ed.), 1981. Marine Geophysics, Plate Tectonics, and the Earth's Core: the Bullard Volume. J. Geophys. Res., 86.
Jacobs, J.A., 1987. Geomagnetism - Volume 1: New York (Academic Press).
Jacobs, J.A., 1987. Geomagnetism - Volume 2: New York (Academic Press).
Jacobs, J.A., 1984. Reversals of the Earth's Magnetic Field: Bristol (Adam Hilger, Ltd.).
Kennett, J. P. (Ed.), 1980. Magnetic Stratigraphy of Sediments: A Memorial to Norman D. Watkins: Stroudsburg, PA (Dowden, Hutchinson and Ross).
Matsushita, S., and Campbell, W.H. (Eds.), 1967. Physics of Geomagnetic Phenomena:- Volume I: New York (Academic Press).
Matsushita, S., and Campbell, W.H. (Eds.), 1967. Physics of Geomagnetic Phenomena - Volume II: New York (Academic Press).
McElhinny, M.W., 1979. Palaeomagnetism and Plate Tectonics: Cambridge (Cambridge University Press).
McElhinny, M.W. and Valencio, D.A. (Eds.), 1981. Paleoreconstruction of the Continent:s: Washington, D.C. (American Geophysical Union).
Merrill, R. T., and McElhinny, M. W., 1983. The Earth's Magnetic Field: New York (Academic Press).
O'Reilly, W., 1984. Rock and Mineral Magnetism: Glasgow and London (Blackie).
Piper, J.D.A., 1987. Paleomagnetism and the Continental Crust: United Kingdom (Open University Press and Halsted Press). Snelling, N.J.( Ed.), 1985. The Chronology of the Geological Record. Geol. Soc. London Mem., 10:211-260.
Stacey, F.D., and Banerjee, S.K., 1974. The Physical Principles of Rock Magnetism: Amsterdam (Elsevier).
Tarling, D.H., 1983. Paleomagnetism: Principles and Applications in Geology, Geophysics, and Archaeology: London, New York (Chapman and Hall).
Van der Voo, R., Scotese, C.R., and Bonhommet, N., 1984. Plate
Reconstruction from
Paleozoic Paleomagnetism: Washington, D.C. (American Geophysical Union).
Manuals have been provided by manufacturers for the following pieces of
equipment and are available in the shipboard paleomagnetics laboratory:
Magnetometers
I. INTRODUCTION
A. BACKGROUND
This Deep Sea Drilling Project (DSDP) file contains paleomagnetic
measurements made on discrete sediment samples by the Digico computerized
spinner magnetometer. This instrument measures the direction (inclination
and declination) and intensity of magnetization of the sample. The file
holds two sets of measurements for each sample:
1) Natural remanent magnetization (NRM) values. For some DSDP legs these will be the only available results.
2) Stable magnetic values. These are the results from
optimally demagnetized samples. Usually pilot demagnetizations were carried
out on a few samples to determine how strong a field was needed to produce
stable directions of magnetization. Once the optimum demagnetizing field was
determined, all of the samples were demagnetized in that field.
Data were encoded primarily from the shipboard Hole Summary Book, the DSDP
data archives, and the Initial Reports of the Deep Sea Drilling Project. The
file contains both shipboard measurements and measurements made at on-shore
laboratories. Shipboard paleomagnetic apparatus included a Digico balanced
fluxgate spinner magnetometer, a Schonstedt alternating-field GSD-1
demagnetizer, and a Bartington magnetic-susceptibility meter.
Magnetic measurements contained in this file are from core samples
recovered by the punch core-rotary drilling and the hydraulic piston coring
methods. Each record contains a code for the coring method.
B. METHODS
Magnetic properties recorded in the file include natural remanent
magnetization (NRM) intensity, declination, inclination, initial
susceptibility, stable magnetization intensity, and mean demagnetizing field.
Results of more than one demagnetization — pilot demagnetizations fall
into this class — are contained in the Alternating Field Demagnetization
file.
In some cases thermal rather than alternating-field demagnetization was
used. Information about the temperature of demagnetization was stored in the
comment record.
The following quote concerning data reliability is taken from the Hole
Summary Book, paleomagnetics section, for Leg 79: "It is important to mention
here a crucial limitation of the shipboard magnetometer. Magnetization
intensity values are often not repeatable and can fluctuate by up to 50% for
samples with intensities one order of magnitude above noise level. . . .
Magnetization directions are generally repeatable."
Each record contains an identifying code for the analyst's or first
author's name. See Table 1 for the index to analysts' codes.
A blank field means not determined.
Magnetic intensities are expressed in emu/cm3. In a few later DSDP
reports, data were expressed in SI units. The DSDP encoders converted these
to cgs units. The following conversions were used:
A/m × 10-3 = emu/cm3
mT × 10 = oersteds
C. LEGS IN DATA SET
The data set contains data from Legs 108, 13, 15, 17, 22-23, 27-28, 33,
37-38, 41-42, 47-48, 51-52, 54, 57-64, 66, 68, 71-82, 84-87, 89-91, and
93-94. D.
BIBLIOGRAPHY
Partial references to analytical methods for shipboard measurements.
Ludwig, W.J., and Krasheninnikov, V., 1980. Hole Summary Book for Leg 71.
Paleomagnetists: J. Salloway and J. Bloemendal.
Barket, P.F. and Carlson, R.L., 1980. Hole Summary Book for Leg 73.
Paleomagnetists: J.L. LaBrecque, N.P. Peterson, L. Tauxe, and P. Tucker.
Hay, W.W., and Sibuet, J.-C., 1980. Hole Summary Book for Leg 75.
Paleomagnetist: B. Keating.
Roberts, D.G., and Schnitker, D., 1981. Hole Summary Book for Leg 81.
Paleomagnetist: K. Krumsiek.
For methods used in a shore-based study, consult the paper in the Initial
Reports. The results and analytical information about shipboard analyses
similarly are published in the Initial Reports and the Hole Summary Books.
See Table 1 for the index to analysts' codes.
II. FORMAT, FIELD DESCRIPTIONS, AND CODES
The definition of leg, site, hole, core, and section may be found in the
appended explanatory notes. In addition, the special core designations
(CORE_CHAR), as well as the methods of sample labeling and calculating
absolute sample depths, are discussed.
INTERVAL DEPTH:
Refers to the depth in centimeters within the section at which the rock
was sampled.
TOP OF CORE DEPTH:
The sub-bottom depth in meters to the top of the core.
SAMPLE MIDPOINT DEPTH:
The sub-bottom depth in meters to the level at which the core was sampled.
REPEAT:
The paleomagnetist occasionally repeated the measurement. A "0" was
entered in REPEAT if there was only one measurement for the interval. There
is a "1" for the first repeat and so on.
CORING DEVICE CODE:
H = Hydraulic Piston Corer (includes Variable Length Piston Corer)
R = Conventional Rotary Drilling Corer (includes Extended Core Barrel)
ANALYST CODE:
Expressed here in cgs units and in scientific notation. The negative
exponent of the power of 10 is stored in the appropriate intensity exponent
field.
NRM, AFD, SUS INTENSITY EXPONENTS:
In this file magnetic intensity is recorded in scientific notation. Each
magnetic-intensity value should be multiplied by 10 to the negative value of
the number in the appropriate intensity field.
DECLINATION:
Units are degrees.
INCLINATION:
The sign (-, or blank for +) gives the polarity of the inclination. Units
are degrees.
MEAN DEMAGNETIZING FIELD:
Alternating field necessary to erase half the original magnetic intensity.
It is a measure of stability of remanence.
ALTERNATING FIELD DEMAGNETIZATION:
Demagnetizing force in oersteds. In some cases thermal demagnetization
was used. Information about heat demagnetization was stored in COMMENTS.
INITIAL SUSCEPTIBILITY:
Always represented in scientific notation. The negative exponent of the
power of 10 is stored in EXPONENT SUS INTENSITY. Units are gauss/oersteds.
COMMENTS:
The rock name and comments about the results belong here. Lithological
information about the rock sample is taken from the Visual Core Description
forms, which are completed by the shipboard scientists soon after core
recovery.
Part 2. DEEP SEA DRILLING PROJECT
LONG-CORE SPINNER MAGNETOMETER
SEDIMENT PALEOMAGNETICS DATABASE
I. INTRODUCTION
A. BACKGROUND AND METHODS
The long-core spinner magnetometer file contains shipboard data taken by
the Digico long-core spinner magnetometer. This instrument measures the
direction (declination) and intensity of the horizontal component of
magnetization of the sediment in unsplit 1.5-m core sections. The
measurements were made immediately after the cores were brought aboard. Leg
47A measurements are from rotary-drilled sediment cores. The remaining
measurements are from sediments recovered by the hydraulic piston corer.
Listings of the computer-processed magnetometer data were usually included
with the Hole Summary Book paleomagnetics report. On Legs 70 and 71 the
paleomagnetists transcribed the data from the computer listings to data
forms.
To ensure compatibility with DSDP plotting routines, records containing
all null data fields were discarded. For example, on Legs 68 and 70,
measurements at a few levels yielded no recorded values, but under
sedimentological notes "range" meaning "saturated" was printed. These
records were discarded.
B. LEGS IN DATA SET
The database contains data from Legs 47A, 68, 70, 71, 72, 75, and 90.
C. BIBLIOGRAPHY
Ryan, W.B.F., and von Rad, U., 1976. Hole Summary Book for Leg 47A.
Paleomagnetist: N. Hamilton.
Montadert, L., and Roberts, D.G., 1976. Hole Summary Book for Leg 48.
Paleomagnetist: E.A. Hailwood.
Gardner, J.V. and Prell, W.L., 1979. Hole Summary Book for Leg 68.
Paleomagnetists: D. Kent and D. Spariosu.
Honnorez, J., and Von Herzen, R.P., 1979. Hole Summary Book for Leg 70.
Paleomagnetist: S. Levi.
Ludwig, W.J., and Krasheninnikov, V., 1980. Hole Summary Book for Leg 71.
Paleomagnetists: J. Salloway and J. Bloemendal.
Barker, P.F., and Carlson, R.L., 1980. Hole Summary Book for Leg 72.
Paleomagnetists: N. Hamilton and A. Suzyumov.
Hay, W.W., and Sibuet, J.C., 1980. Hole Summary Book for Leg 75.
Paleomagnetist: B. Keating.
Kennett, J.R., and von der Borch, C.C., 1983. Hole Summary Book for Leg
90.
Paleomagnetist: C.E. Barton.
DATA RELIABILITY
The user should refer to the Hole Summary Books for complete discussions
of the results and their reliability.
Leg 47A
Hole 397A: The paleomagnetist experimented with using the long-core
spinning unit for Hole 397A rotary-drilled cores. Two suitable 1.5-m core
sections were spun on separate occasions. The system worked according to
specifications. It was concluded that major lithological changes could
easily be recognized by intensity values and by swings in relative
declination, which then could be used as a guide to sampling.
Leg 48
Sites 401 and 402: A total of seven 1.5-m rotary-drilled core sections
were measured. Measurements were usually taken at 1-cm intervals with
triplicate measurements at each 10-cm point. The data were included in the
Hole Summary Book paleomagnetism section. The data were described as mostly
unreliable with inconsistent repeat readings most likely due to slippage of
the core section within the plastic liner during rotation. The results were
not included in the database.
Leg 68
Site 502: Shipboard personnel attempted to maintain relative orientation
between successive cores, but the paleomagnetist reports they may have been
only partially successful. They did maintain relative orientation between
the sections cut from each 4.4-m core. Cores were measured immediately after
being brought aboard ship. "Very high values of remanent intensity often
occur in the disturbed parts of the core and may be caused by magnetic grain
alignment (due to) sediment shearing, by realignment of magnetic grains in a
relatively strong magnetic field, perhaps associated with the steel drill
string (or possibly we are detecting the shear pins that fall into the hole
after each core)."
Site 503: Rust scale from the drill string was a serious problem. Dark
flecks were concentrated at the top of virtually every core, and the core was
smeared inside the liner to several meters, even in undisturbed parts of the
core. Rust scale, of course, is highly magnetic. This was a serious problem
in Hole 503A, but less so in Hole 503B. Long-core magnetic data from the
topmost 1.5 m of most cores could not be used because of the rust
contamination. Modification to the corer between Sites 502 and 503 greatly
improved core to core orientation, and at Site 503 greater attention was paid
to handling the cores on deck.
In August 1981, the Leg 68 co-chief scientists forwarded a list of
orientation angles (phi) that go with each core for Sites 502 and 503. Phi
is the rotation angle measured from the orientation ring for each core. The
rotation angles have been entered in the "remarks" field of Leg 68 sediment
paleomagnetics records.
Leg 70
Site 506: The paleomagnetist, S. Levi, states (personal communication)
that he would not have confidence in Leg 70 long-core spinner magnetometer
data (especially Site 506) because of rust contamination and physical
disturbance of the sediment. However, the data might show trends and gross
differences. Data for declination and intensity are usually good beyond the
first section, sometimes beyond the top 50 cm of the first section.
Site 507: Similar to Site 506.
Site 509: Cores from Hole 509A are composed of foraminifer-nannofossil
ooze. The results are similar to those at the previous sites. The manganese
oxide fragments show weak magnetization intensity. Cores from Hole 509B are
composed of layers of MnO2 fragments, "hydrothermal clays," and
foraminifer-nannofossil oozes.
Leg 71
Site 512: In most cases an approximate orientation was preserved between
cores. However, orientation was lost on Cores 2, 12, and 13. Large
quantities of gravel occurred in the upper parts of many cores. The gravel
probably fell down the hole from above. It produced the relatively high
intensities (often over 1000 microgauss) and the scattered declinations
visible in Section 1 of many of the cores. Site 514: Pipe rust occurred
frequently in the cores, particularly in Section 1, but also in variable
quantities in the lower sections of the cores. "This problem constitutes a
severe limitation on the use of the long-core spinner to measure weakly
magnetized sediments."
Leg 72
Hole 515A: "Invariably the upper 50 cm or so of Section 1 from each core
gives anomalous declination and intensity results. This appears to correlate
with evidence of visible disturbance and is often reflected in the G.R.A.P.E.
determination." Wildly fluctuating values for a single reading can occur
below the first 50 cm of the first section. Rust was probably not a factor
in the anomalous readings, as the drill pipe was used for rotary coring at
Hole 515.
Site 517: Quality of the long-core data at Site 517 is inferior to that
produced for the more cohesive sediments from Site 515. Anomalous changes in
declination and intensity were most common in the upper part of a section of
each core.
Results measured on Cores 1 and 2 cannot be directly compared with the
discrete samples because the sections changed length when rotated.
Sedimentologists in the core lab tried to reduce the sections to their
original length.
Site 518: The sediments recovered here were generally firmer than at Site
517. Cores were carefully inspected for evidence of voids, soupy
disturbance, and excessive water between liner and sediment surface before
selection for spinning.
Leg 75
Hole 530B: Paleomagnetic studies were unsuccessful except for Core
530B-8, Sections 2 and 3, which did give stable paleomagnetic directions.
There were three reasons for the failure:
1) Much of the sediment consisted of debris flows and turbidites.
2) The sediments were weakly magnetized, and in many cases the noise
level of the magnetometer exceeded or was equal to sample magnetization. For
these reasons no NRM intensity values are available for Hole 530B.
3) There was considerable contamination of sediments with rust from the drill string.
Leg 90
The objective of the on-board studies was to obtain a detailed magnetic
stratigraphy by making closely spaced long-core measurements of the
horizontal component of NRM for all HPC cores. It was not always possible to
achieve this objective, and the cores were sampled for subsequent laboratory
studies. Fluid sections and sections containing air pockets were not
measured.
Hole 587: Contamination by rust was not a serious problem.
High-intensity spikes were attributed to grease spots/rust particles,
although contamination was not always visible in the section. Measurements
were discontinued after Core 7 because of the poor quality of the results.
Site 588: All well-preserved cores from Holes 588, 588A, and 588B were
measured, with the exception of Hole 588B, Cores 10-19. The Digico
magnetometer was noisy and much of the sediment failed to give a signal
significantly higher than the noise level of the instrument (about 0.1
microgauss at 26 spins). Absolute orientations were obtained on most cores
using the Kuster device. Declination plots for all the cores measured were
presented in an appendix to the Hole Summary Book paleomagnetism section.
The Site 588 results were summarized on Summary Paleomagnetic Measurements
forms, copies of which are kept on microfilm in the ODP Data Archives.
Measurements were made at 10-cm steps (26 spins). Below Core 588B-20,
intervals of 20 cm were used. The Summary Paleomagnetic Measurements
tabulation lists the mean NRM intensity value with standard deviation of the
measurements taken in each section. The standard deviations are rather large
because of the presence of a small number of high values in the section.
Thus, the means are much higher than typical values. This data file lists
the mean value for each section, but not the standard deviation.
Hole 589: Paleomagnetic properties are similar to those of Site 588. The
better consolidated sections were measured at 20-cm intervals. The material
in Core 1 is more strongly magnetized than the lower cores. The scattered
declinations of the lower cores are attributed to contamination and the
effect of core liners rather than to instrument noise.
II. FORMAT AND FIELD DESCRIPTIONS
The definition of leg, site, hole, core, and section may be found in the
appended explanatory notes. In addition, the special core designations
(CORE_CHAR), as well as the methods of sample labeling and calculating
absolute sample depths, are discussed.
INTERVAL DEPTH:
Refers to the depth in centimeters within the section at which the top or
bottom of a measurement was taken. No bottom interval depths are given for
the measurements in this file. Measurements are usually made at 10-cm
intervals; however, measurements may be more closely spaced, at 2-cm or 5-cm
intervals, for example.
CORE DEPTH:
The sub-bottom depth in meters to the top of the core.
SAMPLE DEPTH:
The sub-bottom depth in meters to the level at which the measurement was
made.
REPEAT COLUMN:
The paleomagnetist often returned to make measurements at higher levels in
the section or to repeat measurements following the usual sequence. A field
has been reserved for recording repeat measurements. "0" is entered in the
field if there is only one measurement for an interval. There is a "1" for
the first repeat measurement, a "2" for the next repeat, and so on. Records
of a section with the same number in the repeat column are from a single
measurement sequence.
SEDIMENTOLOGICAL NOTES:
Only 25 columns were available for the sedimentological notes. In
encoding, the notes were abbreviated when necessary. A note may be continued
from the "sedimentological notes" field of one record to the same field on
the next record.
NATURAL REMANENT MAGNETIZATION (NRM) INTENSITY:
NRM intensity is encoded in gauss (cgs units). Every value in the NRM
intensity field should be multiplied by 10-6 to arrive at the NRM intensity
value.
NRM DECLINATION, ANGLES UNCORRECTED:
The horizontal angle in any given location between true north and magnetic
north. Values range from 0 to 360 and are always positive. The
paleomagnetists tried to maintain relative orientation between successive
cores. Attention was paid to handling the cores on deck to preserve relative
orientation.
NRM DECLINATION, ANGLES CORRECTED:
This field was used only when the paleomagnetist noted corrected value.
Part 3. DEEP SEA DRILLING PROJECT
PALEOMAGNETICS MEASUREMENTS
IGNEOUS AND METAMORPHIC ROCKS DATA FILE
I. INTRODUCTION
A. BACKGROUND
This file contains paleomagnetic and rock magnetic measurements of igneous
and metamorphic rocks and a few sedimentary rocks composed of volcanic
material. Data were encoded primarily from the Initial Reports of the Deep
Sea Drilling Project. The shipboard Hole Summary Book and the DSDP data
archives also were sources. The file contains both shipboard measurements
and measurements made at on-shore laboratories. Magnetic properties measured
on the ship include magnetic intensity, declination, inclination, and initial
susceptibility. Shipboard paleomagnetic apparatus included a Digico balanced
fluxgate spinner magnetometer, a Schonstedt alternating-field GSD-1
demagnetizer, and a Bison magnetic-susceptibility meter. Shipboard
measurements of magnetic properties of igneous and metamorphic rocks were
made during DSDP Legs 34, 37, 45-46, 49, 51-55, 58-66, 68-73, 75-78, 81-85,
89, and 92.
B. METHODS
Magnetic properties recorded in the file include natural remanent
magnetization (NRM) intensity, declination, inclination, initial
susceptibility, stable declination, stable inclination, mean demagnetizing
field, Curie temperature, saturation intensity, saturation remanence,
coercive force, and remanent coercive force. The Koenigsberger ratio (Q)
when calculated also is included. In a few instances the paleomagnetist has
indicated the quality of orientation, and a field is available for this
information. There is also a field for the grain size or the grain-size
range.
Each record includes an identifying code for the analyst's or first
author's name. See Table 1 for the index to analysts' codes.
Most records contain a code or data source (Table 3). The codes indicate
whether the source was the Initial Reports of the Deep Sea Drilling Project,
the Hole Summary Book, or the prime data archives. Each record has a code
indicating whether the rock is igneous, sedimentary, or metamorphic. Rock
type can be further specified by the codes for tuff (sedimentary), volcanic
breccia (igneous), and brecciated (igneous). See Table 2 for rock-type
codes.
Codes indicate whether the measurements were done on board ship or at a
shore laboratory.
A blank field means not determined.
NRM intensities and initial susceptibilities are expressed in scientific
notation. The symbol @ is used to represent 10.
Units for the magnetic parameters follow: In a few later DSDP reports, data were expressed in SI units. The DSDP
encoders converted SI units to cgs units. The following conversions were
used. Lithological information about the rock sample, including the rock name
and a visual estimate of the degree of alteration, is taken from the Visual
Core Description for Igneous Rocks forms, which are completed by the
shipboard scientists soon after core recovery.
Each paleomagnetic-measurement record contains routine measurements (NRM
INTENSITY through KOENIGSBERGER RATIO) and up to four groups of extra
measurements (THERMOMAGNETIC CURVE through GRAIN SIZE) which include the
CURIE TEMPERATURE. Several temperatures may have been read from the
thermomagnetic curve. This means that some of the extra measurement groups
will contain only additional CURIE TEMPERATURE readings.
C. LEGS IN DATA SET
The data set contains data from Legs 14-16, 19, 23, 25-29, 32-34, 37-38,
41-43, 45-46, 51-55, 58-66, 68-73, 75-78, 81-85, 89, and 91-92.
D. BIBLIOGRAPHY
Partial references to analytical methods for shipboard measurements:
Ade-Hall, J.M., and Johnson, H.P., 1976. Paleomagnetism of basalts, Leg
34. In Yeats, R.S., Hart, S.R., et al., Initial Reports of the Deep Sea
Drilling Project, Vol. 34: Washington (U.S. Govt. Printing Office), pp.
513-532.
Hall, J. M., and Ryall, P.J.C., 1977. Paleomagnetism of basement rocks,
Leg 37. In Aumento, F., Melson, W. G. et al., Initial Reports of the Deep
Sea Drilling Project, Vol. 37: Washington (U.S. Govt. Printing
Office), pp. 425-448.
For methods used in a shore-based study, consult the paper in the Initial
Reports. The results and analytical information of shipboard analyses
similarly are published in the Initial Reports. See Table 1 for the index to
analysts' codes.
II. FORMAT, FIELD DESCRIPTIONS, AND CODES
The definition of leg, site, hole, core, and section may be found in the
appended explanatory notes. In addition, the special core designations
(CORE_CHAR), as well as the methods of sample labeling and calculating
absolute sample depths, are discussed.
INTERVAL DEPTH:
Refers to the depth in centimeters within the section at which the rock
was sampled.
TOP OF CORE DEPTH:
The sub-bottom depth in meters to the top of the core.
SAMPLE DEPTH:
The sub-bottom depth in meters to the level at which the core was sampled.
ANALYST CODE:
The sample number assigned to the rock is included when available.
LITHOLOGIC CODE:
C = Shipboard
S = On-shore
DATA SOURCE CODE:
NRM intensity is encoded in gauss or emu/cm3 units. It is always
represented in scientific notation.
NATURAL REMANENT MAGNETIZATION INCLINATION:
Information about the polarity is contained in the sign preceding the
inclination. Units are degrees. No absolute value should exceed 90 degrees.
NATURAL REMANENT MAGNETIZATION DECLINATION:
Values range from 0 to 360 degrees and are always positive.
STABLE INCLINATION:
The value after alternating field demagnetization.
STABLE DECLINATION:
The value after alternating field demagnetization.
QUALITY OF ORIENTATION:
Symbols for greater than ¢ and less than may appear in the MDF
field.
INITIAL SUSCEPTIBILITY:
Always represented in scientific notation.
KOENIGSBERGER RATIO:
Obtained by the formula: NRM intensity (initial susceptibility × H),
where H is the Earth's magnetic field at the sampling location.
THERMOMAGNETIC CURVE:
A "C" is encoded in this field if the Curie temperature is from the
cooling curve, an "H" if it is from the heating curve.
CURIE TEMPERATURE:
Temperature read from the thermomagnetic curve.
SATURATION INTENSITY:
Entered as a decimal.
SATURATION REMANENCE:
Entered as a decimal.
COERCIVE FORCE:
Symbols for greater than ¢ and less than may appear in this
field.
REMANENT COERCIVE FORCE:
Symbols for greater than ¢ and less than may appear in this
field.
GRAIN SIZE:
Grain size may have been determined by a visual estimate. Units are
microns. Often a range is given.
COMMENT RECORD:
The rock name, degree of alteration, and comments about the results belong
here. Lithological information about the rock sample, including the rock
name and a visual estimate of the degree of alteration, is taken from the
Visual Core Descriptions for Igneous Rocks forms, which are completed by the
shipboard scientists soon after core recovery.
I. INTRODUCTION
A. BACKGROUND
The alternating-field demagnetization file contains alternating-field
demagnetization data on the sediments. The purpose of alternating-field
demagnetization is to remove soft magnetization acquired since the sediments
were deposited. Often, this means removal of magnetization acquired during
the present Brunhes Normal epoch. Pilot demagnetizations are usually carried
out on a few samples to determine how strong a field is required to produce
stable directions of magnetization. Once the optimum demagnetizing field has
been determined, all of the samples are demagnetized in that field.
Data were encoded primarily from the shipboard Hole Summary Book, the DSDP
data archives, and the Initial Reports of the Deep Sea Drilling Project . The
file contains both shipboard measurements and measurements made at on-shore
laboratories. Shipboard paleomagnetic apparatus included a Digico balanced
fluxgate spinner magnetometer and a Schonstedt alternating- field GSD-1
demagnetizer.
Paleomagnetic measurements contained in this file are from core samples
recovered by the punch core-rotary drilling and the hydraulic piston coring
methods. Each record contains a code for the coring method.
B. METHODS
Magnetic properties recovered in this file include magnetic intensity,
declination, and inclination. The normalized intensity, a measure of
magnetic stability, is included when available.
In many cases only one set of alternating-field demagnetization results
was reported for the sample. Fields in the data record of the Natural
Remanent Magnetization - Sediment Paleomagnetics Data File have been reserved
for these results.
In some cases thermal rather than alternating-field demagnetization was
used. Information about the temperature of demagnetization was stored in the
comments field.
The following quote concerning data reliability is taken from the Hole
Summary Book, paleomagnetics section, for Leg 79: "It is important to mention
here a crucial limitation of the shipboard magnetometer. Magnetization
intensity values are often not repeatable and can fluctuate by up to 50% for
samples with intensities one order of magnitude above noise level. . . .
Magnetization directions are generally repeatable."
Each record includes an identifying code for the analyst's or first
author's name. See Table 1 for the index to analysts' codes.
A blank field means not determined.
Magnetic intensities are expressed in emu/cm3 in this file. In
a few later DSDP reports data were expressed in SI units. The DSDP encoders
converted these to cgs units. The following conversion was used: (A/m) ×
10-3 = emu/cm3.
C. LEGS IN DATA SET
The data set contains data from Legs 4, 7, 17, 23, 27, 33-34, 41-42,
47-49, 51-52, 59, 66, 72-73, 79, 81-82, 84, 86, and 90.
D. BIBLIOGRAPHY
Partial references to analytical methods for shipboard measurements.
Barker, P.F., and Carlson, R.L., 1980. Hole Summary Book for Leg 72.
Paleomagnetists: N. Hamilton and A. Suzyumov.
Hsü, K.J., and LaBrecque, J.L., 1980. Hole Summary Book for Leg 73.
Paleomagnetists: J.L. LaBrecque, H.P. Petersen, L. Tauxe, and P. Tucker.
Hinz, K., and Winterer, E.L., 1981. Hole Summary Book for Leg 79.
Paleomagnetist: J.E.T. Channell.
For methods used in a shore-based study, consult the paper in the Initial
Reports. The results and analytical information of shipboard analyses
similarly are published in the Initial Reports and the Hole Summary Book.
See Table 1 for the index to analysts' codes.
II. FORMAT, FIELD DESCRIPTIONS, AND CODES
The definition of leg, site, hole, core, and section may be found in the
appended explanatory notes. In addition, the special core designations
(CORE_CHAR), as well as the methods of sample labeling and calculating
absolute sample depths, are discussed.
INTERVAL DEPTH:
Refers to the depth in centimeters within the section at which the rock
was sampled.
TOP OF CORE DEPTH:
The sub-bottom depth in meters to the top of the core.
SAMPLE MIDPOINT DEPTH:
The sub-bottom depth in meters to the level at which the core was sampled.
CORING DEVICE CODE:
H = Hydraulic Piston Corer (includes Variable Length Piston Corer)
R = Conventional Rotary Drilling Corer (includes Extended Core Barrel)
ANALYST CODE:
The total number of AFD measurements for a sample.
REPEAT:
The paleomagnetist occasionally repeated demagnetization steps on a
sample. A "0" was entered in REPEAT if there was only one measurement for an
interval. There is a "1" for the first repeat measurement, a "2" for the
next repeat, and so on. AFD results belonging to a single sample with the
same number in REPEAT are from the same measurement sequence.
MAGNETIC INTENSITY EXPONENT:
In this file magnetic intensity is recorded in scientific notation. Each
magnetic-intensity value should be multiplied by 10 to the negative value of
this number.
ALTERNATING FIELD DEMAGNETIZATION
Demagnetizing force in oersteds. "NRM" was entered in this field when the
demagnetizing field is zero. In some cases thermal demagnetization was used.
Information about temperature of demagnetization was stored in the comment
field.
MAGNETIC INTENSITY:
Expressed here in cgs units and in scientific notation.
The negative exponent of the power of 10 is stored in "Magnetic Intensity
Exponent" for each AFD measurement.
NORMALIZED INTENSITY J(H)/J0:
This is the ratio of magnetic intensity measured after demagnetization to
the NRM intensity. J(H) = magnetic intensity (J) after demagnetization in
field H. Field H is the demagnetization force given in "Alternating Field
Demagnetization." J0 = NRM intensity.
DECLINATION:
Units are degrees.
INCLINATION:
The sign (-, or blank for +) gives the polarity of the inclination. Units
are degrees.
The following Technical Notes are available from the Manager of Science
Operations, Ocean Drilling Program, 1000 Discovery Drive, College Station,
Texas 77845-9547, U.S.A.
Also available from ODP Science Operations are the following pamphlets and
booklets:
Cryogenic Magnetometer Programs
A. Programs Available
The cryogenic magnetometer can be used to measure both whole core and
discrete samples. The following programs are available on the IBM PC to run
the cryogenic magnetometer:
A - Cryosect This program measures whole sections.
B - Cryocube This program measures discrete samples.
C - MAGRAPH-Data Browser Enables user to view data from all sections of
the core.
B. Formatting Disks
Prior to using any of the above programs, the user must first format a
high-density 3-1/2-in. diskette on which to collect data. These diskettes
fit into drive A of the PC. Drives C and D are the hard disk drives for the
computer. Drive B accepts 5-1/4-in. floppy disks. The following procedure
shows how to format all diskettes for the IBM. (The bold lettering is what
the computer will print, and the italic lettering is what you must type in.)
First, go to drive C. Press F7 in order to escape from the menu.
PROCEDURE FOR 3-1/2-in. DISKETTES PROCEDURE FOR 5-1/4-in. DISKS Check to see that the byte size is the same between total disk space and
available space on the diskette or disk. If it is not, the diskette or disk
is bad, and another should be used. Disks and diskettes are cheap, so use a
new one for each different site/hole or shift change. Disks and diskettes
are available in the lab or from the lab specialist, storekeeper, or computer
specialist.
C. Running Programs
When a section is placed in the boat, make sure the top of the section is
to your left. The cryo program always assumes the top to be at this point.
If doing individual samples using the discrete sample boat, then Sample 1
must be in the most leftward sample position.
1. Program Option A - Cryosect
Program A, which measures the declination, inclination, and intensity
(DII) of sections of core, is the most frequently used program in the
paleomagnetics lab. Program A has been modified several times, and therefore
has a patchwork look. (The marine paleomagnetics specialists request that
users do not alter any of the paleomagnetic software. Modifications may not
be useful on other legs and may cause problems for future users. Any
suggestions for improvements are welcome; please discuss them with the marine
paleomagnetics specialist.)
a) In order to activate a program from the menu, type in the letter of
the program you wish to use. To measure a core section, type A. A brief
introduction will appear. The first two questions ask if you wish to print
the data graphed: the raw data plot shows the intensities of all three axes,
and the DII plot shows the declination, inclination, and intensity of a
section. If the lab is busy, then it is best to answer "no" to both
questions. Graphs, especially DII plots, are recommended if time permits,
however, and if you would like a hard copy of the data.
b) The computer will then ask if you wish to use old holder data. An
empty sample holder should be run once per shift to establish baselines for
that shift. The old holder data is the last that was recorded on the site.
If the computer crashes or something else happens to the cryogenic
magnetometer, a new empty sample holder must be measured.
c) After this first set of questions, a prompt will appear asking if
everything is all right (if so, press Return), or if answers need to be
changed (press 2). This prompt is known as the "change your mind prompt," or
"CYMP."
d) The next series of questions asks for the leg number, the sub-leg
number (rarely used), the site number (three digits), and the hole letter.
Look through the directory for the site and hole that you just typed in. If
it is there, press Y (yes); otherwise press N (no). If the site was not on
the disk directory, it will be created and you may begin to record data. (Any
subsequent data for that hole will then be put on the diskette.)
e) The next question asks for identification /location description for
site. If you have no comments, you may bypass this by pressing Return. A
statement will appear on the screen: "If you are running a blank just hit
Return here!" This will enable you to bypass the recording of a core
number; hitting Return again will bypass recording the core type when
measuring a blank holder. When measuring a blank, type in any value at the
prompt for section number. When measuring a section, type the appropriate
core number (up to 3 characters), core type (H, X, R), and section number
(one character only). The CYMP will appear again.
f) The next question asks if you wish to change anything; this may be
bypassed by pressing Return. The next important item is to enter the
demagnetization steps. Read over the options carefully. The first step, to
measure the NRM, is indicated by typing 0. You may program in as many mT
steps as you wish. To indicate that you are programming no additional steps,
type an X at the prompt for the next step.
g) Three more questions follow the demagnetization steps. The first asks
if the current measurement parameters are satisfactory. The standard is 10
cm between points and no repetition. If you wish to change these parameters,
answer N. If you wish to change the size of the section measured, answer N
here as well. Otherwise, the standard will be used (150 cm). The second
question is if the leader/trailers of 15 cm is OK. Type in Y for this
question. The last question is if you wish a printout of the raw data (you
probably won't have time). The last CYMP will appear; press return to go to
the beginning of the program.
h) After data collection is complete, the computer will beep, and a
10-second delay will appear asking if you wish to abort the run. If you do
wish to abort, press F10; otherwise do not touch the keyboard. The same
message appears after the DII plot. If you measure an empty sample holder,
then after the measurements are taken and the DII plot is shown, you will be
automatically taken to the beginning of the program. Otherwise, if you have
just completed a section, then several choices are given to you that shorten
the question process and allow you to go quickly to the next core, section,
or demagnetization level.
Up to seven discrete samples can be measured and AF-demagnetized using
program option B - Cryocube. The discrete sample program follows the same
general question format as the whole-section program, with a few differences.
a) As in the whole-section program, the first two questions ask if you
want hard copies of the raw data and the DII plots. Again, whether or not
these plots are desirable depends on the amount of time you have available.
b) The next set of questions asks for leg number, sub-leg, site number,
and hole. Answer accordingly.
c) The program then asks you to enter the subdirectory for data. Just
press Return. If the directory exists, the program will go to the next
question. If the directory does not exist, the program will ask if it should
make the directory. Type in Y, and the program will go to the next question.
Squid operation will be in COUNTER mode.
d) The program then asks if you wish to run a blank holder first. If you
respond with a Y, the next question is "Do you wish to demagnetize the
holder?" If you answer N, the program will ask if the empty sample holder is
ready. A Y answer starts the measurements. If you answer Y to the
demagnetization question, the program will automatically use 20 mT. After
answering the demagnetization level question, the computer will ask if the
sample holder is ready; a Y answer begins the measurements. Holder data
cannot be stored after quitting Cryocube. The blank holder must be
remeasured whenever the program is started.
e) When samples are measured, the program will ask a series of questions
for each sample.
f) If you type in N for the last question, the series of questions will
repeat. Otherwise you will answer the same series of questions for the next
six samples. If you have fewer than seven samples to run, typing 0 at the
core-number prompt will end the question series.
g) The program will ask you for the demagnetization levels. This is
exactly the same as Cryosect. Demagnetization levels greater than 24 mT
(done on the GSD-1) will generate a screen message as such and will be
written to the file without attempting to ramp up the demagnetization coils
on the cryo. Last, the program will ask if you are ready to run your
samples. If so, type in Y.
h) From this point, the program is like Cryosect. The only difference is
that at the end you have an automatic printing of the sample, its
declination, inclination, and intensity. Also, the selections at the end of
the run are more limited:
Magraph/Browser gives the user three graphic options. The first shows a
DII chart. The other two options are Schmidt projections or Zijderveld
diagrams.
a) First, the program asks for the directory name and the cores you wish
to examine. b) It will take the data and graph a DII plot. A prompt for commands
will appear at the bottom of the screen. If you wish to look at the
commands for the program, press return at this time and they will appear on
the screen.
You may also use the "up" and "down" arrows to move through the data set
at a quicker pace than the "forward" or "backward" commands. This program is
good for seeing the overall trends in declination, inclination, and intensity
in a core or site.
Loading and Processing Data on the Vax
A. Loading Data
(The bold lettering is what the computer will print, and the italic lettering is what you must type in.)
1) Put the data diskette into drive A of the PC.
2) Access the VAX by clicking twice on the VAX Terminal icon. At the
username prompt, type Paleomag. If you are in the Paleomag account on the
VAX, you will see a prompt that looks like this: PM> 3) Create the site directory in the Paleomag account on the VAX. (A
directory must be created for every site before data from the site may be
loaded into the VAX for processing.) Create the site by typing the
following: 4) Log out of the Paleomag account (by typing LO) and return to the shell
setup screen.
5) Magblast is the program that transfers data from the diskette to the
VAX. (MAGBLAST DOES NOT RUN UNDER WINDOWS.) Place your disk in drive A.
Type the following to transfer your data to the VAX. (Remember: The site
directory must be on the disk, and the 3-digit site number must be followed
by the hole letter.)
6) Once on the VAX, hit Return until something appears on the screen.
Let the computer run until it asks you for your site number again. NOW, WHEN
THE COMPUTER ASKS YOU FOR THE SITE NUMBER, USE FOUR DIGITS!! (i.e., 0999).
The program will ask if the data file is from whole core (WCC) or discrete
samples (DSC). The program will upload the data into the VAX. When the
program is done loading, it will log out of the VAX and return you to the DOS
prompt.
7) Once your data files have been transferred to the VAX, you may begin
processing. Return to the Windows environment ( C:\> win , or reboot the
system.), and click twice on the VAX terminal icon. Type Paleomag at the
username prompt. You may now type in whatever program you wish to use.
B. Commands for PC, VAX, and Paleomag
1) PC Commands 2) VAX Commands Logical names are useful in referring to these directories or files within
them. Using a logical name, you can refer to a minispin data file, for
example, as DSS0688.688A013.DSS instead of
DATA: [PALEOMAG.LEG111:DSS0688]688013.DSS This will save a lot of typing.
4) Depths Utility
C. Data-Processing Program
The program PROCESS puts sections into a core file and adds depths to all
the measurements.
PM>process Processes any type of paleomag data files as transferred from
diskette to the appropriate data directory. PROCESS
sorts all data into files for each core and assigns
sub-bottom depths to all records.
Select option, answer questions. At the demag level prompt, type 00 (2 zeros) for zero demag level (NRM).
D. Orientation Data
1. The program ORIENT allows you to correct the direction of the
cores. Answer the questions the program will ask you. Two marine specialists are
assigned to the multishot and Tensor orientation tools and will provide you
with the data if you request them. You will need the offset of magnetic
north from true north (see figure in Paleomag. textbook, or ask the captain
or a mate). When orienting with the multishot tool, use the same file name,
but replace the extension WCC with MOR (multishot orientation). If you use
the Tensor tool or some other method to determine core orientation, replace
the extension WCC with SOR (secondary orientation). The computer will ask
two questions regarding the orientation of the sample. The first question
will ask for the magnetic variation of the sample (get from the chart). The
computer will then ask for the declination, which comes from the multishot or
Tensor orientation data.
2. Correction of Working-Half Data
If you measure a working half, the orientation program can be used to
correct that section file by 180 degrees. When the program asks for the
output file name, give it the same name as the input file name. Example:
ENTER INPUT FILENAME........?WCC0854:854B0021.D15 The core section is then corrected for the 180-degree offset that occurs
when the working half is measured. (You may also correct the data by 180
degrees in the cryo program at the time you measure the working half.)
E. Transferring Data to Macintosh
Once the data have been processed and oriented, you can transfer to the
Macintosh to use graphics and text programs. Go into the Paleomag directory
on the VAX and follow this procedure:
Procedure on the MAC: Procedure on the PC: Eventually, the magnetics files should transfer over to the MAC. This may
take a while, as the files from a hole can be large.
F. PLOTS
Once in the Paleomag directory on the VAX, you have access to two graphics
programs. They both plot declination, inclination, and intensity. The first
program plots the whole core, whereas the second plots discrete sections.
1) DII
2) DII Plot
PM> diiplot
Data Filename:wcc0854:854b002_15.wcc
Filter the data file: N
Title: (This will be on the plot)
Delete finished chart: Y
We would appreciate any questions/comments/suggestions/complaints about
this Technical Note, the lab equipment, laboratory procedures, software, or
any other topics related to paleomagnetism on board the JOIDES Resolution.
Please send your comments to:
APPENDIX 4
EQUIPMENT MANUALS AVAILABLE ABOARD
THE JOIDES RESOLUTION
Demagnetizers
Rock Magnetic Equipment
Schonstedt TSD-1 Thermal Demagnetizer
Schonstedt GSD-1 AF Demagnetizer
Magnetic Susceptibility Instruments
ASC Impulse Magnetizer
DTECH Partial Anhysteretic Magnetizer
Gaussmeter (Magnetometer)
Bartington Susceptibility Meter
Kappabridge KLY-2 Magnetic Susceptibility Bridge
MG-5D Hall-Effect Gaussmeter
APPENDIX 5
DSDP PALEOMAGNETIC DATABASE DESCRIPTION
Part 1. DEEP SEA DRILLING PROJECT
PALEOMAGNETICS MEASUREMENTS
SEDIMENT PALEOMAGNETICS DATA FILE
A. RECORD FORMAT
FIELD FORMAT
===== =======
LEG I3
SITE I4
HOLE A1
CORE I3
CORE_CHAR A2
SECTION A2
TOP INTERVAL DEPTH (centimeters) F5.1
BOTTOM INTERVAL DEPTH (centimeters) F5.1
TOP OF CORE DEPTH (meters) F8.2
SAMPLE MIDPOINT DEPTH (meters) F8.2
REPEAT I1
CORING DEVICE CODE A1
ANALYST CODE A4
NRM INTENSITY A7
EXPONENT NRM INTENSITY I1
NRM DECLINATION A6
NRM INCLINATION A5
MEAN DEMAGNETIZING FIELD I3
ALTERNATING-FIELD DEMAGNETIZATION I4
AFD INTENSITY A7
EXPONENT AFD INTENSITY I1
AFD DECLINATION A6
AFD INCLINATION A5
INITIAL SUSCEPTIBILITY A7
EXPONENT SUS INTENSITY I1
COMMENTS A150
B. FIELD DESCRIPTIONS AND CODES
TABLE 1 - ANALYSTS'/AUTHORS'/ CODES
"IR" = Initial Reports of the Deep Sea Drilling Project
"HSB" = Hole Summary Book
"ARCH" = Data Archives of the Deep Sea Drilling Project
LEG CODE ANALYST/AUTHOR SHIP ONSHORE DATA SOURCE
=== ==== =============== ==== ======== ============
1 OP Opdyke, N.D. X IR
2 OP Opdyke, N.D. X IR
3 OP Opdyke, N.D. X IR
4 OP Opdyke, N.D. X IR
5 DOEL Doell, R.R. X IR
6 DOEL Doell, R.R. X IR
7 SCLA Sclater, J.G. X IR
8 DOEL Doell, R.R. X IR
13 RYAN Ryan, W.B.F. X IR
15 OP Opdyke, N.D. X IR
17 JARR Jarrard, R.D. X IR
22 JARR Jarrard, R.D. X IR
23 HAM Hamilton, N. X IR
27 BREC Brecher, A. X IR
JARR Jarrard, R.D. X IR
28 ALL Allis, R.G. X IR
33 JARR Jarrard, R.D. X IR
37 HALL Hall. J.M. X IR
38 LVL Lovlie, R. X IR
41 HAWO Hailwood, E.A. X IR
42 HAM Hamilton, N. X IR
47 HAM Hamilton, N. X IR
MGAN Morgan, G. X IR
48 HAWO Hailwood, E.A. X X IR
51 BLEI Bleil, U. X IR
KELT Kelts, K. X IR
52 BLEI Bleil, U. X IR
54 PET Petersen, N. X IR
57 HALL Hall, J.M. X IR
58 KNS Kinoshita, H. X X IR
59 KEA Keating, B. X X IR
60 BLEI Bleil, U. X X IR
61 STR Steiner, M. X X IR
62 SYR Sayre, W.O. X X IR, HSB
63 DEN Denham, C.R. X IR
64 LV Levi, S. X MANUSCRIPT
66 NM Niitsuma, N. X IR
68 HAWO Hailwood, E.A. X X IR
71 SAL Salloway, J. X HSB
72 HAM Hamilton, N. X HSB
73 PET Petersen, N. X ARCH
74 CHA Chave, A. X MANUSCRIPT
75 KEA Keating, B. X X MANUSCRIPT
76 OGG Ogg. J. X IR
77 TEST Testarmata, M. X HSB
78 WIL Wilson, D. X IR
79 CNL Channell, J. X HSB
80 TOWN Townsend, H.A. X X IR
81 KRMK Krumsiek, K. X X IR
82 KHAN Khan, M. X HSB
84 LIE Lienert, B. X HSB
85 WEIN Weinrich, N. X X IR, HSB
86 BLEI Bleil, U. X HSB
LV Levi, S. X IR
(Additional data available on magnetic tape from ODP)
87 NM Niitsuma, N. X IR
89 OGG Ogg, J. X X HSB, IR
90 BRTN Barton, C. X X ARCH,HSB,IR
91 MONT Montgomery, A. X IR
93 OGG Ogg, J. X IR
94 CLE CLEM Clement, B. X ARCH
NRM, AFD INTENSITY:
A. DATA FORMAT
FIELD FORMAT
===== =======
LEG I3
SITE I4
HOLE A1
CORE I3
CORE_CHAR A2
SECTION A2
TOP INTERVAL DEPTH (cm) F5.1
TOP OF CORE DEPTH (meters) F8.2
SAMPLE DEPTH IN HOLE (meters) F8.2
REPEAT COLUMN I1
SEDIMENTOLOGICAL NOTES A25
NRM INTENSITY (gauss × 10-6) F10.3
NRM DECLINATION, ANGLES UNCORRECTED (degrees) F7.1
NRM DECLINATION, ANGLES CORRECTED (degrees) F7.1
B. FIELD DESCRIPTIONS
a) Magnetic intensity emu/cm3
b) Mean demagnetizing field oersteds
c) Initial susceptibility gauss/oersteds
d) Saturation intensity emu/cm3
e) Saturation remanence emu/cm3
f) Coercive force oersteds
g) Remanent coercive force oersteds
(A/m) / 79.6 = oersteds
(A/m) × 10-3 = emu/cm3
mT × 10 = oersteds
A. RECORD FORMATS
FIELD FORMAT
===== =======
LEG I3
SITE I4
HOLE A1
CORE I3
CODE_CHAR A2
SECTION A2
TOP INTERVAL (centimeters) F5.1
BOTTOM INTERVAL (centimeters) F5.1
TOP OF CORE (meters) F8.2
SAMPLE DEPTH (meters) F8.2
ANALYST CODE A4
PIECE NUMBER A4
LITHOLOGY CODE A1
MEASUREMENT CODE A1
DATA SOURCE CODE A1
NRM INTENSITY A8
NRM INCLINATION A5
NRM DECLINATION A5
STABLE INCLINATION A5
STABLE DECLINATION A5
QUALITY OF ORIENTATION A2
MEAN DEMAGNETIZING FIELD A5
INITIAL SUSCEPTIBILITY A8
KOENIGSBERGER RATIO A5
THERMOMAGNETIC CURVE 1 A1
CURIE TEMPERATURE 1 I4
SATURATION INTENSITY 1 A8
SATURATION REMANENCE 1 A8
COERCIVE FORCE 1 A4
REMANENT COERCIVE FORCE 1 A4
GRAIN-SIZE 1 A10
THERMOMAGNETIC CURVE 4 A1
CURIE TEMPERATURE 4 I4
SATURATION INTENSITY 4 A8
SATURATION REMANENCE 4 A8
COERCIVE FORCE 4 A4
REMANENT COERCVE FORCE 4 A4
GRAIN-SIZE 4 A10
COMMENTS A196
B. FIELD DESCRIPTIONS AND CODES
TABLE 1 - ANALYSTS'/AUTHORS' CODES
LEG CODE ANALYST/AUTHOR
=== ==== ===============
14 LO LOW Lowrie, W.
15 LOW Lowrie, W.
16 HALL Hall, J.M.
19 WHIT Whitney, J.23 HAM Hamilton, N.
25 WOLE Wolejszo, J.
26 PEIR Peirce, J.W.
27 MCEL McElhinny, M.W.
28 LOW Lowrie, W.
29 LOW Lowrie, W.
32 LARS Larson, R.
33 CKM Cockerham, R.S.
34 HALL Hall, J.M.
TARA Tarasiewicz, G.
GROM Gromme, S.
ELL Ellwood, B.
DEN Denham, C.
LOW Lowrie, W.
37 HALL Hall. J.M.
BLEI Bleil, U.
ELL Ellwood, B.
KENT Kent, D.
BREC Brecher, A.
DEUT Deutsch, E.
SCHW Schwartz, E.
CARM Carmichael, C.
38 KENT Kent, D.
41 KENT
KENT Kent, D.
LEG CODE ANALYST/AUTHOR
=== ==== ===============
42 PET Petersen, N.
43 PET Petersen, N.
45 JOH Johnson, P.
46 PET Petersen, N.
49 DAY Day, R.
51 BLEI Bleil, U.
LEVI Levi, S.
HAMY Hamano, Y.
52 LEVI Levi, S.
BLEI Bleil, U.
HAMY Hamano, Y.
RIG Rigotti, P.
53 RIG Rigotti, P.
HAMY Hamano, Y.
LEVI Levi, S.
54 PET Petersen, N.
55 KONO Kono, M.
58 KNS Kinosha, H.
59 KEA Keating, B.
60 BLEI Bleil, U.
61 STR Steiner, M.
SYR Sayre, W.
62 SYR Sayre, W.
63 DEN Denham, C.
SUR Pal Verma, S.
64 VAC Vacquier, V.
SUR Pal Verma, S.
65 DAY Day, R.
PECH Pechersky, D.M.
66 NM Niitsuma, N.
68 Unknown
69 PECH Pechersky, D.M.
FUR Furuta, T.
ODON O'Donovan, J.B.
70 FUR Furuta, T.
PECH Pechersky, D.M.
LEVI Levi, S.
71 SAL Salloway, J.
72 HAM Hamilton, N.
73 PET Petersen, N.
HOUS Housden, J.
75 KEA Keating, B.
76 TEST Testarmata, M.
77 KNS Kinoshita, H.
TEST Teestarmata, M.
78 WIL Wilson, D.
81 KRMK Krumsiek, K.A.O.
82 SMIT Smith, G.M.
KNS Kinoshita, H.
NEW Newmark, R.
FACY Facey, D.
84 LIE Lienert, B.
85 WEIN Weinreich, N.
89 OGG Ogg, J.
91 MONT Montgomery, A.F.
92 NISH Nishitani, T.
PIECE NUMBER:
TABLE 2 - LITHOLOGIC CODES
I = Igneous
S = Sedimentary
M = Metamorphic
T = Tuff (sedimentary)
V = Volcanic breccia (igneous)
B = Brecciated (igneous)
MEASUREMENTS CODE:
TABLE 3 - DATA SOURCE CODES
R = Initial Reports of the Deep Sea Drilling Project (IR)
S = Hole Summary Book (HSB)
A = Prime data archives
NATURAL REMANENT MAGNETIZATION INTENSITY:
TABLE 4 - QUALITY OF ORIENTATION CODES
G = good
MG = medium good
P = poor
VP = very poor
U = unstable
M = medium
R = reversed
N = none
F = fair
PC = polarity corrected
UC = unoriented
SI = shallow orientation
MEAN DEMAGNETIZING FIELD:
TABLE 5 - ALTERATION CODES
ALT FRESH = ROCK IS FRESH
ALT MOD = MODERATELY ALTERED
ALT EXT = EXTENSIVELY ALTERED
ALT INTENSE = INTENSELY ALTERED
ALT SLIGHT = SLIGHTLY ALTERED
Part 4. DEEP SEA DRILLING PROJECT
ALTERNATING-FIELD DEMAGNETIZATION
SEDIMENT PALEOMAGNETICS DATA FILE
A. RECORD FORMATS
FIELD FORMAT
===== =======
LEG I3
SITE I4
HOLE A1
CORE I3
CORE_CHAR A2
SECTION A2
TOP INTERVAL DEPTH (centimeters) F5.1
BOTTOM INTERVAL DEPTH (centimeters) F5.1
TOP OF CORE DEPTH (meters) F8.2
SAMPLE MIDPOINT DEPTH (meters) F8.2
CORING DEVICE CODE A1
ANALYST CODE A4
NUMBER OF AFD MEASUREMENTS I2
REPEAT 1 I1
MAGNETIC INTENSITY EXPONENT 1 I1
ALTERNATING FIELD DEMAGNETIZATION 1 A4
MAGNETIC INTENSITY 1 A8
NORMALIZED INTENSITY 1 A8
DECLINATION 1 A8
INCLINATION 1 A8
COMMENTS 1 A16
REPEAT 15 I1
MAGNETIC INTENSITY EXPONENT 15 I1
ALTERNATING FIELD DEMAGNETIZATION 15 A4
MAGNETIC INTENSITY 15 A8
NORMALIZED INTENSITY 15 A8
DECLINATION 15 A8
INCLINATION 15 A8
COMMENTS A16
B. FIELD DESCRIPTIONS AND CODES
TABLE 1 - ANALYSTS'/AUTHORS' CODES
"IR" = Initial Reports of the Deep Sea Drilling Project
"HSB = Hole Summary Book
"ARCH" = Data Archives of the Deep Sea Drilling Project
LEG CODE ANALYST/AUTHOR SHIP ONSHORE DATA SOURCE
=== ===== =============== ==== ======== ============
4 OP Opdyke, N.D. X IR
7 SCLA Sclater, J.G. X IR
17 JARR Jarrard, R.D. X IR
23 HAM Hamilton, N. X IR
27 JARR Jarrard, R.D. X IR
BREC Brecher, A. X IR
33 JARR Jarrard, R.D. X IR
34 JOH Johnson, H.P. X X IR
41 KENT Kent, D.V. X IR
HAWO Hailwood, E.A. X IR
42 HAWO Hailwood, E.A. X IR
47 HAM Hamilton, N. X X IR
48 HAWO Hailwood, E.A. X X IR
49 STR Steiner, M. X HSB
51 BLEI Bleil, U. X HSB
KELT Kelts, K. X IR
52 LV Levi, S. X HSB
59 KEA Keating, B. X X IR
66 NM Nittsuma, N. X IR
72 HAM Hamilton, N. X HSB
73 PET Petersen, N. X ARCH
79 CNL Channell, J. X HSB
81 KRMK Krumsiek, K. X ARCH
82 KHAN Khan, M. X HSB
84 LIE Lienert, B. X HSB
86 LV Levi, S. X IR
90 BRTN Barton, C. X HSB, ARCH
NUMBER OF AFD MEASUREMENTS:
APPENDIX 6
BIBLIOGRAPHY OF ODP TECHNICAL NOTES
Technical Note 1: Preliminary Time Estimates for Coring Operations (revised edition, December 1986)
Technical Note 3: Shipboard Scientists' Handbook (revised edition, March 1990)
Technical Note 5: Water Chemistry Procedures Aboard JOIDES Resolution (May 1986)
Technical Note 6: Organic Geochemistry on the JOIDES Resolution - An Assay (May 1986)
Technical Note 7: Shipboard Organic Geochemistry on JOIDES Resolution (October 1986)
Technical Note 8: Handbook for Shipboard Sedimentologists (February 1988)
Technical Note 9: Deep Sea Drilling Project Data File Documents (January 1988)
Technical Note 10: A Guide to ODP Tools for Downhole Measurements (June 1988)
Technical Note 11: Introduction to the Ocean Drilling Program (February 1989)
Technical Note 12: Handbook for Shipboard Paleontologists (1989)
Technical Note 14: A Guide to Formation Testing Using ODP Drill String Packers (1990)
Technical Note 15: Chemical Methods for Interstitial Water Analysis Aboard JOIDES Resolution (1991)
Technical Note 16: Hydrogen Sulfide - High Temperature Drilling Contingency Plan (1991)
Technical Note 17: Design and Operation of a Wireline Pressure Core Sampler (PCS) (1992)
Technical Note 20: Science Prospectus - FY93-FY94 Atlantic Program (1993)
APPENDIX 7
USERS' GUIDE: CRYOGENIC MAGNETOMETER
PALEOMAGIC
(Leg 146)
M. Sweitzer, M. Hastedt, L. Stokking
C:\FORMAT A: This formats high-density diskettes.
C:\FORMAT A:/N:9/T:80 This formats double-density diskettes.
C:\FORMAT B: This formats high-density floppy disks.
C:\FORMAT B:/4 This formats double-density floppy disks.
(1) set Takes you directly to beginning of program.
(2) core Allows you to select the next core.
(3) sect Allows you to select the next section of a core.
(4) demagnetization Allows you to select the next demagnetization level.
(5) END Takes you back to the menu (data are saved).
(6) END Saves holder data and exits from program.
2. Program Option B - Cryocube
Core No. [0 for end](0)? Type core number.
Core Type ()? Type corresponding letter (H,R,X).
Section No. ()? Type sample section number.
Top interval? Type top of sample distance to top of
section in cm (numbers only).
Actual declination of +X axis (0)? If this information is unavailable,
type 0.
Is this sample information correct? Type Y or N.
(1) hole If the hole changes.
(2) sect If the section changes.
(3) demagnetization For different demagnetization levels.
(4) END If you wish to end the program.
3. Program Option C- Magraph/Browser
The format is: What is Directory name? A:\SITE999A or
What is Directory name? C:\SITE999A depending on where the file is.
c) The commands are
B: Backward Moves the red marker backward through the data set
D: Demag Level Changes demag level of interval being looked at
F: Forward Moves the red marker forward through the data set
J: Search and Jump Finds a specific core and section to move the marker to
N: Change dir name Changes name of the directory
Q: Quit Leaves the program for the main menu
S: Schmidt Projection Gives a Schmidt Projection for the data point the red marker is on
T: Jump to Top Will go to first data point on the DII plot
Z: Zijderveld Diagram Gives a Zijderveld Diagram for the data point the red marker is on
If your site directory exists, go to Step 5.
PM>CREATESITE............The program will ask for a 3-digit site number. If the site already exists, the program will inform you and will abort the process.
C:\> D:\MAGBLAST\MAGBLAST SITE999A
I I I I
drive directory file name directory name
C:\> DIR A: Gets the directory of disk from drive A.
(Note: Some parts of the VAX are mapped onto the PC's E drive.)
a. The following VAX commands are used regularly :
log off or lo Log off the VAX.
log on Log on the VAX.
createsite Creates data directories for a site.
process Processes all Paleomag data (puts on depths).
orient Corrects DII data using multishot orientation.
diiplot Makes downhole PicSure plots of DII data.
iiiplot Makes special downhole PicSure plots of NRM and
higher demagnetization level inclination data.
susplot Makes downhole PicSure plots of susceptibility.
zplot Makes Zijderveld plots of DII data.
dii Easy and quick way to run DIIPLOT.
sus Easy and quick way to run SUSPLOT.
b. The following VAX commands are used less frequently:
coredata Generates coredata field (gets core data and
depths from the VAX database).
cmag_reprocess Processes a WCC raw data file.
depthsort Sorts any Paleomag file by depth.
chop Segments large files on SBD.
diifilter Filters DII data by demagnetization level and
circular standard deviation (CSD).
qplot Makes QUICK downhole plots of DII data.
printc Prints to laser printer.
work Sets default to WORK directory. (This is your workplace.)
wcsfix Prepares WCS files for processing.
3) Logical Names That Apply in Paleomag
PMWORK USER:[LAB.PALEOMAG.WORK]
LAB### USER:[LAB.COMMON.LEG###] (coredata found here)
LEG### DATA:[LAB.LEG###]
DSC#### DATA:[PALEOMAG.LEG###.DSC####]
DSS#### DATA:[PALEOMAG.LEG###.DSS####]
SUS#### DATA:[PALEOMAG.LEG###.SUS####]
WCC#### DATA:[PALEOMAG.LEG###.WCC####]
WCS#### DATA:[PALEOMAG.LEG###.WCS####]
The following is the ODP depths utility, needed for discrete samples.
PM>depths May be used from any data directory.
PM>orient
ENTER OUTPUT FILENAME.....?WCC0854:854B0021.D15
ENTER MAGNETIC VARIATION FOR SITE 854? 0
ENTER DECLINATION FOR SITE 854...............?180
Go to Drake Share and open up the Magnetics_Reports folder. Inside this
folder, create a new folder, naming it SITE999A. Do not open this folder,
but go up to the Apple menu in System 7 and check SHOW PRIVILEGES. Make sure
that the three boxes for privileges for everyone are checked off. Save this
information and close the window. Now go back to the PC.
PM>Set Default DATA:[PALEOMAG.LEG141] May abbreviate Set Default to Set
Def.
PM>DIR Lists out the data directory for the leg.
PM>Set Def [.WCC0999] Opens up the site directory with all the data
files.
PM>DIR Lists all files in the site directory PM>COPY *.*
ALISA:[MAGNETICS_REPORTS.SITE999A] Transfers files to Drake
Share by copying onto the folder created in Drake Share on the MAC.
Copies all files out of the 999 directory that has been opened on the PC
to a folder in Drake Share on the MAC. All holes are dumped into the same
site folder on the PC. Thus if you want to copy one hole into one folder
on the MAC (this is recommended since the files are so large), then use the
copy command to edit which files you wish to copy. Here is an example:
PM>COPY 999A*.*
PM>dii
Enter File Extension .eg WCC: wcc
Enter Directory Prefix.eg WCC: wcc
Enter Site Number (3 digits): 854
Hole:
Comments: (These will be placed on every plot.)
To stop the program, type in
APPENDIX 8
COMMENTS FOR SUGGESTIONS AND IMPROVEMENTS
Ocean Drilling Program
Manager of Science Operations
1000 Discovery Drive
Texas A&M Research Park
College Station, Texas 77845-9547
U.S.A.