DSDP Screen 4/87 =============================== = DEEP SEA DRILLING PROJECT = = SCREEN DATA BASE = =============================== I. INTRODUCTION A. BACKGROUND AND METHODS The SCREEN file contains computer-generated lithologic classifications of the sedimentary material collected by the Deep Sea Drilling Project (DSDP). The computer program outlined in Davies et al., 1977, uses a modified deep-sea sediment classification scheme developed by the JOIDES Advisory Panel on Sedimentary Petrology and Physical Properties (van Andel et al., 1973). The file provides the user with a standardized lithologic data base. The file also contains information on basic composition, average density and porosity, geologic age and the shipboard observer's lithologic description. B. LEGS IN DATA SET The data set currently contains data for legs 1-96; C. BIBLIOGRAPHY Davis, Thomas A., Musich, Lillian F. and Woodbury, Peter B., 1977, Automated Classification of Deep-Sea Sediments: Journal of Sedimentary Petrology, Vol. 47, No. 2, June 1977, pp. 650-656. Supko, Peter R., Perch-Nielsen, Katharina, and Carlson, Richard L., 1977. Introduction and Explanatory Notes, Leg 39. Deep Sea Drilling Project, Appendix A - Classification of Sediments. In Supko, P.R., Perch-Neilsen, K. et al., 1977. Initial Reports of the Deep Sea Drilling Project, Volume 39. Washington (U.S. Government Printing Office) pp. 19-24. van Andel, T.H., Winterer, E.L., and Duncan, J., 1973, Report of subcommittee on sediment classification, of advisory panel on sedimentary petrology and physical properties: Unpublished JOIDES Report. II. FORMAT AND FIELD DESCRIPTIONS A. DATA FORMAT Record length is 240 characters COLUMN FIELD FORMAT ====== ============================================ ====== 1-2 LEG A2 3-5 SITE A3 6 HOLE A1 7-9 CORE A3 10-11 SECTION A2 12-15 TOP INTERVAL DEPTH (cm) (implied decimal pt) F4.1 16-19 BOTTOM INTERVAL DEPTH (cm) (implied decimal pt) F4.1 20-26 TOP OF LAYER (meters) F7.2 27-33 BOTTOM OF LAYER (meters) F7.2 34-40 THICKNESS OF LAYER (meters) F7.2 41-70 LITHOLOGY CODE A30 71-78 PROCESSING HISTORY FLAG A8 79-138 LITHOLOGY NAME FROM SCREEN PROGRAM A60 139-198 LITHOLOGY NAME FROM SHIPBOARD OBSERVER A60 199-202 AVE. CALCAREOUS MATERIAL ** see note below I4 203-206 AVE. SILICEOUS MATERIAL ** see note below I4 207-210 AVE. DETRITAL MATERIAL ** see note below I4 211-216 AGE MNEMONIC AT TOP OF LAYER A6 217-222 AGE MNEMONIC AT BOTTOM OF LAYER A6 223-230 AGE CODE I8 231-234 AVERAGE DENSITY FROM G.R.A.P.E. F4.2 235-237 AVERAGE POROSITY FROM G.R.A.P.E. I3 238-240 NUMBER OF G.R.A.P.E. MEASUREMENTS AVERAGED I3 NGDC Note: original documentation file lists these fields as normalized to 100%. The fields are not normalized. B. FIELD DESCRIPTIONS The definition of leg, site, hole, core and section may be found in the explanatory notes. In addition, the special core designations, as well as the methods of sample labeling and calculating absolute sample depths are discussed. INTERVAL DEPTH: Refers to the depth in centimeters within a section to the top or bottom of a lithological layer (see TOP AND BOTTOM OF LAYER). Values are encoded with an implicit decimal point. TOP AND BOTTOM OF LAYER: The distance in meters from the ocean floor to the top or bottom of a layer. Layer is defined to be a lithological unit confined within a single core section. Since a layer has a maximum thickness of a single section, the data base provides at least one record per section. THICKNESS OF LAYER: The layer thickness is equal to the bottom layer depth minus the top layer depth. The layer thickness is limited to the length of the section. LITHOLOGY CODE: The SCREEN lithology code is devised to provide information on a sample's basic lithology, its primary component and any modifying components. A sample's basic lithology code (digits 1-4) is constructed according to the outline shown below. A primary component code (digits 5-8) is added as long as the major component represents at least half of the aggregate total of components within its class. For example if the basic lithology of a sample was 70% siliceous, radiolarians would have to make up at least 35% of the sample in order for them to be encoded as the primary component. Any other components (greater than 10%) are encoded, in descending order, as four-digit modifying component codes. The modifying component codes are separated from the primary component code and each other by decimal points. An example of how these codes are combined to from a SCREEN code may be useful. Consider the sample above which was found to be 70% siliceous, and was 35% radiolarians. In addition, the basic lithology was described as being transitional, monogenic and soft. Following the outline below the sample would be given 2211 as its basic lithology code. Since radiolarians make up at least 50% of the components within its class (35% of a 70% siliceous sample). The code for radiolarins (2210), taken from the code list below, would be appended to the basic lithology code. The SCREEN code at this point would be 22112210. If the same sample was then found to contain both biotite (15%) and feldspar (11%) the code would contain modifying component codes. The codes for biotite (3402) and feldspar (3320) (separated by a decimal point) are appended to the SCREEN code above. The complete SCREEN code for this sample is 22112210.3402.3320. BASIC LITHOLOGY CODE ===================================== Digit 1 designates : calcareous = 1 siliceous = 2 detrital = 3 Digit 2 designates : pelagic = 1 transitional = 2 terrigenous = 3 Digit 3 designates : monogenic = 1 heterogenic = 2 Digit 4 designates : soft = 1 firm = 2 hard = 3 MODIFYING COMPONENT CODES ===================================== CODE ABBREV COMPONENT ==== ====== ====================== 1999 UNCOMP MYSTERY COMPONENT 1450 ALGAE ALGAE 3909 ALTERI ALTERITE 3614 AMPH AMPHIBOLITE 3915 AMOROX AMORPHOUS OXIDE 3351 ANAL ANALCITE 3629 ANATASE 3151 ANHYD ANHYDRITE 3608 APAT APATITE 1140 ARAGON ARAGONITE 3601 AUGITE AUGITE 1100 AUTCAR AUTHIGENIC CARBONATE 3902 AUTCRY AUTHIGENIC CRYSTAL 2100 AUTSIL AUTHIGENIC SILICA 3251 BARI BARITE 3710 BASALT BASALT 3402 BIOTIT BIOTITE 1440 BRYOZO BRYOZOA 1420 CALSPI CALCAREOUS PICULE ??? 3872 CARBON FRAGMENT 2110 CHALC CHALCEDONY 2130 CH FRA CHERT FRAGMENT 3870 CHIT CHITTANOZOA 3450 CLAMIN CLAY MINERAL 3202 COLLOP COLLOPHANE 1430 CORAL CORAL 3312 CRISTO CRISTOBALITE 3911 DETMAT DETRITAL MATERIAL 3912 DETMIN DETRITAL MINERAL 2220 DIAT DIATOM 3622 DIOPSI DIOPSIDE 1130 DOLOMI DOLOMITE 3612 EPID EPIDOTE 1000 ESTCAR ESTIMATED CARBONATE 3552 FE IRON 3871 FECPEL FECAL PELLET 3320 FELD FELDSPAR ???? 3113 FLUORITE 1221 FORAMS FORAMINIFERA 3852 FSHDEB FISH DEBRIS 3607 GARNET GARNET 3651 GLAS GLASS 3501 GLAUC GLAUCONITE 3626 GLAUPH GLAUCOPHANE 3152 GYPSUM GYPSUM 3153 HALITE HALITE 3613 HORNBL HORNBLENDE 3600 HVYMIN HEAVY MINERAL 3621 HYPERS HYPERSTHENE 3453 ILLITE ILLITE 3555 ILMENI ILMENITE 3752 ISOAG ISOTROPIC SILVER 3906 ISOMIN ISOTROPIC MINERAL 3611 KYANIT KYANITE 1410 LAMELI LAMELLIBRANCH 3901 LIMNIC LIMNIC 3553 LIMONI LIMONITE 3754 MAGNSM MAGNESIUM 3554 MAGNET MAGNETITE 3751 MANGAN MANGANESE 3903 MESOST MESOSTASIS 3400 MICA MICA 3904 MICAGG MICROGRANULAR AGGREGATE 3905 MICPHE MICROPHENOCRYST 3910 MICRON MICRONODULE 3753 MOLYBD MOLYBDENUM 3201 MONAZI MONAZITE 3452 MONTMO MONTMORILLONITE 1210 NANNOS NANNOFOSSIL 3634 OLIVIN OLIVINE 1120 OOLITE OOLITE 2120 OPAL OPAL 2240 OPALPH OPAL PHYTOLITH 3903 OPMESO OPAQUE MESOSTASIS 3550 OPMINR OPAQUE MINERAL 3850 ORGDEB ORGANIC DEBRIS 1460 OSTRCO OSTRACOD 1110 OTHCAR CARBONATE 2300 OTHPAL OTHER FOSSIL 2000 OTHSI OTHER SILICEOUS 3652 PALAG PALAGONITE 3200 PHOPHT PHOSPHATE 3203 PHOSPH PHOSPHORITE 3851 PLDEBR PLANT DEBRI 1300 PTEROP PTEROPOD 3711 PUMICE PUMICE 3551 PYRITE PYRITE 3652 PYROXE PYROXENE 3311 QTZ QUARTZ 2210 RADS RADIOLARIA 3112 RDSCHRO RHODOCHROSITE 3800 ROCFRA ROCK FRAGMENT 3604 RUTILE RUTILE 3712 SCORIA SCORIA 3500 SERPEN SERPENTINE 3111 SIDERI SIDERITE 2230 SIFLAG SILICOFLAGELLATE 2200 SIFOSS SILICEOUS FOSSIL 3620 SILMAN SILLIMANITE 3628 SPHALE SPHALERITE 3616 SPHENE SPHENE 3907 SPHERU SPHERULITE 2310 SPICUL SPICULE 3627 SPINEL SPINEL 3609 STAURO STAUROLITE 3250 SULFID SULFIDE 3908 TERDET TERRIGENOUS DETRITUS 3615 TOPAZ TOPAZ 3606 TOUR TOURMALINE 3623 TREMOL TREMOLITE 1200 UNICAL UNIDENT CALC FOSSIL 3000 UNMINS UNIDENTIFIDED MINERAL 3705 VOLCANIC CLAY 3700 VOLFRA VOLC MATERIAL FRAG 3350 ZEOL ZEOLITE 3605 ZIR ZIRCON 3617 ZOISIT ZOISITE PROCESSING HISTORY FLAG: This field contains one of the processing history flags listed below. #UNCLAS# = Unclassified: Classification failed for unspecified reasons. Usually due to a lack of data. ##NSMR## = No Smear: Classification failed because no smear slide data exists. *SCREEN* = Classification was successful. *PRECODE = Precoded data: Data was incomplete but interpretation allowed manual encoding to be done. Classification was successful. **INF*** = Inferred code: The lithologic code was inferred from the surrounding layers. Classification was successful. PERCENT MATERIAL: The relative percents of calcareous, siliceous and detrital material. See Smearslide documentation file for details. (NGDC Note: DSDP documentation indicates that these values are normalized to 100%, they have not been) AGE MNEMONIC: An abbreviation of the age assigned to that depth in the hole. AGE CODE: An eight digit hierarchical age code which represents the age that has been assigned to that depth. The age code glossary is available as a separate data base. The glossary contains the numeric age codes, age names and age mnemonics used by DSDP. The numeric code is designed to provide age level information as shown below. CODE DIGIT AGE LEVEL ========== ========= 1 ERA 2-3 PERIOD 4 SUBPERIOD 5 EPOCH 6 SUBEPOCH 7 STAGE 8 SUBSTAGE G.R.A.P.E.: Stands for Gamma Ray Attenuation Porosity Evaluator. The DSDP maintained the G.R.A.P.E. as a separate data base. NGDC NOTES: (list of deviations from field descriptions) In addition to the deviations listed, much editing was done to the component code fields to correct non-4-digit codes. This editing was done in consultation with DSDP data management staff and checked carefully. However, the "Lithology name from SCREEN program" field was NOT modified, so that field may be more general than the new, edited component codes, although it will not differ other than in its specificity. Age codes were also modified in consultation with DSDP staff where even numbers were found embedded within the codes. The even numbers were originally interpolations when the age was unclear, which were later to have been replaced by zeros from the unclear position all the way to the right-most digit of the age code. Codes within SCREEN were modified to follow this rule. Description of deviation Record Number(s) ======================================= ================ Section number may be out of sequence 26388,69945,81126,91752 Bottom interval depth is 0, top is not?? 1842,1847,1848,1930,1935,1936, or top depth exceeds bottom depth 1938,1940,17425,36230 DSDP Screen 4/87