DSDP/X-RAY 6/85 ================================== = DEEP SEA DRILLING PROJECT = = X-RAY MINERALOGY DATA BASE = ================================== I. INTRODUCTION A. BACKGROUND AND METHODS This data set results from x-ray diffraction analyses made by the University of California at Riverside X-ray Mineralogy Laboratory which operated from Leg 1 through Leg 37 under DSDP contract. There are 14,578 individual analyses in the data set. These are distributed among the three sample fractions as follows - Bulk: > 20 microns = 7005 analyses Silt: 20 - 2 microns = 3645 analyses Clay: < 2 microns = 3928 analyses The silt and clay fractions are decalcified with buffered acetic acid and thus calcite and other such minerals will not be found in these fractions. The x-ray data for each of the Legs 1 through 37 is published in the respective Initial Report of the Deep Sea Drilling Project along with useful ancillary information that is not included in the file described here. Because the Riverside laboratory used a variety of methods to assign subbottom depths to the samples, it is recommended that the Initial Reports be consulted whenever it is important to know how down-hole sample positions were determined on a particular leg. B. LEGS IN DATA SET The data set comprises analyses from Legs 1 through 37. Bulk fraction analyses exist for each leg. Legs which do not have analyses for either the silt or the clay fraction are listed below. Silt: No analyses for Legs 1,2,3,5,7,10 and 11 Clay: No analyses for Legs 1,2,3,4,5 and 6 In the Initial Reports there are histograms and other non-numerical presentations for some of the above listed 'missing' fractions. C. REFERENCES The laboratory procedure for the x-ray analyses is discussed in Volume 28 of the Initial Reports of the Deep Sea Drilling Project. For an overview of this data set see G. Ross Heath, 1984. X-ray Mineralogy Studies. In G. Ross Heath (Ed.), Sedimentology, Physical Properties, and Geochemistry in the Initial Reports of the Deep Sea Drilling Project Volumes 1-44: An Overview, World Data Center A for Marine Geology and Geophysics Report MGG-1, pp. 71-91. D. RECORD AND FILE DESCRIPTION The encoded data set is segregated by mineral fraction into three separate files. Each file is written in ascending order by 'DSDP label' (record columns 1-29) in the format described below. An individual x-ray analysis will comprise one or more 120 character length logical records in the following format. Character FORTRAN Position Format Field Content ========= ======= ============= 1- 2 (A2) leg number 3- 6 (A4) hole 7- 9 (A3) core 10- 11 (A2) section designator or blank field 12- 19 (F8.2) subbottom depth (M) of top of sample interval or top of cored interval 20- 27 (F8.2) subbottom depth (M) of bottom or middle of sample interval 28 (A1) fraction: B=bulk,S=silt,C=clay 29 (I1) relative position of record in sample: 0 = lead record segment 1,2,.. = following record segments (as needed) 30 (1X) blank field 31- 32 (I2) number of minerals in sample 33-120 11(A4,F4.1) mineral mnemonic/weight percent couplets for those minerals occurring in sample(i.e., zero percentages do not occur). Note: The mnemonic/percentage couplets occurring in columns 33-120 will usually begin with the mnemonics DIFF and AMOR for the analyses from Legs 10 through 37. Although these are not minerals themselves (see table below), they are included in the total mineral count of an analysis as given in columns 31-32. The percentages attached to the actual minerals are weight percents relative to the particular sample and fraction, but for some analyses these values have not been normalized to 100 percent. Despite the fact that percentages are written to 1/10 of 1 percent, this data set must be viewed as semiquantitative. In some cases, percentages are negative to indicate one of the following relative abundance codes. -5.0 = TRACE -25. = PRESENT -65. = ABUNDANT -99. = MAJOR In addition, a mineral weight percentage may be given as "100." to indicate 100%. E. X-RAY MINERAL MNEMONIC LIST: Inventory of DSDP/UC Riverside X-ray Minerals Over All Legs and All Fractions (ordered by frequency of occurrence) Four Character Mineral Mnemonic No. of Occurrences ======= ======== ================= 'diffuse scattering' measure DIFF 10192 'amorphous material' measure AMOR 10171 QUARTZ QUAR 11999 MICA MICA 9160 PLAGIOCLASE PLAG 9059 MONTMORILLONITE MONT 7546 CHLORITE CHLO 5420 CALCITE CALC 4942 KAOLINITE KAOL 4911 K-FELDSPAR K-FE 4635 CLINOPTILOLITE CLIN 2389 PYRITE PYRI 2017 BARITE BARI 1611 PALYGORSKITE PALY 1402 AMPHIBOLE AMPH 1148 PHILLIPSITE PHIL 1145 CRISTOBALITE CRIS 829 DOLOMITE DOLO 762 AUGITE AUGI 579 GOETHITE GOET 371 MAGNETITE MAGN 352 TRIDYMITE TRID 349 GYPSUM GYPS 329 HALITE HALI 305 ANALCITE ANAL 296 HEMATITE HEMA 257 ARAGONITE ARAG 177 ANATASE ANAT 175 SIDERITE SIDE 135 FELDSPAR (undifferentiated) FELD 98 APATITE APAT 75 GIBBSITE GIBB 62 SEPIOLITE SEPI 43 SANIDINE SANI 29 RHODOCHROSITE RHOD 28 MAGNESIAN CALCITE MGCA 26 CALCIUM DOLOMITE CADO 25 MIXED LAYER CLAY MIXL 20 BEIDELLITE BEID 16 TALC TALC 8 ANHYDRITE ANHY 6 "variety of MONTMORILLONITE" 2-MO 6 ILMENITE ILME 5 ERIONITE ERIO 4 CHABAZITE CHAB 3 CUPRITE CUPR 3 CELESTITE CELE 2 PSILOMELANE PSIL 2 BASSANITE BASS 1 SPHALERITE SPHA 1 ILLITE ILLI 1 "UNKNOWNS" U- 1 285 U- 2 117 U-1 116 U-2 116 U-10 66 U- 4 55 U- 3 53 U-11 44 UNKN 16 U- 5 9 U-12 6 U- 6 5 U- 7 3 U- 9 3 U- 8 2 NGDC NOTES: (list of deviations from field descriptions) Please note that additional xray mineralogy data are described in "xrdwhoi" documentation. Description of deviation Record Number(s) ======================================= ================ Weight percentage: col 45-48 6130,6132-6144,6147,6166,6169, - negative weight percentages given 6171,6173,6175,6189-6195,6200, are not legal relative abundance 6235-6251,6570,6626,6660 codes as described in documentation Mineral weight percentage does not total 157,302,369,377,1245,1570,1588, to one hundred 1602,1609-1610,1619,1853-1854, 1896,1909,1912,1929,1999,2323, 2356,2383,2404,2475-2477,2732, 2876,3278-3687,3689-3713,3715- 4195,4197-4296,4298-4306,4308- 4309,4311-4371,4374-4381,4383- 4434,4436-5257,5259-5264,5268, 5270-7167 DSDP/X-RAY 6/85