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Core data from the Ocean Drilling Program legs 101-129
ODP hard-rock thin section description - verbose form
leg : 109 section: 01 unit/subunit : 0001
hole: 669A top int: 007 cm observer code: DIV
core: 001D pieces: 001
rock name: Aphyric basalt
texture: Variolitic to microlitic
where sampled: Unit 1, pillow or flow interior,(cont.)
grain size: Fine
***** PHENOCRYSTS *****
Olivine present % Tr original % Tr size 0.3-0.6
morphology : Subhedral
***** GROUNDMASS *****
Radiating. Associated with rare ol nucleus of plag. L/W = 10-30.
Plagioclase present % 29 original % 29 size 51
****** VESICLES *****
Type: Vesicles %: 1.5
shape : Rounded to irregular
Miaroles in alteration halos are more commonly filled with clays than the
vesicles. Empty in fresh mesostasis.
****** SECONDARY MINERALIZATION ******
mineral name: Clays percent: 2
replacement: Mesostasis
comments : Yellow birefringent clay.
****** OVERALL COMMENTS ******
WHERE SAMPLED CONTINUED: cut perpendicular to dark halo. SECONDARY MINERAL
COMMENTS CONTINUED: Opaque Fe hydroxide; Occurs as central parts of two or three
miarole linings. Point count of halo zone; 26 yellow clay (5%), 7 red Fe
hydroxides (1.5%), 1 opaque Fe hydroxide (Tr), and 466 primary phases. Central
zone (fresh); Traces of orange to red Fe hydroxide, mainly near vesicle walls.
Radiating aggregates of aragonite (biaxial, low 2V, extreme birefringence) in
large (5 mm), irregular miarole (also containing hopper ol). This and a smaller
aragaonite-filled miarole are in connection with the halo zone. MAIN COMMENTS:
Rare ol phenocrysts are rather microphenocrysts. Mesostasis is cryptocrystalline
to microcrystalline with plag,cpx and ol microlites. this section might represent
a coarser equivalent of Section 669A-1D-1 (Piece 2, 11-13 cm).
ODP hard-rock thin section description - verbose form
leg : 109 section: 01 unit/subunit : 0001
hole: 669A top int: 011 cm observer code: DIV
core: 001D pieces: 002
rock name: Aphyric basalt
texture: Intergranular (felty)
where sampled: Unit 1, pillow or flow interior
grain size: Microcrystalline to fine
***** PHENOCRYSTS *****
Olivine present % 0.5 original % 0.5 size 0.2-0.4
morphology : Euhedral-subhedral
comments : Some embayment. Some glass inclusions.
***** GROUNDMASS *****
Radiating, swallow tail.
Olivine present % 5 original % 7 size <0.1
****** VESICLES *****
Type: Vesicles %: 2
filling : Clays, Fe hydroxide
shape : Rounded or irregular
****** SECONDARY MINERALIZATION ******
mineral name: Clays percent: 3
replacement: Vesicles, miaroles, ol, cpx
comments : Yellow. Replaces olivine and
clinopyroxene (staining).
****** OVERALL COMMENTS ******
groundmass continued: Segregation vesicle, % present = Tr, % original = Tr, size
= 0.2-0.5 mm, morphology = rounded, comment = mostly devitrified glass.
ODP hard-rock thin section description - verbose form
leg : 109 section: 01 unit/subunit : 0001
hole: 669A top int: 011 cm observer code: DIV
core: 001D pieces: 002
rock name: Aphyric basalt
texture: Spherulitic to variolitic
where sampled: Unit 1, pillow or flow interior
grain size: Microcrystalline
***** PHENOCRYSTS *****
Olivine present % Tr original % Tr size -2.5
morphology : Anhedral
comments : Yellow hydroxide attached to the phenocryst.
***** GROUNDMASS *****
Morphology continued: acicular. COMMENTS: Radiating. Associated with cpx or
attached ol.
Plagioclase present % 34 original % 35 size <0.6
****** VESICLES *****
Type: Vesicles %: 2
filling : Fe hydroxide
shape : Irregular
****** SECONDARY MINERALIZATION ******
mineral name: Fe hydroxide percent: 2
replacement: Vesicles, mesostasis
comments : Yellow to reddish brown. Associated with
plag, cpx, and ol or randomly distributed
in the groundmass. The granules are
attached to the crystals or interfingered
with cpx.
****** OVERALL COMMENTS ******
Actual interval is from 11-13 cm, however the preceeding thin section had the
same ID. Ol phenocrysts are in fact microphenocrysts. These are, however,
different from quenched ol grains. Mesostasis is cryptocrystalline with
recognizable cpx and plag in a radiating pattern. Segregation vesicles consisting
of minute crystals of plag + cpx + cryptocrystalline material constitute
approximately 1% of the rock.
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These Web pages are from the Core Data from the Ocean Drilling Program Legs 101-129 CD-ROM produced in 2001 by the U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Environmental Satellite, Data, and Information Service, National Geophysical Data Center, and collocated World Data Center for Marine Geology and Geophysics, Boulder. Data were compiled in cooperation with the U.S. Science Support Program, the Joint Oceanographic Institutions, Inc., and the U.S. National Science Foundation. Please see the NGDC privacy, disclaimer, and copyright notices. Additional ocean drilling data are available from NGDC and from the ODP/IODP.
questions to: carla.j.moore@noaa.gov