Table
T4. Basement unit thicknesses and general characteristics and
criteria used for defining unit boundaries, Hole 1187A.
Unit/
Subunit
Thickness
(m)
Characteristics
Unit top
defined by
192-1187A:
1
8.22
Pillowed
First
appearance of basalt (below white chalk and brown claystone)
2A,
2B
0.05
+ 1.61
Pillowed
Recrystallized
limestone containing altered glass clasts (5-cm piece: Subunit 2A)
3A,
3B
0.04
+ 41.23
Pillowed
Recrystallized
limestone with minor hyaloclastite (3-cm piece: Subunit 3A)
4
5.41
Pillowed
Hyaloclastite
(11-cm interval)
5
19.4
Pillowed;
contains one cooling unit that is 2.43 m thick
Hyaloclastite
(13-cm interval)
6
29.99
Pillowed
(upper ~19.5 m) and massive (lower ~9 m)
Interval
dominated by hyaloclastite (57 cm) with minor aphanitic basalt pieces
7
3.86
Small-scale
pillowed cooling units (upper 0.9 m) overlying a 3-m-thick cooling unit
Downward
change from massive cooling unit to pillowed cooling units
8
5.02
Pillowed
Downward
change from large-scale (massive?) cooling unit to small-scale pillowed
cooling units
9
0.7
Pillowed;
only one pillow present
Hyaloclastite
(22-cm interval)
10
2.48
Pillowed
Hyaloclastite
(15-cm interval)
11
16.46
Pillowed;
contains one cooling unit that is 2.23 m thick
Hyaloclastite
(11-cm interval)
12
>6.86
Pillowed
Hyaloclastite
(17-cm interval)