Laterite of Meyer Lake, Molokai — Sherman et al. 
53 
occur in all of the samples. A much higher 
percentage of free titanium oxide occurs in 
the concretions. The data support the hypo- 
thesis that the primary titanium minerals 
break down in weathering to form a soluble 
form of titanium which is deposited and ac- 
cumulated in concretions by weathering syn- 
thesis mechanism. Analysis by X-ray diffrac- 
tion of similar soils has identified anatase, a 
secondary titanium oxide mineral. Further 
evidence of the occurrence of free titanium 
oxide and the weatherability of the primary 
titanium minerals can be obtained from the 
analysis of these samples for titanium oxide 
and ferrous oxide. The analysis of the surface 
soil of site A showed that this soil contained 
13.7 per cent Ti0 2 . This amount of Ti0 2 
would require 15.1 per cent ferrous oxide to 
form ilmenite. The ferrous oxide content was 
found to be 14.8 per cent, which would mean 
that in this soil most of Ti0 2 would exist as 
ilmenite with a small fraction of free titanium 
oxide. The results of analysis of the surface 
soil of the same sampling site indicate 22.7 
per cent Ti0 2 and 12.5 per cent ferrous oxide. 
The titanium content of this soil would re- 
quire 25.1 per cent ferrous oxide to exist as 
ilmenite. The analysis of the soil shows that 
there is approximately 12 per cent free titan- 
ium oxide. 
The data in Table 3 show a movement of 
iron in this deposit as shown by the high iron 
oxide content of the concretions. The ferric 
iron oxide content of the concretions was 
found to be 68 per cent as compared to a 
much lower content in the soil. The concre- 
tions have accumulated ferric oxide. The de- 
hydrated soil has a higher content of ferric 
oxide than the soil of the hydrated soil area. 
The dehydrated soil and concretions are 
strongly magnetic, and as the concretions 
have a low ferrous oxide content the presence 
of maghemite is suggested. Sherman and 
Kanehiro (1954) reported similar observations 
in the analysis of concretions of the Naiwa 
family on Kauai. 
The derived molecular ratios are given in 
Table 4 for some of the samples of this area. 
The silica to sesquioxide ratio of these sam- 
ples ranged from 0.35 to 1.10 with the highest 
ratio occurring in the sample from the top of 
the slope. The silica to sesquioxide ratio of 
the concretions was found to be very low, 
0.08 and 0.12. The silica to iron oxide (ferrous 
oxide + ferric oxide) ratio was found to be 
similar to the silica to sesquioxide ratio except 
that it was slightly higher. The ratio of ferrous 
oxide to titanium oxide was lower in the 
dehydrated soil area, which indicates that 
titanium oxide increased with dehydration. 
TABLE 4 
The Derived Molecular Equivalent Ratios from Data Given in Tables 2 and 3 to Show 
the Relative Accumulation of Iron and Titanium Oxides 
SAMPLING SITE 
DEPTH 
INCHES 
DERIVED MOLECULAR RATIOS 
Si0 2 
R 2 O 3 
Si0 2 
Fe20.3 
FeO 
Ti0 2 
2 FeO 
Fe 2 0 3 
A 
0- 9 
1.10 
1.28 
1.19 
0.80 
B 
0-10 
0.78 
1.05 
0.78 
0.46 
D — soil 
0-24 
0.67 
0.69 
0.61 
0.26 
D— concretions 
0-24 
0.12 
0.13 
0.46 
0.07 
F — soil 
0-9 
0.84 
1.02 
0.77 
0.49 
F — concretions 
0-9 
0.08 
0.09 
0.33 
0.05 
G 
0-9 
0.35 
0.53 
0.41 
0.16 
H 
0-20 
0.44 
0.66 
0.90 
0.36 
