de Broekert: Stratigraphy and origin of regolith, SW Yilgarn Craton 
Table 1 
Descriptions of lithology for cored boreholes YN41, YN43 and YN45 at East Yornaning. See Fig 2 for locations. 
DEPTH (m) 
DESCRIPTION ROCK UNIT 
Bore YN41 
0-0.5 
Sand; yellow, massive, loose, framework supported, bimodal coarse and fine sand, with framework Gibson 
particles* of poorly sorted, fine skewed quartz and kaolin spherites**; minor rounded quartz in Formation 
coarser size fractions and trace microcline feldspar in finer size fractions and. 
0.5-2.8 
Sandy clay; yellow, massive, poorly indurated, matrix supported, coarse sandy clay, with 
framework particles of poorly sorted, fine skewed quartz and kaolin spherites in a matrix of 
moderately disordered kaolinitic clay, quartz, gibbsite and hematite; common yellow to red 
2.8-5.9 
authigenic ferruginous nodules at base. 
Clayey sand; yellow grading to white at base, massive, poorly indurated, framework supported, 
clayey bimodal coarse and medium sand, with framework particles of poorly sorted, near- 
5.9-9.1 
symmetrical quartz and kaolin spherites in a matrix of highly disordered kaolinitic clay, quartz, vVestonia 
gibbsite and hematite; common reddish brown mottles and yellow, granule-sized, spheroidal to p 0rma ti 0 n 
ovate, authigenic ferruginous nodules above 5.5 m. 
Clayey sand; white, massive, poorly indurated, framework supported, clayey medium sand, with 
framework particles of moderately sorted, near-symmetrical quartz in a matrix of highly disordered 
kaolinitic clay, quartz and gibbsite, diffuse light red mottles at top and dark red, indurated mottles 
and strongly magnetic, authigenic maghemite and hematite nodules at base. 
9.1-10.1 
Sandy clay; white, massive, poorly indurated, framework to matrix supported, coarse sandy clay, 
with framework particles of poorly sorted, fine skewed quartz in a matrix of slightly disordered 
kaolinitic clay and quartz; minor rounded quartz in coarser size fractions. 
10.1-28+ 
Granitic (upper) saprolite; white grading to yellow (goethite stained) at base, massive, poorly 
indurated, matrix supported, coarse sandy clay, with framework particles of moderately to poorly Archaean 
sorted, very fine skewed quartz in a matrix of disordered kaolinitic clay (disorder increasing with basement 
depth) and mica group minerals; quartz grains have remnant granitic fabric and kaolinite occurs a 
millimetre-sized vermiform books. 
Bore YN43 
0-2.4 
Gravelly clayey sand; brown grading to grey at base, crudely stratified, poorly indurated, 
framework supported, granular clayey very coarse sand, with framework particles of moderately to 
poorly sorted, near-symmetrical to fine skewed quartz, feldspar (fresh) and mica in a matrix of 
moderately disordered kaolinitic clay and quartz; occasional rounded quartz, detrital ferruginous 
nodules and angular granitic rock fragments in coarser size fractions. 
2.4-17.2 
Interstratified clayey, muddy and silty sand; grey, massive, poorly indurated, framework supported, 
interstratified clayey coarse sand, muddy bimodal coarse and fine sand, and silty medium to fine i\j ue ndah 
sand. Framework particles typically poorly sorted, near-symmetrical to coarse skewed and composed p 0rma ti 0 n 
dominantly of quartz and feldspar, with feldspar decreasing in abundance and freshness with depth; 
17.2-17.6 
occasional rounded quartz and detrital ferruginous nodules in coarser size fractions. 
Clay; white, massive, poorly indurated, halloysite and kaolinite clay, common sharp red mottles 
17.6-18.4 
and authigenic ferruginous nodules. 
Silty sand; light grey, massive, poorly indurated, framework supported, silty very fine sand, with 
18.4-19.2 
framework particles of moderately sorted, coarse skewed quartz. 
Gravelly clayey sand; light grey, massive, poorly indurated, framework supported, granular clayey 
coarse sand, with framework particles of poorly sorted, fine skewed quartz. 
19.2-23+ 
Granitic saprock; white grading to yellow (goethite stained) at base, massive, poorly indurated, Archaean 
moderately weathered, medium grained, anhedral-equigranular, aphyric, muscovite granite. basement 
Bore YN45 
1-4.2 
Gravelly muddy sand; light grey to brown, crudely stratified, poorly indurated, framework 
supported, fine pebbly muddy coarse sand, with framework particles of poorly sorted, near- 
symmetrical to fine skewed, granule to fine pebble-sized magnetic ferruginous nodules and sand- Nuendah 
sized quartz and feldspar (fresh) in a matrix of moderately disordered kaolinitic clay; occasional Formation 
rounded quartz in coarser size fractions. 
4.2-11.0 
Granitic (upper) saprolite; white to reddish brown, massive, poorly indurated, matrix supported, 
very coarse sandy clay; with framework particles of poorly sorted, fine to very fine skewed quartz 
and mica group minerals in a matrix of slightly disordered kaolinitic clay and goethite; quartz 
11.0-23+ 
grains have remnant granitic fabric; slightly silicified at top. Archaean 
Granitic (lower) saprolite; white to yellow; massive, poorly indurated, matrix supported very basement 
coarse sandy clay, with framework particles of poorly sorted, fine skewed quartz, feldspar 
(weathered) and mica group minerals in a matrix of moderately disordered kaolinitic clay; quartz 
grains have distinct remnant granitic fabric. 
* Framework particles are >63 mm in size; matrix particles <63 mm in size; ** framework particle types listed in decreasing order of 
abundance. 
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