- 89 -

Uranium Metallogenic Studies: Clay Mineral Distribution in the Athabasca Group, Southwest Part of the Basin

by J. Hoeve1, 0. Quirt1 and D. Alonso 2

])Jring the past few years we have conducted a program to study the relationships between Athabasca Group diagenesis and host rock alteration in unconformity-type uranium deposits. Clay mineral distribution and diagenetic patterns in the Athabasca Group have been corrpared with clay mineral host rock alteration at individual deposits (Ibeve et al., 1981, a, b; Ibeve, in press).

The application of clay mineralogy to stratigraphic interpretation has been demonstrated (Ibeve et al., 198la) and in this article we report on the clay mineral stratigraphy in the little-known southwestern corner of the Athabasca Basin.

!Saskatchewan !Esearch Council, Saskatoon. 2AMQK Exploration Ltd •

• - .. ____ _,

... Figure 1 - Location of drillholes and cross-sections.

Clay Mineral Stratigraphy

Core samples were taken at 5 to 10 m intervals fran several drillholes located to the south, east and north of the Carswell strix::ture (Fig. l; drillholes ASl, AS2, CAR 114, BM-1 and CSPl0-1). 'I.be interstitial clay of these rocks was found to consist of the same mineral species as reported for other parts of the Athabasca Basin (i.e. varying proportions of kaolinite, illite and di, trioctahedral chlorite (sudoite)).

Using previously established correlations (Ibeve et al., 19Bla), the clay mineral logs for these drillholes can be subdivided into distinct lithostratigraphic units (Figs. 2, 3, 4, 5 and 6).

- 90 -

CAR-T 14 -sst. CRo I I ing Mean)

0

LL+OF i

-200 .. ~

WPb c -400 ..

WP a K

-600 ..

-800 ..

LzL I

-1000 ..

-1200 ..

L_. __ _ - 1 400 .. L---- ----''----

0 50 100 0 5 10 15 Figure 2 -.Clay minernl log of drillhole CAR 114. Clay composition: K, kaolinite; I, illite; C, chlorite. Athabasca Group stratigraphy: FPa, b, Fair Point Formation a and b; MF a, b, c, d, Manitou Falls Formation a, b, c and d; Lzl, Lazenby Lake Formation; WPa, b, Wolverine Point Formation a and b; LL. Locker Lake Formation; OF, Otherside Formation.

In drillhole CAR 114, located to the east of the carswell structure, the Manitou Falls and Fair Point Formations are ixlth absent and, instead, 600 m of Lazenby Lake Fonnation is found underlying the lower Wolverine Point Formation. In drillhole AS!, to the south of the carswell stucture, 350 m of Lazenby Lake Formation is sandwiched between the Wolverine Point Formation and a thin 100 m intersection of Fair Point Formation, whereas A.52, though not reaching basement, intersects 400 m of Lazenby Lake Formation before terminating in this unit. In drillhole BM-1, the Lazenby Lake Formation is absent and the lower Wolverine Point Formation is directly underlain by upper Manitou Falls Formation. In the previously reported drillholes CSP2-l and IAJV-2 (aaGE:2), located to the north and northwest of the carswell structure, the Lazenby Lake Formation is present as a poorly defined, 100 m thick interval between the lower Wolverine Point and either the Fair Point or Manitou Falls Formations. In drillhole CSP8-l, the Lazenby Lake Formation does not appear to be present, whereas farther to the southeast in drillhole CSPl0-1, which does not reach basement, it is at least 200 rn thick.

These relationships indicate that the Lazenby Lake Formation is restricted to the Jackfish sub-basin of Ramaekers (1980) and forms a thick wedge which undergoes rapid northeastward thinning over the Patterson High (Figs. 7 and 8). 'Ihe Lazenby Lake Formation occurs between the Fair Point and Manitou Falls Formations, against which it onlaps to the west, north and east. 'Ihis interpretation is consistent with Ramaekers' (1980) observation of increasing grain size towards the southwest, indicating sediment transport from that direction.

We here propose that the Lazenby Lake Formation is stratigraphically equivalent to the Fair Point Formation in the west and to the Manitou Falls Formation in the north and east. 'Ihis equivalence further supports Ramaekers' (1980) argument for correlation of the Fair Point and Manitou Falls Formations.

lcknowledgements

We wish to thank Marline Oil Ltd. and Bonn Energy corporation for pennission to publish the logs for drillholes AS! and AS2.

- 91 -

AS1 -ssl (Ro! I ing Mean) 0

WP K c

-100.

-200 .. Lzl

I

-300 ..

-400 ..

FPb K

- '-------._ - - - - --s00 .. ~ ___ ___,._ ___ ___..__ ___ __,

0 50 100 0 5 !0 15

CLAY COMPOSITION KUBLER INDEX

Figure 3- Clay mineral log of drillhole AS1. See Fig. 2 for explanation of symbols.

References

Hoeve, J. {in press): Clay mineral host rock alteration and its application as an ore guide at the Midwest uranium deposit, northern Saskatchewan; C!M Bull.

Hoeve, J., Rawsthorne, K. and O,Jirt, D. (198la): Uranium metallogenic studies: clay mineral stratigraphy and diagenesis in the Athabasca Group; in Surnnary of Investigations 1981, SasiZ:" Geol. Surv., Misc. Rep. 81-4, p. 76-89.

Hoeve, J., Rawsthorne, K. and Quirt, D. {198lb): Uranium metallogenic studies: Collins Bay B Zone, II. clay mineralogy; in Surnnary of Investigations 1981, Sask. Geol. Surv., Misc. Rep. 81-4, p. 73-75,

Ramaekers, P. {1980): Stratigraphy and tectonic history of the Athabasca Group (Helikian) of northern Saskatchewan; in Sunmary of Investigations 1980, Sask.­Geo!. Surv., Misc. Rep. 80-4, p. 99-106.

- 92 -

AS2 -ssl (Roi I ing Mean) 0

WP a K

-100.

-200.

Lzl I

-300.

-400.

-500.

-600.---~~~_,_~~~~"--~~~~ 0 50 100 0 5 10 15

CLAY COMPOSITION KUBLER INDEX

Figure 4 - Clay mineral log of drillhole AS2. See Fig. 2 for explanation of symbols.

- 93 -

BM-1 -ssl (Roi I ing Mean) 0

LL+OF I

-200 .. WPb

-300 ..

WP a -400 ..

-500 ..

MF c-t--d -600 ..

-700 ..

-800 .. ~~~~'---~~----''-----~~---l

0 50 100 0 5 10 15

CLAY COMPOSITION KUBLER INDEX

Figure 5 - Clay mineral log of drill hole BM-1. See Fig. 2 for explanation of symbols

- 94 -

CSP 10- l (Roi I ing Heon) -ssl

0

LL+OF

-100-

WPb

- 200..,

I

-300-

Lzl

-400-

-500-,__~~ ~_..._~~~-L-~ ~~-' 0 50 100 0 5 10 15

CLAY COMPOSITION KUBLER INDEX

Figure 6 - C lay mineral log of dri llhole CSP10- 1. See Fig. 2 tor explanation of symbols.

see

e

-sea

-seea

see

-see

-1e

-,, .. -• I!

• -... -1

A

B

B

SB 100

kl loa•tree

J, 0. Ill u

I u,

0.

l1

- 95 -

I :c ID

A'

Figure 7 - Interpreted clay mineral strat igraphy, section A-A' (Fig. 1).

-I II)

0.. Ill u

I cg

B'

Figure 8 - Interpreted c lay mineral stratigraphy, section B-B' (Fig. 1).