THE I[RON-FORMATION ON BELCHER ISLANDS 
This algal limestone is also well 
exposed on the mainland just north of 
the mouth of Great Whale River, where 
it lies directly on) thie Mauren tian 
granites. 
GEOLOGICAL STRUCTURE 
The structure of the islands is, on 
the whole, simple. The rocks have 
been folded into large pitching anti- 
clines and synclines, with dips varying 
from 75 to almost zero and with com- 
paratively few minor folds. The heavy, 
igneous flows and sills have had some 
influence on the control of the structure, 
as seen in the accompanying structure 
section (Fig. 2). The general strike is 
nearly north and south, showing that 
these rocks were squeezed up against 
the land mass along the eastern side of 
the basin in which they were deposited, 
probably because of a settling of the 
central portion of the Hudson Bay 
basin. They are more steeply folded 
than the rocks which occur along the 
coast of Hudson Bay, from Cape Jones 
beyond Richmond Gulf, and which form 
the chain of islands skirting the shore 
in that region. 
THE IGNEOUS ROCKS 
The Tookcarak diabase and basalt 
bear a remarkable resemblance to the 
Keweenawan basic rocks of the Lake 
Superior region. Like those rocks, they 
are extremely monotonous in texture 
and composition. In some places they 
carry an abundance of pyrite, and 
WS 
SSS 
sss 
SS: 
RE 
BSS \ 
TNs We 
~~? 
~\ 
Sy 
a: 
ae 
SSS 
Say 
SS 
A 
(THE BELCHER SERIES) 
loo 7 > if SSS 
epalce ren formation; FE Red and winle ) «y., PEIEe| 
SEDIMENTA. 
l6nfous Rocks 
Jookcarak basan 
eal rerrerae 
kaseealick Lake EASTWARD To THE SEA 
Abal imestone STRUCTURE SECTION ACROSS A PORTION OF THE BELCHER /SLANDS FROM 
Y Scale: (erizentally: /-inch=1-Mile 
ROCKS 
hoe 
I Silicified and shal 
ET 
Ee Graywacke and slate {1 
Te 
stone 
While To gre fi 
Peat alee 
47 
2.—Geological structure section across a portion of the Belcher Islands 
Fic. 
