The Salt Lake tribune. [volume] (Salt Lake City, Utah) 1890-current, 1910-10-18
SAN JUAN FIELD
REPORTED UPON
William T. Macdonald Visits
Utah Section for Salt Lake
interests.
REPORT
HAS BEEN PREPARED
Detailed Description of Region
Which Promises Much TO
the State.

|
heids has been prepared and submitted
10 number Of prominent Salt Lakcrs
| ny William T. Macdonald the well known
mining engineer, who has made an en-
| hauslivo examination OF the section in
! question for tho local interests men,
| TONED. portion OF this report is here
given In the realization that the geology
OF the field and Mr.. MacDonald's con-
clusons will prove very timely for n
great many who have already invested,
or plan 10 invest. heavily in the devcl-
opment OF what looks like q coming rich
| oil production section
Without access 10 literature and
| scientific appliances not obtainahle by
| mo in the field. II would he unwise to
| attempt really accurate and authorita-
| tivc geological classification of the va
| rious formations exposed" SAYS the re-
| port. "a brief and general description
OF the topography, and the essential geo
| logical features Will not bc out OF place,
| however. In the immediate vicinity OF
| Blun the same thick and nearly hort
| zonial scdimcntary deposits Of reddish
sandstoncs that have been noted Tor
| much OF the way along the stage jour
ncy from Cortez are SIN In evidence.
Proceeding from Bluff. on the road
| into the fields. this same even forma-
| tlon continues without an apparent break
OF any kind for distance Of. perhaps
| encountered. Here has occurred a tre-
| mendous disturbance and upheaval Of the
| earths crust, resulting in the formation
| OF the above mentioned ridge, which Is
several hundred feet In height. and eX-
| tends for many miles In a northerly and
| southerly direction. The strata are here
| stecply tilted, crumnlcd and broken, and
a gigantic iaulting has taken place along
the noriherly and southerly axis Of the
| ridge. The vertical displacement OF the
| strata amounts To certainly several hum
4
feet. and brings to a surface exposure
formations which have hitherto been
deeply buried. llmcstoncs here appear
in great profusion. The lowest forma.
| ton made visible probably belongs TO
the carboniferous age, although the Up
per Devonian may possibly he reached
Passing from here on down the river.
one soon enters the eastern limits of what
is at present claimed TO be the proba
bic oil producing territory. The district
included within the limits Of the oil
broadly described as what was once all
| almost horizontal plateau region, now
bent into a series of enormous anti
clines trendinS generally northerly and
and sloping gently. perhaps so 10 100
feet per mile but in places attaining
considerable steepness. In no place
that observed was there any evidence
Of sufficient abrupt vertical displacc-
ment to be the result OF faulting
Most of the drilling that has been
done thus far has been confined to the
eastern slope OF the second antlcline. pro-
cecding westward from Comb ridge. Some
few wells have been drilled or arc now
being drilled in the syncline al the cast
ern limit of this anticline.
"Thc first anticline encountered after
leaving Comb ridge approaches more
nearly 10 being a. quaquaversal dome
than il does simple antclne. as an
examination shows the strata on every
side to be tilted upward and extending
smoothly over The top Of the dome. eN-
cepting where cut through by surface
erosion. This dome probably measures
some five by ten miles in extent, and
is cut sduarely through some distance
north of its center by the canyon OF the
San Juan river,
aside from antclinal folding here
noted. the otherwise horizontal stratif
cjtion Of the entire district is practl-
cally undisturbod, and the region is at
a considerable distance from any prcmi
ncnt range Of mountains. Under these
conditions. a possible explanation as 10
the cause OF this anticlina structure
would be the probable presence of under
lying laccollthe OF isncous rock which
surface erosion has yet not brought
to light and which. when injected into
the lower formations. caused the local
upward bulsing OF the everything strata.
This theory receives partial support from
! the fact that on the south side OF the
river and little to the west OF Good
ridge. there is d bold outcropping of a
dark greenlsh. igncous rock, known To-
cally as the Alhambra. j visited this
locality. but did not have time TO ac-
tually reach the AhaElbra itself. and
could detect no signs OF any serious or
extensive disturbances resulting from its
presence. II mny have been an igneous
the overlyng and semi plastic scdi-
mentary deposits, or IL may he the top
: Of some old submerged igneous peak.
} around which the ancient inland ocean de-
: posted Its sediments undisturbed
q. "On the north side Of the river. how
ever. noted and carefully examined an
! other isneous dixie. which ] am inclined
) TO think may have a certain influence
> on the productivcness Of portion OF the
| field. This dixie appears 10 be horn
blcnde schist. and has an average width
of from four to six feet. II strikes
: nearly due north and south and can
readily he traced for some two or three
miles. II seems to be nearly vertical
in dip and outcrops along the eastern
slope OF the before mentioned second
10 anticline, perhaps two miles from the
bottom of the synclinal valley, I fol-
lowed this dixie down 10 within about
two and half miles of the river. and
there ] WAS unable TO farther locate IT,
Whether 1t actually stops there. oi
whether it continues 10 the river
and is simply hidden by surface forma
lions, j cannot state.
"Up TO date. no particular Significance
appears TO have been attached 10 the
presence and location oil this dixie by
those operating in the Held. But IL Ger
tainly is a fact worthy of note that uy
10 the present time none OF the wells
tOf which tncrc are seVcraD which hav,
been drilled east of this dixie have giver
anything like good showing of oil a.
have several of the wells drilled wes
e OF It. or west OF II line which the dik'
would trace should IL continues down tt
the river in its noted direction Of strike
All the wells cast OF the dixie. and sit
uatcd In the synclinal basin. have. how
ever, shown the presence OF ccnsid
erable amount uf water.
THE entire district now cmbra ccI
II within the limits OF the fields was origi
naly covered by horizontal water-dc
at posted strata aggrogating tremcndou
thickness. In most places. however. sur
face erosion has removed the overlyini
formations TO depth OF several hun
dred feet. and possibly for thousands o
feet AS a result OF the erosion AN,
dfterential weathering which have oc
Cured various reddish colored, ISOLATED
~ and picturesque bluffs, buttes and monu
- ments have been left dotted here an,
there over the fields. rising in man.
cases TO hundreds OF feet above the sur
rounding territory. They have bee
carved into many peculiar and fantasti
SHAPES during the passage OF the age