Page 10 - edwards1947

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Valle ••••• 011 field and the .tiliooene•.Miooene contact at the

type aeotion of the 1£odelo formation.'' He f'urtmr states that

this unoon:form1 ty is not sufficient to alter greatly the Modelo

structure ae interpreted from the overlying .::liocene sediments.

Repetto formation. lower Iliocenel

The amount of ?liooene penetrated by the wells depends,

of course, on the position on the structure, but about 5700

feet seems to be t~:ie maximum. This includes both Repetto and
;,· 100. The section as described by s~e geologists for t.be

sam.e locality contains arproximately 500 feet of Saugus in

formations penetrated by the same wells. The writer could find

no basis for this if the division between the :.·too and Saugus

18 limited to the marine-non-marine basis.

The Repetto formation orops out at the su.rface in the

producing area west of the San Martinez Grande Canyon. It

has been carried. to the surfaoe here by the Del Valle thrust

f'ault (see geologic map and Structure Sectiono-c'). !be top

of the Repetto is plaoed by the writer at the base of a con•

glomerate bed that rep~esents a stratigranhic break between the

Repetto and lower : ioo. 800 to 900 feet of Repe too ie exposed

here. where it consists of e11tstones 1 brown, and gray-brown.

Sande grade upward into the massive gray s1lts:>nee and aands

of the lower : loo. The Re:petto is t,l'P raeterized b:, slumping•

even on relatively moderate slor~s. In fact, the slu.~ping is