Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Trilogy Glaciat ion depos its 1. First published use NiChola , R. L. MUlt iple glaciat ion in the Wright Valley , MCMUrdo Sound , Antarctica : Abstracts , Tenth Pacific S cience Congress of Pac . Sci . As soc . , p . 3 17 , 196 1 . 2 . Definition "Small diacont inuous indistinct end moraines in the valley approxi mately five miles west of Lower Wright Glacier can be traced into lateral moraines WhiCh on dbe north a ide of the valley near the Clark Valley are approximately 1000 feet above the floor . These were depos ited durins the oldest and mos t extens ive stage of the Trilogy Glaciat ion, the younges t glaciat ion recognized in Wright Valley . " (NiChola , 317 ) 3 . Type section a. Locat ion S miles wes t of Lower Wright Glacier , Victoria Land b . Lithology 1 . Small amount o f wind cutt ins 2 . Abaence o f odd-shaped weathered rocks and boulders weathered to ground level 3 . Many upstanding boulders 4 . Only minor atainins c . Relation to other units Younger than Loop Glaciation d . Evidence for age "Carbon-14 analys is of an elephant seal buried in a raised beaCh indicates that the full-bodied stage of the Trilogy Glaciation probably occurred more than 7000 years ago . " (Nichols , 3 1 7) Unnamed MOuntains basalt 1. Firat published use Doumant , G . A. Geologic Observat ions in West Antarctica durins recent overanow traverses : IGY Bull . 41 , Trans . Am. Geophya . Union 41 (4) , p . 706-710 , 1960 . - 119 -
2 . Definit ion " Brownish bas alt crops out eas t of the tuff and probably overlies it unconformably . This basalt has been sub jected to intense mechanical weathering , result ing in s tepped , tombs tone -shaped pinnacles , Wh ich occur from the ice surface to the top of the mountain . Underlying the basalt is a th in layer of rhyolite containing pyrite . " (Doumani , 709 ) 3 . Type sect ion a. Locat ion Eastern peak of unnamed mountai ns (76° S , 123° -125° W) , Mar ie Byrd Land b . Relation to other units Overlies Unnamed MOuntains tuff unconformably 4 . Remarks Local ity now known as Benes Peak , USAS Es carpment Unnamed Mountains dior ite 1. Firs t published use Douman i , G . A. Geolog ic Observat ions in West Antarctica during recent oversnow traverses : IGY Bull . 41 , Trans . Am. Geophys . Union 41 (4) , p . 706 -7 10 , 1960 . 2 . Definit ion "The wes tern mountain is composed of diorite ' basement ' ro Ck unconformably overlain by ol ivine basalt , and a yellowish tuff . " (Doumani , 709 ) 3 . Type sect ion a. Locat ion Western peak of unnamed mountains ( 76 ° s , 123 ° - 12 5⢠W) 4 . Remarks Locality now known as Mt . Aldaz , USAS Escarpment , Marie Byrd Land - 120 -
