Tephra Layers in the Byrd Station Ice Core and the Dome C Ice Core, Antarctica and Their Climatic Importance

Kyle, P. R., Jezek, P. A., M o s l e y T h o m p s o n , E. and T h o m p s o n , L. G., 1981. T e p h r a layers in the Byrd S ta t ion ice core and the Dome C ice core, A n t a r c t i c a and the i r c l imat ic impor t ance . J_ Volcanol . G e o t h e r m . Res., 11: 29---39. Volcanic glass shards f r o m t e p h r a layers in the Byrd S ta t ion ice core were chemmal ly analyzed by e l ec t ron m i c r o p r o b e . T e p h r a in seven layers have similar pera lka l ine t r achy t e compos i t ions . The t e p h r a are bel ieved to or ig inate f rom Mr. Takahe , o n the basis of the i r chemica l s imilar i ty to ana lyzed rocks f r o m Mt. T a k a h e and because da t ed rock samples f rom the vo lcano are younge r t h a n 2 5 0 , 0 0 0 years old_ Glass shards f rom 726 m deep in the D o m e C ice core, w h i c h is 2400 k m f rom Byrd S ta t ion , are c o m p o s e d of pera lka l ine t r achy te and may have also been derived f rom Mt_ Takahe . The t ephra could have resul ted f rom e r u p t i o n s which were t r iggered by increased ice loading dur ing the late Wisconsin glaciat ion. Pre l iminary grain size da ta suggest the e rup t i ons were on ly m i n o r and they were un l ike ly to have i n s t an t aneous l y a l te red global c l imate as have explosive e rup t i ons in the tropics. Never theless , t he e f fec t of th is local ized volcanic act ivi ty u p o n the An ta r c t i c energy b u d g e t war ran t s f u r t h e r invest igat ion. I N T R O D U C T I O N Volcanic eruptions during historic times have been associated with temporary surface cooling and stratospheric warming at some latitudes. Particulate mat ter (dust) and aerosols injected into the stratosphere can scatter and absorb shortwave radiation and scatter, absorb and emit longwave radiation. The resulting alteration of the atmosphere 's optical properties may create a temporary imbalance in the radiation budget resulting in an adjustment of the globally averaged surface temperature (Pollack et al., 1976). A major problem is to determine the long-term effects of prolonged, explosive volcanism on global climate. The study of ice cores offers a means to evaluate the f requency of volcanic eruptions and their possible relationship to climate over the last 100,000 years or so. C o n t r i b u t i o n No. 395 of the Ins t i t u t e of Polar Studies , The Ohio Sta te Univers i ty , Co lumbus , Ohio 43210 (U.S.A.) 0 3 7 7 0 2 7 3 / 8 1 / 0 0 0 0 0 0 0 0 / $ 0 2 . 5 0 © 1981 Elsevier Scient i f ic Publ i sh ing C o m p a n y