DEPARTMENT OF THE INTERIOR UNITED STATES GEOLOGICAL SURVEY GEORGE OTIS SMrL'J:I, DIRECTOR '· PROFESSIONAL PAPER 88 LAVAS OF HA_ WAil AND THEIR RELATIONS· BY WHITMAN CllOSS WASHINGTON GOVERNMENT PRINTING OFFICE 1915 • CONTENTS. Page. Introduction ......................................... , .. _, ................................... : .......... 7 Publications cited ..................... ·_ .............................................................. _. ... 8 Petrography ....................................... _... ____ . ________ .. _.... __________ .. _____ ...... _____ ... 9 ~'he lesser islands ................................................................................... 9 Island of ](u.uai .................................................................................... 9 bccu.rrence and sources of material studied ...............................· ........................ 9 Olivine-plu.gioclase basalt ....................................................................... 10 Genet·al characters.~ ............................ -.- ............... : .......................... 10 Chemical composition ....................................................................... 10 Quu.ntitative classification .................................................................. 12 Helation of norm and mode in rocks analyzed ................................................ 12 Plu.gioclase basalt (poor in olivine) .......................· ......................................... 13 ]~itnburgite .......................... ~ ........ -... -..... ------------ .. -.-.--- ·----- -.-------- ·--- 13 Oligoclase gabbro or kauaiite ..................................................................... .. 14 Occurrence .............................. -·- .................................................. 14 ])escription .......................... _.... _. ____ . _............. _. _. ___ . _... _... _... ______ ... 14 Chemical composition ........ : ................................................................ 15 Quantitative classification ................................................................... 15 Systematic relations and name kauaiite ............- .......................................... 16 Melilite-nephelite basalt ........................................................................ 16 Occurrence ................................................................................. 16 Description ...................................................... _____ ... __ .................. 16 Chenlical con1position ........................................................................ 16 Quantitative classification ................................................................... 17 Basalts des·cribed by Mohle ...................................................................... 17 Island of Oahu ........................................................................................ 17 -. Introductory note .............................................· .................................... 17 T Hange of lavas ............................ __ .............· ............................... __ ._._ .. 18 Olivine-plagioclase basalt ............................ ·- ........................................... 18 Bronzite-bearing basalt ........................................................................... 19 Plagioclase basalt (olivine free) .................· ...........· ...................................... 20 Nephelite-melilite basalt ................................................... ·...... ·.· ............ 20 Occurrence ..................................... ~ ........................................ __ . 20 Hock :from quarry near Moiliili Chmch ........................................................ 21 Quantitative classification .................................................................. 22 Nephelite basalt and allied rocks ....................· ............................................. 23 Bu.saltic tuffs and ashes of recent eruptions ....... , ............................................... .23 Island of Molokai .................................................................................... 24 Hocks described by Mohle ........................................................................ 24 l~ocks described by Lindgren ..............· ....................... : .............................. 24 Island of Maui ............................... __ ....... __ .... _.............................. _..... __ .. 25 West 1\~faui ................................. _____________ .... ________ .... _. _....... _.... ___ . _.. __ .. _ 25 Bowlders of Waihee Valley ................................................................. 25 Bowlders of lao Valley . ." ................................................................... 26 Rocks described by Mohle .................................................................. 26 Soda trachyte near Lahaina .................................................................. 26 Occurrence and character ............................................................... 26 Che1nical composition ................................................................... 27 Quantitative classification ....... : ...................................................... 28 3 4 CONTENTS. Petrography-Continued. Island of Maui-Continued. Page. East Maui ...................................................................................... 28 Picritic basalt ............................................................................. 28 Occurrence ............................................................................ 28 Description ............................................................................ 28 Chemical composition .................................................................... 29 Qualitative classification ... : ........................................................... 29 Quantitative classification ................................................................. 29 Esse xitic andesite or trachyandesite .................. ·....................................... 30 General character and occurrence ........................................................... 30 Rocks analyzed ........................................................................ 30 Chemical composition ................ : .................................................. 31 Quantitative classification .............................................................. 32 Island of Hawaii ................................................................................... 32 Centers of eruption ............................................................................. 32 Kohala Mountains ............................................................................... 32 Mount Hualalai ................................................................................ 34 Basaltic lavas ............................................................................... 34 Dunite, gabbro, and other granular inclusions in basalt ......................................... 34 Basaltic xenoliths .................... ·........................................................ 35 Trachyte of Puu Waawaa and Anahulu ............................ ; ........................... 35 Mauna Kea ........................... · ............................................................ 36 Rocks described l;>y Cohen ................................................................... 36 Lavas collected by Preston ........................... ·............. · ..................... : ..... 36 Observations of Dutton ..................................................................... 37 Rocks noted by Hitchcock .................... ·.............................................. 37 Rocks described by Daly ................................... : ................. ·............... 37 Other rocks on Mauna Kea ................................................................... 38 Mauna Lo~ ..................................................................................... 38 Rocks described by Cohen .................................· ~ ................................ 38 Rocks described by E. S. Dana ............................................................. 38 Rocks described by Daly .......................................· ............ ~ ................ .. 39 Rocks collected in 1902 ..................................................................... 39 Review .................................................................................... 39 Kilauea ......................................................... ·............................... 39. General statement ............................................ : ................................ 39 Recent lavas ................................................................................ 40 Rocks of the caldera walls ................................................................... 41 Fragments in the tuffs ....................................................................... 42 Gabbro of Uwekahuna "laccolith" ................................................ ·......... .. 43 Summary ......................... :. 43 Puna ..................................... .'..................................................... 43 General discussion........................................................................................ 44 Introduction................ 44 Cha::-acteristics of the rocks............................................................................ 45 Mineral composition