what have volcanoes and soils told me?

7/27/2019 What Have Volcanoes and Soils Told Me?

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DISCUSSED | New Zealand geology, soi l horizons, El len Whit e, volcanic ash, Usher chronology, confl icted viewpoin ts

What Have Volcanoes and SoilsTold Me? I B Y G R A H A M W I L LI n t r o d u c t i o n I wa s born in New Zealand a nd ha ve spent most of my lifethere. It is a small country consisting of t wo main islands which lie along th eboundary between the Pacific and Indian-Australian Plates in the crust of theearth. Lying on the ring of fire around the Pacific Ocean, many parts of thelandscape in the North Island of New Zealand have been formed by theaction of volcanoes.

Wh en I began my university studies in science in 1946, my majors werein chemistry and zoology. Although I had quite an interest in gardening (andin general the surface of the ground), I didn't dare include geology in mystudies because man y in my church expressed the belief that th e geologicalcolumn was in some way associated with Satan and his delusions.

Having finished m y studies, I spent some time in physical work layingwat er m ains in my hom etow n. Alth ough I wa s in and on soil for severalmonths, I didn't really come to understand all that much about it. I was stillvery much in the same position as the a verage man-in-the-street who looksat and possibly walks on a soil of some type without knowing or even think-ing much about it. For me the situation was to change quite dramatically as Itook up a position as a chemist at the New Zealand Forest Research Institute.The Institute is situated in Rotorua, w hich is a city in the central region of th eNorth Island. It lies beside a lake which is 26 miles in circumference, and theylie in a very large caldera left behind after wh at must have been a huge vol-canic eruption many years ago. I became one of a team studying poor treegrow th a s it wa s related to soil mineral deficiencies.

A Few Basic Facts About SoilsI soon learned that in nature the soil in one place can bever y d i f fer ent f r om the soi l in another par t of the countr yand in some cases even d i f fer ent f r om that only a fewmeter s away. As in other countr ies ther e ar e hundr eds ofd i f fer ent soi ls in New Zealand: these ar e the r esul t of (1 )d i f fer ent par ent r ocks , (2 ) d i f fer ent c l imatesheat andcold , r a in and wind, (3 ) d i f fer ent land s lopes and (4 ) t ime .Soi ls ar e for med as the r ocks weather (br eak apar t ) intosmal ler and smal ler miner a l par t ic les , and plants becomeestab l ished . The plants add or ganic mat ter (humus) to thesurface, and soil fauna (worms, insects, etc.) help move it

down into the soil i tself .I t i s per haps har d to appr ec ia te jus t what complex sys-

tems soi ls ar e . They ar e a lso l iving and dynamic . On adairy farm the weight of the animal l ife in the soil underthe pastur e can be sever a l t imes gr eater than the weight ofthe animals gr az ing the pastur e . A teaspoon of soi l canconta in 100 b i l l ion bacter ia and 15 km of fungal thr eads !A number of soi l pr oper t ies and r eact ions ar e r e la ted tothe sur faces of the c lay par t ic les : a teaspoon of the c laymineral allophane has a total surface area equal to a foot-ball field!

As a soil develops, several horizons (layers) are formed,and together they ar e ca l led a Soi l Pr of i le : these can beseen on the edg es of excavat ions such as r oadside cu t t ings .A ver y s impl i f ied descr ipt ion of soi l hor izons i s as fol lows:

A h o r i z o n Topsoil Surfa ce layer, usually dark in colour du eto the humus it contains.

B h o r i z o n Subsoil Next layer dow n. Less hum us and bio-logical activity but still much chemicalactivity under the influence of rain as itwashes through.

C h o r i z o n Parent Material Bottom layer. Unconsolidated weath eredrock. Little or no biological activity.

R h o r i z o n Underlying bedrock

As my knowledge an d exper ience gr ew, I beca me fasc inatedby soi ls , and a l though some wer e obvious ly older and mor edeveloped than other s , I thoug ht (hope d) that maybe th eywere not as old as they looked and were dated by scientists .A worldwide flood could not have left any soils in place onthe surface of the earth, so every soil that we examine todaymust have had to begin i t s deve lopment less than 5 ,000years ago to fit in with Usher 's or a similar t ime scale.


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Some of the thoughts tha t w ent through my mind inc lud-ed the fo l low ing q ues t ions . The deep a nd w el l -developedsoils on al luvial f lats were obviously quite young, but whatabout the soils that had developed on hard rocks such asgranite? How long did i t take for the rock surface to weatherto the place where pioneer plants could gain a foothold andthen the soil formation processes begin? Rock s labs in ceme-teries , many hundreds of years old, show only a few mms orless of weathering; how old are the soils where the weather-ing has penetrated several metres into solid rock?

Pumice Soils in the Central Regionof the North IslandT h e n o n e o f m y r e s e a r c h p r o j e c t s i n v o l v e d t r e e s g r o w i n gon Pumice So i l s nea r Rotorua a nd how deep thei r rootsw e n t b e l o w t h e s u r f a c e . D i g g i n g d o w n , w e w e n t t h r o u g hthe norma l A , B a nd C hor iz ons on ly to f ind a deepers er ies o f da rk la yers tha t looked s imi la r to tops oi l ( s eeP h o t o 1 , page 66). Other s c ient i s t s on the s a me ca mpusw ere ma king a s tudy of thes e la yers . They expla ined tha tthey w ere pa leos o ls (bur ied s o i l s ) tha t ha d formed beforethe y w ere cove red by pumice a s h from a s ubs eq uent vo l -ca n ic eru pt ion . I w a s then fa ced w i th the ta s k o f f inding a nexpla na t ion a s to how there could ha ve been t ime for notone but s ix s o i l s to form in the la s t 5 ,0 0 0 yea rs . There i sgood ev idence tha t the la s t erupt ion (Ta upo) occurreda bout 2 ,0 0 0 yea rs a go , a nd w hen i t occurre d, a t one s i t e , i tf l a t t e n e d a m a t u r e 7 0 0 - y e a r - o l d f o r e s t g r o w i n g o n t h eexis t ing tops oi l .2 Allow ing t ime for co lon iz a t ion by p io-neer s pec ies before the c l ima x fores t beca me es ta bl i s hed,there mus t ha ve been a t l ea s t 1 ,0 0 0 yea rs betw een theTa upo erupt ion a nd the one before i t . Tha t l ea ves on lya bout 2 ,0 0 0 yea rs or l es s for the forma t ion of s evera l low erburied s o i l s .

It was at this s tage that I was taken to a no the r loca li ty,a roa ds ide cut t ing nea r Rotorua Airport , w here there a res even pa leos o ls under the Ta upo a s hs even s o i l - formings eq uences to f i t in 3 ,0 0 0 yea rs ! ( s ee Photo 2 , page 67). Butthen I l ea rned tha t fa r ther to the no rth there w e re s o i l s(a nd pa leos o ls ) on even o lder vo lca n ic a s h s how ers a ndfurther north s t i l l even o lder ones . 3 H o w o l d ? P e r h a p s t h ec la y content could give a n es t ima te . Cla ys a re the s ma l les tminera l pa rt i c les in a s o i l being les s tha n 0 .0 0 2 mm india meter . By compa ris on the f ines t s a nd pa rt i c le i s 1 0 0t imes th i s d ia meter . The c la ys in pumice s o i l s a re s econd-a ry minera ls , tha t i s , they ha ve formed by the or igina l a s h

being dis s o lved a nd the new minera ls prec ip i ta t ing out o fthe s o i l s o lu t ion . Th is i s a s low proces s . Th e a m oun t o fc la y tha t ha s formed in the Ta upo s o i l s ince i t s ta r tedforming 2 ,0 0 0 yea rs a go i s a bout 2 % of the to ta l minera lcomponent o f the s o i l . The o lder a s h s o i l s ha ve up to 8 0 %cla y. 4 T w o p e r c e n t c l a y i n 2 , 0 0 0 y e a r s p r e c e d e d b y 7 0 + %in 3 ,0 0 0 yea rs ? I t d idn ' t s eem to a dd up to me. The ra tes o fchemica l rea c t ions a re t empera ture regula ted; perha ps i tw a s w a rmer in the pa s t . But New Zea la nd' s h i s tory o fgla c ia t ion s ugge s t s tha t i t w a s pro ba b ly co ld er .

N ot fa r to the north o f Rotorua ther e a re la kes w her eover the yea rs pea t s ediment ha s bui l t up on the la kebed.Cores f rom thes e la ke bot toms s how la yers o f vo lca n ic a s hs epa ra ted by depos i t s o f pea t s ediment . Some of the a s hla yers a re f rom the s a me erupt ions tha t produced the pa le-os o ls a t the Rotorua Airport . The depths o f the pea t la yersbetw een the a s h la yers gives fur ther ev idence tha t cons id-era ble per iods o f t ime mus t ha ve e la ps ed betw een thes ev o l c a n i c e r u p t i o n s . 3

It does not seem possible to explain the presence of allthe paleosols in the Rotorua district, the highly weath-ered state of the older pumice ashes and the p eat/ashsequences in lake beds all within a n Usher short chron ol-ogy. Topsoil, clay content and lakebed sequences sup-port C14 dating of 50,000 plus years.6

Soils Formed on Basalt Volcanoes Near AucklandW h a t a b o u t o t h e r s oi ls ? H o w l o n g h a v e t h e y t a k e n t odevelop? Another s er ies o f s o i l s tha t I ha ve looked a t a rethe ba s a l t s o i l s in a nd nea r Auckla nd, a c i ty w hich i s a bout1 5 0 north o f Rotorua . Pumice a s h erupt ions a re explos ive ,throwing ash high into the air for i t to fa l l and cover largea rea s up to t ens or hundreds o f thous a nds o f hec ta res . Incont ra s t , ba s a l t erupt ions f low or founta in over very muchs ma l ler a rea s . Wi th in the immedia te v ic in i ty o f Auckla ndCi ty there ha ve been more tha n 4 0 ba s a l t erupt ions lea v-ing indiv idua l vo lca n ic cones (h i l l s ) .

T h e l as t e r u p t i o n ( a n d t h e l a r g e s t ) f o r m e d R a n g i t o t oIs la nd in the ent ra nce to Auckla nd' s ha rbor . From a dis -t a n c e t h e i s l a n d g i v e s t h e a p p e a r a n c e o f s o m e a g e , b e i n gs e e m i n g l y c o v e r e d i n f o r e s t . H o w e v e r , w a l k i n g a b o u t o nthe i s la nd revea ls tha t la rge a rea s a re s t i l l ba re la vaf l o w s , a n d w h e r e v e g e t a t i o n h a s b e c o m e e s t a b l i s h e d , t h er o o t s o n l y p e n e t r a t e b e t w e e n t h e r o c k s a n d s c o r i a o rexis t in the s ha l low la yer o f orga nic debr i s tha t ha s bui l t


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up on the s urfa ce ( s ee Photo 3 , page 6 8 ) . T h e r e h a s b e e nn o s i g n i f i c a n t s o i l f o r m a t i o n . H o w l o n g h a s R a n g i t o t oIs la nd been in th i s inc ip ient s o i l forma t ion s ta ge? Ava i l -a b l e e v i d e n c e f r o m t r e e r i n g c o u n t s a n d a r c h e o l o g y s u g -g e s t s u p t o 5 0 0 - 7 0 0 y e a r s .

In Auckla nd Ci ty "One Tree Hi l l " i s a much o lder vo l -canic cone. There remain a few basalt ic boulders in thecrater and on the lower s lopes, but by and large the volcaniccone i s covered by young s ha l low s o i l s tha t grow good gra s sto feed the farm animals that graze there. However, the shal-low depth of the soils and the s lope of the land mean thata ny mecha niz ed cu l t iva t ion i s impos s ible . Compa red to Ra n-gi to to Is la nd, the a ppea ra nce o f the pres ent One Tree Hi l lsoi l agrees with an assigned age of 15 ,000 years plus.

The Bomba y Hi l l s l i e s ome 2 0 km s outh o f Auckla ndCi ty . T h is d is t r ic t is one o f the la rges t ma rke t g a rdenin gcenters in New Zea la nd. Ma ny of the s o i l s ha ve formed onpumice a s h f rom volca n ic erupt ions fa r ther s outh ( s eeabove), but the tops of the hil ls are covered in soils devel-oped f rom the ba s a l t rock w hich formed the h i l l s them-s elves / Here the dis t inc t ive red s o i l s a re both deep a ndea s i ly cu l t iva ted. I t ha s been es t ima ted tha t on ma ny of thes lopes up to a meter o f s o i l ha s eroded a w a y due to cont in -uous cu l t iva t ion for ma ny yea rs . Th is indica tes tha t thedepth o f w ea ther ing a nd the extent o f s o i l forma t ion w ereor igina l ly ma ny, ma ny t imes grea ter tha n on One TreeHi l l . Wh en com pa re d to Ra n gi to to Is la nd, i t i s a comp lete-ly di f ferent s cene! An a ge o f 1 0 0 ,0 0 0 yea rs p lus s eems to f i tin w i th the v i s ua l ev idence a nd our know ledge o f s o i lw e a t h e r i n g a n d d e v e l o p m e n t p r o c e s s e s .

If after 50 0 years there has been absolutely minimal soilformation on the basalt flows on Rangitoto Island, theshallow soils on One Tree Hill and the d eep soils on theBomba y Hills seem to have developed over considerableperiods of time. The soil evidence doesn't sup port ashort chronology but rather a longer period for thedevelopment of a deep soil on basalt rock.

Some Non-Volcanic Soils in New ZealandGlacial Moraine So i ls In the s outh o f the South Is la nd(Fiordla nd a nd the Southern Alps ) there ha s been exten-sive glaciat ion in the past , and as the glaciers have retreat-ed they ha ve lef t beh ind s er ies o f mora ines o fp r o g r e s s i v e l y y o u n g e r a g e s . T h e s e h a v e f o r m e d t h e p a r e n t

ma ter ia l s for a s eq uence o f s o i l s . Cons idera ble cha ngesha ve occurred a s the s o i l s ha ve formed a nd a ged. As thepa rent rock ha s w ea thered, over ha l f the phos phorus i tc o n t a i n e d h a s b e e n e i t h e r c o m b i n e d w i t h o r g a n i c m a t t e ror l ea ched (w a s hed) out o f the s o i l . So i l s c ient i s t s es t ima tetha t i t ha s ta ken 2 0 ,0 0 0 yea rs for thes e s o i l s to form. 8

From an earth covered by a flood, how long must it haveneeded for glaciers to (1) form, (2) cut fiords and canyonsthousands of meters deep, (3) and retreat, leaving behindmoraines on which (4) soils have then forme d and aged?

Loess Soils O n t h e e a s t e r n s i d e o f t h e S o u t h I s l a n d t h e r ea re extens ive p la ins w here s o i l s ha ve formed in loes s .This i s f ine ma ter ia l or igina t ing f rom the rocks o f theS o u t h e r n A l p s . T h e r o c k s h a v e w e a t h e r e d u n d e r t h ein f luence o f g la c ia l a c t ion , a nd the f ine ma ter ia l ha sb e e n t r a n s p o r t e d b y r i v e r s o u t o n t o t h e f l o o d p l a i n . T h i sf ine ma ter ia l ha s then been blow n out o f r iverbeds bys t r o n g w i n d s a n d d e p o s i t e d o v e r w i d e a r e a s . I n p l a c e s ,m a n y k i l o m e t e r s f r o m t h e r i v e r s , t h e l o e s s h a s a c c u m u -

Photo 2:Soi l layers,Rotorua Airport.Nine buried soi lsdeve loped oneafter the other assuccessivei> ; . fr.eruptions coveredthe landscapeover a period of15,000 yea rs.

KAHAR0A900TAUPO1.800

ROTOKAW.WHMAMKE4700

MAMAKU7400

R0T0MA

R0TSM13400


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l a ted to depths o f up to 1 0 meters a nd i s ma de up off o u r d i s t i n c t l a y e r s w i t h a s o il d e v e l o p e d o n e a c h . T h i ss e e m s t o i n d i c a t e t i m e p e r i o d s o f c o n t i n u o u s a c c u m u l a -t ion s epa ra ted by per iods o f a di f ferent a nd les s fa vor-a b l e c l i m a t e . S c i e n t i s t s e s t i m a t e t h a t m a j o r d e p o s i t s o fl o e s s d a t e b a c k 1 0 , 0 0 0 - 8 0 , 0 0 0 y e a r s . I t i s o f p a r t i c u l a rin teres t to note tha t , in China , loes s depos i t s up to 3 0 0m e t e r s h a v e b e e n f o u n d in w h i c h 2 0 p a l e o s o l s h a v eb e e n i d e n t i f i e d . 9

Weathering action in the mountains has reduced hugequantities of rock to fine material prior to its transportby river and wind. What period of time must have beeninvolved in this sequence of events?

In the l ight o f ev idences for a longer per iod of ea r thhis tory tha n a l low e d for in a s hort chro nolo gy , ho w a ref a i t h a n d s c i e n c e r e c o n c i l e d w i t h i n t h e A d v e n t i s t C h u r c h ?I bel ieve that i t is absolutely essential for there to be ano n g o i n g a n d r e g u l a r d i a l o g u e .

I n 1 8 9 2 E l l e n W h i t e w r o t e r e g a r d i n g s e a r c h i n g t h es cr ip tures : "We have many lessons to learn and many, many tounlearn. God and heaven alone are infallible. Those who think thatthey will never have to give up a cherished view, never have to changean opinion, will be disappointed." 10 T h i s s t a t e m e n t i s a s s o c i a t e dw ith a p lea for much more s tudy of the Scr ip tures . Ibel ieve tha t i f th i s a ppl ied to the Bible in her da y, i t i snot o ut o f co nte xt to a pp ly i t to the Bib le , a s w el l a sn a t u r e a n d s c i e n c e , t o d a y . E l le n W h i t e m a d e a n o t h e r

Photo 3: - >a v " .-r- .. '-Five-hundred-yearold lava flow,Rangitoto Island.No soil formationoccurred; sct- ,tered vegetation

* if*' *with roots amongrocks is visible.'

ConclusionsI ha ve been a Seventh-da y Advent i s t a l l my l i fe . I f i rmlyb e l i e v e i n a C r e a t o r - G o d a n d h a v e b e e n t h r i ll e d asa dva nces in molecula r b io logy ha ve revea led the ha ndi -w or k of a ma s ter des igner . H ow eve r , a s I ha ve s tudied s o i l sa n d t h e i r d e v e l o p m e n t , I c a n n o t r e c o n c i l e w h a t I s e e a n dw ha t ca refu l s c ient i f i c s tudies ha ve s how n w i th a s hortc h r o n o l o g y f o r t h e h i s t o r y o f t h e e a r t h .

s t a t e m e n t : "The book of nature and the written word shed lightupon each other."u T o m e t h a t m e a n s i t ' s n o t a o n e - w a ys t reet , but there ' s a rea l p la ce for s tudents in bot h dis c i -p l ines to ke ep ta lking to ea ch o th er . M a y be I w i l l be l e dt o c h a n g e m y o p i n i o n ( a n d t h a t w o u l d s o l v e s o m e o t h e rt h e o l o g i c a l p r o b l e m s f o r m e ! ) , o r m a y b e o t h e r s w i l l b eled to cha nge thei rs . Res ea rch s c ient i s t s l ive w i th uncer-ta in ty a nd not know ing a l l the a ns w ers . I f a res ea rch s c i -


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ent i s t w ere cer ta in a bout a l l the a ns w ers , there w ould ben o t h i n g t o r e s e a r c h , a n d r e s e a r c h e r s w o u l d b e o u t o f aj o b ! T h e r e i s a n e e d f o r e v e r y o n e i n t e r e s t e d i n f ai t h a n ds c ie nce s tudies to a dopt a t ru ly s c ien t i f i c out lo ok. I don ' tkn ow a l l the a ns w ers , but I w a n t to ha ve a pa rt in f indinga t l e a s t s o m e o f t h e m . A s k n o w l e d g e i n c r e a s e s , I w a n t t ohea r a bou t i t a nd ent er the dis cus s ion . I

Footnotes1. There are a number of soil science textbooks available, but an

easy-to-read book about soil formation and New Zealand soils has beenwritten by Les Molloy. See Malloy, Les. 1988. Soils in the New Zealandlandscape: The living mantle. New Zealand Society of Soil Science.

2. Clarkson, et al. 1988. "Composition and structure of forest over-whelmed at Pureora Central North Island, New Zealand, during the Taupoeruption (c.AD 130)." Journal of the Royal Society of New Zealand 18:417-436.

3. Lowe, D. J. 2002. "Norman Taylor Memorial Lecture: The TimeMach ine . " New Zealand Soil News 50.6: 124-135. This review articlecites numbers of relevant articles.

4. See Molloy, 1988, 19.5. Lowe, D. J. 1988. "Stratigraphy, age, composition and correlation

of late Quaternary tephras interbedded with organic sediments in Waika-to lakes, North Island, New Zealand." New Zealand Journal of Geologyand Geophysics 31:125-165. This article gives a full description of theoccurrence of 41 ash and lapilli layers that have been found in 14 lakes.The layers are from c.2 to 110 mm in thickness.

6. Vucetich, C. G., and W. A. Pullar. 1973. "Holocene tephra forma-tions erupted in the Taupo area and interbedded tephras from other vol-canic sources. " New Zealand Journal of Geology and Geophysics16:745-780.

7. Schofield, J. C. 1958. "Notes on volcanism and structure FranklinCounty." New Zealand Journal of Geology an d Geophysics 1:541-59.

8. See page 19 in Molloy above (footno te #1).9. Burbank, D .W. and Li Jijun. 1985. "A ge an d Paleoclimatic signifi-

cance of the loess of Lanzhou, North China." Nature 316:429-31.10. Whi te, Ellen G. Review and Herald (vol. 7 1892): 26. There are

similar statements in other publications.11. Whi te, Ellen G. Education. 128.

G r a h a m W i l l is a retired research scientist for the NewZealand Forest Service. He established many trials to identifymineral deficiencies in a range of soils and developed correc-tive fertilizer applications to increase tree growth. He can bereached at [email protected]

MATURITY Continued from page 61

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Communities Form our Newest Citizens. Oxford: Oxford University, 2007.Jenkins, P. The Next Christendom; The Coming of Global Christianity.

Oxford: Oxford University, 2007.Keller, E. The Road to Clarity: Seventh-day Adventism in Madagascar.

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Mission of the Ghanaian Seventh-day Adventist Church in Amsterdam."African Diaspora 2 (2009): 203-226.

Lawson, R. "When Immigrants Take Over: The Impact of ImmigrantGrow th on American Seventh-day Adventism's Trajectory from Sect toDenominat ion." Journal for the Scientific Study of Religion 38.1 (1999):83-102.

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what have volcanoes and soils told me?

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