bhautik bhoovijnyaaan

bhooprushtheeya parivrtanon ke adhyayan ko bahudha gatikeeya bhoovijnyaaan (dynamical geology) bhi kehte hain. spasht hai ki yeh naam prushtheeya vaataavaran ki gatisheel sthiti ki or sanket karta hain, kintu aajkal yeh naam kuchh vishesh prachalit naheen hein aur iske sthaan par bhautik bhoovijnyaaan (Physical geology) adhik prachalit hai. is vigyaan ke teen mukhya ang hote hain, jo is prakaar hain :

(1) praakrutik kaarakon dvaara prushtheeya shailon ka kshaya (decay), aparadan (erosion) evam anaachhaadan (denudation) tatha usase utpann avasaad ityaadi ka parivhan (transport),

(2) avasaad ka sanchayan (accumulation) tatha

(3) sanchit avasaad ka sanyojan (cementation) aur drudheebhavan

anukram

praakrutik kaarakon dvaara kshaya

jo praakrutik kaarak prushtheeya padaarth ko prabhaavit karte hain, ve apne kreedaakshetr ki paristhiti ke anusaar do vargaan mein vibhaajit kiye ja sakte hain :

(a) dharaataleeya (surface) aur

(b) aantabhaum (subgterranean)

inmein dharaataleeya kaarakon ki kriyaatmak oorja pradhaanataya evam charamat: soorya se utpann hoti hain. is varg mein (k) vaayumandal ke vibhinn avayav, varsha ityaadi, (kh) aantabhaum jal aur sote, (g) nadi tatha (gh) himnadi, samudra tatha jheel vishesh ullekhaneeya hain. inka kreedaakshetr mukhyat: bhumandal ka thal bhaag hota hain, jismein samudri tat bhi sammilit honge. samudra ke nitl par inka kuchh prabhaav naheen padta aur prushth ke gahre bhaagon mein bhi inki praveshyata apekshaakrut ati sookshm hoti hain.

aantabhaum kaarakon ki oorja ka pradhaan strot pruthvi ki aantarik ushnata hi hai. is varg mein patalaviroopan (diastrophism) jvaalaamukhi kreeda, ushn aur bhookamp ityaadi aate hain. spasht hai ki inka mool kreedaakshetr dharaatal ke neeche hai aur unase utpann prabhaav dharaatal ke oopar kabhi aa jaate hain aur kabhi naheen aa paate.

vaayumandal ke vibhinn avayav

vaayumandal mein chaar aise mukhya avayav hain jo bhooprushth ke prati kaaryasheel rahate hain: (1) varsha, (2) taap parivartan, (3) tushaar aur (4) vaayu.

varsha

varsha ek bahut saamaanya, kintu atyant shaktimaan kaarak hai. iske kaarya ki vidhi kuchh raasaayanik aur kuchh balakrut (mechanical) hoti hai. poornataya shuddh jal mein raasaayanik kriya karne ki kshamata praaya: bilkul naheen hoti. yadyapi varshaajal pruthvi par pahuainchane se poorv adhikaansh shuddh hota hai, fir bhi aakaashamaarg se aate samay usamein vaayumandaleeya okseejan aur kaarban daaioksaaid donon hi paryaapt maatra mein vileen ho jaate hain. aakseekrut aur kaarbaneekrut varshaajal ki abhikriya se prushtheeya shailon ke anekaanek khanij apni apni prakruti ke anusaar oksaaidon aur kaarbaneton mein parivrtit ho jaate hain. kuchh khanij, athva anake anu, jal ke saath raasaayanik yaugik haaidret bhi bana lete hain. is prakaar varshaalaya ki raasaayanik kriya dvaara shilaaeain apaghatit (decomposed) ho jaati hain. nae bane hue padaarthon mein kuchh vileya hote hain aur kuchh avileya. vileya ansh banane ke saath hi jal mein vileen hokar bah jaate hain aur avileya ansh jahaaain ke tahaaain chhoot jaate hain. avileya bhaag mein mitti ke anu aur baaloo ityaadi hote hain, jo kaalaantar mein sanchit hokar vividh bhaaainti ki mitti ke star banaate hain.

kabhi kabhi avileya padaarth ko sanchit hone ka avsar hi naheen mil paata, apitu varsha ka jal dharaatal par bahate hue use bhi poornataya athva anshat:, apne saath bahaakar le jaata hai. jab tak jal mein padaarth ko baha le jaane ki shakti rahati hai, tab tak vah bahata chala jaata hai aur shakti ke ksheen hone par vah jahaaain tahaaain baith jaata hai. is prakaar varsha ke jal dvaara bahaae hue padaarth ko (rain wash) kehte hain. iski maatra dharaatal ki dhaal aur varsha ki gati par nirbhar hoti hai. dhaal ki pravanata aur varsha ki teevrata donon hi varsha ke jal ke bahaane ki shakti ko varddhit karti hain.

varsha ki kriya ke parinaamon par sthaaneeya jalavaayu ka bhi bahut prabhaav padta hai, yadi do pradeshon mein vaarshik varsha ki maatra praaya: samaan ho, kintu ek mein halake halake chheente baar baar padte hon aur doosare mein kabhi kabhi kintu bahut teevr varsha hoti ho, to in donon pradeshon mein varsha ka prabhaav bhinn bhinn hoga. isi prakaar sookhe aur barasaati mausamon ke ekaantaranavaale pradeshon mein bhi varsha ka prabhaav ekdam bhinn ho jaata hai. taap ki vibhinnata ka bhi varsha ki kriyaasheelata par prabhaav padta hai. ushnataapradhaan deshon mein varsha ke jal mein apaghatan karne ki shakti, sheetapradhaan deshon ki apeksha, kaheen adhik hoti hain.

taapaparivrtan

baari baari se garami aur sardi ke prabhaav mein padkar chattaanein shanai: shanai: chhinn bhinn hokar mote ya maheen choore ke roop mein parivrtit ho jaati hain. dravya ka yeh saadhaaran gun hai ki garami ke prabhaav se failata hai aur sardi paane par sikudta hai. failane evam sikudne ki maatra dravyavishesh par nirbhar hoti hai, arthaat koi dravya adhik failata hai aur koi kam. bahut si shilaaeain do, teen ya aur adhik khanijon ki bani hoti hain. at: din ki garami mein ye sab khanij apne apne gunon ke anusaar failate hain aur raatri mein thandhe hote hue sikudte hain. kaai khanij kam failata hai, kaai adhik. jo khanij adhik failata hai, vah doosaron par ek prakaar ka dabaav daalata hai jisse kan chhinn bhinn hone lagte hain. din prati din is prakram ke chalte rahane se prabhaav badhta jaata hai aur kaalaantar mein shailon ki oopari paratein choornapraaya ho jaati hai. pratyaksh hai ki din aur raat ke taap mein jitna hi adhik antar hoga, utane hi adhik veg se shilaaeain chhinn bhinn hongi.

is kriyaamein khanijon ke raasaayanik sanghatan mein praaya: bilkul hi parivartan naheen hota, keval khanijon ke paarasparik bandhan itne dheele pad jaate hain ki ve ek doosare se pruthak ho jaate hain. isi se is kriya ko vightan (Disintegration) kehte hain. varsha aur taapaparivrtan donon ki sammilit kriya se, jo bahudha prakruti mein hoti hai,

shilaaon ke apaghatan aur vightan donon ko protsaahan milta hai.

tushaar

tushaar ki kriya bhi keval balakrut hi hoti hai. is kaarak ki shakti ka srot yeh saamaanya vrutt hai ki 4 degree sein0 (praaya: 39 degree faa0) par jal ka aapekshik ghanatv adhiktam hota hai. isse aur adhik thandha hone par ghanatv kam hone lagta hai, arthaat doosare shabdon mein yeh kehna chaahiye ki jal ke aayatan mein vruddhi ho jaati hai. 0 degree sein0 (32 degree faa0) par jab jal barf mein roopaantarit hota hai, tab usaka aayatan praaya: dashamaang badh jaata hai. at: krutrim vidhi se barf jamaane mein is baat ka dhyaan rakhana nitaant aavashyak hota hai ki barf ke badhe hue aayatan ke liye paatr mein rikt sthaan hona chaahiye. is sthaan ke abhaav mein failati hui barf ke dabaav se paatr ke foot jaane ki aashanka haati hai. isi vrut ke anusaar sheetapradhaan deshon mein jab shilaaeain tushaar ke prabhaav mein aati hain, to unke ang ang chhinn bhinn ho jaate hain. shilaaon ke chhidron aur vidron mein jal ghus jaata hai aur vah prati din sardi paane par jamata hai aur garami paane par pighlata hai. isse kuchh hi kaal mein chattaanon ki oopari paraton ke avayav kamjor aur praaya: asanbaddh ho jaate hain. baad mein varsha tatha vaayu aadi ke aaghaat se ve sahaj hi choor choor ha jaate hain. bahudha tushaar ka yeh prabhaav visfoti hota hai. sheetapradhaan dashon ke un bhaagon mein jahaaain vanaspati kam ho, khuli, anaachhaadit chattaane is prakaar toote hue shail khandon se dhaki rahati hain evam pahaadiyon ke talon mein is prakaar se bane khandon ki badi raashiyaaain ekatrit ho jaati hain, jise shailamalaba (Talus) kehte hain. in khandon ka koi nishchit aakaar naheen hota aur inke kone bahudha nukeele evam paine hote hain. shail vightan ke liye tushaar bahut hi shaktishaali kaarak hai, kintu iska kaaryakshetr keval sheetapradhaan pradesh hi hai.

vaayu

vaayu ke vishisht kreedaakshetr registaan aur ooainche paarvatya pradesh hain, jahaaain yeh bahudha teevr gati se bahti hai. anukool paristhitiyon mein ismein balakrut aparadan karne ki apoorv kshamata hoti hai. iski shakti ka mukhya rahasya is baat mein hai ki yeh anaginti chhote bade baaloo aur mitti ke kanon ko badi teevr gati se uda le jaati hai. prachand vaat mein bahate hue ye kan baaranbaar ek doosare se takaraate hain, jisse apagharshan hota hai aur shanai: shanai: kan laghutar hote jaate hain. saath hi jhanjhaavaat ke maarg mein jo pahaad, chattaanein evam patthar ke khand aa jaate hain, un sabke upar bhi ye baaloo jhonka (sand blast) ki bhaaainti aaghaat karte hain, jisse ve sabhi apagharshit hote rahate hain.

saadhaaranataya baaloo dharaatal se adhik ooainchaai tak naheen uth paati. is kaaran vaayu ki aparadan-kriya-kshetr ki ooainchaai bhi usi anupaat se seemit rah jaati hai. falat: bahudha registaani pradeshon mein pahaadiyon aur chattaanon ke nichle bhaag to apagharshit ho patale evam sankeern ho jaate hain, kintu oopar ka dhad aprabhaavit chhoot jaata hai. is prakaar ke adhoradan (undercutting) se kukuramutta aadi saddash kuchh vilkshan aakrutiyaaain ban jaati hain.

registaani pradeshon mein vaayu ki disha praaya: bahut samay tak samaan bani rahati hai, jisse inki apagharshan aur aparadan ki disha bhi bahut samay tak aparivrtit rahati hai. is kaaran registaanon mein vaayutpann golaashm (boulder) gol matol na hokar, koneeya aur falakeeya hote hain. vastut: inke liye golaashm shabd anupayukt hai aur uske sthaan par jarman shabd dreekaintar (dreikanter) ka prayog karna chaahiye.

vaayu mein aparadan ke saath saath parivhan ki bhi vilkshan shakti hai. maheen baaloo aur dhool ke kanon ko bade vishaal parimaan mein vaayu varsh prati varsh registaani pradeshon se udaakar le jaati hai aur aise sthaanon mein nikshepit kar deti hai jahaaain usaka veg kam ho jaata hai aur ghaas evam jhaadiyaaain uske maarg mein rukaavat daalati hain. is prakaar se parivaahit padaarth ke nikshepon ko vaayoodh baaloo (aeolian sand) aur vaayoodh mruttika kehte hain. uttari cheen mein is prakaar se bani vaayoodh mruttika ka ek bada vishaal nikshep hain, jiski motaai 300 se 450 meter tak hai aur jise vaayu madhya Asia ke registaanon se uda kar yahaaain le I hai.

aantarbhaunm jal or sote

varsha dvaara laae hue jal ka kuchh bhaag vaashpeekaran se pun: vaayumandal mein chala jaata hai, kuchh dharaatal par bahata hua nadiyon ke maarg se samudra mein pahuainch jaata hai aur kuchh pruthvi mein ant:sravit ho jaata hai. jo bhaag dharaatal par bah jaata hai, use apavaah (run off) kehte hain aur jo prushth mein ant:sravit hota hai, use bhoomigat athva aantabhaunm jal (Ground water or Vadose water) kehte hain. in teenon bhaagon ka paarasparik anupaat sthaaneeya jalavaayu, sthalaakruti aur bhaumiki par nirbhar rahata hai. aadrr jalavaayu ke pradeshon mein vaashpeekaran ki maatra prabal hoti hai. samaan jalavaayu ke pradeshon me sthalaakruti ki vishmata ke saath apavaahit jal ki maatra adhik hoti jaati hai. bhaumiki ka vrutt bhi atyant mahatvapoorn hota hai, kyonki kuchh shilaaeain bahut randhri to hoti hain, par saath hi unki praveshya (perviousness) bahut alp hoti hai, jese shail aur mruttika. inke atirikt ek teesari shreni ki shilaaeain na to randhri hoti aur na praveshya, jese grainaait. at: ant:sravit jal ki maatra sthaanavishesh ke shailon ke bhautik lakshanon par nirbhar hoti hain.

dharaatal mein kuchh gaharaai par pahuainchane par, bhoomi aur shail jal se santrupt ho jaate hain. santrupti ki satah ko bhaunmalaj star (Water table) kehte hain. is star ki gaharaai kshetravishesh ki vaaÐaashak varsha ki maatra, sthaalaakruti aur sthaaneeya bhaumikeeya sanrachana par nirbhar hoti hain. saadhaaranataya bhaumajalaantar sookhe pradeshon ki apeksha aadrr kshetron mein dharatal ke sameep hota hai. samudra, jheel, sarovar evam badi nadiyon ke sameepasth bhaagon mein bhi yeh star apekshaakrut dharaatal ke sameep hota hai. sookha pad jaane se yeh gaharaai mein chala jaata hai aur ati vrushti hone par oopar aa jaata hai.

aantabhaunm jal prushth mein kitni gaharaai tak sama sakta hai, yeh baat bhi sthaaneeya shailon ki sanrachana par nirbhar hai. jal shailakanon ke beech ke randhri sthaanon aur vivron mein sama jaata hai, at: jitni gaharaai tak shailon mein randhr, athva vidr honge, utani hi door tak aantabhaunm shailon ke dabaav ke kaaran adhikaansh vidr mein sandhitl band ho jaate hain. randhraavakaash bhi alp ho ja sakta hai. aisi sthiti mein aantabhaunm jal adhik gaharaai mein na jaakar paashrv ki or agrasar hone lagta hai. antat: iska lakshya samudra hai. kabhi to yeh bhoomigat maargo se hi vahaaain pahuainch jaata hai aur kabhi use aise maarg mil jaate hain, jinse vah pun: dharaatal par soton ke roop mein pahuainch jaata hai.

khule hue tatha chaude vidron aur sandhitlon ke atirikt, anyatr aantabhaunm jal ki pravaahagati saadhaanaya ati mand hoti hai. isi kaaran usamein kisi prakaar ki balakrut kriya karne ki shakti naheen hoti, kintu anukool paristhitiyon mein yeh raasaayanik kriya avashya kar sakta hai. vidr aur sandhitlon ke anuprasth aage badhte hue yeh, varshaajal ki hi bhaaainti, deevaaron ke shailon ke khanijon ko okseekrut, kaarbaneekrut, athva jalayojit kar deta hai aur is prakaar shail ka apaghatan ho jaata hai.

jis bhoobhaag mein choonaapatthar ke shail hon, vahaaain aantabhaunm jal ko kaarya karne ka bahut bada kshetr mil jaata hai. kaarbaneekrut jal mein choonaapatthar vileen ho jaata hai. at: choonaapatthar ke sttaron mein se bahata hua jal uske anekaanek bhaagon ko vileen kar gufaaeain bana daalata hai. kabhi kabhi is prakar bani gufaaon ka aakaar bada, kai sau meter tak lamba aur 4-5 meter gahra ho jaata hai aur inmein se bahata hua jal aantabhaunm nadi bana deta hai.

kaheen kaheen kaarbonetayukt jal gufa ki chhat se tapakane lagta hai. tapakate paani ki kuchh bhaag vaashpeekrut hokar ud jaata hai aur usamein vileya kailsiym kaarbonet tapakanevaale sthaan par avakshepit ho jaata hai. ek hi sthaan par booaindon ke baaranbaar tapakane or usi sthaan par kailsiym kaarbonet ke nirantar avakshepan se ek stanbhaakar raashi ban jaati hai, jise stailektaait (Stal actite) kehte hain. isi prakaar ki kriya gufa ke farsh par tapake hue jal ke vaashpakaran se bhi hoti hai aur usase bhi avakshepit kaarbonet se aisi stanbhaakar aakruti banti hai jo farsh se chhat ki or badhti hai. in aakrutiyon ki stailegmaait (stalgmite) kehte hai. kabhi kabhi stailegmaait ek doosare ki or badhte hue milkar gufa ki chhat se farsh tak ka satat stambh bana dete hain. kabhi is prakaar avakshepit kaarbonet ki raashi ka koi vishisht roop naheen hota. aisi avastha mein use kailk nisaad (calc sinter), toofa (tufa) ya traivartaain (travertine) kehte hain. kinheen kinheen gufaaon mein is prakaar avakshepit kaarbonet ki maatra itni vishaal ho jaati hai ki aise kaarbonet se vyavasaaya chal sakta hai.

sote

oopar yeh ullekh kiya gaya hai ki kabhi kabhi aantabhaunm jal soton ke roop mein pun: dharaatal par laut aata hai. yeh ghatna sthaaneeya shailon ke vishisht vinyaas ke oopar nirbhar karti hai. yadi koi baaloopatthar ka randhri shail, r, is prakaar vinyast ho ki uske oopar aur neeche poornataya athva praaya: apaaragamya shail, mruttika, shel (shale) ya anya koi usi gun ki shilaaeain sthit hon, to aantabhainm jal randhri shail mein rista hua, apaaragamya shila ke oopari sansparsh tal tak pahuainchane ke baad, staron ki dhaal ke anusaar paashrvavarti disha mein badhne lagega. usi disha mein jahaaain kaheen vah shail kisi praakrutik kaat (naala, khadd ityaadi) mein anaachhaadit ho pragat hoga, to us sthaan par aantabhaunm jal soton ke roop mein bahne lagega.

bahudha shailon mein upasthit bhranshatal bhi soton ke banane mein sahaayata dete hain. yadi kisi bhransh ke kaaran kaai apaaragamya shail visthaapit hokar randhri aur paaragamya shail ke saannidhya mein avasthit ho jaaya to us sthaan par jahaaain bhranshatal kisi praakrutik kaat (naala, ityaadi) ke anuprasth anaachhaadit hoga, vahaaain sote footane lageinge.

soton ke paani mein praaya: sadaiv khanij padaarth thodi bahut maatra mein vileen hote hain. jab inki maatra bhaar ke anusaar 1 prati shat se adhik ho, tab use khanij sota kehte hain. par sarvasaadhaaran vyavahaar mein kisi bhi aise sote ko, jiske paani mein vileen khanij padaarth ke kaaran kuchh vishisht svaad ho, khanij sota kehte hain. par sarvasaadhaaran vyavahaar mein kisi bhi aise sote ko, jiske paani mein vileen khanij padaarth ke kaaran kuchh vishisht svaad ho, khanij sota kehte hain; kintu kailsiym kaarbonet jaise khanij bahut prachur maatra mein hone par bhi kuchh svaad naheen dete aur maigneeshiym ke lavan ati alp maatra mein bhi svaad dene lagte hain.

soton ka paani bahudha dabaav ke adheen hota hai. paani ke baahar aate hi dabaav mein kami ho jaati hai aur uske saath paani ki vileyata mein bhi hraas ho jaata hai. at: soton ke udgam sthaan par bahudha khanij padaarth avakshepit ho jaata hai. is padaarth ka sanghatan praaya: choornik athva silikeeya hota hai aur ye nikshep sanghatan ke anusaar, kailk nisaad (calc sinter), athva silikeeya nisaad (siliceous sinter) kahalaate hain. kabhi kabhi lauh kaarbonet, athva anya lavan, ya gandhak bhi avakshepit ho jaate hain.

kisi kisi sote ka paani bahut garam hota hai aur kabhi kabhi paani rediyoektiv bhi hota hai. Bihar raajya mein raajagiri ke garam paani ke sote bahut prasiddh hain. in soton ka paani praayaya: prushth ke bahut gahre bhaagon se aata hai. kuchh soton ka paani aantabhaunm na hokar maigmeeya utpatti ka bhi hota hai, arthaat aisa jal jo sudoor garbh mein maigmeeya padaarth (draveebhoot shail padaarth) se nikle hue vaashp se yukt hota hai. aise sote ko maigmeeya (magmatic) sota kehte hain.

utsrut (Artesian) koop

kaheen kaheen aantabhaunm jal aisi vishisht paristhiti mein vidyamaan hota hai ki us sthaan par kuaaain banaane se paani svat: oopar chadh aata hai aur kaheen kaheen to paani ki dhaar fauvaare ki bhaaainti dharaatal se kai meter tak oopar uchhalati hui niklati hai. inhein utsrut koop kehte hain. inke banane ke liye anivaarya praveshya pratibandh ye hain: (1) aantabhaunm jal ek aise randhramaya aur apraveshya shail ke andar sanchit ho jiske oopar aur neeche donon or apaaragamya shail avasthit hon, (2) staron ke pravan ki disha mein jal ke bahakar nikal jaane ka maarg avarooddh ho aur (3) jal ka mool srotasthaan, kuainaa banaane ke sthaan se itni ooainchaai par ho ki vaanchhaneeya taral sthaitik daab utpann ho, jiske prabhaav se kuaaain banane par jal svat: dharaatal tak oopar uth jaaya.

Madras praant ke dakshin aarkat jile mein naiveli sthaan par, jahaaain peet (peat) ke vishaal nikshep mile hain, bahut hi ullekhaneeya utsrut sthiti pai gayi hai. vahaaain utsrut jal ki daab aur maatra donon hi itni adhik hain ki peet ke utkhanan mein bahut kathinaai hui hai, tatha jal ko niyantrit karne ke liye vishesh saadhan prayukt karne pade hain.

nadi

praakrutik kaarakon mein nadi bahut hi prabhaavi tatha kaaryasheel hai. yeh aparadan, parivhan aur nikshepan, teenon hi prakaar ke kaarya atyadhik parimaan mein karti hai. yadyapi varshaajal ke kaarya ka mahatva kuchh kam naheen hai, fir bhi nadi ki kriya lambi evam apekshaakrut sankeern ghaatiyon mein sankeindrit hone ke kaaran, iska prabhaav va fal adhik spasht prateet hota hai.

aparadan

varshaajal ki bhaaainti hi nadi ka jal bhi apni ghaati ke tal aur kinaaron ke shailon ko raasaayanik kriya dvaara apaghatit kar sakta hai. is prakaar utpann apaghatit padaarth ka vileya ansh nadi ke jal mein ghul jaata hai aur avileya bhaag bhi dhaar ke saath bah jaata hai. yeh kriya nadi apne parvateeya pradesh ke maarg mein sugamata se karti hai, kyonki vahaaain ghaar itni vegavaan hoti hai ki praaya: sadaiv nae, anapaghatit shailon ki starein anaachhaadit hoti rahati hain jisse ki ve sahaj hi kriya ke prabhaav mein aati rahati hain. kintu maidaani pradesh mein dhaar ka veg kam ho jaane par, ghaati ka tal mruttika aur baaloo ke aavaran se aachhaadit ho jaata hai. falat: anapaghatit shailon se sampark bhi kam ho jaata hai. jin pradeshon mein choonaapatthar ke shail adhik hon, vahaaain raasaayanik kriya bahut prachur parimaan mein hoti rahati hai, kyonki kaarboneti jal mein choonaapatthar sahaj hi vileen ho jaata hai.

raasaayanik ki apeksh balakrut aparadan karne ki shakti nadi mein bahut adhik hoti hai. saadhaaranataya shuddh jal shailon ko apagharshit naheen kar sakta, kintu jab usamein baaloo aur bajari mili ho to sthiti badal jaati hai, kyonki ve donon ek doosare ko sanbalit karte hain. nadi ka ka jal shakti pradaan karta hai aur baaloo evam bajari apagharshan karte hain, jiske prabhaav se tah aur kinaare shanai: shanai: chhote hote jaate hain. saath hi ve swayam bhi tah ke shailon ko apagharshit karne mein bhaag lete hain.

nadi ki apagharshan shakti ghaar ki teevrata par nirbhar hai aur dhaar ki teevrata sthalaakruti par aadhaarit hai. dhaal jitni hi pravan hoti hai, dhaar bhi usi ke anusaar teevr hoti hai. saath hi jal ki maatra bhi dhaar ki gati ko prabhaavit karti hai. jal ki maatra ke saath dhaar ki gati uske ghanamool ke anupaat se badhti hai, arthaat yadi jal ki maatra aathaguni ho jaaya, to dhaar ki teji duguni ho jaati hai. falat:, jin deshon mein sookhe aur barasaati mausam pruthak pruthak hote hain, vahaaain nadiyon ki aparadan shakti barasaat ke dinon mein bahut badh jaati hai.

aarambh mein, visheshakar kathor chattaanon ke pradesh mein, nadi ke tat praaya: ekdam khade aur prapaati hote hain. kintu vaayumandaleeya kaarakon ke prabhaavavash, kinaaron ke oopari bhaag shanai: shanai: apaksheen hone lagte hain. isse utpann apaghatit aur khandit padaarth nadi baha le jaati hai. iske falasvaroop kaalaantar mein nadi ki ghaati ka parichhed j aakaar ka ho jaata hai arthaat uske donon kinaare tal ki or dhaaloo ho jaate hain.

nadi ooainche sthaan se bahakar samudra ki or jaati hai, at: usaka prayatn sadaiv yahi hota hai ki vah thal bhaag ko kaatkar itna neecha kar de ki vah samudratal ke baraabar ho jaaya. is tarah nadi ke sheersh se sangam tak ke anudaidhrya parichhed ki pravanata sheersh ki or sabse adhik aur sangam ke sameep sabse kam hoti hai. doosare shabdon mein, nadi ka oodhrvaadhar kataav ghaati ke oopari bhaagon mein sabse adhik hota hai aur samudra ki or badhne par kam hota jaata hai. jab nadiyon ki ghaati aisi sthit mein pahuainch jaati ki oodhrvaadhar kataav ek dam band ho jaaya aur usaki ghaati ka tal samudratal ke samaan ho jaaya, to vah aparadan ke charam star (level erosion) par pahuainch jaati hai. vah ghaati, jismein oodhrvaadhar kataav teevrata se pragatisheel ho, taroon kahalaati hai, jo charamastar par pahuainch chuki ho use vruddh evam inki antasth avastha ko praudh kehte hain. ek hi ghaati ke vibhinn bhaagon mein teenon avasthaaeain vidyamaan ho sakti hain.

yadi kisi vruddh sarita ki ghaati ke pradesh mein vivenik (tectonic) shaktiyon ke prabhaav se sthalaakrutik parivartan ho jaae tatha sthal vaishamya pun: utpann ho jaae to nadi ka punaryukt ho jaata hai aur vah ek baar fir oodhrvaadhar kataai aarambh kar deti hai.

saadhaaranataya nadi ki ghaati ki pravanata (gradient) kramik haati hai, yadyapi pravanata ki maatra sthaan sthaan par ghat badh sakti hai. kintu kabhi kabhi pravananata akramik bhi ho jaati hai aur jal prapaat ban jaate hain. yeh sthiti visheshakar aise pradeshon mein hoti jahaaain kathor aur mrudu shilaaon ka ekaantaran hota hai. mrudu jal sugamata se aparadit hokar bah jaata hai, jisse vahaaain ghaati ke utkeernan adhik maatra mein ho jaata hai. kathor star avarodhi hai aur jahaaain ka tahaaain khada rah jaata hai. paani uske oopar se bahata hua ghaati ke mrudu staravaale adhik utkeern bhaag mein girne lagta hai. is prakaar ghaati ki pravanata akramik ho jaati hai aur jal prapaat ban jaate hain.

bahudha kaalaantar mein in prapaaton ka sthaan bhi kramash: nadi ke sheersh ki or hatata jaata hai. hota yeh hai ki prapaat ke sthaan par paani ke ooainchaai se girne ke kaaran nadi ki dhaar mein teji aa jaati hai, jisse usaki aparadan shakti aur badh jaati hai. prapaat ke theek neeche ek prakaar ka dah ban jaata hai, jismein bhainvar padne lagte hain tatha unamein teevrata se ghoomta hua paani prapaat ki deevaar ko kaatne lagta hai. is prakaar neechevaala mrudoo star aur bhi teji se katata jaata hai aur ek prakaar ka talochhedan hone lagta hain, jisse kathor star nirvalanb hokar baahar ko nikal aata hai. kaalaantar mein talochhedan ke aur badh jaane par, kathor star ka sabse agrim bhaag abalanb ke abhaav mein tootakar gir padta hai aur prapaat ka sthaan gire hue shail ki naap ke baraabar peechhe hat jaata hai. yeh kriya baaranbaar hoti rahati hai aur prati baar prapaat ka sthaan kramash: peechhe hat jaata hai. is prakaar ke aparadan ke kaaran kadi chattaan ke tootane se, prapaat ke praarambhik sthaan se peechhe ki or ek gahari dhaati banti chali jaati hai. jabalapur ke seep narmada nadi ki sangamarmar ke shailon mein utkeern ghaati aur bhedaaghaat ka jalaprapaat is ghatna ka sundar ddashtaant hai. vishvavikhyaat nyaagara nadi ka prapaat isi prakaar bana hai. vahaaain ki gayi maapon se maaloom hota hai ki prapaat prati varsh apne sthaan se praaya: dedh meter peechhe hat jaata hai. anumaanat: isi gati se praaya: 11 kilometer lambi nyaagara ki ghaati ko banane mein 20 se 35 hajaar varsh tak lage honge. aur bhi kai paristhitiyon mein jalaprapaat ban sakte hain, kintu moolat: har avastha mein ghaati ke vibhinn avayavon ke aparadan ki gati mein antar hona aavashyak hai. ye jalaprapaat ghaati ki taroon avastha ke upalakshak hote hain.

aparadan ki charam star avastha mein pahuainchane par nadi ki shakti apne paashrvo ko kaatne mein lag jaati hai. jab ghaati ekdam seedhi ho, to donon paashrv ek se katate hain, kintu thodi bhi vakrata aa jaane se asamaanata utpann ho jaati hai. ghaati ke avatal (concave) paashrv ki or dhaar mein adhik teevrata hoti hai aur isaliye udhar kataav adhik maatra mein hota hai. isliye vipreet uttal (convex) paashrv ki or dhaar ka veg kam ho jaane se, na keval kataav band ho jaata hai balki nadi dvaara vishmata aur badh jaati hai aur nadi ka maarg adhikaadhik vakr hota jaata hai. is prakaar visrpi mod (meander) ki utpatti hoti hai. bahudha in modon ka aayaam (amplitude) atyadhik badh jaata hai aur mod bhi bahut jatil ho jaate hain. kabhi kabhi do mod ek dusare ke itne paas aa jaate hai ki unke beech ki ekdam seedhi doori, nadi ke anuprasth maarg ki doori ka dashamaansh ya aur bhi kam hoti hai. aisi avastha mein kabhi kabhi do modon ke beech sankeern greeva ko kaatkar, seedhe maarg se bahne lagti hai aur ek ya adheek visrpi mod parityakt ho jaate hain, jinhein chhaadn (ox-bow) kehte hain.

parivhan

nadi ka parivhan kaarya, praaya: sabhi praakrutik kaarakon ki apeksha adhik prabhaavi hota hai. niji aparadan se utpann jo shail choorn, bajari, baaloo aur mitti utpann hoti hai, vah sab nadi bahaakar samudra ki or le jaati hai, saath hi vaayumandaleeya kaarakon, vishesh kar varsha jal dvaara utpann shail choorn tatha khand bhi, kaalaantar mein kisi na kisi maarg se nadi ki ghaati mein pahuainch jaate hain aur usaki dhaar mein pakadkar ve sab samudra ki or dheere dheere aage badhte jaate hain. jin bade bade khandon ko nadi ki dhaar uthaane mein asamarth hoti hai, ve tah ke anuprasth ludhakate hue chalte hain aur chhote kan nilambit badhte hue chale jaate hai.

parivhan ki shakti dhaar ki gati par nirbhar hai. yadi gati mein vruddhi ki maatra va ho, to parivhan shakti va6 ho jaayegi. arthaat yadi gati badhkar dugani ho jaaya, to parivhan shakti 64 guni ho jaaegi. isse spasht hai ki varshaati baadh ke samay nadiyon ki parivhan shakti aur saath saath vinaash shakti ki maatra bahut bhayaanak ho jaati hai. ganga, brahaaputr ityaadi badi nadiyon ke tatavarti nivaasi is vinaashakaari shakti se bhali bhaanti parichit hain.

nilambit baaloo aur mitti ke atirikt anekaanek padaarth nadiyaaain apne jal mein vileen kar, mahaadesheeya bhaagon se samudra ki or le jaati hain. jaisa varsha jal aur aantabhaum jal ke prakaranon mein bataaya ja chuka hein, unki raasaayanik kriya prachur parimaan mein hoti hain, jisse vileya padaarth bhi usi anupaat mein banta hain. yeh sabhi padaarth kaalaantar mein nadiyon mein pahuainch jaate hain. nadiyaaain swayam bhi apni kriya se kuchh vileya padaarth utpann karti hain aur yeh sab kramash: samudra mein pahuainch jaata hain.

ganana kar yeh anumaan kiya gaya hai ki ganga aur brahamputr apne sammilit maarg se praaya: 1100 n 106 ghan meter mitti aur baaloo prati varsh Bengal ki khaadi mein pahuaincha deti hai amareeka ki misisipi nadi dvaara prati varsh parivhit padaarth ki maatra 200n106 ghan meter hain. cheen ki hvaangaho nadi itne vishaal parimaan mein mitti le jaati hain ki uske muhaane ke paas ka samudra meelon door tak peela bana rahata hain aur isi se vah peet saagar (Yellow sea) kahalaata hain. dakshini amareeka mein amejaun nadi dvaara bahaai mitti aur baaloo se uske muhaane ke saamane samudra ke tal mein jo delta saddash bhoomi ban gayi hain, vah praaya: 200 kilometer lambi hai. anumaanat:, vishv ki samast nadiyon dvaara prati varsh parivhit padaarth ki maatra 16 ghan kilometer aaainki gayi hain.

nikshepan

jaisa poorvavarti khand mein bataaya gaya hain, nadi ki parivhan shakti usaki dhaar ki gati par nirbhar hoti hai. at: jyonhi usaki dhaar ki gati mein haas hota hai, usaki laad ka kuchh ansh turant nikshepit hone lagta hai.

nadi ke maarg mein sabse pehla mahatvapoorn nikshepan kendra pahaad ke tal mein us sthaan par hota hai jahaaain vah paarvatya pradesh chhodkar maidaan mein pravesh karti hai. kaafi bade bade golaashyam aur chhoti badi batiyaaain, jo ghaati mein paarvatya bhaag mein sugamata se ludhkati hui chali aati hai, nadi ke maidaan mein pravesh karte hi tal mein baith jaati hain. is prakaar pahaadon ke tal bhaag mein ek nikshep ban jaata hai, jise jalodh shanku, athva pankha (alluvialo cone or fan) kehte hain.

doosra mahatvapoorn gati parivartan ka sthaan nadi ke sangam ke sameep hota hai. ek to ghaati ki dhaal vahaaain pahuainchate pahuainchate yon hi bahut kam ho jaati hai, doosare samudra va jheel ka paani bhi bahaav ko rokata hai. bahudha dhaar ka veg itna kam ho jaata hai ki jvaar ka veg nadi ke veg se adhik hota hai, jise jvaar ke samay nadi ki dhaar ulti bahne lagti hain. iska fal yeh hai ki sangam ke paas ke pradesh mein nadi badi teevrata se avasaad aur talachhat nikshepit karne lagti hai aur usaki apni banaai hui ghaati hi bharne lagti hain. avasaad ke jama hone se nadi ka bahana aur bhi kathin ho jaata hai aur nadi kat katakar kai chhoti dhaaraaon mein vibhkt ho jaati hai. kaalaantar mein is nikshepit avasaad mein ek chauras maidaan sa ban jaata hai, jismein se anek chhoti dhaaraaeain ati manthar gati se bahti hui samudra ki or jaati hain. yeh maidaan tribhujaakaar hota hai, jiska ek sheersh nadi ki ghaati ke us sthaan par hota hai jahaaain se dhaara ka vibhaajan aarambh hota hai aur uske saamane waali aadhaar rekha samudra ke tat ke anuprasth hoti hai. is prakaar ke pradesh ko delta kehte hain.

nadi ke sangam par gati ke avarooddh hone se bahudha baaloo deerdhaakaar raashiyon mein nikshepit ho jaata hai, jise baalukaabhitti, athva rodhika (sand bar) kehte hain.

jalodh shanku aur delta ke beech ke bhaag mein nadi bahudha mausami baadh aur utaar se prabhaavit hoti rahati hai. baadh ke samay nadi mein itna paani aa jaata hai jo usaki ghaati mein naheen sama sakta. falat: vah donon kinaaron ke oopar se hota hua kuchh door tak fail jaata hai. jo pradesh is prakaar baadh ke prabhaav mein aa jaata hai, use baadh maidaan (flood plain) kehte hain. us bhaag mein nadi ki dhaar ki gati mukhya dhaar ki apeksha bahut kam ho jaati hai, jisse vahaaain prachur maatra mein mitti aur baaloo nikshepit ho jaati hai. iske vipreet baadh ke samay mukhya dhaar ki gati saadhaaran samay ki gati se bahut adhik hoti hai, isaliye vahaaain aparadan badh jaata hai aur nadi pehle jama ki hui baaloo aur mitti ko kaatkar le jaati hai.

jaisa pehle ullekh kiya ja chuka hai, nadi ki cheshta apni ghaati ko nirantar gahra kar, aparadan ke charamastar par pahuainchaane ki hoti hai. ghaati ki gaharaai badh jaane par bahudha aisi sthiti aa jaati hai ki baadh ke samay bhi pehle waali baadh ke maidaan tak na pahuainchane paae. aisi dasha mein nadi ek naya baadh-maidaan banaati hai. puraanaavaala baadh-maidaan nadi vedika (river terrace) kahalaata hai. bahudha nadi ki ghaatiyon mein Abhinav tal se kaafi oopar donon kinaaron par, athva ek hi or, is prakaar ki vedikaaeain dikhaai padti hai. kaheen kaheen to 2-3 ya aur bhi adhik vedikeain kramash: ek doosari ke oopar vibhinn talon par milti hain. unke adhyayan se nadi ki ghaati ke vikaas ka itihaas jaana ja sakta hai.

himnadi aadi

ooainche parvateeya bhaagon aur sheetapradhaan deshon mein thande mausam mein jal ke badle him varsha hoti hai. jin pradeshon mein him-varsha us maatra mein adhik ho jitna garmi ke samay mein him pighlata hai, ve pradesh sadaiv himaachhaadit rahate hain. jis ooainchaai par aisa hota hai, use him rekha kehte hai. yeh ooainchaai vibhinn vibhinn akshaanshon aur pradeshon mein vibhinn hoti hai, yatha himaalaya mein iski ooainchaai praaya: 4,500 se 5,500 meter tak hai, aalps parvat 2,400 meter aur Norway mein keval 1,500 meter hai. dhruvon ke paas, vishesh kar dakshini dhruv par to samudra ka bahut bada bhaag sadaiv himaachhaadit rahata hai.

aakaash se aate samay him rooi ke gaalon ke samaan komal hota hai. vastut: usamein prachur maatra mein vaayu mili hoti hai. jab ek badi raashi ekatrit ho jaati hai, to oopari staron ki daab se neeche ki staron mein se hava nikal jaati hai aur himkan aapas mein milkar kathor barf ke roop mein parivrtit ho jaate hain. bahut vishaal parimaan mein ekatrit hone par gurootvaakarshan ke prabhaav se, anukool sthalaakrutti pradeshon mein barf ki raashi dheere dheere neeche ki or khiskane lagti hai aur is prakaar ek nadi si ban jaati hai, jise himnadi (glacier) kehte hain. kaalaantar mein nadi ki bhaaainti vah bhi apne liye ek ghaati bana leti hai. jise vah shanai: shanai: adhikaadhik gahra karti jaati hai.

thos barf se utkeern hone ke kaaran himnadi ki ghaatiyon ke kuchh vishisht lakshan hote hain, jinmein se teen pramukh hai:

(1) unka nitl chauda aur kinaare prapaati hote hain, jisse unka oodhrv parichhed chh aakaar ka hota hai,

(2) unki ghaatiyaaain sarpil na hokar bahut door tak ekdam seedhi chali jaati hai aur

(3) mukhya himnadi aur sahaayak himnadi ke sangam ke sthaan par donon ghaatiyon ka tal kramik na hokar prapaati hota hai. is kaaran sahaayak nadiyon ki ghaati nilanbi ghaati (hanging valley) kahalaati hai.

thos hone kaaran himnadi ki gati bahut kam hoti hai. kaheen kaheen to dinbhar mein keval 30 seinteemeetar hi aage badhti hai. kabhi kabhi veg apekshaakrut adhik bhi hota hai. alaaska mein kuchh himnadiyaaain ek din mein praaya: dhaai teen meter badh jaati hai. yeh gati, nadi ki gati ke samaan hi, barf ki maatra aur praadeshik dhaal ki pravanata par nirbhar hoti hai.

himrekha ke neeche pahuainchane par barf pighlane lagti hai aur saadhaaran nadi ka roop dhaaran kar leti hai. himaalaya se aane waali praaya: samast nadiyon ke jal ka mool srot yeh pighlati hui himnadiyaaain hi hain. jin pradeshon mein himrekha samudratal mein praaya: baraabar hi hoti hai, vahaaain himnadi swayam samudra mein gir jaati hai. aise sangamon par bahudha barf ki badi badi raashiyaaain peechhe se aanevaali barf ke dabaav se mool nadi se tootakar pruthak ho samudra mein pravaahit ho jaati hai aur bahate bahate kaafi door nikal jaati hain. in raashiyon ko plaavi himshail (iceberg) kehte hain. plaavi himshail anya kaaranon se bhi ban sakte hain. bahut thandhe pradeshon mein kabhi kabhi aisa bhi hota hai ki samudra ke paas jaane par bhi himnadi apna roop banaaye rahati hai aur tat ke sameep ki samudra tah ko bhi uttkeern kar apni ghaati kaafi door tak aage badhaati chali jaati hai. naarve aur sveeden mein is prakaar se bani ghaatiyon ke bahut udaaharan hain evam unhein fiyrd (fiord) kehte hain.

nadi ki bhaaainti, himnadi bhi chattaanon ko aparadit tatha unase toote hue khandon ka parivhan karti hai. kintu donon ki kriya vidhi mein bahut antar hai. jahaaain nadi ki tah mein anek chhote-bade rode dhaar ke veg se ludhkate hue aage badhte hain, himnadi mein unke ludhkane ke liye koi avsar naheen. jo tukada jis dasha mein barf mein fains jaata hai usi avastha mein aage badhta hai. yatr tatr chattaanon ke bahut se tukade tootakar himnadi ke oopar gir jaate hain. jyon jyon himdhaar aage badhti hai, ye khand bhi jyon ke tyon pade hue aage badhte hain. is bhinnata ke falasvaroop jahaaain nadi dvaara parivhit patthar kuchh kaal ludhkate hue tatha aapas mein takaraate hue gol matol batiya svaroop ho jaate hain, himdhaar dvaara le jaaye gaye khand ant tak koneeya va nukeele hi bane rahate hain.

iske atirikt dhaar ki sahaayata se nadi apne parivhit padaarth ko aakaar aur ghanatv ke aadhaar par pruthak pruthak bhaagon mein vibhkt kar deti hai, yatha tej dhaar ki jagahon par keval moti bajari, usase kam tej dhaar mein moti baaloo evam gati ke kramash: aur kam hone par maheen baaloo aur mitti baari baari se ghaati ki tah mein jama hoti hai. iske vipreet himnadi padaarth ko isaprakaar chhaaaint naheen sakti, apitu usaki laad mein bade rode, maheen baaloo aur mitti, vibhinn aakaaron ke khand, sab ek saath mile hue aage badhte hain. aur jahaaain himnadi ka pighlana aarambh hota hai usaka sabka sab bina kisi vibhaajan ke ek saath nikshepit ho jaata hai.

himnadi mein padaarth ke parivhan ki shakti aparimit hai. shilaaon ke bade khandon ko bhi himdhaar usi sugamata se parivhit kar sakti hai jisse ki chhote kanon ko. is prakaar jahaaain nadi ki ghaati mein maatr shail se pruthak krut badi badi raashiyaaain bina chhote khandon mein toote hue vishesh door tak aage naheen ja sakti, himnadi ki ghaati mein ve nirantar aage parivhit hoti rahati hai. himnadi ka jahaaain ant hota hai aur barf pighlati hai, vaheen ye bade bade khand gir padte hain. sthaaneeya praadeshik shailon se inka koi maatru sambandh naheen hota, isliye ve visthaapit (erratic) khand kahalaate hain. himnadi se dharaatal par girte samay jis pahal par bhi ye tik jaayain, usi par tike hue anek kaal tak khade rah jaate hain. kabhi kabhi ye keval ek chhote se kone ke bal girte hain aur usi ke bal khade rah jaate hain. aisi sthiti mein inka santulan bada sthir sa dikhaai padta hai aur inhein du:sthit (perched) khand kehte hain.

ghaati ki tah ke paas barf mein fainse hue khand apne nukeele konon se tah ki shilaaon ko kharonch daalte hain. barf ke dabaav aur shilaaon ki kathorata ke anusaar, ye kharonchein kam ya adhik gahari hoti hain. kabhi kabhi bahut se chhote chhote khand paas paas hote hain. un sabki ragad se ek hi shila mein anek kharonchein ban jaati hain. in khandon ki ragad himnadi ki pravaah ki disha mein hi lagti hai, isliye sab kharonche ek doosare ke samaantar hoti hai. is prakaar kharonchi hui shilaaon ko rekhaanvit (striated) kahatein hain. is vipreet kabhi kabhi aisa bhi hota hain ki himnadi mein nitil ke paas fainsa hua koi shailakhand ghaati ki tah ki kathor shilaaon sein ragad khaata hua aage badhta hai, jisse tah se sata hua usaka paashrv chikna aur faladaar ho jaata hain aur anya paashrv poorvavat koneeya va nukeele chhoot jaate hai. is prakaar himnadeeranjit (glaciaed) pahaladaar (facetted) khand bante hain. kabhi kabhi himnadi ki ghaati mein avasthit shailon ke teele, barf ke apagharshan se kaafi chikne ho jaatein hain aur unke paashveerya kone jhad jaate hain. adhikaansh chiknaahat teele ke us bhaag mein hoti hai jo dhaar ki vipreet disha mein hota hain, kyonki barf aage ki or ragad deti hui badhti hain. jo bhaagapaashrv ki dasha mein hota hain, vah jyon ka tyon khudara aur nukeela chhut jaata hai. is prakaar ke teelo ko raash muhaane (rocks montonnecs) kehte hein.

adhikaanshat: himnadi chattaanon ke khandon ko apne oopari tal par hi parivhit karti hanai. ghaati ke kagaaron ki chattaanon tushaar aadi ke prabhaavavash samay par tootati rahati hain, jisse shailakhand evam choorn himnadi ke oopar uske kinaaron ke paas girte rahate hain aur is tarah himnadi ke donon kinaaron par parivhit padaarth ko paashrv moren (lateral moraine) kehte hain. himnadi ke madhya bhaag ke oopar aarambh mein shailakhand praaya: bilkul naheen hote, kyonki vah bhaag ghaati ke kinaaron se door hota hai. par do him-nadiyon ka sangam hone par ek ke daahani or tatha doosari ke baai or ke more na paraspar mil jaate hain aur sangam ke aage se madhya moren ban jaata hai. ant mein jahaaain himnadi samaapt hoti hai aur barf ke pighlane se jal banta hai, vahaaain barf ki satah par aur beech mein laaya hua samast padaarth girkar ekatrit ho jaata hai. ise agraantasth moren kehte hain. ismein stareekaran ka nitaant abhaav hota hai. yadi jalavaayu mein parivartan, ya kisi aur kaaran se himnadi apni pehli seema se agragaami hone lage, to barf pehle bane hue agraantasth moren ki samast raashi ko aage dhakelati hui chalegi. iske vipreet yadi himnadi sheersh ki or hatati ho, to agraantasth moren ka ek aastar peechhe ki or banta chala jaaega.

samudra tatha jheel

dharaatal ke teen chauthaai bhaag par aadhipttya hote hue bhi samudra apna vistaar badhaane ke liye nirantar prayatnasheel rahata hai. pratyakshat: usaka kaaryakshetr tatasth pradesh hai, jahaaain vah apni prabal tarangon dvaara chattaanon ko chhinn bhinn kar bhoomi ke oobad khaabadpan ko nasht karta hua mahaadesh ko apni satah ke baraabar chauras banaane ka prayatn karta hai. yon to shaant mausam mein bhi laharein baar baar chattaanon se takaraakar unhein aaghaat pahuainchaati hain, par toofaan ke samay to unki shakti sahastron guna adhik ho jaati hai. bade bade toofaanon ki laharein praaya: 14-15 meter ooainchi uthati hain. unke dvaara feinka hua fen, bajari aur chhote rode 40-50 meter ooainche uchhalate hue dekhe gaye hain. pratyek lahar apni samast jalaraashi ke bhaar se tat par aaghaat karti hai aur aisa prateet hota hai maano prakruti bahut bade ghan se tatasth pradesh ko peet rahi ho.

laharein paroksh dhang se bhi apni aparadi kriya mein sahaayata leti hein. sabhi chattaanon mein maheen daraarein aur chhote chhote chhidr hote hain. jab laharein jor se aakar achaanak chattaanon se takaraati hain, tab in daraaron aur chhidron mein bhari hui hava ko baahar nikalne ka avsar naheen mil paata aur vah jahaaain ki tahaaain dabakar sankuchit ho jaati hai. laharon ki vaapasi ke samay paani ka dabaav hatne par hava fir fail jaati hai. yeh kriya itni sheedhrata se hoti hai ki achaanak faili hui hava ko baahar nikalne ka maarg bhi naheen mil paata aur vah ek prakaar se visfotak shakti ka kaarya karti hai. kriya ke baar baar duharaane se daraaron aur chhidron ke chaaron or ki chattaane fatakar tootane lagti hain aur chhidr kramash: bade hote jaate hain.

kabhi kabhi aisa bhi hota hai ki daraarein samudra aur mahaadesh donon ki or khuli hoti hain. aisi avastha mein laharon dvaara dabaav padne par daraar ki hava teji se jameen ki or nikal bhaagati hai aur laharon ki vaapasi par utani hi teji se fir daraar mein ghus jaati hai. baar baar aisa hone se maheen chhidr bade hote jaate hain aur kramash: surangein ban jaati hain, jinhein fdhamichhidraf (blow hole) kehte hain.

is prakaar tatasth chattaanein laharon ki pahuainch ki ooainchaai par dheere-dheere khekhali hone lagti hain, jisse ooparavaali chattaanon ka abalanb bhi kamjor hota jaata hai aur ve bhi shanai: shanai: tootakar girne lagatati hain. gurootvaakarshan bhi is kriya mein bahut kuchh bhaag leta hai.

jahaaain chattaanein kai prakaar ki hon, kuchh kamjor aur kuchh kadi, vahaaain laharon ko, vastut: kisi bhi praakrutik abhiktrta ko apna kaarya karne mein adhik suvidha hoti hai; kyonki jab kamjor chattaan kat jaati hai, tab usase sanparkavaali kadi chattaan ka aadhaar bhi kamjor ho jaata hai aur usaki niji kadaai ka mahatva kam ho jaata hai.

laharon ke prabhaavavash chattaanon ke tootane se vividh aakaar ke tukadon ko to laharein teji se ludhkaakar chattaanon par de maarati hain, jisse ve swayam bhi tootakar chhote tatha golamatol ho jaate hain. isse samudra ki aaghaat karne ki shakti aur bhi badh jaati hai. kaalaantar mein tukade bajari mein parivrtit ho jaate hain. uske baad laharein unhein pal bhar bhi vishraam naheen lene deteen, nirantar apne saath aage peechhe dhaseetati firti hain. falat: kuchh samay baad bajari ke tukade bahut maheen aur ekdam golaakaar ho jaate hain, kabhi kabhi itne chhote ki tah mein baith bhi naheen paate aur paani mein latake rah jaate hain. kanon ke is prakaar chhota va gelamatol karne ki laharon ki shakti nadi ki apeksha kaheen adhik hoti hai, kyonki ek to nadi ki tah mein ragadvaali gati keval ek hi disha mein, nadi ke bahaav ki or hoti hai, doosare nadi ki ghaati ke nichle bhaag mein dhaar ke kam ho jaane par bade bade kan jyon ke tyon pade rah jaate hain aur is prakaar unki uttarottar chhote hone ki kriya band ho jaati hai.

jvaarabhaata tatha samudri dhaaraaeain

jvaarabhaata aur anya prakaar se utpann hui samudri dhaaraaeain bhi laharon ke kaam mein sahayog deti hain. inka vishesh ullekhaneeya prabhaav sangam ke paas nadiyon ki sainkari ghaatiyon mein hota hai, jahaaain jvaarabhaate ke kaaran tej dhaaraaeain utpann ho jaati hain, jo balui kinaaron aur paani mein nimgn chattaanon ko kshaya karne ka prayaas karti hain. ye dhaaraaeain mitti aur baaloo ko nadi ke muhaane tatha samast samudratat ke paas se beech samudra ki or bahut door tak baha le jaati hain.

samudri anaachhaadan ka maidaan

laharon ke aaghaat ka prabhaav paani ki satah se oopar nikli hui bhoomi tak hi seemit naheen rahata, varan samudra ke chhichhle bhaagon ki tah par bhi padta hai. anubhav se maaloom hota hai ki praaya: 30 meter ki gaharaai tak unki kshaya karne ki shakti kaaryasheel rahati hai. satah ke neeche laharon ka kaarya praaya: vaisa hi hota hai jaisa badhi hui ghaas ko hainsiye se kaatne ka, arthaat yon samajhna chaahiye ki laharein apne aaghaat se samudra mein doobe hue shailon ki ooainchaai mein asamaanata door kar ek chauras sthaan banaane ka prayaas karti hain. sthaan sthaan par samudra ki gaharaai naapane se maaloom hota hai ki samast bhoobhaag ke chaaron or praaya: 30 meter ki gaharaai par ek chauras maidaan sa hai. is maidaan ki samudri anaachhaadan ka maidaan (plain of marine denudation) kehte hain.

jheel

samudra aur jheelon ke praakrutik gunon mein keval aakaar ka hi antar hai. samudra jahaaain ati vishaal evam athaah jalaraashi hai, jheel apekshaakrut bahut chhota jalaashaya hai. isi se jheel mein uthi tarangon ka veg evam jvaarabhaate ka parimaan samudra ki apeksha ati laghu hota hai. falat: bhooprushth ke prati jheel ki aparadi kriya praaya: samudra ke samaan hi hoti hai, keval usaki maatra jheel ke aakaar ke anuroop laghu ho jaati hai.

avasaad ka sanchayan

uparyukt vivran mein vibhinn praakrutik kaarakon ki aparadi aur anaachhaadi kriya evam usase utpann avasaad ityaadi ke parivhan ka vrut bataaya gaya hai. yahaaain yeh baat dhyaan dene yogya hai ki pratyek kaarak ka kaaryakshetr vishisht hai. vah apni kriya se utpann aparadit evam apaghatit padaarth ko apne kriyaakshetr ke sabse nichle sthaan tak le jaata hai, jahaaain se samay evam vaataavaran ke anusaar doosra kaarak use apne prabhaav mein lekar apne kriyaakshetr ki sabse neeche ki satah tak le jaata hai. udaaharanaarth, varshaajal ki kriya se utpann apaghatit padaarth jal ki chhoti chhoti dhaaraaon evam naaliyon dvaara nadi mein pahuainch jaati hain aur fir nadi use samudra athva jheel mein pahuaincha deti hai. is prakaar tushaar dvaara utpann shailakhand gurootvaakarshan ke prabhaav se pahaadi ke tal mein pahuainchate hain aur fir jab tak vah kisi anya kaarak ke prabhaav mein na aa jaayain, vaheen sanchit pade rahate hain. himnadi apni kriya se utpann avasaad ko parivhit kar apne galane ke sthaan tak le jaati hai. vahaaain usaka prabhaavakshetr samaapt ho jaata hai aur fir vah avasaad nadi ke prabhaav mein aa jaata hai.

bhooprushth ka sabse nichla sthaan samudra hai. at: shailon ke aparadan aur apaghatan se utpann avasaad ka antim thikaana samudra hi hai. avasthaavishesh ke kaaran yeh ho sakta hai ki yeh padaarth maarg mein kisi kisi sthaan par kuchh kaal tak rookata hua aage badhe; fir bhi, der saber, kabhi mand gati se, kabhi tej gati se, vah samudra ki or yaatra karta hi rahata hai.

avasaad ko samudra tak pahuainchane ka sabse adhik bhaar nadi ke oopar hai. is baat ka pehle ullekh kiya ja chuka hai ki nadi mein apne parivhit padaarth ko uske aakaar ke aadhaar par bajari, baaloo, mitti ityaadi mein vargeekrut karne ki shakti hai. at: adhikaansh avasaad mota, madhyam aur maheen teen vargon mein vibhkt ho jaata hai, jo kramash: tat se adhikaadhik doori par jaakar nikshepit hote hain, arthaat ek hi star ke tat ke niktavaale bhaag mein kan bade aur dooravaale bhaag mein maheen aur chhote honge. kisi bhi ek sthaan par jyon jyon avasaad adhik maatra mein sanchit hoga, vahaaain ka jal bhi apekshaakrut chhichhla hota jaaega aur iske falasvaroop dhaar ka veg bhi kuchh badh jaaega. at: samast avasaad pehle ki apeksha kuchh doori par jaakar avakshepit hoga aur pratyek sthaan par sanchit avasaad kuchh mota ho jaaega, yatha chhote kankadon tatha bajari ke oopar moti baaloo, moti ke oopar maheen baaloo aur maheen baaloo ke oopar mitti jama hogi. kuchh kaal ke uparaant aur adhik avasaad ke sanchit hone se samast pradesh fir aur chhichhla ho jaaega aur tab avasaad ka nikshepan pun: ek ek pag aur aage pahuainchane lageinge.

yadi kisi kaaran uparyukt nikshepan kendra mein samudra ki tah dheere dheere khiskakar neechi hone lage aur khiskane ki gati avasaad ke sanchit hone ki gati ke baraabar ho to adhikaadhik avasaad ke sanchit hone ke baad bhi samudra ki antat: gaharaai jyon ki tyon bani rahegi aur pratyek sthaan par ek hi aakaar ke kanon ka nikshepan chirkaal tak aviraam hota rahega.

ek aur dasha aisi bhi ho sakti hai jab samudra ki tah ke khiskane ki gati avasaad ke sanchit hone ki gati se adhik ho jaaya. us avastha mein prabhaav ulta hoga aur avasaad ke sanchit hone par bhi samudra adhikaadhik gahra hota jaaega. falat: vibhinn aakaar ke kanon ke nikshepan ka sthaan kramash: ek ek pag tat ki or badhta jaaega.

uparyukt pehli aur teesari sthitiyon mein vibhinn aakaar ki raashiyon ka ekaantaran hota hai aur doosari sthiti mein samaan aakaar ka avasaad moti moti raashiyon mein sanchit ho jaata hai.

starikaabhavan (Lamination)

adhikaansh nadiyon dvaara laae hue avasaad ki maatra varsha rituon mein bahut kam hoti hai. at: varshaakaal mein avasaad bahut prachur maatra mein samudra mein nikshepit hota hai. bahudha do uttarottar varsha rituon ke beech ki avadhi mein sanchit avasaad ki maatra naganya hoti hai. aisi sthiti mein avasaad sanchayan rook rookakar hota hai aur ek varsha ritu mein aae hue avasaad ko doosari ritu ke avasaad ke aane ke poorv kuchh kada hone tatha dab jaane ka avsar mil jaata hai. uparishaayi jal ke bhaar se avasaad ko dabane mein sahaayata milti hai. falat: uttarottar varsha rituon mein aae hue avasaad pehle aae hue avasaadon se ekdam mishrit naheen hote, apitu pruthak pruthak starikaaon mein sanchit hote hain. is kriya ko starikaabhavan kehte hain. pratayek starika ki motaai ek varsha ritu mein aae hue avasaad ki maatra par nirbhar hogi. ausat mein yeh 2 se 4 mileemeetar tak hoti hai.

stareebhavan (Stratification)

yadi avasaad ka nikshepan kai varshon tak satat hota rahe, to spashtataya patali patali starikaaon mein sthaan par kuchh mote staron mein avasaad sanchit hoga aur in staron ki motaai avasaad aane ki gati evam us avadhi par nirbhar hogi jismein avasaad ka nikshepan aviraam hota rahe.

aabhaasi sanstaran (False bedding)

staron mein sanchit avasaad ke kanon ki vyavastha par bahaav ki gati aur disha ki sthirta ka prabhaav bhi padta hai. maheen mitti aur maheen baaloo ke kan jal mein bahut der tak nilambit rahate hain aur bahut hi shanai: shanai: tah mein baithate hain. unka nikshepan bhi apekshaakrut gahre paani mein hota hai, jahaaain dhaar ekdam shithil pad jaati hai. aisi avastha mein kanon ke sanchit hone ki vyavastha nirantar ek si bani rahati hai aur star suvyavasthti aur niyamit bante hain. kanon ko jamane ke liye paryaapt samay milta hai aur star samudratah ke samaantar bante chale jaate hain.

iske vipreet moti baaloo aur bajari ityaadi ke sanchit hone ka sthaan apekshaakrut chhichhla hota hai. aise sthaanon mein dhaar ki gati bahudha parivrtanasheel hoti hai, kabhi mand ho jaati hai aur kabhi teevr. mand avastha mein sanchit avasaad ka oopari bhaag, teevr gati ki avastha mein aparidit hokar bahne lagta hai aur jahaaain dhaar mand ho vahaaain pun: nikshepan ho jaata hai. is prakaar pun: nikshepit padaarth pehle star ke samaantar naheen hota. iske atirikt chhichhle paani mein, jahaaain in mote kanon ka nikshepan hota hai, bahudha dhaar ki disha bhi badalti rahati hai. yeh parivartan jvaarabhaata aur prachand pavan ityaadi ke kaaran hota rahata hai. at: dhaar ki disha ke saath saath avasaadeeya staron ki disha bhi sthaaneeyat: badalti rahati hai.

is prakaar chhichhle paani mein sanchit avasaadeeya shailon ke star bahudha samaantar na hokar ek doosare se kon banaate hain, jinki maap sthaan sthaan par bhinn bhinn ho sakti hai. is ghatna ko aabhaasi sanstaran kehte hain.

tarangachinh (ripple marks) paadachinh (foot prints) ityaadi

kabhi kabhi avasaad kshetron mein aisi sthiti hoti hai ki jal ki tarangon ki chhaap bhi avasaadeeya staron mein mudrit ho jaati hai. chhichhle pradeshon mein, vishshakar jvaarabhaataantar (littoral) katibandh mein, tarangon ka veg itna adhik haata hai ki vahaaain nikshepit baaloo aur mitti unke sanketon par naachati firti hain aur bahudha unhein bhi tarang roop de deti hain. nae avasaad ke aane se poorv yadi is tarangit baaloo ko sookhakar kuchh ddadh hone ka avsar mil jaaya, to yeh tarang roop surakshit rah jaata hai. bhaate ki avastha mein avasaad ko sookhane evam ddadh ho jaane ka avsar bahudha mil jaata hai.

isi prakaar kekadon, keedon makodon tatha anya jantuon ke paadachinh bhi jvaarabhaataantar pradesh mein sanchit avasaad mein surakshit rah ja sakte hain. kabhi kabhi varshaajal ki booaindon se bane aaghaatachinh bhi in avasaadon mein surakshit ho jaate hain.

choonedaar avasaad

samudra mein rahanevaale naana prakaar ke shalkadhaari jantuon ke marne ke uparaant unke shalk samudratah mein sanchit hone lagte hain. tarangon ke pravaah se bahudha ye shalk idhar udhar ludhkate rahate hain, jisse kaalaantar mein ve tootakar choor ho jaate hain aur nadi dvaara laai hui baaloo aur mitti mein mil jaate hain. adhikaansh shalk kailsiym kaarbonet ke bane hote hain aur is prakaar kailsiymamaya (arthaat choonedaar) avasaad, baaloo aur mitti banti hai. shuddh mitti, athva baaloo, ke star keval unheen sthaanon mein sanchit ho paate hain jahaaain shalkadhaari jeev praaya: anupasthit hon. kabhi kabhi shalk tootane se poorv hi avasaad mein dab jaate hain aur us avastha mein ve jyon ke tyon surakshit ho jaate hain. is prakaar surakshit shalkon ko jeevaashm (faasil) kehte hain.

samudra ke gahre bhaagon mein, jahaaain nadi dvaara laai hui baaloo aur mitti ka avasaad naheen pahuainch paata hai, shalkon ke choore ka shuddh avasaad nikshepit hota hai, jiski raashi kaalaantar mein bahut prachur ho sakti hai.

is prakaar baaloo ke star chhichhle paani mein, mitti ke star apekshaakrut kuchh gahre paani mein aur choonedaar avasaad ke shail adhik gahre samudri bhaagon mein sanchit hote hain.

lavaneeya star

shushk evam ushnataapradhaan deshon mein jalavaashpan bahulata se hota hai. in pradeshon mein yadi koi aisi jheel ho jismein nadiyon evam varshaavaah dvaara laae hue jalan ki maatra bhaap bankar ud jaanevaale jal ki apeksha kam ho, to vah jheel shanai: shanai: sookhane lagti hai aur kaalaantar mein poornataya vinsht ho ja sakti hai. nadiyon ke paani aur varshaavaah mein saadhaaranataya kuchh na kuchh lavan ghule rahate hain. at: jheel mein nadiyon dvaara nitya prati naya lavan padaarth aata rahata hai. ushnata ke prabhaav se paani bhaap bankar ud jaata hai, parantu lavan peechhe hi chhoot jaata hai. at: jheel ka paani uttarottar adhik lavaneeya athva khaara hota jaata hai. kaalaantar mein lavan itni adhik maatra mein sanchit ho sakta hai ki jheel ka jal usase santrupt ho jaae. isse adhik vaashpan se lavan avakshipt hone lagega, jisse avasaad lavaneeya ho jaaega. yadi lavan ke avakshepan ke samay nadiyon dvaara laae hue avasaad ki maatra bahut kam ho, to praaya: vishuddh lavaneeya star avakshepit ho sakte hain. Tibet ki anekon jheelein is kriya ki udaaharan hain. vahaaain varsha bahut kam hoti hai, jisse jheelein uttarottar sookhati ja rahi hain aur inki tahon mein lavaneeya star avakshepit ho rahe hain. Pakistan ke sault rainj parvat mein, khevada ke pradesh mein saindha namak tatha jipsam ke nikshep isi prakaar kisi praacheen saagar ki shaakha ke sookhane se bane honge.

avasaad ka sanyojan evam drudheebhavan

isi prakaar vibhinn praakrutik abhikrtaaon ki kriya se bhoo-prushtheeya shailon ka kshaya evam aparadan nirantar ho raha hai aur usase utpann avasaad antat: samudra ke gart mein sanchit hota ja raha hai. jyon jyon avasaad ke staron mein vruddhi hoti hai, neechevaale staron ke oopar nae aae hue padaarth ki daab badhti jaati hai. praaya: 300 meter mote avasaadeeya staron ki daab 80 kilogram prati varg seinteemeetar hoti hai. at: keval 60 meter maute staron ke sanchit hone par, sabse neeche ke staron par praaya: 13 kilogram prati varg seinteemeetar ki daab padne lagegi. jalaashaya ke paani ki daab bhi kuchh kam naheen hoti. prati ek meter paani ki daab 100 gram prati varg seinteemeetar hoti hai. in sabhi daabon ke prabhaav se avasaad ke gun niktatam aakar aapas mein ek doosare se guainth jaate hain. inke beech ka paani nikal jaata hai aur ve shushkapraaya ho jaate hain. jal ki patali patali jhilliyaaain kanon se fir bhi chipki rah ja sakti hain aur unka tanaav kanon ko paraspar juda rakhane mein sahaayata deta hai.

sanyojan

jalaashayon athva aantarbhom jal mein saadhaaranataya kuchh na kuchh lavan vileen hote hain1 jab yeh jal rista hua avasaad mein se bahata hai, to kuchh vibhinn kaaranon se (yatha, daab athva kaarbonlik aml gas ki maatra mein house se athva avasaadeeya padaarth aur vileen lavan mein paarasparik raasaayanik kriya hone se) ismein ka kuchh lavan avasaad ke kanon ke beech mein avakshepit hokar, uske mukt kanon ko aapas mein ddadh roop se sanyojit kar deta hai aur avasaad kathor, subaddh paashaan mein parivrtit ho jaata hai. is prakaar sanyojan karanevaale lavanon mein kailsiym kaarbonet, lauh oksaaid, evam silika vishesh ullekhaneeya hai. inmein se silika ka bandhan sabse suddadh hota hai. is prakaar bane hue paashaan ki jaati avasaad ke padaarth par nirbhar hogi. yatha baaloo ke avasaad se bana shail (mitti prastar, mud stone) athva shel (shale), batiyon ke samooh ke sanyojan se sangutikaashm (conglomerate) ityaadi baneinge. yadi mitti mein thodi baaloo ho, to baluaa shail ityaadi shail baneinge.

samudra va anya jalaashayon mein avasaad staron athva pararto mein shanai: shanai: sanchit hota hai. daab ke prabhaav se unke sanpeedit hone evam kisi na kisi lavan tatha anya aadhaarak ki sahaayata se avasaad ke kan sanyojit ho jaate hain. is kriya mein bhi avasaad ka starabhaav bana rahata hai. avasaad se utpann hone ke kaaran inhein avasaadeeya shail bhi kehte hain.

avasaadeeya shail padaarth samudra athva anya jalaashayon ki tah mein bahut kaal tak sanchit hota rahata hai. kaalaantar mein bhoosanchalan aadi kisi vrut ke prabhaav se vah saagar ki tah mein se oopar uthakar, parvat ka roop dhaaran kar, mahaadesh ka bhaag ban sakta hai. yeh ek pralayakaari parivartan hota hai. aisa hone se avasaadeeya padaarth pun: praakrutik abhikrtaaon ki kriya ki prushthabhoomi banaata hai aur unke prabhaav mein aakar fir se kshaya hota hua nae avasaad ko janm deta hai, jo tatkaaleen saagar ki tah mein jaakar nikshepit hone lagta hai. is prakaar bhooprushth ka padaarth ninratar ek avasaadeeya chakr mein bhaag leta rahata hai. pratyek chakr ke ant mein saagar aur mahaadeshon ka punassansthaan hota hai aur inmein nae thal aur jal bhaagon ka nirmaan hota hai. is prakaar ke praaya: 4 bruhat aur 14 laghu chakr pruthvi ke sampoorn itihaas mein ho chuke hain

inhein bhi dekhein

baahari kadiyaaain