f„Zvwî½K wkjv`j-Õ¦imgwÓ¡   (Geological Group/Formation)  wkjv`j nGœQ f„Zvwî½K Õ¦i Abyò×g, hv ˆ^GK cieZÆxGZ mÁ·ƒYÆ Ask A^ev AskweGkl Õ¦imgwÓ¡GZ wefî× nIqvi mÁ¿vebv ^vGK| Õ¦imgwÓ¡ nGœQ wkjvjÞY ŠewkÓ¡Åvw` ‰es Õ¦ixq AeÕ©vb «¼viv kbvî×K‡Z ‰KwU wkjvi mgwÓ¡, hvGK f„-c†GÓ¤ gvbwPòvqY Kiv mÁ¿e A^ev f„MGfÆ wPwn×Z Kiv hvq| wbGÁ² Õ¦iZvwî½K w`K ˆ^GK evsjvG`Gki ài‚Z½cƒYÆ wkjv`j-Õ¦imgwÓ¡ cÉexYZg ˆ^GK bexbZg wnGmGe mwäZ KGi AvGjvPbv Kiv nGjv:

MG´£vqvbv wkjv`j (Gondwana Group) cvwgÆqvb (28 ˆKvwU 60 jÞ ˆ^GK 24 ˆKvwU 50 jÞ eQi cƒGeÆ) hyGMi MG´£vqvbv wkjv`j nGœQ evsjvG`Gki cÉexbZg cvjwjK wkjv ‰KK| ‰B wkjv ‰KK wcÉKÅvwÁ¼Ëqvb ˆKjvwmZ wfwîwkjvi Dci AmsMZfvGe (unconformably) AwakvwqZ| KsG™ÏvgvGiU, ˆdΣշviRvZxq ˆeGjcv^i, Aãvixf„Z ˆeGjcv^i, aƒmi I Aãvixf„Z K`Ægwkjv ‰es KqjvÕ¦i «¼viv ‰B wkjv`j ŠewkÓ¡ÅgwíZ| ‰ mKj cjj PzÅwZMÉÕ¦ wcÉKÅvwÁ¼Ëqvb AeevwnKvq mwçZ nGqGQ ‰es DGÍÏLGhvMÅ cyi‚Z½ ARÆb KGiGQ| MG´£vqvbv wkjv`Gj we`Ågvb cyi‚ KqjvÕ¦i ‰es Aãvixf„Z K`Ægwkjv ˆZj A^ev MÅvGmi ˆKvb mÁ¿vebv wbG`Æk KGi bv| KzPgv Õ¦imgwÓ¡ ‰es cvnvocyi Õ¦imgwÓ¡ - ‰B `yBfvGM MG´£vqvbv wkjv`j wefî×|

KzPgv Õ¦imgwÓ¡  gvbwPGò ˆ`LvGbv hvq eãxq AeevwnKvi ‰gb cÉexY cviwgqvb wkjvÕ¦i| ‰wUGK wkjvi ŠewkÓ¡Å I Õ¦iZvwî½K AeÕ©vGbi wfwîGZ wbYÆq Kiv nq| wU AvnGg` I ‰g.‰ RvGni KZƆK eàov ˆRjvi KzPgv AçGji f„MfÆÕ© wkjvÕ¦Gii bvgKiY KzPgv Õ¦imgwÓ¡ Kivi cÉÕ¦ve KGib| ‰wUi cÉwZkõ nGjv eivKi ˆmvcvb I eivKi wmwiR| UvBc ˆmKkb nGjv eàov ˆRjvi KzPgv AçGji (24°42´ Dîi AÞvsk, 89°16´ cƒeÆ `ËvwNgvsk) 2,364 wgUvi ˆ^GK 1,858 wgUvi MfxGi cÉvµ¦ wkjvÕ¦i| Õ¦imgwÓ¡wU ˆeGjcv^i, wMÉU I mvgvbÅ cwigvGY K`Ægwkjv I A¯¦tÕ¦ivwqZ Kqjv «¼viv MwVZ| 6 wgUvi, 22 wgUvi, 13 wgUvi, 4 wgUvi I 6 wgUvi wewkÓ¡ cuvPwU KqjvÕ¦i UvBc ˆmKkGb iGqGQ| Õ¦imgwÓ¡wU 495 wgUvi cyi‚| KzPgv Õ¦imgwÓ¡ wfwîwkjvi DcGi AmsMZfvGe AwakvwqZ ‰es msMZfvGe cvnvocyi Õ¦imgwÓ¡i wbGP AeÕ©vb KiGQ| wkjv ‰KKwUGK fviGZi cÉexY MG´£vqvbv wkjv`Gji cÉexY cviwgqvb eivKvi ˆmvcvGbi mGã ˆgvUvgywUfvGe mÁ·KÆhyî× Kiv hvq, hw`I ‰B mÁ·KÆKiY ˆKvb cÉKvi RxevkÄÕ¦iZî½ wfwîK bq| ÷aygvò wkjvwfwîK mÁ·KÆKiY mgmÅveüj nGZ cvGi| ‰B mgÕ¦ welq weGePbv KGi KÑvP AvjwiL ivqgÅvb ‰B ‰KKwUGK cieZÆx DœP Õ¦iZvwî½K ‰KK A^Ævr WvgyWÅv ˆmvcvGbi mGã mÁ·KÆKiY KGiGQb|

cvnvocyi Õ¦imgwÓ¡  Aãvigq ‰B ‰KKwU evsjvG`Gki DîicwøGg bIMuv ˆRjvi cvnvocyi-RvgvjMé KqjvGÞGò LbbKvGj AvweÓ•‡Z nq| ‰wU wfwîwkjv KgGµÏGÝi (basement complex) DcGi ‰es AmsMZfvGe ˆgGmvGRvwqK hyGMi Þvixq AvG™²qwkjvq (basalt) MwVZ ivRgnj wkjv ˆmvcvGbi (Rajmahal Trap) wbGP AewÕ©Z| Õ¦imgwÓ¡i wkjvmgƒn (512 wgUvi) Mvp aƒmi K`Ægwkjvi cvZjv ˆjG´Öi mGã aƒmi, gvSvwi ˆ^GK LyeB ˆgvUv `vbvwewkÓ¡ ˆeGjcv^i ‰es 4wU weUzwgbvm KqjvÕ¦Gi MwVZ| Kqjvi wbw`ÆÓ¡ AãvGii cwigvY 33% ˆ^GK 54% hvi Mo 47%, fGÕÃi cwigvY 10% ˆ^GK 60% hvi Mo 22.4% ‰es D«¼vqx c`v^Æ 30-40%| ‰KKwUi Õ¦ixq Abyò×g AskZ wkjvZî½, RxevkÄZî½ I civMZGî½i «¼viv ‰es AskZ ævZ AçGji mGã Õ¦ixq I wkjvjÞY cviÁ·GhÆi «¼viv wbYÆxZ nGqGQ| cvnvocyi Õ¦imgwÓ¡ ‰KwU cÉkÕ¦ AMfxi Õ¼v`yRjxq AeevwnKvq AeGÞwcZ wQj| cieZÆxGZ ‰i weÕZ‡wZ PzÅwZ I ÞGqi dGj nËvm cvq| Õ¦imgwÓ¡wU Dîi cviwgqvb hyGMi mnGMvòxq ‰es fviGZi cwøgeGãi cÉexY MG´£vqvbv wkjv`Gji ivYxMé ˆÕ¡GRi mgKÞ eGj gGb Kiv nq|

ivRgnj ˆmvcvb (Rajmahal Stage)  fviGZi ivRgnj cvnvGoi (24°30´ Dîi, 87°30´ cƒeÆ) AbyKiGY ‰B bvgKiY| ivRgnj Avew«¬K ˆmvcvb (Rajmahal Traps Stage) bvGgI ‰KKwUGK DGÍÏL Kiv hvq| Lvwmqv cvnvGo `†kÅgvb wmGjU wkjvGmvcvbGK (Sylhet Trap) ivRgnj ˆmvcvGbi cƒeÆgyLx mÁ·ÉmviY eGj gGb Kiv nq| UvBc ˆmKkGb ivRgnj ˆmvcvb 450-600 wgUvi eÅvmwΟq jvfv ‰es A¯¦tÕ¦ivwqZ K`Æg I K`ÆgÕ¦i «¼viv MwVZ| ‰àGjvi gGaÅ wKQy wmwjKvwqZ I wKQy ˆcviwmGjbGqGW i…cv¯¦wiZ nGqGQ| cÉevnàwji gGaÅ `ywU wcPGÕ¡vb (Pitchstone)| eÅvmwΟq jvfvi mGã cvjwjK Õ¦imgƒGni ˆgvU cyi‚Z½ gvò 30 wgUvi ‰es cÉwZwU Õ¦i 1.5-6 wgUvi| wbÁ²eZÆx 5wU eÅvmwΟq cÉevGni gGaÅ 4wU cÉevGni gaÅKvi Av¯¦tUÇÅvcxq AeGÞGc cÉPzi Dw«¿G`i AewkÓ¡vsk we`Ågvb AvGQ| UÇÅvc wkjvmgƒn cÉavbZ nbÆGeд£ eÅvmΟ, aƒmi myeRvf eÅvmΟ I ‰ÅvbGWmvBU ‰es ‰àGjv AwaKvskB ‰ÅvwgMWvjqWj (amygdaloidal), hvi i®¬ÌàGjv KÅvjmvBU, KÅvjwmwWwb I ‰ÅvbvjmvBU «¼viv cƒYÆ| eÅvmΟmgƒn Mvp iGOi ‰es LyeB wgwn gÅvwUÇGÝ cƒYÆ| mGeÆvœP eÅvmΟ cÉevnwU meGPGq cyi‚, cÉvq 76 wgUvi| ZGe AbÅ cÉevnàGjv AviI Kg cyi‚| evsjvG`Gk cwøgvçjxq eàov, RvgvjMé, wkeMé I wmsov AçGji f„MGfÆ ivRgnj UÇÅvc wkjvi m®¬vb cvIqv ˆMGQ| ‰àGjvi cyi‚Z½ 68 wgUvi ˆ^GK 546 wgUvi| wmsovq (24°29´ Dîi, 89°19´ cƒeÆ) ‰KwU Av¯¦tUÇÅvcxq Õ¦Gii mGã `ywU UÇÅvc Õ¦i iGqGQ|

ivRgnj ˆmvcvb UvBc ˆmKkGb ‰es evsjvG`Gki Dfq ˆÞGò cvnvocyi Õ¦imgwÓ¡i Dci AmsMZfvGe kvwqZ (eivKvi ˆmvcvb) ‰es wkeMé UÇÅvcIqvk «¼viv (Mahadek Trap Wash) AmsMZfvGe AwakvwqZ| ivRgnj cvnvGoi Av¯¦tUÇÅvcxq Õ¦imgƒn weGkl KGi wbcvwbqvi KvGQ PvUÆ (chert) Õ¦imgƒGn Dw«¿` RxevkÄ cvIqv wMGqGQ| RxevkÄàGjv ˆ^GK BwãZ cvIqv hvq ˆh, UvBc ˆmKkGb ivRgnj ˆmvcvb RyivwmK hyMxq| evsjvG`Gki wmsovq Av¯¦tUÇÅvcxq Õ¦Gi ˆKvb Dw«¿ä A^ev cÉvYxR RxevkÄ cvIqv bv hvIqvq evsjvG`Gk ivRgnj ˆmvcvGbi ˆKvb wbfÆiGhvMÅ eqmKvj wbi…cY mÁ¿e nq wb| ZGe ‰wUGK RyivwmK-cÉexY wò×GUwmqvm eGj gGb Kiv ˆhGZ cvGi|

ˆevjcyi Õ¦imgwÓ¡ (Bolpur Formation)  fviGZi cwøgeã ivGRÅi ˆevjcyi bvgK Õ©vGbi (23°37´ Dîi AÞvsk ‰es 87°45´ cƒeÆ `ËvwNgvsk) bvgvbymvGi f„MfÆwÕ©Z ‰B Õ¦imgwÓ¡i bvgKiY Kiv nGqGQ| 160 wgUvi cyi‚Z½wewkÓ¡ ‰B Õ¦imgwÓ¡ mgy`Ëc†GÓ¤i 1,032 wgUvi ˆ^GK 1,193 wgUvi wbGP AewÕ©Z| ivRgnj wkjvGmvcvGbi Dci ‰B Õ¦imgwÓ¡ AmsMZfvGe AwakvwqZ ‰es ‰i DcGi bexb wò×GUwmqvm (14 ˆKvwU 40 jÞ ˆ^GK 6 ˆKvwU 60 jÞ eQi cƒGeÆ) NvUvj Õ¦imgwÓ¡ A^ev Rvjvãx Õ¦imgwÓ¡ msMZfvGe AwakvwqZ iGqGQ| ˆevjcyi Õ¦imgwÓ¡ ˆjvwnZ eGYÆi K`Æg, K`Ægcv^i I meyRvf ˆeGjcv^i (Trapwash) ‰es ˆKvb ˆKvb Õ©vGb ˆk¼ZeGYÆi ˆeGjcv^i «¼viv MwVZ| ‰B Õ¦imgwÓ¡GZ ˆKvb ˆdvivwgwbGdiv cvIqv hvq wb, ZGe ‰i EGa»Æ kvwqZ Rvjvwã Õ¦imgwÓ¡i mGã cwieZÆbkxj gíGj (transitional zone) KLbI KLbI Pviv (Chara)-‰i RxevkÄ AeGkl (gyrogonites) ‰es jeYvî×-Õ¼v`yRj (brackish) I DcnË`xq (lagoonal) AÕ¡ËvGKvWv cvIqv hvq| ˆevjcyi Õ¦imgwÓ¡i Õ©vGb Õ©vGb Avw`g w«¼exRcòx Dw«¿G`i civMGiYy (pollen) we`Ågvb ^vKGZ ˆ`Lv hvq| ‰B Õ¦imgwÓ¡ cÉavbZ Õ¼v`ycvwbi mçqb, ZGe ‰i Ea»ÆvsGki ˆKvb ˆKvb Õ©vGb ˆgvnbvR mçqbI mswkÏÓ¡ iGqGQ| ‰GZ we`Ågvb exRGiYy (spore) I civMGiYy ˆevjcyi Õ¦imgwÓ¡i MVbKvj wò×GUwmqvm hyGMi eGj wbG`Æk KiGQ| ˆevjcyi Õ¦imgwÓ¡i wkjvjÞY, Õ¦iZvwî½K AeÕ©vb I eqGmi K^v weGePbv KGi ‰wUGK Lye mnGRB DîieGãi ˆmvcvb AçGji f„MfÆÕ© wò×GUwmqvm wkeMé UÇvcIqvm ‰es AvmvGgi wò×GUwmqvm gnvG`e Õ¦imgwÓ¡i mGã mÁ·KÆhyî× Kiv hvq|

Zziv Õ¦imgwÓ¡ (Tura Formation) MvGiv cvnvGo cÉKwUZ cÅvwjIwmb/cÉexY BGqvwmb hyGMi ˆeGjcv^img†«¬ f„Zvwî½K Õ¦iò×g| AvmvGgi Zziv knGii (25°31´ Dîi AÞvsk, 99°15´ cƒeÆ `ËvwNgvsk) AbyKiGY f„Zî½we` wm.‰m dÝ ‰B Õ¦imgwÓ¡i bvgKiY KGib| wkeMé Õ¦imgwÓ¡i EGa»Æ ‰B Õ¦imgwÓ¡ AmsMZfvGe kvwqZ ‰es wmGjU Pzbvcv^Gii wbGÁ² msMZfvGe AewÕ©Z| ‰B Õ¦imgwÓ¡wU wmGjU ˆRjvi UvGKiNvU bvgK Õ©vGb evsjvG`k-fviZ mxgv¯¦eZÆx AçGj we`Ågvb| eàov ‰es ivRkvnx ˆRjvi f„MGfÆI ‰B f„Zvwî½K ‰KGKi DcwÕ©wZ iGqGQ eGj Rvbv wMGqGQ| Zziv Õ¦imgwÓ¡i wkjvMVb AcÉavb (subordinate) K`Ægwkjv I KÅvjGKwiqvm K`Æg (marl) ‰es KLbI KLbI Aãvigq K`Ægwkjvmn cÉavbZ ˆeGjcv^i «¼viv MwVZ| ˆeGjcv^Gii eYÆ nvÍ•v aƒmi, mv`v, dÅvKvGk mv`v ‰es nvÍ•v ev`vwg nGq ^vGK| ‰B Õ¦imgwÓ¡ mƒß ˆ^GK ˆgvUv `vbvwewkÓ¡ ‰es ˆKvb ˆKvb Õ©vGb bywogq (pebbly)| AvovAvwo Õ¦ivqbI (cross bedding) jÞÅ Kiv hvq| ˆeGjcv^Gii gGaÅ cvZjv Õ¦i wnGmGe K`Æg wkjv DcwÕ©Z ^vGK ‰es ‰i eYÆ aƒmi ˆ^GK aƒmivf ev`vwg nGq ^vGK| gvjÆ-‰i Õ¦i aƒmivf ev`vwg eGYÆi ‰es RxevkÄmg†«¬| Aãvigq wkjvi Õ¦i Õ©vbxqfvGe Kqjv LwbGZ m†wÓ¡ nGq ^vGK| MvGiv cvnvGo ‰B Õ¦imgwÓ¡ cÉvq 152 wgUvi cyi‚| eàov MÉÕ¦ DcZÅKvq AewÕ©Z wmsov-9, KzPgv-11 ‰es eàov-11 "‰i cyi‚Z½ h^vò×Gg 360 wgUvi, 270 wgUvi ‰es 169 wgUvi ˆiKWÆ Kiv nGqGQ| wmGjGUi jvjNvGU AewÕ©Z wW.‰BP-5 "‰ Zziv ˆeGjcv^Gii cyi‚Z½ cvIqv wMGqGQ 237.80 wgUvi| ZGe evsjvG`Gki DîivsGk B.wW.‰BP-3 "‰ Zziv ˆeGjcv^Gii mGeÆvœP cyi‚Z½ wbYÆq Kiv nGqGQ 105 wgUvi| Av¯¦RÆvwZK ˆZj ˆKvÁ·vwb Õ¡Åv´£vWÆ fÅvKzqvg AGqj KzPgv ‰es eàov K„Gci avivò×g eYÆbvq mycÉwZwÓ¤Z ˆPiv Õ¦imgwÓ¡GK eÅenvi KGiGQ|

ˆPiv Õ¦imgwÓ¡ (Cherra Formation)  Dîivçjxq A¯¦ixc ˆmvcvGbi, weGkl KGi Lvwmqv I ŠRw¯¦qv cvnvGo Uviwkqvix hyGMi cÉavbZ evjygq Õ¦i| MvGiv cvnvGo we`Ågvb Abyi…c AeGÞc Zziv Õ¦imgwÓ¡ bvGg cwiwPZ| civMÕ¦ixq weGkÏlGY ˆ`Lv ˆMGQ wkjs gvjf„wgi `wÞYvçjxq Xvj eivei ˆPiv I Zziv Õ¦imgwÓ¡ ‰es Avcvi AvmvGgi wUIK Õ¦imgwÓ¡i (Teok formation) eqm wgwKi Õ¦imgwÓ¡i mgvb| evsjvG`Gk Zziv Õ¦imgwÓ¡ chÆvqò×wgK mv`v, ˆMvjvwc I ev`vwg wgwn ˆ^GK ˆgvUv `vbvwewkÓ¡ eÅvcKfvGe AvovAvwo Õ¦ivwqZ ˆeGjcv^i, nvÍ•v, aƒmi, QvB aƒmi K`Æg wkjv, Kv`vcv^i I Aãvigq eÕ§«¼viv ŠewkÓ¡ÅcƒYÆ|

ˆmvcvGbi cÉvw¯¦K AsGk Uviwkqvix wfwî Õ¦iò×g MVbKvix ˆPiv I Zziv Õ¦imgwÓ¡i eqm wbYÆq wbGq `xNÆw`b weZKÆ wQj| wkjvMZ mv`†kÅ QvovI AbycyÓ·K (microfloral) mgvnvGii cviÁ·hÆ (correlation) `ywUi gGaÅ ‰KwU NwbÓ¤ mÁ·KÆ cÉ`kÆb KGi| civMxq DcvGî ˆ`Lv hvq Zziv Õ¦imgwÓ¡GK 4wU ˆmGbvGRvGb wefî× Kiv hvq, ˆhLvGb ˆPiv Õ¦imgwÓ¡GK 3wU ˆmGbvGRvGb wPwn×Z Kiv ˆMGQ, hw`I wkjv Õ¦iò×Gg AbycyÓ·K mgvnvGii Dcv`vGb wewf®²Zv LyeB A͸| cÉKvwkZ AGbK wbeG®¬ `ywU Õ¦imgwÓ¡GKB cÅvwjIwmb AeGÞc weGePbv Kiv nGqGQ| AekÅ ˆKvb ˆKvb ˆjLGKi gGZ cixwÞZ Õ¦iò×Ggi civMÕ¦iZvwî½K MGelYv ˆ^GK Abygvb Kiv ˆhGZ cvGi ˆh, ˆPiv Õ¦imgwÓ¡ cÉexY BGqvwmb hyGMi| cieZÆxGZ AbÅvbÅ MGelKivI Abyi…c hywî× ˆgGb ˆbb| gvwKÆb hyî×ivGÓ¡Ëi Õ¡Åv´£vWÆ fÅvKzqvg AGqj ˆKvÁ·vwb KzPgv I eàov K„cmgƒGni Õ¦iò×g eYÆbvq mycwiwPZ bvg ˆPiv Õ¦imgwÓ¡ MÉnY KGiGQ| cieZÆxGZ ‰B wkjv ‰KKGK KzPgv ˆeGjcv^i bvGg AwfwnZ Kiv nq|

ˆKvwcwj Õ¦imgwÓ¡ (Kopili formation)  fviGZi AvmvgÕ© ˆKvwcwj b`xi bvgvbymvGi wc. Bfv´Ö (P Evans) ŠRw¯¦qv wmwiGRi bexb ‰KGKi bvgKiY KGib ˆKvwcwj ˆÕ¡R| evsjvG`Gk wmGjU ˆRjvi WvDwK b`xi ZxGiB ÷ay ‰B Õ¦imgwÓ¡i cyi‚Z½ 360 ˆ^GK 460 wgUvGii gGaÅ| evsjvG`Gki cwøgvçjxq A¯¦ixc ˆmvcvb AçGji MvBev®¬vq 88 wgUvi I wmsovq 40 wgUvi A¯¦f„Æ-c†GÓ¤ ˆKvwcwj ˆÕ¡GRi m®¬vb cvIqv wMGqGQ| ‰B Õ¦imgwÓ¡i ài‚Z½ meGPGq ˆewk Avcvi AvmvGg, hv 700 wgUvi eGj Rvbv ˆMGQ| ‰B Õ¦imgwÓ¡ BGqvwmb Pzbvcv^Gii DcGi ‰es IwjGMvwmb jvBms Õ¦imgwÓ¡i wbGP AewÕ©Z|

Pzbhyî× ˆeGjcv^Gii (calcareous sandstone) mGã Mvp aƒmi K`Ægwkjv w`Gq ‰B Õ¦imgwÓ¡ MwVZ| WvDwK b`xGZ ‰B K`Ægwkjv eÅvcKfvGe we`Ågvb ^vKGjI MvBev®¬v AçGj K`Æg I evjyi AbycvZ cÉvq 1:1| Õ¦imgwÓ¡wU RxevkÄmg†«¬| ài‚Z½cƒYÆ RxevkÄmgƒn nGœQ Quinqueloculina bouena, Q. carinata, Q. seminulum, Q. zealandica, Q. praelongirostrata, Pyrgo bulloides, Triloculina gibba, Lagena globosa, L. hexagons, L. hispidula, Discorbis globiformis, Chiloguembelina parallela, Nonion ovatum, Globigerina, Cibicides mimulus, Pullenia quinqueloba, Pararotalia audouini, P. armata, Nummulites pengaroensis, Pellatispora inflata, P. irregulaaris, P. glabra, Guembelitria oveyi, Discocyclina, Hantkenina, Globorotalia ‰es Cancris| civMZî½MZ Dcvî Zonocostities ramonae, Dicolpopollenites kalewensis, Ephedra BZÅvw`i DcwÕ©wZi BwãZevnx| ˆKvwcwj Õ¦imgwÓ¡ AMfxi mvgyw`ËK ˆ^GK AaÆ jeYvî× cwiGeGk gRyZ wQj| ‰B Rj wQj AaÆ jeYvî× ˆ^GK jeYvî× ‰es Zvcgvòv wQj 100 ˆ^GK 300 ˆmw´ŸGMÉGWi gGaÅ| ‰B Õ¦imgwÓ¡ bexb BGqvwmb hyGMi eGj cÉgvwYZ nGqGQ|

eaÆgvb Õ¦imgwÓ¡ (Burdwan Formation)  IwjGMvwmb I gvGqvwmb mgqKvi AeGÞc wbGq MwVZ| ‰wU avGc avGc gvGqvwmb cvíyqv Õ¦imgwÓ¡ I IwjGMvwmb ˆggvix Õ¦imgwÓ¡i mGã wgGj hvq| Õ¦iò×Ggi wbGPi w`GK eaÆgvb Õ¦imgwÓ¡ Õ¼v`yRj cwiGeGk AeGÞc wbG`Æk KGi, hv cÉavb IwjGMvwmb mgGqi mgyG`Ëi cøv`&MwZi (regression) mGã mvgémÅcƒYÆ| wK¯§ Õ¦iò×Ggi DcGii w`GK eaÆgvb Õ¦imgwÓ¡ mvgyw`ËK A^ev ˆgvnbvR cwiGeGk AeGÞc wbG`Æk KGi| eaÆgvb Õ¦imgwÓ¡ gƒjZ wgwn I ˆgvUv `vbvhyî× ˆeGjcv^i w`Gq MwVZ, hvi gGaÅ A¯¦tÕ¦ivwqZ AeÕ©vq AvGQ K`Ægwkjv ‰es weGkl KGi Õ¦iò×Ggi wbGPi w`GK wjMbvBwUK K`Ægwkjv| eaÆgvb-1 K„Gc wjMbvBwUK K`Ægwkjvi cyi‚Z½ cÉvq 163 wgUvi| ‰B K„cwUGK ‰B Õ¦imgwÓ¡i UvBc ˆmKkb wnGmGe aiv nq| ‰B Õ¦imgwÓ¡i cÉexY Õ¦imgƒn I bexb Õ¦imgƒGni gaÅKvi mxgvbv nGjv cwieZÆbgƒjK| ‰B Õ¦imgwÓ¡wU ˆKvb ˆKvb K„Gc ˆhgb, eaÆgvb-1, Mvjwm-1, ˆevjcyi-1, ˆ`eMÉvg-1 ‰es RvjbvR-1"‰ msMZfvGe DcGi kvwqZ wbIwRb cvíyqv Õ¦imgwÓ¡i mGã avGc avGc wgGk ˆMGQ| Avevi ˆKvb ˆKvb K„Gc ˆhgb, ˆggvix-1 ‰es NvUvj-1 ‰ eaÆgvb Õ¦imgwÓ¡ ˆggvix Õ¦imgwÓ¡ (IwjGMvwmb) «¼viv AwakvwqZ| civM Õ¦iZî½ MGelYvq eaÆgvb Õ¦imgwÓ¡GK eãxq civM Õ¦iZvwî½K IwjGMvwmb ˆRvb-iv ‰i A¯¦fÆyî× Kiv nq| ZGe ‰B ‰KGKi DcwiwÕ©Z AskwU cÉexY gvGqvwmb wnGmGe wPwn×Z|

eivBj wkjv`j (Barail Group)  AGbKàwj Õ¦imgwÓ¡i mg¯¼Gq MwVZ IwjGMvwmb wkjvÕ¦iZvwî½K ‰KK| AvmvGgi eivBj k†Gãi AvGjvGK wc. Bfv´Ö ‰B wkjv ‰KKwUi bvgKiY KGib eivBj ˆmvcvb| cieZÆxGZ we. wek¼vm ‰wUGK msGkvab KGi bvgKiY KGib eivBj wkjv`j| ‰wU IwjGMvwmb mgGqi f„-AeZjfGãi (geosyncline) wewf®² MVb chÆvq wbG`Æk KGi| eivBj myigv DcZÅKv, KvKGii Dîivçj ‰es AvmvGgi Lvwmqv I ŠRw¯¦qv cvnvGo cÉKwUZ| ‰wU ˆeGjcv^i ‰es Õ©vGb Õ©vGb K`Ægwkjv ‰es Aãvigq wkjv «¼viv MwVZ| ‰B wkjv`Gji wZbwU Õ¦imgwÓ¡ iGqGQ| cÉexY ˆ^GK bexbZg Õ¦imgwÓ¡àwj h^vò×Gg ˆjBms Õ¦imgwÓ¡, ˆRbvg Õ¦imgwÓ¡ I ˆibwR Õ¦imgwÓ¡| evsjvG`Gk wmGjGUi ŠR¯¦vcyGii cƒGeÆ ‰es WvDwK b`xi cwøGg ˆibwR Õ¦imgwÓ¡ cÉKwUZ| wmGjGUi AvUMÉvGg LbbKvR PjvKvGj K„cbÁ¼i AvUMÉvg- ix ˆZ 4,740 wgUvi ˆ^GK 4,980 wgUvi MfxiZvq ˆRbvg Õ¦imgwÓ¡i wkjv cvIqv ˆMGQ| ‰KBfvGe AvUMÉvg- ix K„Gc ˆibwR Õ¦imgwÓ¡i wkjv 4,015 wgUvi ˆ^GK 4,740 wgUvi MfxiZvq cvIqv ˆMGQ| eivBj wkjv`j ˆRbvg wmwiGRi DcGi AsmMZfvGe mÁ·wKÆZ| Avcvi AvmvGg ‰B ‰KKwUGZ evwYwRÅKfvGe jvfRbK Kqjv I ˆZjGÞò cvIqv wMGqGQ|

ˆevKvwej Õ¦imgwÓ¡	[ˆmŒRGbÅ: wmdvZzj KvG`i ˆPŒayix]

myigv wkjv`j (Surma Group)  eivBj wkjv`Gji Dci AmsMZfvGe ‰es wUcvg wkjv`Gji wbGP msMZfvGe kvwqZ| ‰B wkjv`j f„eb Õ¦imgwÓ¡ ‰es ˆevKvwej Õ¦imgwÓ¡ - ‰B `yB f„Zvwî½K Dc-‰KGK wefî×| evsjvG`Gki Dîi-cƒeÆvsGk AewÕ©Z wmGjGU ˆevKvwej Õ¦imgwÓ¡ ‰es wUcvg Õ¦imgwÓ¡i gGaÅ Õ©vbxq AmsMwZ we`Ågvb| eZÆgvGb myigv wkjv`j evsjvG`k ‰es fviZ - Dfq ˆ`GkB ‰KwU wkjv ‰KK wnGmGe wPwn×Z nGqGQ|

ˆevKvwej Õ¦imgwÓ¡ (Bokabil Formation) myigv wmwiGRi bexb ‰KK| wc. Bfv´Ö ‰B f„Zvwî½K ‰KKwUGK fviGZi Avmvg ivGRÅ AewÕ©Z KvQvo ˆRjvi DîivsGk nvBjvKvw±` (24°26´ Dîi AÞvsk, 92°32´ cƒeÆ `ËvwNgvsk) DcZÅKvi bvgvbymvGi ˆevKvwej wkjvGmvcvb wnGmGe bvgKiY KGiGQ| ˆevKvwej ‰KKwUGK kbvî× Kivi ˆÞGò wkjvjÞY ài‚Z½cƒYÆ f„wgKv cvjb KGi ^vGK ‰es ‰ KviGY evsjvG`k ‰es fviZ- Dfq ˆ`GkB ˆevKvwej wkjvGmvcvbGK ˆevKvwej Õ¦imgwÓ¡ Z^v ‰KwU wkjv ‰KK wnGmGe wbG`Æk Kiv nGq ^vGK| AvmvGg ˆevKvwej Õ¦imgwÓ¡ 900 ˆ^GK 1500 wgUvi cyi‚ evjygq K`Ægwkjvi mGã cvjvò×Gg cwjcv^i I ˆjŒnR ˆeGjcv^i we`Ågvb AvGQ|

e†nîi wmGjU, PëMÉvg ‰es cveÆZÅ PëMÉvg AçGji ceÆZmvwiGZ ˆevKvwej Õ¦imgwÓ¡ cÉKwUZ| mvaviYZ ‰B Õ¦imgwÓ¡i Ea»Æ I wbÁ²fvGM K`Ægwkjv I cwjcv^Gii cÉvavbÅ ^vGK, ZGe gaÅfvGM ˆeGjcv^Gii cÉvavbÅ AwaK| wbGÁ² kvwqZ cÉavbZ evjygq cÉexY fzeb Õ¦imgwÓ¡ ‰es EGa»Æ kvwqZ wUcvg ˆeGjcv^i Õ¦imgwÓ¡i gaÅeZÆx Õ©vGb ˆevKvwej Õ¦imgwÓ¡ AewÕ©Z| ‰B Õ¦imgwÓ¡ fvwi gwYK aviY KGi ‰es ˆRvBmvBU (zoisite), ‰wcGWvU (epidote), ˆÕ¡GivjvBU (staurolite), KvqvbvBU (kyanite) ‰es nbÆGeÐG´£i (hornblende) DcwÕ©wZ «¼viv ŠewkÓ¡ÅgwíZ|

MvGiv cvnvGoi `ywU Õ©vGb ˆevKvwej Õ¦imgwÓ¡ ˆ^GK ‰ hver 100wUiI AwaK cÉRvwZi RxevkÄ kbvî× Kiv nGqGQ| ‰G`i AwaKvskB cÅvwjwmGcvWv (Pelecypoda) ‰es MÅvmGUÇvGcvWv (Gastropoda) cÉRvwZfzî×| wbGÁ²i KGqK cÉRvwZi ˆdvivwgwbGdivi DcwÕ©wZI ˆevKvwej Õ¦imgwÓ¡GZ jÞÅ Kiv wMGqGQ| ‰àGjv nGœQ: Chiloguembelina globigera, Globigerina bulloides, G. falconensis, G. cf bradyi ‰es G. quinqueloba| mxZvKzí cvnvGo ˆevKvwej K`Ægwkjvq Ostrea digitalina, O. gryphoides ‰es AmsLÅ Bolanus, Arca, Pecten Trochus, Oliva ‰es cÉevGji ˆLvjK cvIqv wMGqGQ| aviYv Kiv nq ˆh, ‰B Õ¦imgwÓ¡ AMfxi mvgyw`ËK ˆ^GK e«¼xcxq ‰es ˆgvnbvRvZ cwiGeGk AeGÞwcZ nGqGQ| ˆevKvwej Õ¦imgwÓ¡GZ A^Æ‹bwZKfvGe jvfRbK cÉvK‡wZK MÅvm gRyZ iGqGQ|

wUcvg wkjv`j (Tipam Group)  KGqKwU Õ¦imgwÓ¡ wbGq eãxq AeevwnKvi ‰B µÏvGqvwmb wkjvÕ¦ixq ‰KKwU MwVZ| fviGZi Avmvg ivGRÅ AewÕ©Z wUcvg cvnvGoi (27°16´ Dîi AÞvsk, 95°30´ cƒeÆ `ËvwNgvsk) bvgvbymvGi ‰d. Avi gÅvGj (Mallet) ‰B wkjv`Gji bvgKiY KGib| AvmvGgi wWwns b`x ‰jvKv (27°15´ Dîi AÞvsk, 95°25´ cƒeÆ `ËvwNgvsk) ‰i UvBc ‰jvKv| Avcvi Avmvg ‰es myigv DcZÅKv ˆ^GK AvivKvb DcK„j chƯ¦ weÕ¦†Z ‰jvKvq ‰B wkjv`j cÉKwUZ| ZGe wWwns AeevwnKvi gƒj wUcvg wkjv`Gji mGã eãxq AeevwnKvi wUcvg wkjv`j ˆKvbfvGeB mÁ·KÆhyî× bq| ‰B wkjv`j `ywU Õ¦imgwÓ¡GZ wefî×: wUcvg ˆeGjcv^i Õ¦imgwÓ¡ ‰es wMi‚Rvb K`Æg Õ¦imgwÓ¡| ˆevKvwej Õ¦imgwÓ¡i Dci kvwqZ wUcvg ˆeGjcv^i Õ¦imgwÓ¡ ˆgvUv `vbv`vi ˆeGjcv^i «¼viv MwVZ| eãxq AeevwnKvi cÉvw¯¦K Ask ‰es cwøGgi ˆmvcvb ‰jvKvmgƒGn ‰B `yB wkjv ‰KGKi gaÅKvi mÁ·KÆ AmsMZ, cÞv¯¦Gi, AeevwnKvi MfxiZi AsGk msMZ| wUcvg ˆeGjcv^i Õ¦imgwÓ¡i mGã DcwifvGMi wMi‚Rvb K`Æg Õ¦imgwÓ¡i mÁ·ÆKI msMZ| ZGe wMi‚Rvb K`Æg Õ¦imgwÓ¡i AbycwÕ©wZi ˆÞGò WzwcwUjv Õ¦imgwÓ¡ AmsMZfvGe wUcvg ˆeGjcv^i Õ¦imgwÓ¡i Dci AwakvwqZ ^vGK|

wUcvg ˆeGjcv^i Õ¦imgwÓ¡ cÉavbZ aƒmi-ev`vwg ˆ^GK weeYÆ aƒmi, ˆgvUv `vbvhyî×, AvovAvwofvGe kvwqZ ˆeGjcv^i «¼viv MwVZ| aƒmi K`Æg wkjv, KsG™ÏvgvGiU wÞwZRmgƒn (conglomerate horizons), bywocv^i, KvÓ¤Lí ‰es wkjvwqZ e†Þàuwo ‰B Õ¦imgwÓ¡GZ wbweÓ¡ (intercalated) ^vGK| cveÆZÅ PëMÉvGgi `wÞYZg Ask ˆ^GK fviGZi wgGRvivg ivGRÅi cwøg Ask ‰es wòcyiv ˆ^GK myigv AeevwnKv chƯ¦ weÕ¦†Z mÁÃyL ewjZ ejGqi (frontal folded belt) meÆò cÉKwUZ wUcvg ˆeGjcv^i Õ¦imgwÓ¡i mçqb msNwUZ nGqGQ| ‰B Õ¦imgwÓ¡ wbqwgZfvGe mÁÃyL ewjZ ejq ‰jvKvi Ea»Æfãxq cÉeYZvmgƒGni (anticlinal trends) cvk¼ÆG`Gk we`Ågvb ^vGK ‰es Lvov cvGoi (cliffs) m†wÓ¡ KGi| MÉvwgbx (gramineae) ˆMvGòi civMGiYy (gymnospermous pollen) ‰es gGbvGcvGiU civMGiYy (monoporate pollen) RxevGkÄi cÉvavbÅ «¼viv wUcvg Õ¦imgwÓ¡ ŠewkÓ¡ÅgwíZ|

AvmvGgi wWMeq bvgK Õ©vGb (27°23´ Dîi AÞvsk, 95°38´ cƒeÆ `ËvwNgvsk) cÉevwnZ ‰KwU Þz`Ë ˆmËvZwÕ¼bxi bvgvbymvGi wc. Bfv´Ö wMi‚Rvb K`Æg ˆmvcvGbi bvgKiY KGib| wbÁ²kvwqZ wUcvg ˆeGjcv^i Õ¦imgwÓ¡ ˆ^GK msMZfvGe ‰es chÆvqò×wgKfvGe ‰B Õ¦imgwÓ¡ MwVZ nGqGQ| evjygq Wzwc wUjv Õ¦imgwÓ¡ AmsMZfvGe ‰B Õ¦imgwÓ¡i Dci AwakvwqZ iGqGQ| cÉavbZ KeÆywiZ K`Æg I AaxbÕ¦ KeÆywiZ ˆeGjgq K`Æg, ˆeGjcv^i I AaxbÕ¦ ˆjŒngq ˆeGjcv^i «¼viv wMi‚Rvb K`Æg Õ¦imgwÓ¡ MwVZ| RxevkÄ KvV ‰es wjMbvBUI ‰B wkjv ‰KGK we`Ågvb| cÉavbZ ewjZ ejGqi AatfvR cÉeYZvi mGã mv`†kÅcƒYÆ e†nr DcZÅKvmgƒGn ‰B Õ¦imgwÓ¡ mwçZ nGqGQ| AvmvGg wMi‚Rvb K`Æg Õ¦imgwÓ¡i cyi‚Z½ 915 wgUvi ˆ^GK 1,829 wgUvi, mxZvKzí Ea»ÆfGã 168 wgUvi, KÝevRvGii mw®²KGU 107 wgUvi, nviviMé ‰jvKvq 366 wgUvi, kvwi b`x ‰jvKvq 762 wgUvi ‰es jyev Lvj ‰jvKvq 1,077 wgUvi| wMi‚Rvb K`Æg Õ¦imgwÓ¡ nË`xq µÏvebf„wg (lacustrine floodplain) ‰es Zxi AwZò×gKvix (overbank) mçqb cÉ`kÆb KGi| ‰B cwj mçqb AaÆevqe (subaerial) cwiGeGk msNwUZ nGqGQ|

Wzwc wUjv Õ¦imgwÓ¡ (Dupi Tila Formation)  gvbwPòvqb mÁ¿e eãxq AeevwnKvi ‰gb ‰KwU µÏvGqvwmb-µÏvBmGUvwmb wkjvÕ¦i| wmGjU ˆRjvi kvwi b`x AeevwnKv ‰jvKvq (25°06´ Dîi AÞvsk; 92°08´ cƒeÆ `ËvwNgvsk) WzwcwUjv cvnvoGkÉYxi bvgvbymvGi wc.Bfv´Ö ‰B Õ¦imgwÓ¡i bvgKiY KGib| PëMÉvg wefvGM ‰es evsjvG`k I fviGZi Avmvg ivGRÅ AewÕ©Z ŠR¯¦v ceÆZGkÉYxi `wÞY cÉvG¯¦ ‰B Õ¦imgwÓ¡ cÉKwUZ| DîieGã ˆekwKQy f„Zvwî½K LbbK„Gc ‰B Õ¦imgwÓ¡i DcwÕ©wZ jÞÅ Kiv wMGqGQ| wUcvg wkjv`Gji Dci ‰B Õ¦imgwÓ¡ AmsMZfvGe AwakvwqZ ‰es Wzwc wUjv Õ¦imgwÓ¡i EGa»Æ nq wWwns Õ¦imgwÓ¡ A^ev bexb cjj mçqb we`Ågvb ^vGK| AvUMÉvGg ‰B wkjv‰KK ˆevKv wej Õ¦imgwÓ¡i Dci AwakvwqZ| wmGjGU Wzwc wUjv Õ¦imgwÓ¡ `ywU myÕ·Ó¡ ‰KGK MwVZ| cÉexYZi AskwU cÉavbZ msnZ (massive) ˆeGjcv^i ‰es AcÉavb A¯¦tÕ¦ivwqZ K`Ægcv^i «¼viv MwVZ| ˆeGjcv^Gii eYÆ njy` ˆ^GK njy`vf ev`vwg, gaÅg ˆ^GK ˆgvUv `vbv`vi, AvovAvwo Õ¦ivwqZ ‰es Õ©vGb Õ©vGb bywogq| bexbZi AskwU K`Ægwkjv ‰es cwjcv^i I AcÉavb ˆeGjcv^i «¼viv MwVZ| PëMÉvg AçGji Wzwc wUjv Õ¦imgwÓ¡ njy`vf-ev`vwg ˆ^GK ev`vwg, wgwn ˆ^GK gaÅg `vbvwewkÓ¡ bywogq ‰es AaxbÕ© K`Ægcv^i I cwjcv^i mg†«¬ AvovAvwo Õ¦ivwqZ ˆeGjcv^i «¼viv MwVZ| evsjvG`Gki DîivçGji A¯¦f„Æ-c†GÓ¤ Wzwc wUjv Õ¦imgwÓ¡ bywogq Õ¦i, ˆgvUv ˆ^GK wgwn `vbv`vi ˆeGjcv^i ‰es aƒmi eGYÆi K`Ægwkjv «¼viv MwVZ| ivãvgvwUi wbKUeZÆx Kvµ¦vB nËG` we`Ågvb Wzwc wUjv Õ¦imgwÓ¡i ˆeGjcv^Gi myÕ·Ó¡ còQvc (leaf impressions) jÞÅ Kiv wMGqGQ| Õ¦imgwÓ¡i mçqbKvGj mvaviYfvGe fuvR I PzÅwZ msNwUZ nGqGQ ‰es `Ë‚Z AebwgZ ‰jvKvmgƒGn AZů¦ cyi‚ Õ¦iò×gmgƒn AeGÞwcZ nGqGQ| wmGjGUi kvwi b`x ‰jvKvq ‰B wkjv ‰KGKi cyi‚Z½ cÉvq 1,722 wgUvi, ˆMvqvBb I Kzwkqviv Lv`mgƒGn cyi‚Z½ h^vò×Gg 4,419 wgUvi I 3,669 wgUvi ‰es DîieGãi A¯¦fƃ-c†GÓ¤ cyi‚Z½ 20 ˆ^GK 276 wgUvi| PëMÉvg-KÝevRvi ‰jvKvq AewÕ©Z Wzwc wUjv Õ¦imgwÓ¡i Õ©vGb Õ©vGb PxbvgvwUi mçqb jÞÅ Kiv hvq, hw`I gqgbwmsn ˆRjvq AewÕ©Z Õ¦imgwÓ¡GZ PxbvgvwUi Õ¦i cvIqv wMGqGQ|

wWwns Õ¦imgwÓ¡ (Dihing Formation)  µÏvBmGUvwmb hyMxq RwicGhvMÅ ‰B wkjv eãxq AeevwnKvq wewÞµ¦fvGe eZÆgvb ‰es ‰i ÷aygvò Õ©vbxq ài‚Z½ iGqGQ| fviGZi AvmvGg RqcyGii KvGQ wWwns b`x (17°16´ Dîi, 90°24´ cƒeÆ) ˆ^GK ‰d. Avi gÅvGjU ‰B bvgKiY KGib| evsjvG`Gk ‰B Õ¦imgwÓ¡i DcwÕ©wZ LyeB AwbqwgZ| KÝevRvi ˆRjvi ivgy AçGj ‰i cyi‚Z½ ÷aygvò 24 wgUvi| ZGe AvmvGgi UvBc ˆmKkGb 305 wgUvi ˆ^GK gvbveyg cÉwZGeGk 1,525 wgUvi| Õ¦imgwÓ¡wU njy` I aƒmi, gaÅg `vbv`vi, gvGSgvGSB bywogq ˆeGjcv^i ‰es KeyÆwiZ K`ÆGgi A¯¦tÕ¦imn K`Æggq ˆeGjcv^Gi MwVZ| ‰B wkjvivwk AwaKvsk ˆÞGòB Lye Kg `†p| ‰KKwU Wzwc wUjv Õ¦imgwÓ¡ I cjGji gGaÅ AmsMZfvGe kvwqZ| ˆKvb ˆKvb ‰jvKvq wWwns Õ¦imgwÓ¡i wfwîÕ¦Gi (base) PxbvgvwU cvIqv wMGqGQ| 

[gywRei ingvb Lvb, wmdvZzj KvG`i ˆPŒayix, ˆgvt wbnvj Dwób ‰es ‰.ˆK.‰g ˆLviGk` Avjg]