As you want I am telling Union Public Service Commission (UPSC) Combined Geologist & Geo-Scientist Examination eligibility details are given below;

Age: Candidate age must be between 21 years and 32 years for Geologist, Geophysicist & Chemist posts, between 21 years and 35 years for Jr Hydrogeologist posts.

Age Relaxation:
i. 5 years in case of SC/ST candidates
ii. 3 years for OBC candidates.
iii. Age is additionally relaxable by 5 years for those applicants who had ordinarily been domiciled in the Kashmir Division in the State of Jammu & Kashmir during the period 01-01-1980 to 31-12-1989.
iv. 3 years for Defence Services personnel (disabled in operations during hostilities with any foreign country or in a disturbed area and released as a consequence thereof).
v. 5 years in case of ex-servicemen including Commissioned Officers and ECOs/SSCOs.
vi. 10 years in the case of blind, deaf-mute and Orthopaedically handicapped persons.

Educational Qualification:
(i)

Master's degree in Geology/Applied Geology or Marine Geology from a recognized university; or
(ii)

Diploma of Associateship in Applied Geology of Indian School of Mines, Dhanbad; or
(iii)

Master's degree in Mineral exploration from a recognized university (for posts in GSI); or
(iv)

Master's degree in Hydrogeology from a recgonized university (for posts in CGWB)

Examination pattern

Part I

Written Examination

Candidates competing for both categories have to appear in the following papers
(i) General English

100 Marks
(ii) Geology Paper-I

200 Marks
(iii) Geology Paper-II 200 Marks
(iv) Geology Paper-III 200 Marks
(v) Hydrogeology 200 Marks

For Category I candidates have to appear in Papers (i) to (iv) above only and for Category II in Papers (i) to (iii) and (v) above only.
Part II : Interview for Personality Test 200 Marks

UPSC Geologist & Geo-Scientist Exam syllabus