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Facies Analysis and Paleontology of Carbonate Sedimentary Rock In ADDIS ABABA UNIVERSITY SCHOOL OF EARTH SCIENCE POST GRADUATE PROGRAM IN STRATIGRAPHY AND SEDIMENTOLOGY FACIES ANALYSIS AND PALEONTOLOGY OF CARBONATE SEDIMENTARY ROCKS IN HAGERE-SELAM, MESSOBO AND WUKRO STRATIGRAPHIC SECTIONS; NORTHERN ETHIOPIA, TIGRAI: IMPLICATION FOR DEPOSITIONAL ENVIRONMENT RECONSTRUCTION AND AGE DETERMINATION. BY WEREDE GIRMAY TESFASILASIA A Thesis Submitted to the School of Earth Science, Addis Ababa University in partial fulfillment of the requirement for the Degree Master of Science (Stratigraphy and Sedimentology Program). May 2018, Addis Ababa, Ethiopia ADDIS ABABA UNIVERSITY SCHOOL OF EARTH SCIENCE POST GRADUATE PROGRAM IN STRATIGRAPHY AND SEDIMENTOLOGY FACIES ANALYSIS AND PALEONTOLOGY OF CARBONATE SEDIMENTARY ROCK IN HAGERE-SELAM, MESSOBO AND WUKRO STRATIGRAPHIC SECTIONS; NORTHERN ETHIOPIA, TIGRAI: IMPLICATION FOR DEPOSTIONAL ENVIRONMENT RECONSTRUCTION AND AGE DETERMINATION. BY WEREDE GIRMAY TESFASILASIA ADVISOR: BALEMWAL ATNAFU (PhD) A Thesis Submitted to the School of Earth Science, Addis Ababa University in partial fulfillment of the requirement for the Degree Master of Science (Stratigraphy and Sedimentology Program). May, 2018 Addis Ababa, Ethiopia ADDIS ABABA UNIVERSITY SCHOOL OF GRADUATE STUDIES SCHOOL OF EARTH SCIENCE FACIES ANALYSIS AND PALEONTOLOGY OF CARBONATE SEDIMENTARY ROCK IN HAGERE-SELAM, MESSOBO AND WUKRO STRATIGRAPHIC SECTIONS; NORTHERN ETHIOPIA, TIGRAI: IMPLICATION FOR DEPOSTIONAL ENVIRONMENT RECONSTRUCTION AND AGE DETERMINATION. BY WEREDE GIRMAY TESFASILASIA APPROVED BY EXAMINATION BOARD AND DEPARTMENT CHAIRMAN Name Signature Date Dr. Balemwal Atnafu ________________ ________________ Head, School of Earth Science Dr. Balemwal Atnafu _________________ ________________ Advisor Dr.Mulugeta Fissha _________________ ________________ Examiner1 Dr.Gilamichael _________________ _________________ Examiner 2 May, 2018 Addis Ababa, Ethiopia DECLARATION OF ORIGINALITY I hereby declare that the thesis entitled “Facies Analysis and Paleontology of carbonate sedimentary rock in Hagere-Selam, Messobo and Wukro stratigraphic sections, Northern Ethiopia: Implication for Depositional Environment Reconstruction and Age Determination” has been carried out by me under the supervision of Dr. Balemwal Atnafu, School of Earth Science, Addis Ababa University, Addis Ababa, Ethiopia during the year 2017-18 as part of Masters of Science program in Stratigraphy and Sedimentology. I Furthermore, declare that this thesis is my original master degree work and has not been submitted to any university or institution in the past for the award of any degree or diploma at any other university. All sources and materials used for this thesis work have been well referenced and duly acknowledged. Werede Girmay Tesfasilasia _____________ _______________ Signature Date This is to certify that the above declaration made by the candidate is correct to the best of my knowledge. Dr. Balemwal Atnafu (Advisor) _____________ _______________ Signature Date ABSTRACT There is carbonate unit deposited in the Mekelle Outlier during the Upper Jurassic Period as a result of flooding of the area by Paleotethys Ocean toward the southeast direction. The Mekelle Outlier is situated in the northern most part of Northwestern Plateau (NWP) and the study carbonate successions are aligned along the western (Hagere-Selam), southeastern (Messsobo) and northeastern (Wukro section) margin of the Mekelle Outlier. This study focused on detailed investigation of facies analysis and paleontology of the Upper Jurassic carbonate units in order to obtain a detailed picture of depositional environment, age determination and correlation. Three main methods were implemented in order to accomplish the stated research problem and objective of the present study. These are pre-fieldwork, a detailed main fieldwork and laboratory analysis (petrographic analysis, micro and macro fossil description and systematics and microfacies analysis). A total of 65 rocks and 26 productive dry marl sediment samples are collected from the study sections and examined under petrographic microscope. Lithostratigraphically, the carbonate succession has a total thickness about 400m, which is characterized by thin-thick bedded limestone, mudstone, fossiliferous, coquinoidal, oolitic and sandy limestone with different skeletal components and different sedimentary structures. Based on a detailed field investigation, paleontological and petrographical information, 19 microfacies type are recognized. These are grouped into four microfacies association including tidal flat (MFT1-3), lagoon (MFL1-2), shoal (MFS1-6) and open marine environment (MFO1-8). Therefore, the depositional system of the carbonate succession represents a homoclinal ramp setting because of thier wide lateral and vertical distribution of facies. Additionally, the carbonate units of the study area are affected by different diagenetic features including compaction, cementation, dissolusion, micrtization, dolomitization, neomorphism, and silicification. The carbonate rock units are correlated within different measured sections in the Mekelle Outlier and regionally correlated with the Antalo Limestone of Blue Nile, the Urandab Formation of Ogaden, the Antalo Limestone of Eretria and other Arabian platforms based on biostratigraphy and lithostratigraphy. Keywords: Stratigraphy, Microfacies analysis, Age, Paleontology, Depositional environment, diagenesis, Mekelle Outlier. Thesis for MSc on Stratigraphy and Sedimentology By Werede i ACKNOWLEDGMENT Firstly I would like to give my sincere gratitude to Aksum University and Addis Ababa University, School of Earth Sciences for providing an opportunity to study my master degree and funding the research project. My second deepest gratitude goes to my advisor and instructor Dr. Balemwal Atnafu for his follow up, constructive comment, valuable suggestion, encouragement and tireless support. Dr. Balemwal Atnafu is the person to give my respect and acknowledgement for having valuable technical discussion with him and guidance; it is really meant a lot to me. Next I want to express my deepest sincere thanks to Ethiopian Geological Survey laboratory team for facilitating things in order to reach the thin section analysis result on time. During the research field work I got a lot of support from my friends and my colleagues Trhas Hadush and during the laboratory description and analysis, I got a lot of support from my instructor Addis Hailu. Therefore, I ran out of words to express my great appreciation and gratitude for your critical support from the beginning to the end of this thesis work. My acknowledgement goes to my family for giving me courage and unforgettable support when I am in the project work. The last but not the least my gratitude goes to government officials and local peoples of Hagere-Selam, Wukro and Mekelle for allowing and helping me during the field work. Thesis for MSc on Stratigraphy and Sedimentology By Werede ii TABLE OF CONTENTS ABSTRACT ........................................................................................................................................... i ACKNOWLEDGMENT ...................................................................................................................... ii TABLE OF CONTENTS ...................................................................................................................... iii LIST OF APPENDIXES ...................................................................................................................... vii CHAPTER ONE ....................................................................................................................................1 1. INTRODUCTION .............................................................................................................................1 1.1. Background and Justification ...................................................................................... 1 1.2. General setting of the study area ................................................................................. 2 1.2.1. Location of the study area .....................................................................................................2 1.2.2. Accessibility of the study area ...............................................................................................3 1.2.3. Physiography of the study area ..............................................................................................5 1.2.4. Drainage pattern of the study area .........................................................................................5 1.2.5. Climate and vegetation of the study area ...............................................................................5 1.2.6. Population and settlement ......................................................................................................7 1.3. Review of previous works of the carbonate succession .............................................. 7 1.4. Statement of the research problem .............................................................................. 8 1.5. Objectives of the research............................................................................................. 8 1.5.1 General objectives ..................................................................................................................8 1.5.2. Specific objectives .................................................................................................................8 1.8. Limitation of the study
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