Recent geochemical and mineralogical alteration processes in tropical coastal sediments of Vietnam [Elektronische Ressource] / Nguyen Thi Minh Ngoc

NGUYEN Thi Minh Ngoc




Recent geochemical and mineralogical
alteration processes in tropical coastal
sediments of Vietnam














Ernst-Moritz-Arndt-University Greifswald
Germany 2006

Recent geochemical and mineralogical
alteration processes in tropical coastal
sediments of Vietnam

Dissertation
in fulfilment of the academic grade
doctor rerum naturalium (Dr. rer. nat.)
at the Faculty of Mathematics and Natural Sciences
Ernst-Moritz-Arndt-University Greifswald









NGUYEN Thi Minh Ngoc
born on 17.7.1979 in Phu Tho, Vietnam


Greifswald, Germany 2006
























Dekan: Prof. Dr. rer. nat. Klaus FESSER

1. Gutachter 1: Ass. Prof. Dr. Habil Jörn KASBOHM
2. Gutachter 2: Prof. Dr. Georg IRION

Tag der Promotion: 17.11.2006


Lu ận án, con dành t ặng gia đình
& các cháu B ống, Nhím, cu Tít, cu Mít th ương yêu
- n ơi luôn cho con tình yêu và ngh ị l ực

TABLE OF CONTENT
INDEX OF FIGURES ..................................................................................................................................iii
INDEX OF TABLES....viii
ABBREVIATIONS........... x
ACKNOWLEDGEMENTS..........................................................................................................................................xi
1 INTRODUCTION.........................1
1.1 Motivation............ 1
1.1.1 Meaning of coastal zone for regional development & problems ............................. 1
1.1.2 Coastal sediments in the view of a real complex of geological process.............. 2
1.2 Aims of this Ph.D. work................................................................................................................. 3
2 COASTAL SEDIMENTS IN TROPICAL CONDITIONS ............................................................................ 5
2.1 Environmental setting of coastal sediments ....................................................................... 5
2.1.1 Climate and Oceanography ................................................................................................... 5
2.1.2 Geological and geographical setting.................................................................................... 7
2.2 Sources of coastal sediments and yields ............................................................................... 8
2.3 Transport to the sea........................................................................................................................ 9
2.4 Morphology and driving forces................................................................................................. 10
2.4.1 Vegetation.................................................................................................................................. 11
2.4.2 Anthropogenic effects ............................................................................................................ 14
2.5 Maturation process in coastal sediments............................................................................ 15
2.5.1 Difference between soil profile and coastal sediment profile......................................... 15
2.5.2 Nutrients, geochemistry and mineralogy of coastal sediment profiles............................. 17
2.5.3 Expected models of driving forces........................................................................................ 23
3 MATERIALS & METHODS....24
3.1 Sampling and Materials ............................................................................................................... 24
Sampling sites in Red River Delta 25 3.1.1
3.1.2 Sampling site in Dam Mon .................................................................................................... 26
3.1.3 e in Nha Phu ...................................................................................................... 27
3.2 Methods .............................................................................................................................................. 29
3.2.1 Grain size analysis................................................................................................................... 29
3.2.2 Chemical analysis .................................................................................................................... 31
3.2.3 Nutrients...... 32
3.2.4 Mineralogical analysis............................................................................................................. 33
3.2.5 Mathematical methods ........................................................................................................... 52
4 RESULTS.....................................54
4.1 Grain size analysis......................................................................................................................... 54
4.1.1 Red River Delta ........................................................................................................................ 54
4.1.2 South Central Coast............................................................................................................... 59
4.2 Nutrients............. 66
4.2.1 Red River Delta 66
4.2.2 67
4.3 Geochemistry.... 69
4.3.1 Physico-chemical condition (pH, Eh)................................................................................ 69
4.3.2 Major elements 70
4.3.3 Minor chemical elements...................................................................................................... 80
4.4 Mineralogy......................................................................................................................................... 91
4.4.1 Red River Delta 91
4.4.2 South Central Coastline 107
5 DISCUSSION.............................124
5.1 Coastal sedimentary environment – an interface between terrigenous and
marine sedimentation, biota as well as human activities........................................................ 124
5.1.1 Sedimentological meaning of grain size distribution data....................................... 124
5.1.2 Reconstruction of paleogeographical situation ........................................................... 130
5.2. Syn-sedimentary processes - mirroring in elemental distribution and
mineral matter.............. 134
5.2.1. Hydrodynamic – mirroring in elemental distribution and mineral matter....................... 134
5.2.2. Physico-chemical processes................................................................................................. 144
5.2.3. Clarification of coastal sediments ...................................................................................... 149
i5.2.4. Summary on syn-sedimentary processes ........................................................................ 153
5.3. Post-sedimentary processes - mirroring in elemental distribution and
mineral matters........................................................................................................................................... 154
5.3.1. Geochemical mirror of post-sedimentary processes.................................................. 154
5.3.2. Mineralogical mirror of poimentation ................................................................. 157
5.3.3. Dissolution of clay minerals in saline water ................................................................ 160
5.3.4. Smectitization......................................................................................................................... 165
5.3.5. Kaolinitization ........................................................................................................................ 169
5.3.6. Meta-stable neoformed phases during post-sedimentary processes.................... 175
5.3.7. Summary on post-sedimentary processes .................................................................... 176
5.4. Post-sedimentary processes with involvement of mangrove biota – mirroring
by elemental distribution and mineral matter.............................................................................. 179
5.4.1. Diagenetic process of nutrients........................................................................................ 179
5.4.2. pH/Eh zoning along depth profile in MF sediments.................................................. 180
5.4.3. Trapping processes in mangrove forest ......................................................................... 183
5.4.4. Intensification of dissolution process under effects of root system...................... 184
5.4.5. Intenson of smectitization under effects of root system ................................ 184
5.4.6. Intensification of kaolinitizatior effeem 186
5.4.7. Summary on biota-induced post-sedimentary processes........................................ 187
5.3. Post-sedimentary processes influenced by human activities
(e.g. shrimp pond cultivation)..........................................................................