GEOLOGY OF THE
LEBYIN-YEBU AREA, THAZI AND KALAW TOWNSHIPS
ABSTRACT
The study area is located about 40 miles
S-E of Thazi. It covers about 25 square miles of fairly rugged terrain in
one-inch topographic map 93 D/6.
The eastern rolling hills are made up of
the clastic sedimentary rocks of the Lebyin Group.
The Lebyin Group is a succession of
greywacke, indurated mudstone, pebbly mudstone, tuffaceous sandstone and
conglomerate. These rocks can be subdivided into four lithostratigraphic units
of formation rank which are only informally named. These are, from older to
younger; L1 Indurated Mudstone and Greywacke; L2 Pebbly Mudstone and Indurated
Mudstone; L3 Indurated Mudstone and Greywacke; L4 Conglomerate and Tuffaceous
Sandstone. The faunal evidence indicates that the Lebyin Group is lower
Carboniferous in age.
Petrographically, the sandstones of the
Lebyin Group may be regarded as immature sandstones of greywacke type. Most of
the sandstones contain high parcentages of clay matrix and unstable mineral
grains. The clastic rocks of the Lebyin Group may have been deposited by a
combined process of turbidity current and debris flow in a deep-sea fan.
Thitsipin Limestone Formation was
firstly named by Garson et al, (9176) after Thitsipin village. Garson et al.
(1976) divided the Thitsipin Limestone into three main facies; a massive
limestone facies with abundant big brachiopods; a massive cherty limestone
facies; and a well-bedded calcarenite facies. In the eastern part of the study
area, light grey to bluish grey, fine-grained limestone is well exposed.
Fusulines are known to have been very sensitive. They are thought to have lived
in an open shallow sea environment.
The contact between these two groups is
probably an unconformity. The folded Lebyin Group is unconformably overlain by
the gently-dipping Kalaw Formation.
In the eastern most part of the area,
diorite intruded the Thitsipin Limestone late Mesozoic.
The gold and the stibnite deposit of
Lebyin are two economic ore deposits in this area. Primary gold mineralization
is found in the skarn rocks. Antimony mineralization of Lebyin has been worked
as a medium-sized mine in the fine-grained silicified quartzite of L3 unit.
GEOLOGY OF THE
KYAUKPON-SINTHEGAN AREA, KYAUKPADAUNG AND NATMAUK TOWNSHIPS, MANDALAY AND
MAGWAY DIVISIONS
ABSTRACT
The study area is located about 8 miles
SE of Kyaukpadaung. It is referred by the topographic maps 84 P/5 and 84 P/6
and covered about 112 square miles.
In the study area, clastic sedimentary
rocks ranging in age from Miocene to Pliocene and Volcanic rocks (Pontian to
Pliocene) are exposed. The sedimentary sequence, from older to younger,
consists of the Moza Formation (1500 ft in thickness), the Khabo sandstone and
Irrawaddy Formation. Subordinate amount of volcanic rocks are interfingering
with and overlying the Irrawaddy sediments.
Sedimentary structures, lithologic
characters and faunal assemblage indicate that the Moza Formation and Khabo
Sandstone were accumulated in shallow marine (near-shore) and tidal flat
environments, respectively. The Irrawaddy Formation was formed in fluvial
environment.
Volcanic rocks are subdivided into three
group, they are, from older to younger, the Mongwe Andesite, Taungni Silicified
Tuff and Dangyin Andesite, which are equivalent to the older volcanic rocks of
Chhibber (1934). The magma generation is attributed to the warning stages of
orogeny as the eastward subduction of the Indian Plate beneath the Eurasia
Plate gave way to the strike-slip movement.
The major anticlinal structure exists in
the southern part of the study area, trending NNW-SSE, accompanied with a large
longitudinal fault. Besides, peri-anticlinal and cross faults also are
affiliated with the major fault.
Most of the geological structures in the
study area are closely related to the Sagaing right-lateral strike-slip fault.
GEOLOGY OF THE POPA-SEBAUK AREA,
KYAUKPADAUNG TOWNSHIP
ABSTRACT
The study
area, western part of the Mt. Popa volcanic cone, covering about 10.5 sq. miles
in the Central Cenozoic Belt of Myanmar was mapped on the scale of four inches
to a mile.
Several flows of andesites were mapped and described in
ascending order, viz., (i) Gwegon-Sebauk white tuff, (ii) Thon-htat-gwe black
tuff, (iii) Taunggalat andesite, (iv) V1-flow andesite, (v) Popa plateau
andesite, (vi) V3-flow andesite and pyroclasts and (vii) V4-flow basaltic
andesite. Irrawaddy formation is exposed in the lowlying area.
The area is mainly composed of andesite and basaltic
andesite but each unit has their distinctive lithologic characteristics. In the
Taunggalat andesite, not only the phenocrysts of amphibole are abundant at the
top and less abundant at the base but also pyroxene phenocrysts are abundant at
the base and become lesser amount at the top. So, it is adapted the
discontinuous reaction series of Bowen. Distinguished features of these
andesite very lusterous crystal of hornblende and white patches of feldspar
laths. Augite phenocrysts of the V1-flow
andesite are rounded and larger in size than those of others in the
study area. In V3-flow andesite, phenocrysts of hornblende and augite of the
upper portion are relatively larger in size than those of the lower portion.
V4-flow andesite is characterized by relatively more even grain size.
Gwegon-Sebauk white tuff, lower most unit of the
volcanics in the present area is interbedded with the Pliocene sandstones of
Irrawaddy formation. It may be related that the volcanics activity has been
started in Pliocene time.
Using the chemical analysis data of Chhibber (1934),
Amose (1978), and Stephenson and Marshall (1984), volcanic rocks of the study
area can be identified as basalt and basaltic andesite. The data are plotted in
the alkali Vs. silica diagram and K2O Vs. silica diagram indicate
that most of them are in the calc-alkaline and high-K-calc-alkaline fields.
Important mineral resources have not been investigated in
the study area. The abundant volcanic rocks of phyric andesite may be used as
building stones and construction.
GEOLOGY OF THE POPA-KYAUKTAGA AREA,
KYAUKPADAUNG TOWNSHIP
ABSTRACT
The present area is the northwestern
part of Mt.Popa region which lies in theCentral Volcanic Line of Late
Cretaceous in Myanmar. The study area occupies about 14 square miles between
latitudes 20˚ 55to 20 58 and longitude 95 11 6 to 95 15 20 .It is covered by
vertical grids 40 to 46 and horizontal grids 53 to 61 of one-inch topographic maps
84 P/1 and 84 P/5.
The main four types of rock sequence are
observed in the area. They are following as;
4. KLA-Kyauktaga-Legyi
agglomerate
3.V5-basaltic lavas
2. V3-black tuffs and andesitic lavas
and
1.PA-Popa andesite.
The Irrawaddy formation is well
developed in the northwestern part of the area. It may be investigated as the
basement of the Mt.Popa volcanic cone. The Popa andesite rocks are well exposed
at the Popa village and found as irregular large boulder. They also capped the
Irrawaddy sand rocks. The V3- andesitic lava flow is well exposed on the
western flank of Mt.Popa volcano. Sometimes, this lava flow shows slag and ropy
structure. Andesitic tuffs also have been associated with this unit. In the
upper portion of this flow, the phenocrysts of hornblende, augite and
plagioclase are relatively larger size than those of the lower portion. The V5-
basaltic lava flow is one of the last major flows on the northwestern slope of
Mt. Popa cone and highly distributed near the Taungbaw village and found in the
plantation area. At the northwestern end, this lava break up into partially
cooled blocks which roll over one another and occurs as blocka one upon the
other. The phenocrysts of olivine have not been recognized in the middle parts
of the middle portion of V5-flow basalt.
Kyauktaga-Legyi agglomerate unit
extendes as far as the Legyi village about 10.4kkm from the crater. They
consist of volcanic ash, tuff, pumice, scoria and unsorted volcanic fragments.
There is a beneficial aspect of the
natural pozzolan of Kyauktaga-Legyi agglomerate unit in the study area. The
pyroclastic rocks of the study area are volcanic ash, tuff, pumice, scoria and
agglomerate, etc,. Of these, the volcanic ash, tuff, pumice and scoria are
commony used in the producing the cement. They are crushed and ground into
finely divided materials or powder and called pozzolan. Nowaday , these
pozzolan are widely used in construction of dams and bridges.
GEOLOGY OF THE
SONGON-NAGALE AREA, KYAUKPADAUNG TOWNSHIP.
ABSTRACT
The study area is situated between North
Latitude 20˚ 54' 30'' – 20˚ 58' 30'' and East Longitude 95˚ 15' 4'' – 95˚ 19'
30''. It occupies in one inch topographic map 84 P/5. The study area is cover
approximately 15 miles square. It is located in Kyaukpadaung-Myingyan car road
and about 10 miles from Kyaukpadaung Township.
In the study area, volcanic and
sedimentary rocks ranging in age from Pliocene to Recent times are exposed.
Only one of sedimentary sequence are Irrawaddy Formation. Volcanic rocks are
overlying and interfingering with Irrawaddy Formation.
Sedimentary
structure, lithologic characters and faunal assemblage indicate that Irrawaddy
Formation were deposited in fluvial environment.
The volcanic rock of this area have been
subdivided into four units namely (older to younger). NA-Nagale andesite, V2-flow
(Sinzin agglomerate), V3-flow (Black tuff, Rock fragment &
Andesitic lava) and V4-flow (Andesitic lava) which are equivalent to
the Mt. Popa volcanic group (Aung Moe 1980).
GEOLOGY OF THE
ZELONG TAUNG AREA, THAZI TOWNSHIP
ABSTRACT
The geology of Zelong Taung area,
situated about 13 miles southeast of Thazi township, Mandalay Division was
mapped on one inch scale topographic base map of 93 D/1.
The
map area is composed mainly of igneous and metamorphic rocks. These units are
ranging from Paleozoic to Mesozoic.
Yinmabin Metamorphics is the oldest unit
in this area. Yinmabin metamorphics comprise quartzite, epi-granodiorite and
gneiss. The metamorphic rocks of this unit is effected by high-grade regional
metamorphism which belong to upper amphibolites facies according to metamorphic
mineral assemblages. Yinmabin metamorphic is probably formed early Paleozoic.
Igneous rock unit contains biotite
granite, leucogranite and granodiorite. Biotite granite is well exposed at
Zelong Taung, Taungpuza Hill, and Chauksu Taung. The quartzofeldspathic veins
could by formed by late igneous activity. On the basis of field evidences and
petrological studies, the igneous rocks of Central Belt in Myanmar are possibly
emplaced during Late Mesozoic and early Eocene.
The general trend of metamorphic rocks
are nearly north to south in the study area. There are three major cross
faults.
Economically important mineral deposits
are not observed in the study area. The igneous and Yinmabin metamorphics can
be used as construction and road materials.
GEOLOGY OF THE
PAYANGAZU AREA, THAZI TOWNSHIP
ABSTRACT
The area under the present
investigation, covering about 16 square miles, occupies part of Thazi township
in Mandalay division. It is situated between latitude 20 44 and 20 47 N and
longitude 96 12 and 96 15 E covering parts of the 93 D/1, 93 D/2, and 93D/6.
The study area are present two units,
Yinmabin metamorphic unit and Payangazu granitic rock unit.
Yinmabin metamorphic in the area
consists of epi-granodiorite, gneiss, migmatites and spotted schists. Age of
Yinmabin metamorphic is lower Paleozoic. Regional and contact metamorphism have
affected at the study area.
Igneous rocks such as biotite granite,
leucogranite and microgranodiorite were formed by calc-alkaline magma which
were probably derived from continental margins overriding subducting oceanic
lithosphere. Biotite granite is the main igneous rock of the study area. K/Ar
radiometric data indicate significant and possibly widespread thermal
disturbances in the central granitoid belt during the Tertiary.
Pegmatite dykes and apatite veins
originated during the latest stages of the igneous activities of the study
area.
Gneisses and migmatites were formed as
the narrow margin of the granite plutons.
On the basis of the observed mineral
assemblages, the metamorphic facies are considered to belong to the upper
amphibolites facies.
The general trend of the metamorphic
rocks are nearly north to south. One major cross fault was observed in this
area. Different pattern of migmatite structure such as stromatic (layered)
structure, folded structure and ptygmatic like fold structure have been noted
in the field.
Economic possibility of the study area,
rocks can be used as road materials for the construction of car-road and
ballast for the construction of railway.
GEOLOGY OF THE
MINWUN RIDGE OF THE SAGAING-KYAUKTA AREA, SAGAING TOWNSHIP.
ABSTRACT
The investigated area along the Minwun
Ridge between Sagaing and Kyaukta is situated about one mile north of Sagaing,
covering parts of the 84-O/13 one-inch topographic map and about 14 square
miles. This linear belt is bounded on the east by the Sagaing ridge and on the
west by the Shwebo-Monywa plain.
The study area is equally occupied by
both sedimentary and metamorphic units which vary in age from Mesozoic to
Recent.
Minwun Metamorphics, occurs basement of
the area, mostly forms discontinuous inliers among the Cenozoic sediments,
Metamorphic rock units are generally low to high grade rocks of greenschist
facies and amphibolites facies. Bluish grey, massive to laminated, slightly
metamorphosed limestone blocks occurring on the western flank of Minwun ridge.
They have been metamorphosed from Thanbaya Formation or Ngapyawdaw Chaung
Formation of Upper Triassic age.
The arkosic sandstones of Kyaukta
Formation were deposited under a condition of non-marine deltaic environment
and Irrawaddy sand rocks were river sands deposited under the fluvial
environment.
The regional structural trend of all
lithologic units is generally N-S to NNW-SSE direction. The most common styles
of folding found in the metamorphic units are tight isoclinals and similar
folds.
Economically, various rock units of the
area, such as limestones, schists, clayey silt and Pleistocene gravels are
favourable for industrial raw and construction material and decorative stones.
Placer gold has been extracted by the local people in various parts of the
area.
GEOLOGY OF THE
NAGAMAUK AREA, MADAYA AND SINGU TOWNSHIPS
ABSTRACT
The area under the present
investigation, covering about 12 square miles, occupies north of Mandalay, near
Magwetaya village, Madayar and Singu townships. It is situated between latitude
21 15 to 21 30' N, and longitude 96 0' to 96 15' E, covering parts of the 93
B/3.
The study area is present three units:
Igneous rocks unit, Metaigneous rocks unit and Meta-sedimentary rocks unit.
The metamorphic rocks in the study area
consists of marbles, calc-silicate rocks and granitic gneiss. Age of Mogok
metamorphic is upper Paelozoic. Regional and contact metamorphism have affected
at the study area.
Igneous rocks such as biotite granite
and leucogranite were formed by calc-alkaline magma which were probably derived
from continental margins overriding subducting oceanic lithosphere. Leuco
granite is the main igneous rock of the study area. K/Ar radiometric data
indicates significant and possibly widespread thermal disturbances in the
central granitoid belt during the Tertiary.
Pegmatite dykes and apatite veins
originated during the latest stage of the igneous activities of the study area.
Quartzofeldspathic veins are intruded
into the granitic gneisses.
On the basis of the observed mineral
assemblages, the metamorphic facies are considered to belong to the upper
amphibolites facies and hornblende hornfel facies.
The general trend of the metamorphic
rocks are nearly north to south. One major cross fault was observed in this
area.
Economic possibility of the study area
is rich, Precious and semiprecious stones can be observed. In the study area,
calc-silicate rocks can be used as road materials for the construction of
railway.
GEOLGOY OF THE
NAMTU-MANSAM AREA, NAMTU TOWNSHIP, NORTHERN SHAN STATE
ABSTRACT
The Namtu-Mansam area covering part of
the topographic map of 93-E/8 is located in Namtu Township, at about 42 miles
NW of Hsipaw Township and about 44 miles SW of Lashio Towhship. The study area
lies mainly a part of the western margin of the Eastern Highlands.
The Paleozoic and Mesozoic sedimentary
rocks of the study area can be classified six major lithostratigraphic units
from older to younger namely Pangyun Formation (Late Cambrian), Taungkyun
Formation (Early to Middle Ordovician), Li-lu Formation (Late Ordovician), Panghsa-pye Formation (Early
Silurian), Namhsim Formation (Late Silurian), Plateau Limestone Group(Devonian
to Early Triassic) and Tati Limestone (Middle Jurassic). The general trends of
the mountain ranges of this area are running north-south and nearly parallel to
each others.
Petrographically, Pangyun Formation is
classified as arkose and arkosic arenite. Taungkyun Formation defined as
dominantly wackestone, Li-lu Formation as packstone, Panghsa-pye Formtion as
packstone and Namhsim Formation as quartzose sandstone or quartz arenite.
Plateau Limestone as micritic limestone and Tati Limestone as Pelmicrite.
This
area, a major longitudinal fault, so called Li-lu fault. They are nearly
parallel to the regional tectonic and topographic trend, which runs nearly
north-south.
The depositional environment of Pangyun
Formation may have been deposited in a shelf environment. Taungkyun Formation
may have accumulated in a warm, slightly agitated, shallow-marine environment.
Li-lu Formation of the present area may be deposited in a warm, shallow, marine
shelf environment. Pahghsa-phe Formation is deposited in a deeper ramp environment.
Plateau Limestone Group was probably deposited in a warm, shallow-marine
environment. Tati Limestone may have been deposited in Tidal flat environment.
The present area is an economic
importance. Lead-zinc and iron ores and the construction materials can be
produced in the study area.
GEOLOGY OF THE
TUGON-KINYWA AREA, YAMETHIN TOWNSHIP
ABSTRACT
The study area, the Tugon-Kinywa area,
is covering about 56 square miles of fairly rugged terrain that forms a part of
the Mogok Belt and the central granitoid belt. The rock succession of the area
is from older to younger. Banded marble, calc-silicate rocks (M1)
and Yinmabin Schists (M2) of Mogok Metamorphics. These units were
intruded by the igneous rocks of possibly Tertiary age in the following order
(older to younger): porphyritic biotite granite, leucogranite, pegmatite and
aplite.
Mogok metamorphic are mainly composed of
Yinmabin Schists (M2): (biotite schist, muscovite schist and
sericite schist) and Banded marble interbedded with calc-silicate rocks(M1).
The granitic rocks in this area are
mainly composed of porphyritic biotite granite, leucogranite, pegmatite and
aplite veins. The phenocrysts of alkali-feldspar are present in the porphyritic
biotite granite.
Their mineral assemblages indicate that
the metamorphic rocks of the area belong to the Upper amphibolites facies and
to the hornblende hornfel facies.
The
high grade regional metamorphism of this area may be regarded as the medium
pressure type. The age of metamorphism in this area is tentatively assigned to
Late Eocene. The marbles and related rocks may have been metamorphosed mainly
from the Plateau Limestone, and perhaps partly from the Cretaceous Limestones.
Cross faults in the study area are NW-SE
trending. The joints of the Yinmabin Schists nearly N-S trending is prominent.
It is interpreted that the main force came from the nearly N-S. In the igneous
rocks, the major joint sets are also nearly E-W trending.
The mineral deposits in the study area
are mainly gold in the form of placer. Placer deposit in various parts of the
study area have been worked for gold by local people. The occurrences of galena
disseminated in the skarn rock. The skarns are in the direct contact with the
porphyritic biotite granite. Banded marble and calc-silicate rocks; prophyritic
biotite granite and leucogranite are regarded as good building stone.
GEOLOGY OF THE
ANISAKAN-SAKANGYI AREA, PYINOOLWIN TOWNSHIP
ABSTRACT
The study area, covering about 30.72
sq.km of rugged and mountainous terrain, situated in the topographic map
93-C/5. All the Paleozoic carbonate strata in the study area are generally
trending in N-S and dipping towards the east. The stratigraphic succession in
the present area is Sitha Formation (Middle Ordovician), Kyaingtaung Formtion
(Late Ordovician), Nyaungbaw Formtion (Silurian), Zebingyi Formation (Early to
Middle Devonian), and Plateau Limestone Unit (Carboniferous to Permian).
The Nyaungbaw Formation, mainly consists
of medium to thick bedded, reddish brown, argillaceous limestone intercalated
with calcareous shale in the lower part. The upper part consists of
medium-bedded, greenish grey, subphacoidal limestone with crisscross-silt
partings on the bedding surface. The phacoidal structure is characteristic
feature of this unit.
The Zebingyi Formation, can be divided
into three members. The lower member consists of pteropod-bearing medium
bedded, black shale, pinkish to buff colored siltsont and marl. Small patches
of sub-phacoidal limestone are sparsely intervened within these strata.
Plateau Limestone Unit can be divided
into two parts, namely Lower Plateau Limestone and Upper Plateau Limestone. The
earlier unit is composed of medium to thick bedded, grey to whitish blue grey,
fairly dolomitic limestone.
Petrographically, rock samples of the
study area can be identified by nine microfacies. Sitha Formation is classified
as micritic limestone and sparitized Pelmicrite; Kyaingtaung Formation as silty
biomicrite; Nyaungbaw Formation as
biomicrite and micrite; Zebingyi Formation as biomicrite and sublithic
arenite and Plateau Limestone Unit as dolomitized pelmicrite and silty
biomicrite.
There are three major asymmetrical
synclines, namely Anisakan, Thandaung and Thondaung synclines. Two major tear
faults and many minor folds are recognized in the study area.
Economic minerals are noted that iron
ore (hematite) has been occurred as karst-filling deposit in the Plateau
Limestone and barite mineralization is recognized in the Sitha Formation and
lower part of Kyaingtaung Formation. The construction materials, road
materials, and decorative stones are produced from all stratigraphic units
except Kyaingtaung Formation of the present area.
GEOLOGY OF THE
PAUNGDAW-NYAUNGNI AREA, PYINOOLWIN TOWNSHIP
ABSTRACT
Present study area is mountainous
terrain that located nearly Pyinoolwin. It is referred by the topographic map
93-C/5 and covers approximately 30.72 sq.km in area. This area is covered by
the Paleozoic strata which are generally trending NE-SW in direction. The
stratigraphic succession is formed four units of formation rank. These in
accending order are: Kyaingtaung Formation, Zebingyi Formation, and Plateau
Limestone.
In the study area, only one unit of the
Ordovician system, Kyaingtaung Formation, is recognized. It consists of
thick-bedded, reddish brown, silty limestone in the lower part and thin to
medium bedded, yellow to buff colored, siltstone and marl in the upper part. It
is highly fossiliferous, Orthis sp, Rafinesquina sp, Diplotrypa sp., associated
with abundant crinoids stems and cystidean plates were recovered and they
indicate the late Ordovician age. According to its stratonomic character and
fauna assemblage, it may be deposited under shallow, quiet water environment,
especially in Neritic Zone with high organic productivity.
The Nyaungbaw Formation mainly comprises
medium to thick bedded, purple to reddish brown, phacoidal regillaceous
limestone intercalated with calcareous shale in the lower part. In the upper
part, medium bedded, greenish grey, sub-phacoidal limestone with chlorite
flakes are recorded. Criss-crossed silt partings are characterized on the
surface of bedding. These Strata have been deposited within a fairly deep
basin.
The Zebingyi Formation can be divided
into three members, viz., (1) Upper Member, (2) Middle Member and (3) Lower
Member. The lower member consists of pteropod bearing medium-bedded, reddish to
vivid yellow to buff colored, siltstone, marl, shale and minor amount of some
limestone bands.
The Plateau Limestone, the most wide
spread unit, can be subdivided into two units. The lower member comprises
medium to thick bedded, bluish grey to dark grey, highly jointed limestone.
Small occurrences of hematite are surrounding recognized.
Petrographically, Zebingyi Formation can
be classified as six-microfacies: Silty pelmicrite, Micrite, Biomicrite,
Siliceous biomicrite, Silty biomicrite and Sublithic arenite.
There
are two major asymmetrical overturned anticlines, viz., Paungdaw anticline and
Nya-nyintha anticline. Only one major corssfault is recognized in the study
area.
The construction materials, road
materials and decorative stones are produced from Nyaungbaw Formation, Zebingyi
Formation, and Plateau Limestone. Calcitic limestones of Ordovician units and
Plateau Limestone unit are used for lime baking.
GEOLOGY OF THE
KUNI-KYAUKSIN AREA, MAHLAING AND WUNDWIN TOWNSHIPS
ABSTRACT
The Kuni-Kyauksin area is located in
Mahlaing and Wundwin Townships, Mandalay Region. The study area is a low-lying
rolling terrain. The Taungnyo (Me'nyo) Taung is the most prominent
physiographic feature. The lithology of the study area is the alternate
sequence of resistant and non-resistant beds characterized by cuesta landform.
The major streams, Thinbon Chaung and Minthauk Chaung flow from NE to SW in
direction.
The trellis, dendritic and
subrectangular drainage patterns are present in the study area. The study area
lies in the Central Myanmar with semi-arid climate. The study area is located
in the Central Cenozoic Belt of Myanmar. The bedding nature in the study area
is generally low to moderate dip angle and in some places, the high angle dip
amounts are formed by the faults.
The lithostratigraphic units of the
study area in ascending order are Moza Formation, Khabo Sandstone and Irrawaddy
Formation. The Moza Formation is well exposed in the central parts of the study
area. It occupies in Taungnyo Taung, Kyauksin, Shwethalyaung Taung, along the
Thaphayo and Minthauk Chaungs. It is also cropped out along the road cutting of
the Yangon-Mandalay highway road.
Taungnyo-Kyauksin anticline is the major
tectonic feature of the study area and is situated in the central part of the
area. The name is derived from Taungnyo Taung and Kyauksin Pagoda. It is an
asymmetrical, south plunging anticline. The core of the anticline is
constituted of sandstone and shale interbedded sequence of the Moza
Formation.Minthauk Chaung Fault is a major cross-fault and trend ENE-WSW in
direction. It is located in the middle part of the area. In the study area, the
principle stress which caused the folding, faulting and jointing in the area
would be NE-SW in direction.
Biogenic sedimentary structures are
formed by living organisms interacting within the sediments. Trace fossils or
ichnofossils are formed on the bedding plane of sandstone and shale interbedded
unit of the Moza Formation.
The construction and road materials,
white clay, gypsum and oil and gas may be produced as the economic aspects in
the study area.
GEOLOGY OF THE
TAUNGDAW-MYOGYI AREA, KYAUKSE AND YWA-NGAN TOWNSHIPS
ABSTRACT
The study area is located at the triple
junction of Kyaukse, and Ywa-ngan townships. It is bounded by north latitudes
21 25' -21 30' and east longitude 96 18' – 96 25' in one-inch topographic map,
93C/7.
The stratigraphic sequence in the area
consists of rock units ranging in age from Precambrian to Triassic, generally
younger towards the west. The units mapped are in descending order: Chaungmagyi
Group (Precambrian), Pindaya Group (Ordovician), Mibayataung Group (Silurian),
Thitsipin Limestone Formation (Permian) and Nwabangyi Dolomite Formation (Early
to Middle Triassic).
The dominant lithology of the
Chaungmagyi Group is represented by metasedimentary rocks whereas the younger
units are chiefly composed of carbonates. The Chaungmagyi Group consists mainly
of phyllites, slate and metagreywacke with tight and complex folding. The older
Precambrian rocks are unconformable contact with the overlying Lokepyin and
Wunbye Formations.
The Pindaya Group has two lithologic
units of formational ranks that are Lokepyin and Wunbye Formations. The
Lokepyin Formation is mainly composed of siltstone and argillaceous limestone.
The Wunbye Formation is composed of bluish grey to yellowish brown, medium to
thick bedded, argillaceous limestone with silt partings in the lower part and
silty limestone with silt partings containing small scale cross-lamination and
algal mat in the upper part.
The Linwe Formation is mainly composed
of grey to purple to reddish brown, hard and compact, medium to thick-bedded
phacoidal limestone, argillaceous limestone and intercalated with reddish-brown
siltstone and shale.
The Thitsipin Limestone Formation is
mainly composed of dark grey to bluish grey, hard and compact, thick-bedded,
micritic and calcitic limestone. These limestones are commonly massive but
locally thinly laminated to well-beded, which contains brachiopods, fusulinids,
solitary and compound corals and gastropods. The Nwabangyi Dolomite Formation
is composed of massive or poorly bedded, highly brecciated, light grey to
whitish dolomitic limestone. Moderately preserved ammonites such as Ceratites
sp., Columbites sp. And Danubites sp.? and mostly fragments are collected from
this cephalopodal limestone horizon.
Petrographically, the Lokepyin Formation
is composed of the micrite / mudstone and pelsparite / wackestone. The Wunbye
Formation consists of biomicrite / mudstone and pelsparite / wackestone. The
Linwe Formation comprises of biomicrite / wackestone and micrite / mudstone.
The Thitsipin Limestone Formation is composed of biomicrite/ mudstone and
pelsparite / wackestone. Nwabangyi Dolomite Formation consists of dolomitized
micrite.
The
metasediments of the Chaungmagyi Group in the study area are deposited in
deep-water, reducing environment in a geosynclines. The Lokepyin Formation may
be accumulated in a warm, slightly agitated, shallow-marine environment.
According to the lithologic characters and faunal content, the depositional
condition of the Wunbye Formation was a warm, shallow, marine environment.
On the basis of lithologic and
petrologic features, faunal content and sedimentary structures, the Linwe
Formation was possibly deposited in a slightly agitated, warm, fairly
deep-marine environment with alternating oxidizing and reducing condition. The
depositional environment of the Thitsipin Limestone Formation of the study area
could be warm, shallow, open sea environments. The dolomitic limestone of the
Nwabangyi Dolomite Formation may be deposited in a shallow carbonate shelf.
The major structure of the area assumes
that a homoclinal structure. The regional structure trends nearly NNW-SSW being
subparallel to the linear topographic trend. This area is structurally complex
and figured by complex folding and fault system. The longitudinal joints in the
Chaungmagyi Group are generally trending in N 20 E – S20 W in direction. The
longitudinal joints in the Chaungmagyi Group are generally trending in N 20 E –
S 20 W in direction. The longitudinal joints in the Plateau Limestone Group are
N 40 E-S 40 W in direction.
The study area occur only a few ore
minerals. They are found in the metasediments of the Chaungmagyi Group and
Wunbye Formation. Galena, azurite, malachite and graphite are found in
association with quartz veins in limestones of the Wunbye Formation near the
east of Kin village. Iron ore mineral is also observed in the metasedimentary
rocks of the Chaungmagyi Group at north of Hseywa village.
The calcitic limestone of Plateau
Limestone Group can be obtained the best qualigy lime. Greenish metagreywacke,
shinning luster greenish yellow phyllites and slate in the Chaungmagyi Group
and limestones of the Plateau Limestone Group can be used as decorative stone.
GEOLOGY OF THE
GONYWA-MYATHUKHA AREA, MYITTHA AND WUNDWIN TOWNSHIPS
ABSTRACT
The study area, covering about 72 sq.km,
lies in the Myittha and Wundwin townships, Mandalay region, Myanmar. It is in
the northern part of the Pyetkaywe batholiths, over 460 sq.km in area, is
located between the Central Lowland and the Shan Plateau.
The
area is mainly composed of intrusive rocks which can be subdivided into five
units, i.e, dioritic rocks, prophyritic hornblende biotite granite, biotite
granite, aplite-leucogranite-microgranite, and pegmatite (in ascending order).
Metasedimentary rocks of Early
Cretaceous age expose as rood-pendants in the northwestern part of the area. On
the basis of the mineral assemblages, one regional mentamorphic facies, viz.,
almandine-amphibolite facies, is recognized.
Field and petrographic evidences
indicate that the dioritic and granitic rocks are magmatic in origin. On the
basis of field relationships, the possible depth of emplacement of the
intrusive many be regarded as transitional between masozone and catazone.
The time of metamorphism in the area
probably was post Paleozoic. Metamorphism of these rocks may be partly related
to the igneous activities in the study area.
The prominent structure is a fault
trending NE-SW. The major joint sets ore NE-SW, NW-SE and ENE-WSW.
Some mineral crystals of aquamarine,
tourmaline, topaz and quartz are valued as gem. Other economic minerals are
feldspars, and wolframite for industrials. Granitic and dioritic rocks can be
used for construction and decoration.
GEOLOGY OF THE
SAKANGYI-HTILAING AREA, YWA-NGAN TOWNSHIP, SOUTHERN SHAN STATE.
ABSTRACT
Sakangyi area is located in Ywa-ngan
Township. The study area is easily assessable because of the Sakangyi village
is located on the Ywa-ngan—Myogyi motor road.
Physiographically,
the study area can be subdivided into four divisions such as highly dissected
ridges and valleys, eastern high mountain ranges, central lowland and western
massive mountain ranges. Well-marked highest point protruded is Timbi Taung
(2895' above sea level).
The study area is bounded by the Eastern
Trough on the west and Myogyi Uplift on the east. The eastern part of the
region is made up mostly of Paleozoic rocks in contact with the Precambrian
rocks by a mark structural break in the east. These Paleozoic rocks extend
northward into the northern Shan State and continue southeast to the southern
Shan State.
Chaung Magyi Group is mainly consisted of metasedimentary
rocks, upon which fossiliferous Paleozoic units were laid down. It is
extensively exposed on the east of the Ywa-ngan—Myogyi car road.
The Chaung Magyi sediments of the study
area were deposited in quiet, deep water, reducing environment in a north-south
trending geosynclines. The depositional environment of Lokepyin Formation was a
shallow, warm marine, stagnant, anaerobic marine environment affected by
regular and energetic current. The Wunbye Formation may be accumulated in a
warm, slightly agitated, shallow marine environment. Linwe Formation suggested
the shallow marine environment. The Wabya shales were possibly deposited at bay
or lagoon, but calcareous sandstone at shoal areas under still-stand marine
condition. The depositional environment of the Plateau Limestone Group could be
a warm, shallow, open-sea environment.
The study area is formed as homoclinal
structure with moderate to fairly steep dips towards. Sometimes, local
crenulations can be found. The local folds are observed in some stratigraphic
units. The Sakangyi fault occurs as contact line between Chaung Magyi Group and
Pindaya Group. Htilaing fault separates the rocks of Plateau Limestone Group
and also cut the Mya-lay-nyo range in the north.
The major ore mineral excavated from the
study area is barite. Barite occurs as two to three feet thick veins in
limestone of Wunbye Formation at the southwest of Sakangyi village. The
expected ore minerals from the study area are malachite, azurite, chalcopyrite
and galena. The best quality lime can be obtained from the limestones of
Ordovician units and Plateau Limestone Group exposed in the study area can be
used as a decorative stone.
GEOLOGY OF THE
PYETPYO TAUNG AND MAUNGGWE-KENZE AREA, MYITTHA TOWNSHIP
ABSTRACT
The study area lies just south-east of
Kume, Myittha Township. It is situated between latitudes N21 10 to 21 16 and
Longitude E 96 15 to 96 20 and covers parts of 93 C/7 and 93 C/8 are one inch
topographic maps. A car road connecting Kume and Kinda Reservoir runs along the
eastern part of the study area. So, the study area is easily accessible
throughout the year.
The study area is a rugged terrain
region bounded by the Shan Scarp in the east and Pyetkaywe batholiths in the
west. The highest point, the Ingyin Taung, rising (1960) above sea level is at
the northern part of the study area. The Pan Laungt River is one of the
important river in the area, which flowing in a nearly North-South direction. A
sub-parallel drainage pattern is found in the eastern part of the study area.
The vegetation of Jurassic sequence comprises bamboo, long grass, bushes and
small trees.
The study area as a whole may be
regarded as the boundary zone between the eastern Highlands in the east and the
Central Lowland in the west. The study area is bounded by the Pyetkaywe
batholiths in the west and upper Paleozoic limestone in the east. This area is
structurally bounded by two major fractured zones; the Nwalabo fault belt in
the east and the Sagaing Fault in the west. The Pan Laung Fault, trending
North-south along the Pan Laung River is a major structural feature of the
study area.
The lower and upper units of Maunggwe
Formation were deposited in deltaic and shallow marine shelf with slow
sedimentation rate from relief of old
sediments. Pyinyaung Formation may have been accumulated in the carbonate ramp
environment.
The strata of the all sedimentary units
are shown generally east dipping and may be major syncline. The Panlaung fault
runs nearly N-S trending and through the study area. The Panlaung fault
completely separates the Jurassic-Cretaceous rocks of Panlaung Group the
northern part of the study area. Kyatkyi fault separates the Panlaung sediments
and travertine deposits.
The wolframite content is higher than
tin and anomalous tungsten values (up to 120 ppm) occur at the southwest of
Maungwe. Beryl occurs in the western part of the study area, where bluish green
and whitish beryl and aquamarine occur in the quartz and pegmatite veins.
Travertine and limestone may be used as decorative stones. Black limestone of
Pan Laung Group dacite porphyry may be used as construction and road materials.
GEOLOGY OF THE
SHANMANGE – TANAUNGGYIN AREA, MEIKTILA AND KYAUKPADAUNG TOWNSHIPS
ABSTRACT
The Shanmange-Tanaunggyin area lies in
Kyaukpandaung Township and Meiktila Township, Mandalay Region. Topographically,
the study area is a low-lying rolling terrain. The highest point of the study
area is the summit of Seinbangon Taung which rises to 1677 feet above sea
level. The lithology of the study area is the alternate sequence of resistant
and non-resistant beds. Therefore, the study area is characterized by cuesta
landform. In the eastern part of the present area, the major stream, Nyaungzauk
Chaung flows from SW to NE. In the western part of the study area, the major streams,
Taungyo Chaung and Tanaunggyin Chaung flow nearly N-S. The trellis, dendritic
and subparallel drainage patterns occur in the study area. The study area lies
in the Central Myanmar with semi-arid climate.
In the study area, Upper Pegu Group of
Moza Formation (Middle Miocene), Khabo Sandstone (Middle Miocene) and Irrawaddy
Formation (Late Miocene to Pliocene) are found. Moza Formation is well
distributed in the central part of the area. It underlies Okhmonyo, Thabutkon,
Kyauko, Ywathit, Nyaungzaukpin, Nyaungle and Letpanaing villages. Moza
Formation is formed by the alternated sequence of sandstones and shales. Moza
Formation may be deposited in a shallow marine, tidal flat environment due to
the presence of lenticular bedding and present area. It underlies Shawbyubin,
Sinsyalya, Suyittan, Myintha, Sinmyin, Pyaesayaye, Ywadan and Tanaunggyin
villages. The brackish water fauna such as Cerithium sp and the present of
large scale cross –stratification may be suggested that the sandstone will
deposited in the brackish water environments. In the present area, Irrawaddy
Formation is locally developed in northeastern part of the area. It underlies
Ywathit, Kanaoo and Shanmange villages. The present of fossil woods fragments
indicates that the Irrawaddy Formation was deposited under the arid to
semi-arid condition.
Sandstone of the Moza Formation, Khabo
Sandstone and Irrawaddy Formation may be classified as arkose, according to F.J
Pettijohn, 2000 (Source; Dott,1964, Jour. Sed. Petrology, v.34,Fig.3).
Sedimentary structures such as
cross-stratification, ripple marks, lenticular bedding, flute casts, load
casts, sandstone concretion and cone-in-cone structure were found in the study
area. Biogenic sedimentaty structures are formed by living organisms
interacting within the sediments. Trace fossils such as Helminthoida, is
generally sub-parallel, closely spaced and regular, meandering tunnel trails
are observed on the bedding surface of sandstone in the Moza Formation.
Pyaesayae syncline is the major tectonic
feature of the study area and is situated in the western part of the area. The
general trend of cross-fault is NE-WE. This fault is situated near the
Suyittan, Thabuton and Ywadan villages. The fault pass through the Moza
Formation and Khabo Sandstone. Another fault occurs in the eastern part of the
study area. This fault may be regarded as a thrust fault. Joints are well
developed in the competent rock units such as the sandstone of the Moza
Formation and Khabo Sandstone Unit.
The sandstone, sand, clay, gypsum and
efflorescent salt may be produced as the economics aspects in the study area.
GEOLOGY OF THE
KYAUKPON-SINTHEGAN AREA, KYAUKPADAUNG AND NATMAUK TOWNSHIPS, MANDALAY AND
MAGWAY DIVISIONS
ABSTRACT
The study area is located about 8 miles
SE of Kyaukpadaung. It is referred by the topographic maps 84 P/5 and 84 P/6
and covered about 112 square miles.
In the study area, clastic sedimentary
rocks ranging in age from Miocene to Pliocene and and Volcanic rocks (Pontian
to Pliocene) are exposed. The sedimentary sequence, from older to younger,
consists of the Moza Formation (1500 ft in thickness), the Khabo sandstone
(1300 ft in thickness), and Irrawaddy Formation (2250 ft in thickness).
Subordinate amount of volcanic rocks are interfingering with and overlying the
Irrwaddy sediments.
GEOLOGY OF THE
SINGYON-SEDO AREA, MAHLAING AND MEIKTILA TOWNSHIPS
ABSTRACT
Singyon-Sedo area is situated in
Meiktila and Mahlaing Townships, Mandalay Region. It is located in the Central
Cenozoic Belt of Myanmar. Topographically, the study area is a low-lying
rolling terrain. The highest point of the study area is the summit of Sababon
Taung which rises to 1877 feet above sea level. The lithology of the study area
is the alternate sequence of resistant and non-resistant beds. Therefore, the
study area is characterized by cuesta landform. The study area lies in the
Central Myanmar with semi-arid climate. The bedding nature in the study area
formed by the faulting and folding.
The lithostratigraphic units of the
study area in ascending order are Moza Formation (Middle Miocene), Khabo
Sandstone (Middle Miocene) and Irrawaddy Formation (Late Miocene to Pliocene).
The Moza Formation is well exposed in the western parts. It occupies in
Nabegon, Singyon, Gwenyowin and Thabutyon villages. Moza Formation is formed by
the alternated sequence of sandstones and shales. Khabo sandstone is well
exposed in the central part and westernmost part of the present area. It
underlies Myintha, Thittein, Aungban, Thebuugyaung, Wathondaw, Awzachan,
Yagyigon, Kanywa and Okgale villages. The brackish water fauna such as
Cerithium sp., Turritella sp., Campanile sp., Pecten sp., and the present of
large scale cross-stratification may be suggested that the sandstone will
deposited in the brackish water environments. In the present area, Irrawaddy
Formation is locally developed in the eastern part of the area. It underlies
Ywathit, Ondon, Dahattan, Thibin and Kokkogon villages. The present of fossil
wood fragments indicates that the Irrawaddy Formation was deposited under the
arid to semi arid condition.
Sandstone of the Moza Formation and
Khabo Sandstone may be classified as arkose, according to F.J Pettijohn, 2000
(source: Dott, 1964, Jour.Sed.Petrology, v.34, Fig.3).
Sedimentary
structures such as cross-stratigication ripple marks, lenticular and wavy
bedding, flaser bedding, flute casts, load casts, sandstone concretion and
cone-in-cone structure were found in the study area. Biogenic sedimentary
structures are formed by living organisms interacting within the sediments.
Trace fossils are observed on the bedding surface of sandstone in the study
area.
Nebagon anticline is the major tectonic
feature of the study area and is situated in the southwestern part of the area.
Thittein syncline is also situated in the southwestern part of the area. The
first fault (F1-F1) is generally trend NE-SW. It pass through the Moza
Formation and Khabo Sandstone. Another fault (F2-F2) is trending nearly E-W. It
also pass through the Moza Formation and Khabo Sandstone.
Joints are well developed in the
competent rock units such as the sandstone of the Moza Formation and Khabo
Sandstone. They are commonly related to the thickness of the beds of sandstone.
There are three sets of joints in the study area. They are strike joint, dip
joint, and oblique joint.
The sandstones are used as construction
and road materials for the High-way road and building stone. Sands are basic
material for the construction of the buildings and highways. Gypsum is
distributed in the Moza Formation at the west of Myintha village. It is formed
as discontinuous thinly layers and parallel to the thin to medium bedded,
greenish grey shale and sand. Gypsum plates can be produced as industrial raw
material. Gypsum is used as a reacter in cement. In the study area,
efflorescent salt effect on the exposure as coating on the surface of sandstone
outcrops.
