Xiangshui to Mandal Transect North China

63 Pages·6.231 MB·English

GLOBAL GEOSCIENCE TRANSECT 2
XIANGSHUI TO MANDAL TRANSECT
NORTH CHINA
@ American Geophysical Union
Publication No. 188 of the International Lithosphere Program
ISBN 0-87590-779-2
Copyright 1991 American Geophysical Union. Figures, tables and
short excerpts may be reprinted in scientific books and journals if
the source is properly cited; all other rights reserved.
Printed in the United States of America.
American Geophysical Union
2000 Florida Avenue, N. W.
Washington, D.C. 20009
Preface
The Global Geoscience Transects Project (GGT) is surface-bound field geologist, can attest to the excite-
an ambitious international effort that draws together ment of working with geophysicists from around the
geoscientists in a variety of disciplines to produce the world to consider the nature and evolution of deeper
best possible portrayal of the composition and struc- parts of the crust and to attempt to integrate these data
ture of the Earth's crust. Since its inception in 1985, with surface features.
GGT has encouraged geoscientists in all countries of GGT compilation also plays a significant role in the
the world to compile cross sections of the Earth up to education of geoscientists. The problems being inves-
tigated are global and interdisciplinary in scope, and
a few thousands of kilometers in length and drawn to
international cooperation between geologists, geo-
the base of the crust using all available geological,
physicists, geochemists, and geodesists is required to
geophysical, and geochemical information. Transects
resolve them. Transects cannot be compiled without
are drawn to common scales and formats so that the
such interdisciplinary research.
Earth's crust in different parts of the world can be
The guidelines developed for the transects had to be
directly compared.
flexible enough to accommodate the variations in data
GGT was conceived by the Inter-Union Commis-
available in different parts of the world. Some areas
sion on the Lithosphere (ICL), a "child" of the
have very complete, freely available data bases; others
International Union of Geological Sciences and the
have at best only gravity or aeromagnetic maps as the
International Union of Geodesy and Geophysics
geophysical data base from which to construct crustal
(IUGG), at the IASPEI conference in Tokyo in August
cross sections.
1985. Project coordinators James W. H. Monger and
The first publications of the GGT Project, a transect
Hans-Jurgen Gotze organized a multidisciplinary, mul-
chart and accompanying booklet, are ajoint activity of
tinational committee that coordinated the global proj-
ICL and AGU. The seven transects from China (2),
ect. Meeting at the IUGG XIX General Assembly in
South America (2), Australia (2), and Syria (I), were
Vancouver in August 1987, the committee developed
drafted and hand colored by the compilers. Transects
preliminary guidelines for transect compilations, fol-
combine the available data into interpretive sections
lowing suggestions from transect compilers. Proposals
drawn to the base of the Earth's crust. The product is
for transects were solicited from ICL national commit-
a large display-approximately 1 meter by 2 meters-
tees, government geoscience agencies, universities,
and scientists. A total of 140 proposals were received with the bottom line cross section as a vertical tectonic
from Africa (41), South America (30), China (18), map of the crust. The booklet includes an analysis of
USSR (12), USA (12), Europe (12), Australia and New the transect by the compilers and references to data
Zealand (1 I), India (3), and Southeast Asia (I). sources.
The GGT Project has generated a special intellectual The GGT Project is now embarking on a new
excitement among participants by encouraging geosci- direction that will make this wealth of data even more
entists to understand the evolution and physical be- useful to the scientific community. ICL and AGU plan
havior of the lithosphere by bridging the gap between to publish future transects in electronic format (dis-
surface geology and deeper geophysics. Monger, as a kettes, CD-ROM) that can be manipulated using small
"low-end" computers. A GGT Digitization Group was wide network of scientists cooperating on transects
established in 1988 to prepare guidelines for digitizing would be able to work interactively with these files,
transects; the guidelines and sample will be published adding data to them, analyzing, reconfiguring, and
by AGU. interpreting them.
This endeavor breaks new ground and goes a long Digitization of geoscience material will not only ease
the task of publishing transects and encourage the
way toward a goal of the ICL of closely linking
exchange of data bases, it promises to allow quanti-
geological, geochemical, and geophysical data bases
tative comparisons of elements of different parts of the
and breaking down present barriers between different
Earth's crust. The use of digitized transect material is
Earth science disciplines. With the digitized transects,
the perfect training ground for the new breed: geosci-
geologists, for example, could manipulate gravity data
entists!
to test the validity of their structural models. A world-
James H. Monger
Geological Survey of Canada
100 West Pender Street
Vancouver V6B IR8
Canada
Hans-Jurgen Gotze
Institut fiir Geologie, Geophysik und Geoinformatik
Freie Universitat Berlin
Malteserstrasse 47 100
D-1000 Berlin 45 Germany
XIANCSHUI TO MANDAL TRANSECT, NORTH CHINA
Edited by
MA XINGWAN
Institute of Geology, State Seismological Bureau, Beijing, 100029, China
LIUC HANGQUAN
Geophysical Prospecting Brigade, State Seismological Bureau, Zhengzhou, 450003, China
LIU GUODONG
Institute of Geology, State Seismological Bureau, Beijing, 100029, China
XIANGSHUI TO MANDAL TRANSEn, NORTH CHINA
CHAPTER HEADINGS, AUTHORS AND THEIR INSTITUTIONS
I Introduction: Ma xingyuanl
I1 General statement: bases and philosophy for constructing the Xangshui to Mandal Transect: Ma xingyuanl
I11 Description of major tectonomorphic provinces along the transect comdor: Ma xingyuanl
IV Tectonic setting of the Xiangshui to Mandal Transect: Ma ~ingyuan'
V Major tectonic units: Ma ~ing~uan'
VI A summary of magmatic activity: Zhang yanpol
VII Gravity anomaly map: Feng Rui2, Yin xiuhual, Chcn ~ i b oL~iu, z hanbol, and Liu ~icsheng'
VIII Aeromagnetic anomaly map: Ren xixian2, Liu zhanpol, Bai ~ongxiaa~n,d Wang ~hunha'
IX Heat flow: Zhang Ruhuil, Li Ruchengl, Zhang wanxial, and Peng ~ui~ing'
X Deep seismic sounding results: Liu changquan3, Jia shixu3, and Du Guanen3
XI Electrical conductivity: Jiang zhaol, Sun ~ie'W, ang Ji-junl, and Shi ~hu-linl
XI1 S-wave velocity structure: Cen Guoying2, Song zhonghe2, An changquiang2, Chen ~ihuaZ~h,u ang zhen4,
Fu zhuwu4, and Lu ziling4
XI11 Mantle xenoliths from Cenozoic basalts: Lin chunyongl, Shi anb bin', and He yongnianl
XIV Paleomagnetic results: Bai yunhongl, Cheng ~uolian~S'u,n yuhangl, Li sulingl, and Han zhujunl
XV Seismicity: Feng ~ u iH~ao, J inqi2, Huang pinzhang2, and Zhao Jianguo2
XVI Crustal evolution of the Xiangshui to Mandal transect corridor: Ma ~ingyuan'
Institute of Geology, State Seismological Bureau (SSB) Beijing, 100029, China
Institute of Geophysics, SSB, Beijing, 100081, China
Geophysical Prospecting Brigade, SSB, Zhenzhou, 450003, China
4 Yunnan University, Kunming, 65009 1, China
2 GLOBAL GEOSCIENCE TRANSECI 2
I INTRODUCTION The tectonostratigraphic flow chart summarizes the
stratigraphic, structural, magmatic and metamorphic
The Global Geoscience Transect (GGT) Project relationships in time and space between major
was conceived in 1985 as a new activity by the tectonostratigraphic elements, and is important for
Inter-Union Commission for the Lithosphere (ICL), conveying concepts of crustal evolution. It may be
which runs the International Lithosphere Program used as an aid in reading map relations and provides
(LP). ICL established a Coordinating Committee for an abstract of much of the following text.
GGT (CC-7), which is chaired by J.W.H. Monger and The geophysical and geochemical information
H.-J. Goetze. constrain structure and crustal composition at depth.
"Transect" as used by GGT refers to a cross-section They include seismic interpretations of velocity
showing the composition and structure of the entire structure, magnetotelluric sounding data, density
crust of the Earth and, where possible, the upper models, and microearthquake focal depths, as well as
mantle. It incorporates all available geological, information from xenoliths contained in Cenozoic
geochemical and geophysical data. Transects lie basalts, and isotopic data from magmatic rocks of
along comdors 100 km wide and up to a few thousand various ages. Additional constraints are provided by
kilometres long, positioned by regional experts to Bouguer gravity, aeromagnetic and heat flow maps.
cross major crustal features (Monger, 1986). The All the data bearing on deep structure and
principal objective of GGT is to produce interpretative composition, outlined above, are integrated with the
cross-sections, which in effect are vertical tectonic surface geology of the strip map, and also with
maps that ideally portray the evolution of the Earth's regional structures from outside the transect comdor,
lithosphere along the transect line (Monger, 1987). in an interpretative cross-section which shows the
The Xiangshui to Mandal Transect forms part of possible origin and disposition of crustal components,
the North China Geoscience Transect Project of the and thus the evolution of the upper lithosphere along
State Seismological Bureau, which is a study of the the transect line.
Sino-Korean Craton and its bordering continental
margin. It is one of five transects that were chosen to rn DESCRIPTION OF MAJOR
cross the main earthquake hazard prone regions of TECTONOMORPHIC PROVINCES ALONG
China (see Index Map on transect display). These THE TRANSECT CORRIDOR
provide a comprehensive comparison of the
compositional and structural variations in different The Xiangshui-Mandal comdor comprises three
tectonic domains within the craton and the ancient discrete segments which sequentially cross North
continental margins. China, from the Yellow Sea shore in the southeast to
This explanatory pamphlet supplements the display the Mongolian Plateau in the northwest. Together,
sheet of the Xiangshui to Mandal Transect. It guides they have a length of 1200 km. From southeast to
and assists the reader in the use of the graphic display, northwest, locations of the three segments are:
explains the rationale of the display, supplements the
graphic display with supporting data and discussions 1) from Xiangshui in Jiangsu Province, (longitude
on crustal structure, tectonostratigraphic units, and 119'36'~, latitude 34'12'~) to Sishui in
tectonic evolution, and provides references to data Shandong Province, (long. 117'14'~, lat.
sources. The text is organized in such a way as to be 35'45'N);
used in direct conjunction with the display. 2) from Zibo in Shandong Province, (long.
118'03'~, lat. 36'49'N) to west of Ying Xian in
Shanxi Province (long. 112'12'~, lat. 39'48'N);
I1 GENERAL STATEMENT: BASES AND 3) within Inner Mongolia (Nei Monggol Autono-
PHILOSOPHY FOR CONSTRUCTING THE mous Region), extending from Ijinhoro Qi in the
XANGSHUI TO MANDAL TRANSECT south (long. 109O48'~,l at. 39'42'N). to Mandal
(long. 110 06'E, to lat. 42'31'N).
The graphic display is compiled according to the
Guidelines for GGT established by CC-7 in 1987. The transect crosses eight tectonomorphic
These suggest a common format so that cross-sections provinces, summarized below from southeast to north-
of the crust in different parts of the world can be west. In the southeast (segments 1,2) these generally
compared directly. trend NE to NNE (reflecting regional structural
The main components of the graphic display are trends), whereas in the northwest (segment 3) they
geologic, gravity, and aeromagnetic strip maps, and an trend S. to N.
interpretative cross-section drawn to Moho depth,
which is based on geology and geophysics. Two color 1) (Segment 1) The easternmost tectonomorphic
coding systems are used: (1) that on the geologic strip province comprises the hummocky plain of
map and geological cross-section denotes ages of rock northern Jiangsu Province, which is bounded on
units; (2) that on the interpretative cross-section the east by the Yellow Sea (Huang Hai).
denotes the inferred tectonic settings during the time 2) (Segments 12) West of this, the Shandong Hills have
of formation of the rocks units. an average height of 500-1000 m above sea level.
2 GLOBAL GEOSCIENCE TRANSECI 2
I INTRODUCTION The tectonostratigraphic flow chart summarizes the
stratigraphic, structural, magmatic and metamorphic
The Global Geoscience Transect (GGT) Project relationships in time and space between major
was conceived in 1985 as a new activity by the tectonostratigraphic elements, and is important for
Inter-Union Commission for the Lithosphere (ICL), conveying concepts of crustal evolution. It may be
which runs the International Lithosphere Program used as an aid in reading map relations and provides
(LP). ICL established a Coordinating Committee for an abstract of much of the following text.
GGT (CC-7), which is chaired by J.W.H. Monger and The geophysical and geochemical information
H.-J. Goetze. constrain structure and crustal composition at depth.
"Transect" as used by GGT refers to a cross-section They include seismic interpretations of velocity
showing the composition and structure of the entire structure, magnetotelluric sounding data, density
crust of the Earth and, where possible, the upper models, and microearthquake focal depths, as well as
mantle. It incorporates all available geological, information from xenoliths contained in Cenozoic
geochemical and geophysical data. Transects lie basalts, and isotopic data from magmatic rocks of
along comdors 100 km wide and up to a few thousand various ages. Additional constraints are provided by
kilometres long, positioned by regional experts to Bouguer gravity, aeromagnetic and heat flow maps.
cross major crustal features (Monger, 1986). The All the data bearing on deep structure and
principal objective of GGT is to produce interpretative composition, outlined above, are integrated with the
cross-sections, which in effect are vertical tectonic surface geology of the strip map, and also with
maps that ideally portray the evolution of the Earth's regional structures from outside the transect comdor,
lithosphere along the transect line (Monger, 1987). in an interpretative cross-section which shows the
The Xiangshui to Mandal Transect forms part of possible origin and disposition of crustal components,
the North China Geoscience Transect Project of the and thus the evolution of the upper lithosphere along
State Seismological Bureau, which is a study of the the transect line.
Sino-Korean Craton and its bordering continental
margin. It is one of five transects that were chosen to rn DESCRIPTION OF MAJOR
cross the main earthquake hazard prone regions of TECTONOMORPHIC PROVINCES ALONG
China (see Index Map on transect display). These THE TRANSECT CORRIDOR
provide a comprehensive comparison of the
compositional and structural variations in different The Xiangshui-Mandal comdor comprises three
tectonic domains within the craton and the ancient discrete segments which sequentially cross North
continental margins. China, from the Yellow Sea shore in the southeast to
This explanatory pamphlet supplements the display the Mongolian Plateau in the northwest. Together,
sheet of the Xiangshui to Mandal Transect. It guides they have a length of 1200 km. From southeast to
and assists the reader in the use of the graphic display, northwest, locations of the three segments are:
explains the rationale of the display, supplements the
graphic display with supporting data and discussions 1) from Xiangshui in Jiangsu Province, (longitude
on crustal structure, tectonostratigraphic units, and 119'36'~, latitude 34'12'~) to Sishui in
tectonic evolution, and provides references to data Shandong Province, (long. 117'14'~, lat.
sources. The text is organized in such a way as to be 35'45'N);
used in direct conjunction with the display. 2) from Zibo in Shandong Province, (long.
118'03'~, lat. 36'49'N) to west of Ying Xian in
Shanxi Province (long. 112'12'~, lat. 39'48'N);
I1 GENERAL STATEMENT: BASES AND 3) within Inner Mongolia (Nei Monggol Autono-
PHILOSOPHY FOR CONSTRUCTING THE mous Region), extending from Ijinhoro Qi in the
XANGSHUI TO MANDAL TRANSECT south (long. 109O48'~,l at. 39'42'N). to Mandal
(long. 110 06'E, to lat. 42'31'N).
The graphic display is compiled according to the
Guidelines for GGT established by CC-7 in 1987. The transect crosses eight tectonomorphic
These suggest a common format so that cross-sections provinces, summarized below from southeast to north-
of the crust in different parts of the world can be west. In the southeast (segments 1,2) these generally
compared directly. trend NE to NNE (reflecting regional structural
The main components of the graphic display are trends), whereas in the northwest (segment 3) they
geologic, gravity, and aeromagnetic strip maps, and an trend S. to N.
interpretative cross-section drawn to Moho depth,
which is based on geology and geophysics. Two color 1) (Segment 1) The easternmost tectonomorphic
coding systems are used: (1) that on the geologic strip province comprises the hummocky plain of
map and geological cross-section denotes ages of rock northern Jiangsu Province, which is bounded on
units; (2) that on the interpretative cross-section the east by the Yellow Sea (Huang Hai).
denotes the inferred tectonic settings during the time 2) (Segments 12) West of this, the Shandong Hills have
of formation of the rocks units. an average height of 500-1000 m above sea level.
2 GLOBAL GEOSCIENCE TRANSECI 2
I INTRODUCTION The tectonostratigraphic flow chart summarizes the
stratigraphic, structural, magmatic and metamorphic
The Global Geoscience Transect (GGT) Project relationships in time and space between major
was conceived in 1985 as a new activity by the tectonostratigraphic elements, and is important for
Inter-Union Commission for the Lithosphere (ICL), conveying concepts of crustal evolution. It may be
which runs the International Lithosphere Program used as an aid in reading map relations and provides
(LP). ICL established a Coordinating Committee for an abstract of much of the following text.
GGT (CC-7), which is chaired by J.W.H. Monger and The geophysical and geochemical information
H.-J. Goetze. constrain structure and crustal composition at depth.
"Transect" as used by GGT refers to a cross-section They include seismic interpretations of velocity
showing the composition and structure of the entire structure, magnetotelluric sounding data, density
crust of the Earth and, where possible, the upper models, and microearthquake focal depths, as well as
mantle. It incorporates all available geological, information from xenoliths contained in Cenozoic
geochemical and geophysical data. Transects lie basalts, and isotopic data from magmatic rocks of
along comdors 100 km wide and up to a few thousand various ages. Additional constraints are provided by
kilometres long, positioned by regional experts to Bouguer gravity, aeromagnetic and heat flow maps.
cross major crustal features (Monger, 1986). The All the data bearing on deep structure and
principal objective of GGT is to produce interpretative composition, outlined above, are integrated with the
cross-sections, which in effect are vertical tectonic surface geology of the strip map, and also with
maps that ideally portray the evolution of the Earth's regional structures from outside the transect comdor,
lithosphere along the transect line (Monger, 1987). in an interpretative cross-section which shows the
The Xiangshui to Mandal Transect forms part of possible origin and disposition of crustal components,
the North China Geoscience Transect Project of the and thus the evolution of the upper lithosphere along
State Seismological Bureau, which is a study of the the transect line.
Sino-Korean Craton and its bordering continental
margin. It is one of five transects that were chosen to rn DESCRIPTION OF MAJOR
cross the main earthquake hazard prone regions of TECTONOMORPHIC PROVINCES ALONG
China (see Index Map on transect display). These THE TRANSECT CORRIDOR
provide a comprehensive comparison of the
compositional and structural variations in different The Xiangshui-Mandal comdor comprises three
tectonic domains within the craton and the ancient discrete segments which sequentially cross North
continental margins. China, from the Yellow Sea shore in the southeast to
This explanatory pamphlet supplements the display the Mongolian Plateau in the northwest. Together,
sheet of the Xiangshui to Mandal Transect. It guides they have a length of 1200 km. From southeast to
and assists the reader in the use of the graphic display, northwest, locations of the three segments are:
explains the rationale of the display, supplements the
graphic display with supporting data and discussions 1) from Xiangshui in Jiangsu Province, (longitude
on crustal structure, tectonostratigraphic units, and 119'36'~, latitude 34'12'~) to Sishui in
tectonic evolution, and provides references to data Shandong Province, (long. 117'14'~, lat.
sources. The text is organized in such a way as to be 35'45'N);
used in direct conjunction with the display. 2) from Zibo in Shandong Province, (long.
118'03'~, lat. 36'49'N) to west of Ying Xian in
Shanxi Province (long. 112'12'~, lat. 39'48'N);
I1 GENERAL STATEMENT: BASES AND 3) within Inner Mongolia (Nei Monggol Autono-
PHILOSOPHY FOR CONSTRUCTING THE mous Region), extending from Ijinhoro Qi in the
XANGSHUI TO MANDAL TRANSECT south (long. 109O48'~,l at. 39'42'N). to Mandal
(long. 110 06'E, to lat. 42'31'N).
The graphic display is compiled according to the
Guidelines for GGT established by CC-7 in 1987. The transect crosses eight tectonomorphic
These suggest a common format so that cross-sections provinces, summarized below from southeast to north-
of the crust in different parts of the world can be west. In the southeast (segments 1,2) these generally
compared directly. trend NE to NNE (reflecting regional structural
The main components of the graphic display are trends), whereas in the northwest (segment 3) they
geologic, gravity, and aeromagnetic strip maps, and an trend S. to N.
interpretative cross-section drawn to Moho depth,
which is based on geology and geophysics. Two color 1) (Segment 1) The easternmost tectonomorphic
coding systems are used: (1) that on the geologic strip province comprises the hummocky plain of
map and geological cross-section denotes ages of rock northern Jiangsu Province, which is bounded on
units; (2) that on the interpretative cross-section the east by the Yellow Sea (Huang Hai).
denotes the inferred tectonic settings during the time 2) (Segments 12) West of this, the Shandong Hills have
of formation of the rocks units. an average height of 500-1000 m above sea level.
XIANGSHUI TO MANDAL TRANSECT, NORTH CHINA 3
3) (Segment 2) The North China Plain forms the collisional fold belts (Li Jiliang et al., 1990). Its
lower Yellow River (Huang He) drainage area petrotectonic assemblages suggest that plate tectonics
and is a low and gentle terrain, mostly less than were in operation at least 2.4 Ga ago.
50 m above sea level. Crustal thickening of the transect region
4) (Segment 2) The Taihang, Wutai and Hengshan presumably is due to stacking of thrust sheets and
mountains rise abruptly between the North China crustal imbrication during regional contraction, and
Plain to the east and the loess plateau to the west. addition of mantle-derived plutonic rocks, and
They are the northern part of the Shanxi resulted in general consolidation of the Sino-Korean
Highland, and their highest peak is 3058 m above Platform basement by the end of the early Proterozoic
sea level. (about 1.8- 1.7 Ga; Ma Xingyuan et al., 1984).
5) (Segments 2,3) The loess plateau, named after the There was a marked change in tectonic style in
yellowish loess which covers the Ordos and Middle Proterozoic time, and features associated with
surrounding provinces, rises 800-2000 m above crustal extension and rifting developed in the newly
sea level. consolidated continental crust of the Sino-Korean
6) (Segment 3) On the south is the Hu(Hohot)- Platform. In Middle and Late Proterozoic time, cover
Bao(Baotou) basin, which lies between the Ordos sediments were deposited in cratonic basins, there
plateau on the south and the Yinshan Mountains were deep intra-cratonic subsidence zones (or
on the north. It has an average altitude of less aulacogens), large basic dyke swarms were intruded
than 1000 m above sea level. and represent feeders to eroded lavas, and the ancient
7) (Segment 3) The Yinshan Mountains rise abruptly continental margin of the Sino-Korean craton was
on the north of the Hu-Bao basin, and extend formed. The early Middle Proterozoic deposits of
across the middle of Inner Mongolia to form the Changcheng System underlie the North China Rift
divide between interior and exterior drainage Basin. The Zhaertai Group was deposited in the
basins. The highest peaks of the range reach aulacogen on the Yinshan Block, and inverted and
2337 m above sea level. The peneplain surface folded during the Serteng orogeny, 1.4 Ga ago. The
on top of the mountains declines gently toward Middle and Late Proterozoic Bayan Obo Group was
the north to about 1300 m above sea level near deposited on the continental slope along the northern
the northern margin of the Yinshan massif and margin of the Sino-Korean craton.
then merges towards the north with the Phanerozoic evolution was marked by deformation
Mongolian Plateau. at the platform margins and by intraplate compression
8) (Segment 3) The pastoral Mongolian Plateau is and extension. On the northern margin of the
the northernmost tectonomorphic province of the SineKorean Platform, in the region of the Inner
Xanshui-Mandal transect comdor, and contains Mongolian Fold Belt at the northwestern end of the
the Inner Mongolian Fold System. transect comdor, early and late Paleozoic crustal
convergence involved subduction and accretionary
processes, with amalgamation of island-arc complexes
into large terranes that were then accreted to the
IV TECTONIC SETTING OF THE XIANGSHUI ancient continental margin in respectively Early-
TO MANDAL TRANSECT Middle Silurian and Late Carboniferous to Permian
time (Ma Xingyuan et al., 1988). On the southeastern
Rock units in the Xiangshui-Mandal Corridor margin of the platform, in the southernmost part of the
record the evolution of the continental crust over the transect, tectonic complexities in the deformation zone
last 2.8 billion years and contain evidence for an between the Sino-Korean and the Yangzi platforms
unusually diverse array of tectonic processes. appear to be the result of collision in Triassic time.
The Archean was characterized by formation of the The Subei-Jiaonan terrane, sandwiched between the
four continental nuclei of the Sino-Korean Platform, two platforms, is composed of Proterozoic meta-
that are separated by belts of complexly deformed morphic rocks. It includes the Yuntai Formation with
rocks of Early Proterozoic age. The nuclei are, from its blueschists, which together with the widespread
southeast to northwest, the Taishan Complex in occurrence of ultramafic and eclogite bodies and
western Shandong, the Fuping Complex in intricate ductile shear zones in the underlying Donghai
Taihangshan Mountains, the Hengshan Complex in Group, suggest the collision of two plates (Ma
northern Shanxi and the Wula Shan complex in Inner Xingyuan, 1989).
Mongolia. Late Triassic Indosinian and Jura-Cretaceous
Within the Sino-Korean Platform, the Early Yanshanian orogenies strongly modified the
Proterozoic Wutai fold belt lies between the Archean SineKorean craton, and gave rise to a new tectonic
Hengshan and Fuping complexes. It appears to regime. The most striking result of these orogenic
comprise an accreted island arc system with green- episodes was transformation of the regional structural
stone and I and S type granitic plutons, fragments of orientation, from earlier nearly E-W trending belts
oceanic crust, and a variety of metamorphosed into NNE-NE trending ones. The platform exper-
volcanosedimentary components, and thus appears to ienced both strong compression and extension during
have a tectonic framework similar to that of younger the Mesozoic and Cenozoic. There was thin skinned