Table of Content

20 August 2019, Volume 25 Issue 4

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Physical Model Test of Vertical Deformation of Sand-Clay Layers Based on the BOFDA

LU Yi，SONGZezhuo，YU Jun，GONGXulong，JI Junfeng，LU Jing，ZHOUGangjun

2019, 25(4):  481. 

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Land subsidence as a common geological hazard poses a great threat to urban development. Effective monitoring of vertical
deformation process of soil layers is an important task for land subsidence prevention and control. In this paper, Brillouin Optical
Frequency Domain Analysis (BOFDA) technology is used to monitor the vertical deformation of sand-clay layers in draining-recharging
cycles by using an indoor land subsidence model. Moreover, a compression test is used to analyze the vertical deformation of the soil.
The results show that the clay layer is the main deformation layer. In the draining-recharging cycles, the soil also experiences
compression-rebound cycles. In addition, BOFDA technology can effectively capture the vertical deformation of sand-clay layers in
draining-recharging cycles and monitor in real-time the soil vertical deformation in the process of land subsidence development. The
research results provide some reference for the effective prevention and control of land subsidence.

Experimental Study on Coupling Performance of Fiber and Sand Interface Based on Distributed Sensing

CHENGGang，SHI Bin，ZHU Honghu，CHENDongdong

2019, 25(4):  487. 

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In the field of geology and geotechnical engineering, deformation monitoring has always been an important index to evaluate
stability. Its spatio-temporal evolution law can provide important reference for the optimization of design and construction parameters
of foundation engineering and the determination of early warning index of geological hazards. With the continuous development of
photoelectric sensing technology, its role in deformation monitoring of geological and geotechnical engineering is becoming more and
more important. However, the coupling performance between sensing optical fiber and rock-soil body has a significant impact on
monitoring results, and clarifying the mechanism between them has become a key part in the application of this technology. Based on
the comprehensive analysis of the current deformation monitoring technology of geology and geotechnical engineering, the pull-out test
of fiber-sand coupling performance based on distributed sensing technology was carried out. The coupling performance between
sensing fiber and sand, and the strain transfer law between them were analyzed from the test results and sensing fiber characteristics.
The experimental results show that except for the first stage pull-out, the R2 fitted by the data are all above 0.99, which shows that the
measured strain distribution of the optical fiber has better regularity; the elastic modulus of the optical fiber obtained by the back
calculation of the experimental data is about 0.35 GPa, which is basically consistent with the given value; by measuring the F-Shead and
F-Stail relationship of the optical fiber, it is concluded that the interaction process of the optical fiber-sand interface is mainly divided
into full-coupling, semi-coupling and relative sliding. The above research results provide guidance for the application of distributed
sensing technology in deformation monitoring of various geological and geotechnical engineering, and also provide important reference
for carrying out various model tests.

Experimental Study on Rebound Deformation Characteristics and Rebound Potential of Soil Layer

WUJinghong，CHENGGang，SHI Bin，GUKai，JIANG Na

2019, 25(4):  495. 

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The study of the rebound deformation effect of soil layer is helpful for the scientific implementation of groundwater recharge,
management of groundwater resources and prediction of land subsidence. In this paper, the influencing factors and deformation
characteristics of soil layer rebound are studied through a large number of indoor compression rebound tests. The experimental results
show that the ultimate rebound of soil layer is affected by soil properties, maximum consolidation pressure, consolidation time and
unloading ratio, etc. The higher the content of clay soil is, the greater the rebound is. For the same kind of soil, the shorter the
consolidation time and the greater the unloading pressure are, the greater the rebound is. When the unloading ratio is less than 0.5, the
consolidation pressure has no obvious influence on the soil layer rebound. With the increase of the unloading ratio, the soil rebound
increases and the influence of the consolidation pressure on the same soil becomes greater. And, when the unloading ratio is greater
than 0.9, the rebound increases rapidly. When the type of soil layer and consolidation pressure are determined, the maximum rebound
rate and consolidation pressure show a nearly linear relationship, which can be used to predict the maximum rebound rate of soil layers.

Model Tests and Discrete Element Simulations for Water Flow, Heat Transfer and Thermal Stress in Sparsely Non-Orthogonal Sand-Filled Fractured Rocks

GAOJunyi，XIANG Yanyong，LEI Haibo

2019, 25(4):  502. 

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Model tests and discrete element simulation are conducted to study the effects of water velocity on temperature and stress in
a physical rock mass model with sparse non-orthogonal sand-filled fractures，and the differences in temperatures and thermal stresses
between the tests and the discrete element simulations are analyzed and attributed to mismatches between the test setups and the
discrete model setups. The granite rocks in Beishan area in Gansu Province are studied. Results show that the filled sand fractures
strengthen thermal conductivity of fractures media, and both temperature and thermal stress of rock mass without filling are lower than
those with filling sand. Both the tests and discrete element simulations indicate that the rock mass temperature and stress decrease with
increasing fracture water velocity, but the time required for the system to reach the steady state becomes shorter. The model test shows
that oblique fracture water flow controls the temperature field. Because the existing 3DEC software does not take into account the
changes of thermal property parameters of water with temperatures, thus generating natural convection heat transfer, oblique fracture
water flow and vertical fracture water flow near the heat source control the temperature field.

Experimental Study on Coupling Effects of Water-Holding Capacity and Permeability of Borrowed Soil in Rock Slope Ecological Protection Technology

GAOXiaoying，LIU Qiang，YANG Junjie，SUN Chong

2019, 25(4):  512. 

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For rock slopes, the key to ecological slope protection technology is the formation of vegetation. In order to ensure plant
growth, soils should have good water-holding capacity and permeability. In this paper, the coupling relationship between permeability
and water retention capacity was studied by laboratory permeability experiment and evaporation experiment under different mixing
ratios of loess, diatomite and straw. The results show that the addition of diatomite and straw can effectively reduce the density of mixed
soil, which is beneficial to reduce the self-weight stress of the mixture and improve the stability of a slope. When diatomite and straw
are added separately, the permeability coefficient of the mixed soil increases exponentially. With the same amount of material,
diatomite is more effective in improving the permeability coefficient. When the diatomite and straw are mixed in a similar ratio, they do
not form mutual gains, but rise and fall. The addition of diatomite and straw can increase water retention capacity of the mixed soil, but
the effect of using diatomite is better than that of using straw. Adding diatomite and straw can prolong the steady evaporation stage of
soil and greatly improve the drought resistance of loess.

Particle Flow Simulation of Failure Process of Three-Point Bending Beams with Bias Cracks

DING Yongzheng，DENGQinghai，LIU Zhaobing，LI Hong

2019, 25(4):  519. 

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In order to study the failure mode of three-point bending beams under load, the failure process of three-point bending beams
with preset cracks at different locations and heights were simulated with particle flow code PFC2D. The simulation results show that the
length and location of prefabricated cracks affect the damage of beams together. When the location of prefabricated cracks is far from
the loading point, the height of prefabricated cracks is the main factor affecting the damage of beams. When the height of cracks
exceeds 70 mm, the failure mode of specimens changes. When the height of prefabricated cracks is fixed, the location of prefabricated
cracks is the main factor affecting the failure of specimens. When the distance from the support point exceeds 100 mm, the failure
mode of the specimens changes, and the failure process of the specimens are accompanied by the accumulation and release of energy.
Compared with the finite element method and the finite difference method, the discrete element method can better simulate the process
of material crack generation and development.

Geochemistry and Oil-Source Correlation of Crude Oil in the LD29 Oilfield, Slope Belt in the Southern Sag of the Liaodong Depression, Bohai Sea

TIAN Derui，NIU Chengmin，WANGDeying，PAN Wenjing，ZHANG Rucai

2019, 25(4):  527. 

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High-yield light crude oils and natural gases were produced in the second member of the Shahejie Formation in the LD 29
oilfield on the slope belt in the southern sag of the Liaodong Depression, showing great exploration potential. In order to clarify oil
source, depositional environment and source rock ages, systematic geochemical analyses and oil-source correlation on crude oil, oil
sands and source rock samples were carried out. Results show that the crude oils have low sulfur (0.0733%) and high wax contents
(20.77%), and are light and mature. The saturated hydrocarbon chromatograms of the crude oils have a complete distribution with the
major peak carbon at C19, indicative of non-biodegradation. In contrast, the oil sand samples which were shallowly buried are partially
affected by biodegradation, as indicated by the UCM in the chromatographic baseline. The crude oils have low C19/C23TT (0.10-0.18),
low C24 Tet/C26TT (0.49-0.53), low C27Dia/C27ST (0.30-0.43), medium Ga/C30h (0.14-0.17) and medium-high 4-MSI(0.30-0.36), and are
characterized by relatively heavy carbon isotopic compositions (-27.1‰). Organic matter is dominated by lower aquatic organisms with
minor terrigenous inputs, which was deposited under fresh-brackish lacustrine depositional environment. The crude oils in the LD 29
oilfield are mainly originated from the third Member of the Shahejie Formation in the Liaozhong depression and Liaodong depression,
with a little contribution from the fourth Member of the Shahejie Formation in the Liaozhong depression. The formation of light oil with
high wax content in the study area is mainly controlled by the organic precursors of source rock, i.e., alginite and lower organisms

Thermal Properties Characterization of the Rocks in the Qiongdongnan Basin, Northern Margin of the South China Sea

CAI Li，LI Xianglan，LIU Shaowen，ZHU Jitian，XIONG Xiaofeng，LI Xudong，YIN Hongwei

2019, 25(4):  538. 

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Data regarding thermal properties of sedimentary rocks are fundamental for basin modelling and deep temperature
prediction of sedimentary basins. The Qiongdongnan Basin, located at the northern margin of the South China Sea, currently is the key
area of the offshore hydrocarbon exploration in China. Reliable rock thermal properties are necessary for understanding the thermal
regime and thermal evolution of source rocks of the Qiongdongnan Basin. Although previous studies of rocks thermal properties have
been carried out for this area, there still exist such problems as limited measured data, under-representation and even controversies,
and it is emergent to retrieve some new measured data to fill this gap. In this study, 32 core samples of 19 boreholes were collected from
the Qiongdongnan Basin, and a systemic measurement of the thermal properties, i.e., thermal conductivity, radioactive heat production,
these thermal properties are presented. Integrating previous thermal properties with our new data, the average thermal conductivity and
radioactive heat production of the Cenozoic formation in the Qiongdongnan Basin are established. The radioactive heat contribution of
sediments within the basin account for nearly 33% of observed present-day heat flow. These measured data could provide a benchmark
for basin modelling and geothermal regime in the sedimentary basins of the northern South China Sea.

Jurassic Palaeoclimate Evolution of the Qaidam Basin: Evidence from Chemical Weathering Analyses

HUJunjie，MAYinsheng，WUYi，LI Zongxing，PENG Bo，WEI Xiaojie，LIU Dapeng

2019, 25(4):  548. 

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A series of distinct tectonic-climatic-environmental coupling evolution events were recorded in terrestrial sequences of the
Qaidam Basin during the Jurassic. However, little research has focused on the paleoclimate and paleoweathering variation process of
these sequences. To reconstruct the Jurassic paleoclimate and paleoenvironment of the Qaidam Basin, major and trace elemental
analyses were carried out on the bulk-rock samples that were collected from the Dameigou section, which is a Jurassic standard section
located in the northern basin margin. The reconstruction mainly utilized various chemical weathering indices, including Rb/Sr, K/Na,
CIA and CIW. Results indicated that the Jurassic chemical weathering process and paleoclimate evolution of the Qaidam Basin can be
divided into four stages. During the early to middle episode of the Early Jurassic and middle episode of the Middle Jurassic, intense
chemical weathering occurred in the Qaidam Basin, indicating a temperate-subtropical warm and humid climate. During the late Early
Jurassic to Late Jurassic, due to the decrease of the regional precipitation, the chemical weathering of the basin was significantly
reduced, and the climate was semi-arid or arid. These geochemical analyses are in agreement with previous results on climate-sensitive
sediments and palaeobotany. This investigation will provide complete and continuous geochemical evidence for the change of Jurassic
paleoclimate in the Qaidam Basin and adjacent regions.

Sedimentary Characteristics of the Paleogene Wenchang Formation in the HA Area, Pearl River Mouth Basin

ZHOUQingbo，SHU Yu，ZHU Xiaomin，CHENZhaoming，DONGXiaoyun，LIN Qiujin

2019, 25(4):  558. 

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Abstract：Based on comprehensive analyses of cores drilling, well logging and seismic data, the stratigraphic characteristics and
sedimentary evolution of the Paleogene Wenchang Formation in the HA area of the Pearl River Mouth Basin was analyzed．Results
show that five sequence boundaries were identified and four third-order sequences were divided in the study area, including SQ1, SQ2,
SQ3 and SQ4. SQ1 was mainly developed in the south, SQ2 and SQ3 were developed in the whole area, and SQ4 was denuded due to
the tectonic uplift of the south and it developed mainly in the northern HA4 area. Braided river delta, fan delta, nearshore subaqueous
fans and beach-bar facies were developed. The period of SQ1 was the beginning of rift in Huizhou sag, and during this period, sediment
supply was not abundant. Fan delta was mainly developed near XJ24 fault and XJ30 fault, and braided river delta was developed in HA
transform zone. During the period of SQ2, fault depression became stronger and the water became deeper, and thus braided river delta
was developed in large scale in the HA transform zone and fan delta became smaller. Beach-bar facies was developed in the H4 area
due to wave washing. During the period of SQ3, fault activities of the south became increasingly stronger, the water became continually
deeper, and thus braided river delta was developed in smaller scale, but the nearshore subaqueous fans and fan delta were developed in
larger scale. During the period of SQ4, fault activities became weaker, the depth of water became shallower, but sediment supply was
abundant. Therefore, large-scale fan delta was developed near to the HZ26 fault, and shallow water delta was distributed in large scale
near to the XJ30 fault. Nevertheless, due to the denudation by tectonic uplift, the residual strata was thinner.

Sedimentary Characteristics, Oriqin, and Model of Beach-Bar in the Qaidam Basin: A Case of the Upper Ganchaigou Formation in the Zhahaquan Area

WEI Hengfei，GUANPing，WANGPeng，WUYanxiong，LI Qiuyuan

2019, 25(4):  568. 

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Based on comprehensive analyses of color, sedimentary structure, particle size and thin sections for 600 meters cores, this
paper analyzed the sedimentary characteristics of beach-bar in the Zhahaquan area, Qaidam Basin, studied the distribution and origin
of the beach-bar in the sequence stratigraphic framework, and finally established the beach-bar sedimentary model. Results show that
the single sand body of beach-bar is thin in the Upper Ganchaigou Formation. There are many typical sedimentary structures formed
by wave action in beach-bar. The probability accumulation curve of particle size is mainly composed of two population: jumping and
suspended types. The bar is mainly developed in the large accommodation space of medium-and long-term base level cycle, and mostly
distributed in the large accommodation space of rising half cycle of short-term base level cycle. The beach is mainly developed in the
small accommodation space of base level cycle. The formation of the beach-bar is related to the accommodation space and the
sedimentary hydrodynamic conditions. Under the condition of high accommodation space, the water body is deep and the lake area is
large, which is favorable for forming large lake waves and lake flows. As such, the bar is developed. According to Walter’s law, the
sedimentary model of the Upper Ganchaigou Formation is established in combination with vertical variation of sedimentary types in a
medium- to short-term base level cycle.

Structures and Evolution of Hexiwu Fault, Northern Jizhong Depression since the Neogene

MAOLiguang，TIANJianzhang，ZHANGHongwei,ZHANGChuanbao，WANGXin，XIAOAncheng

2019, 25(4):  578. 

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The Hexiwu Fault is an important boundary fault in the northern Jizhong Depression of the Bohai Bay Basin. It remained
active during the Neogene and Quaternary, when the Bohai Bay Basin entered the thermal depression stage. The earthquake occurred
in Yongqing, Hebei province at 2018 was triggered by activities of this fault. This paper analyzes the structures of the Hexiwu Fault and
its activities during the Neogene and Quaternary using seismic data. Results show that the fault has been dextral transtensional since
the Neogene. It presents negative-flower structures on profiles and is segmented on map view, with the northern and southern segments
of dextral transtensional deformation and the middle segment being dominated by dextral deformation. A kinematic model suggests that
those segmentation features may be determined by the angles between fault orientation of each segment and the dextral shear direction
in this region.

Evolution of Diagenetic Minerals and Classification of Diagenetic Systems in Mudstones: A Case in the Paleogene of the Dongying Sag

LIU Fei，DUJiazong，CAI Jingong，XIE Zhonghuai，LIU Ning，ZHANG Shoupeng

2019, 25(4):  583. 

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The diagenetic minerals in mudstones generally change with diagenetic systems during diagenesis. Therefore, in order to
deeply understand the difference of hydrocarbon generation in mudstones, effectively identifying the diagenetic mineral associations
and dividing diagenetic systems are essential. The Paleogene mudstone samples from the Dongying Sag, China, buried at a depth of
1200-4500 m were selected and evaluated by rock thin section, scanning electron microscopy and X-ray diffraction, to distinguish the
differences in microscopic features between exogenously input minerals (e.g., quartz) and diagenetic minerals (e.g., sparry calcite and
dolomite). Based on the results, a method on quantitatively estimating the diagenetic transformation content of clay minerals is
established: (CTerrestrial=(C/Q)Es1 ×Qsample and Cdiagenetic=CXRD-CTerrestrial (C: clay mineral content, Q: quartz content)). This method can better
reflect the diagenetic evolution of clay minerals. During the burial process, the diagenetic minerals and associations in mudstones
display a two-stage feature. Above 3000 m, the diagenetic transformation of clay minerals and dolomite is slow, forming a smectite+
kaolinite association, which is inferred to have experienced an acidic diagenetic environment and open diagenetic system. The
diagenetic transformation is accelerated below 3000 m, forming an illite+chlorite+dolomite association, which is inferred to have
experienced an alkaline diagenetic environment and closed diagenetic system. This fully demonstrates the differences between deep
and shallow diagenetic environments and systems. This understanding is consistent with the previous results that the boundary of open
and closed systems is caused by the abnormal pressure which is generated by hydrocarbon generation in the mudstones. This implies
that the diagenetic systems revealed by diagenetic minerals have a good response to the pressure system generated by hydrocarbon
generation. Thus, dividing diagenetic systems is significant for understanding the heterogeneities in hydrocarbon generation processes
and mechanisms under different diagenetic systems.

High Frequency Cyclic Sequence Based on the Milankovitch Cycles in Upper Permian Coal Measures in Panxian, Western Guizhou Province

ZONGYi，SHEN Yulin，QIN Yong，JIN Jun4，LIU Jinbang，TONGGencheng

2019, 25(4):  598. 

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The Upper Permian recorded the greatest mass extinction events and the most dramatic environmental changes in geological
history. Fine description of stratigraphic framework and the establishment of high-resolution stratigraphic sequence of the Upper
Permian have been the key and foundation to in-depth understanding of these events and evolutions. Based on comprehensive analyses
of well logging, core observation, and geochemical testing results, this study performs the sequence stratigraphic division of the Upper
Permian coal measures on Milankovitch cycles using wavelet analysis in Panxian, western Guizhou Province. Results show that
well-preserved Milankovitch cycles were contained in the measures. The sedimentary process of coal measures was obviously affected
by astronomical orbital period. The thickness of 16.06-17.24 m, 5.39-5.70 m, 2.11-2.15 m and 1.12-1.21 m were affected by long
eccentricity (405 ka), short eccentricity (123 ka), obliquity (44 ka) and precession (21 ka), respectively. Among the four controlling
factors, the long eccentricity had the strongest effect on the coal measures of Milankovitch cycles. A“floating”astronomical time scale
was established by filtering the long and short eccentricity cycles, which provided geo-chronological constraints on the formation and
duration of the synsedimentary volcanic event layers (known as Tonsteins). Finally, taking the long eccentricity cycles as isochronous
section and combined with the sedimentary succession and characteristics of cycle boundaries, the Upper Permian coal measures in the
study area can be divided into four third-order sequences and sixteen fourth-order sequences. These help to establish the regional
high-frequency cyclic sequence framework.

Characteristics of Fine-Grained Dolostone Reservoirs and Controlling Factors of Favorable Reservoirs in the Upper Assemblage of Ma-5 Member in Yan’an Area of the Ordos Basin

YI Shuo，HUANGWenhui，CHENJing，REN Xingguo

2019, 25(4):  610. 

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A new natural gas exploration breakthrough has been gained in the fine-grained tight dolostone reservoirs of the Upper
Assemblage of the Ma-5 Member in the Yan’an area of the Ordos Basin. This paper presents a detailed research on the characteristics
of low-porosity and low-permeability dolostone reservoirs and the genesis of porosities. Through core observation, thin section analysis
and cathodoluminescence testing, combined with rock physical property analysis, the porosity-permeability characteristics of the
fine-grained dolostone reservoirs and the favorable reservoirs′ evolution process and controlling factors are clarified. Results show that
the lithology of fine-grained dolostone reservoirs is mainly composed of gypsum pseudocrystal dolomite, fine-grained dolomite and karst
breccia dolomite. The porosity types contain gypsum pseudocrystal dissolved pores, intercrystalline dissolved pores and non-selective
breccia dissolved pores, with local fractures developing. Thus, it is a pore type reservoir with low porosity and permeability. The
mould-pore-contained gypsodolomite flat, which is located at the high position and transformed by multi-stage karsts
(penecontemporaneous, epigenetic and burial), is the main distribution area of favorable reservoirs of the fine-grained dolomite in the
study area.

Spatio-Temporal Distributions and Controls of Grain Size in the Sediments from the Qinghai Lake since the 1960 AD

ZHANG Zhijie, ZHOUYuwen，CHENRong，ZHOUChuanmin, SUN Weiwei

2019, 25(4):  623. 

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The study on grain size in the sediments from the large lake basins is helpful to interpret global exploration of tight oil-gas
and shale oil-gas as well as their recorded paleoclimate information. In this paper, the spatial and temporal distribution of grain size in
the Qinghai Lake, the largest lake in China, was studied in detail. Twenty seven cores covering almost the whole lake area spanning the
last 60 years were drilled, and the three typical cores were dated by 210Pb and 137Cs. Based on the magnetic susceptibility age model, the
age framework of sedimentary cores in the whole lake area was established. Results show that sediments in the Qinghai Lake have
multimodal distribution in the grain size and mainly consist of fine grains (< 63 μm). The silt content ranges from 60% to 70%, the clay
component ranges from 10% to 35%, and the sand component is less than 20%. Therefore, the variation of grain size in the Qinghai
Lake sediments is relatively complex on the spatial scale. The median grain size is high in the areas around the Sand Island, the western
and southwestern lakes, while it is low in other lake areas. In the temporal scale, the grain size is roughly coarse, the sand component
increased and the clay component decreased from 1960 AD to 2017AD. The temporal and spatial variations of grain size may be caused
by the combined action of wind and sand activities, soil erosion in the basin, and the changes of river runoff and lake levels.

New Material of Chancelloriids from Cambrian, North China

HAN Qiaoyu，LI Guoxiang，WANGPingli，GAOJian，HAN Ying，ZHANG Tianlu，SUN Zhixin

2019, 25(4):  633. 

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Chancelloriids is a kind of typical Cambrian fauna with an enigmatic biological affinity. Isolated sclerites of chancelloriids
are widespread in Cambrian sedimentary rocks, but chancelloriid sclerites have been seldom reported from the Cambrian of North
China. Herein we described some isolated sclerites of chancelloriids from Cambrian rocks of this area. Specimens were collected from
three localities, i.e., Weifang, Tangshan and Dalian. The isolated sclerites were identified as Chancelloria. According to trilobite
biostratigraphy of the co-occurring trilobites, the age of Chancelloria sclerites from Dalian is considered as Stage 4, Cambrian Series 2;
the age of sclerites of Chancelloria sclerites from Weifang is considered as Wuliuan-Drumian, Cambrian Miaolingian; the age of
Chancelloria sclerites from Tangshan is considered as Jiangshanian, Furongian, and these sclerites are the latest occurrence in China
and one of the latest occurrences in the world. The Chancelloria sclerites from Cambrian Stage2-Furongian, North China, show that
these sclerites tend to be more regular, the basal surfaces tend to be flatter and the integration and organization of sclerites got
improved. These support the conclusions of previous studies.