Magnetic stratigraphy results of a 400-meter-thick Paleocene strata borehole in the Xiaojinggu region, Yunnan

The Simao Basin is located in the south of the Yunnan province and the southeast of the Qinghai-Tibet plateau. It is classified as the Sanjiang tectonic domain belongs to the eastern part of Tethyan tectonic domain. The thick and continuous Early Cenozoic strata preserved in the basin is thought to be an ideal achieve to reconstruct the history of tectonic evolution in this area as well as on the southeastern plateau. The most complete Early Cenozoic strata in the Simao Basin are located in Xiaojinggu Town, Jinggu County, which mainly includes the sedimentary strata of the Mengyejing Formation, the Denghei Formation and the Mengla Formation. Previously, the chronological study of sedimentary strata in the Simao Basin is mainly concentrated in the Mengyejing Formation with potassium salt. However, scholars still have significant controversy about the deposition time of this group at this stage. Further, a complete sedimentary profile containing the middle and lower part of the Mengyejing Formation could not obtain due to vegetation cover and village construction. Through the systematic thermal demagnetization analysis of the 361.86-meter-thick borehole that encompasses the entire Mengyejing Formation, a Paleocene-Cretaceous high-resolution magnetic chronology results were obtained in this area initially.

0 2019-12-05

Geochemical data set of the Paleocene-Eocene thermal maximum at Gamba and Tingri, southern Tibet

This data set comes from shallow marine carbonate sections at Tingri and Gamba, south Tibet. The age of these samples is about 56 Ma (at the Paleocene-Eocene boundary). At Tingri, we studied two parallel sections (13ZS section and 10-11TM section), and at Gamba, we studied one section (11TMG). From the 13ZS section, we analyzed carbon and oxygen isotopic compositions and calcium carbonate content of the whole carbonate rock, as well as the in-situ carbon isotopic compositions and element contents of the foraminifera shell. From the 10-11TM section, we analyzed carbon, oxygen and strontium isotopic compositions of the whole rock. From the 11TMG section, we analyzed carbon and oxygen isotopic compositions of the whole carbonate rock. Carbon and oxygen isotopic compositions of the whole rock were measured by gas isotope mass spectrometer (MAT251), strontium isotope by thermal ionization mass spectrometry (TIMS), calcium carbonate content by acid dissolution, in-situ carbon isotopic compositions by SIMS, and in-situ element contents by LA-ICPMS. Among these data, in-situ carbon isotope data were obtained from the laboratory of Professor John Valley at the University of Wisconsin-Madison in the United States, and the rest are from the relevant laboratories of the Department of Geosciences at the University of Bremen in Germany. Based on these data, we published three peer-reviewed papers on Journals of Gondwana Research, GSA Bulletin, and Global and Planetary Change.

0 2019-11-29

Lithology description of a 400 m-thick Paleocene strata borehole in the Xiaojinggu area, Yunnan

The most complete Early Cenozoic strata in the Simao Basin are located in Xiaojinggu Town, Jinggu County, which mainly includes the sedimentary strata of the Mengyejing Formation, the Denghei Formation and the Mengla Formation. Due to the tectonic uplifting of the mountain in the late Cenozoic, the syncline structure caused the top of the Mengyejing Formation, the Denghei Formation and the Mengla Formation to be exposed to the surface. However, a complete sedimentary profile containing the middle and lower part of the Mengyejing Formation could not be obtained due to vegetation cover and village construction. The chronological study of sedimentary strata in the Simao Basin is mainly concentrated in the Mengyejing Formation with potassium salt. However, there still has significant controversy about the deposition time of this group at this stage. Recently, a continuous and complete high-resolution sequence (361.86 m in thickness) of the Mengyejing Formation was obtained through the continuous drilling. Among them, the Mengyejing Formation (0-353.3 m) is mainly a set of purple-red muddy silt and mudstone combination, while the underlying Mangang Formation (353.3-361.86 m) is a set of gray-white sandstone.

0 2019-11-25

Lithology description of a 300m-thick Oligocene borehole strata in the Qujing area, Yunnan

The thick Cenozoic sediments deposited in Yunnan are ideal achieves used to explore the history of local deformation process affected by the collision of the Indian-Eurasian plate as well as the evolution of the Indian monsoon in the Cenozoic. However, due to the lack of precise age control, the early Neogene strata in Yunnan are poorly constrained. The Qujing Basin in the northern part of Yunnan Province preserves thick and continuous Cenozoic sediments, which can be divided into the Xiaotun Formation, the Caijiachong Formation and the Ciying Formation from bottom to top. Through the combination of the field outcrop profile and the borehole core, the research team obtained the stratified stratum of the Xiaotun Formation and the Caijiachong Formation with a total thickness of 251 m in the Qujing Basin. The U-Pb geochronology of the top volcanic tuff layer (35.49 ± 0.78 Ma), Caijiachong mammal fossil group (late Eocene) as well as magnetic stratigraphy collectively reveals that the age at the bottom of the Xiaotun Formation is 46.2 Ma, the top of the Caijiachong Formation should be < 36.2 Ma, and the epoch line of the two groups is 41.2 Ma. However, due to the weak influence of tectonic activities in the late Cenozoic and the small deformation of the formation, the terrain in the middle of the basin is relatively flat, resulting in the inability to obtain the top of the continuous Caijiachong Formation and the upper Ciying Formation samples. A total of 320.1 meter core covering the entire Ciying Formation and the Caijiachong Formation was obtained through the continuous drilling mission carried out in the center of the basin. Among them, the overall lithology of the core of the Ciying Formation (0-216.3 m) is dominated by gray mudstone and siltstone, and several layers of coal seams are intercalated; while the lower Caijiachong Formation (216.3-305.5 m) is grayish and grayish green mudstone. The lithology of the Xiaotun Formation (305.5-320.1 m) is mainly dominated by red mudstone.

0 2019-11-25

1:1.5 million metamorphic geological map of the Tibetan Plateau and its surrounding areas

Since 2006, China Geological Survey Bureau has organized and implemented the work of "integration and comprehensive research on the basic geological survey results of the Tibetan Plateau". Based on the 1:250,000 regional geological survey on the blank area of the Tibetan Plateau and the latest research results at home and abroad, with the integration and comprehensive research, one of a series of maps, "1:1.5 million metamorphic geological map of the Tibetan Plateau and its surrounding areas" have been compiled. The map is published by the Geological Publishing House. Based on the time-space framework of the regional structure and metamorphic characteristics of the Tibetan Plateau, the metamorphic environment is analyzed according to the metamorphic (Geological) area, metamorphic (Geological) belt, metamorphic sub belt and very low-low-high greenschist facies, low-high amphibolite facies, blue schist facies, high-ultrahigh pressure eclogite facies and malite facies, the metamorphic map of the Tibetan Plateau and its surrounding areas has been compiled, and 16 high pressure-ultrahigh pressure metamorphic belts have been determined. The projection of the map is Conformal Conic Projection, the first standard latitude is 28 °, the second standard latitude is 37 °, the central longitude is 89 °, and the projection origin latitude is 26 ° north latitude. This data is obtained by scanning the paper map "Metamorphic geological map of Tibetan Plateau and its surrounding areas" with high-resolution scanner, and the sub maps have been spliced. In the process of scanning, keep the map surface as flat as possible to reduce the error. The copyright of the map belongs to the publishing house. This data can be used by researchers who are engaged in the geological and geomorphological research of the Tibetan Plateau, it can be used for the research of regional resources exploration, geological science research, construction of major engineering facilities, environmental protection and disaster prevention in the Tibetan Plateau.

0 2019-11-12

1:1.5 million geotectonic map of the Tibeant Plateau and its surrounding areas

Since 2006, China Geological Survey Bureau has organized and implemented the work of "Integration and comprehensive research on the basic geological survey results of the Tibetan Plateau". Based on the 1:250,000 regional geological survey on the blank area of the Tibetan Plateau and the latest research results at home and abroad, with the integration and comprehensive research, one of a series of maps, "1:1.5 million geotectonic map of the Tibetan Plateau and its surrounding areas" have been compiled. It is published by the Geological Publishing House. The geotectonic environment of the geological body is analyzed according to the geotectonic facies division plan (3 major facies, 18 basic facies and 36 subfacies), with the 36 geotectonic subfacies as the basic mapping unit, the geotectonic map of the Tibetan Plateau and its surrounding areas is compiled. The projection of the map is Conformal Conic Projection, the first standard latitude is 28 °, the second standard latitude is 37 °, the central longitude is 89 °, and the projection origin latitude is 26 ° north latitude. This data is obtained by scanning the paper map “1:1.5 million geotectonic map of the Tibetan Plateau and its surrounding areas” with a high-resolution scanner, and splicing the sub maps. In the process of scanning, keep the map surface as flat as possible to reduce the error. The copyright of the map belongs to the publishing house. This data can be used by researchers who are engaged in the geological and geomorphological research of the Tibetan Plateau, it can be used for the research of regional resources exploration, geological science research, construction of major engineering facilities, environmental protection and disaster prevention in the Tibetan Plateau.

0 2019-11-12

1:1.5 million geological map of Tibetan Plateau and its surrounding areas

Since 2006, China Geological Survey Bureau has organized and implemented the work of "Integration and comprehensive research on the basic geological survey results of the Tibetan Plateau". Based on the 1:250,000 regional geological survey on the blank area of the Tibetan Plateau and the latest research results at home and abroad, with the integration and comprehensive research, one of a series of maps, "1:1.5 million geological map of the Tibetan Plateau and its surrounding areas" have been compiled. The map is published by Geological Publishing House. Based on 177 1:250,000 Regional Geological Survey data, the regional strata and structure stratigraphic system are systematically determined, including 9 strata and structure stratigraphic areas, 36 strata and structure stratigraphic areas and 63 strata and structure stratigraphic areas. The lithostratigraphic division and correlation sequence of the Tibetan Plateau and its surrounding areas are established. A large number of geological records of geological evolution and uplift of the Tibetan Plateau are presented, which focus on the new discovery, new progress and new understanding of geological investigation and research. The projection of the map is Conformal Conic Projection, the first standard latitude is 28 °, the second standard latitude is 37 °, the central longitude is 89 °, and the projection origin latitude is 26 ° north latitude. This data is obtained by scanning the paper map “1:1.5 million geological map of the Tibetan Plateau and its surrounding areas” with a high-resolution scanner, and splicing the sub maps. In the process of scanning, keep the map surface as flat as possible to reduce the error. The copyright of the map belongs to the publishing house. This data can be used by researchers who are engaged in the geological and geomorphological research of the Tibetan Plateau, it can be used for the research of regional resources exploration, geological science research, construction of major engineering facilities, environmental protection and disaster prevention in the Tibetan Plateau.

0 2019-11-12

1:3 million Quaternary geological and geomorphological map of the Tibetan Plateau and its surrounding areas

Since 2006, China Geological Survey Bureau has organized and implemented the work of "Integration and comprehensive research on the basic geological survey results of the Qinghai Tibet Plateau". Based on the 1:250,000 Regional Geological Survey in the blank area of the Tibetan Plateau and the latest research results at home and abroad, through integration and comprehensive research, a series of maps of "1:3 million Quaternary geological and geomorphological map of the Tibetan Plateau and its surrounding areas" have been compiled. The map is published by China University of Geosciences Press, it comprehensively expresses basic geological information such as quaternary stratigraphic development, neotectonic activity, magmatic activity and geomorphic characteristics of the Tibetan Plateau, and objectively reflects the coupling and coordination process of stratum, structure, magmatic activity and geomorphic evolution since the uplift of the plateau in the late Cenozoic. The projection of the map is Conformal Conic Projection, the first standard latitude is 28 °, the second standard latitude is 37 °, the central longitude is 89 °, and the projection origin latitude is 26 ° north latitude. This data is obtained by scanning the paper map " Quaternary geological and geomorphological map of the Tibetan Plateau and its surrounding areas " with a high-resolution scanner. In the process of scanning, keep the map surface as flat as possible to reduce the error. The copyright of the map belongs to the publishing house. This data can be used by the researchers who are engaged in the geological and geomorphological research of the Tibetan Plateau. It is of great scientific significance to reveal the uplift process of the Tibetan Plateau and the geomorphic, neotectonic movement, stratigraphic, magmatic activity and environmental evolution since the uplift.

0 2019-11-12

1:3 million gravity series map of the Tibetan Plateau and its surrounding areas

Since 2006, China Geological Survey Bureau has organized and implemented the work of "integration and comprehensive research on the basic geological survey results of the Tibetan Plateau". Based on the 1:250,000 Regional Geological Survey in the blank area of the Tibetan Plateau and the latest research results at home and abroad, through the integration and comprehensive research, the "1:3 million gravity series map of the Tibetan Plateau and its surrounding areas" has been compiled. The map is published by Geological Publishing House. On the basis of comprehensive collection of 1:200,000, 1:500,000 and 1:1,000,000 regional gravity survey results, a series of 1:150,000 gravity maps of the Tibetan Plateau and its surrounding areas are prepared, including: Bouguer gravity anomaly horizontal derivative modulus map, Bouguer gravity anomaly map, isostatic gravity anomaly map, Moho surface and other depth maps, regional gravity inference results map and surplus Gravity anomaly map. The base manuscript scale is 1:1.5 million, and the mapping scale is 1:3 million. The projection of the map is Conformal Conic Projection, the first standard latitude is 28 °, the second standard latitude is 37 °, and the central longitude is 89 °. This data is obtained by scanning the paper map "1:3 million gravity series map of Tibetan Plateau and its surrounding areas" with a high-resolution scanner, and splicing the sub maps. In the process of scanning, keep the map surface as flat as possible to reduce the error. The copyright of the drawing belongs to the publishing house. This data can be used by the researchers who are engaged in the geological and geomorphological research of the Tibetan Plateau, and provide the basic gravity information for the basic geological survey and research, mineral exploration and evaluation of the Tibetan Plateau.

0 2019-11-12

Paleomagnetic data from the lunpola basin

The Lunpola Basin in the central Tibetan Plateau is situated along the southern margin of the east-west stretched Banggong-Nujiang suture belt between the Qiangtang Terrane and the Lhasa Terrane. The thick and continuous Cenozoic sediments in the basin can provide great potential for understanding the tectonic uplift, paleoaltimetry, erosion and depositional history of the Tibetan Plateau and climate environmental evolution. However, the study of geologic and climatic changes has been hindered by poor age constraints on the Cenozoic sedimentary sequence in the Lunpola Basin, especially its upper part with typical lacustrine oil shale sediments due to the discontinuous or unexposed outcrop caused by erosion or weathering. In this study, we investigated a 658 m-thick Cenozoic continuous lacustrine sedimentary section, Lunpori, from the upper sequence of the central basin. We found two layers of tuffs in this section and then carried out detailed paleomagnetic measurements. Constrained by tie points of U-Pb zircon ages, the observed magnetic zones are well correlated with chrons C5Bn.2n to C6AAn of the Geomagnetic Polarity Time Scale, yielding ages of ~21.2 to 15 Ma for the section. Lithofacies, pollen and fossil records suggest a relative temperate, humid climate prevailing in the Lunpola Basin during the period of Dingqinghu Formation, indicating that the Indian monsoon occurred before ~26 Ma.Through paleomagnetic analysis and testing of fluvial and lacustrine facies strata in Lumpola Basin since Miocene, 22Ma-15Ma magnetic stratigraphic chronology has been obtained.

0 2019-10-21