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Late Triassic tuff intervals in the Ordos basin, Central China: Their depositional, petrographic, geochemical characteristics and regional implications

Published on Feb 1, 2014in Journal of Asian Earth Sciences2.76
· DOI :10.1016/j.jseaes.2013.11.004
Xinwei Qiu3
Estimated H-index: 3
(CAS: Chinese Academy of Sciences),
Chiyang Liu4
Estimated H-index: 4
(Northwest University (United States))
+ 3 AuthorsJianqiang Wang3
Estimated H-index: 3
(Northwest University (United States))
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Abstract
Abstract Tuff intervals of Upper Triassic Yanchang Formation are laterally widespread in the Ordos basin, Central China. This paper focuses on magmatic origins and potential source regions of these tuff intervals through detail depositional, petrographic and geochemical analyses. Most of the tuff intervals are well-documented at the bottom of the Chang7 oil reservoir unit and can be correlated laterally, and certain tuff beds are reworked by turbidity current or seismic activity. Petrographic studies of the Chang7 tuffs indicate that they are composed of crystal shards, lithic shards and altered glass shards, and the crystal shards include plagioclase, quartz and biotite. Alteration of the Chang7 tuffs is ubiquitous, thus, most of these tuffs transformed into illite/smectite (I/S) mixed-layers which are identified by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Less common minerals are also detected in the Chang7 tuffs such as zircon, hematite, siderite, anatase. Major elements are determined by the X-ray fluorescence (XRF) analysis, the results indicate that the Chang7 tuffs are enriched in K 2 O (average 4.21%), the ratio of SiO 2 /Al 2 O 3 ranges from 1.73 to 2.85 (average 2.17), and the ratio of TiO 2 /Al 2 O 3 varies between 0.006 and 0.032 (average 0.017), which imply that the Chang7 tuffs originated from a felsic parental magma. Trace elements are determined by inductively coupled plasma mass spectrometry (ICP-MS), indicating the total rare earth element (∑REE) concentrations are variable, and range from 117.46 to 466.83 ppm (average 251.88 ppm). REE distribution pattern of the Chang7 tuffs presents a LREE rightward incline with flat HREE curve. The value of δ Eu ranges from 0.151 to 0.837 (average 0.492), suggesting a strong to weak negative Eu anomaly. The Chang7 tuffs show positive anomalies in Rb, Th and U and negative anomalies in Nb, Sr and Eu on a primitive mantle normalized spidergram. A preliminary analysis of the geochemical composition of the Chang7 tuffs suggests a parental magma origin of rhyodacite/dacite, which came from volcanic arc-related setting along an active continental margin. Combined with the chronology and geochemical studies of the synchronous Tianshui rhyolite in the West Qinling Mountains, we propose that the west Qinling Mountains is one of the potential source regions of these tuffs, and the Middle-Late Triassic terminal closure of eastern Tethys provided the arc-related magma.
  • References (74)
  • Citations (46)
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References74
Newest
Published on Oct 1, 2013in Petroleum Exploration and Development2.54
Hua Yang9
Estimated H-index: 9
(PetroChina),
Xiuqin Deng6
Estimated H-index: 6
(PetroChina)
Abstract A large area of deep-water sandstone was formed under the combined action of delta and gravity flow in the central Ordos Basin during the depositional period of the Ch6 and Ch7 oil-bearing formations of the Yanchang Formation. According to U-Pb dating of zircons by the method of LA-ICP-MS, the ages of the tuff layers at the base and upper parts of the Ch7 oil-bearing formation are 228.2±6.0 Ma and 222.2±2.0 Ma, respectively. Based on the ages of the tuff layers, it is suggested that the...
Published on Jul 1, 2012in Sedimentary Geology3.24
Caineng Zou22
Estimated H-index: 22
(PetroChina),
Lan Wang8
Estimated H-index: 8
(PetroChina)
+ 2 AuthorsLianhua Hou13
Estimated H-index: 13
(PetroChina)
Abstract Deep-lacustrine transformation of sandy debrites into turbidites in the downslope direction is evident in the Upper Triassic Yanchang Formation of the Ordos Basin, central China. This facies trend is used as a template for predicting the distribution of reservoir facies of the Huaqing oilfield, which contains 100-million-tonnes of oil reserves. Based on examination of conventional cores from 30 wells, four major types of lithofacies have been recognized: (1) fine-grained massive sandsto...
Published on Jan 30, 2012
Cari L. Johnson22
Estimated H-index: 22
(UofU: University of Utah),
Bradley D. Ritts24
Estimated H-index: 24
(Chevron Corporation)
Published on May 1, 2011in Journal of Asian Earth Sciences2.76
Yunpeng Dong21
Estimated H-index: 21
(Northwest University (United States)),
Guowei Zhang32
Estimated H-index: 32
(Northwest University (United States))
+ 3 AuthorsChristoph Hauzenberger18
Estimated H-index: 18
(University of Graz)
Abstract This contribution reviews the tectonic structure and evolution of the Qinling orogenic belt, which extends east–west nearly 2500 km across Central China and is a giant orogenic belt formed by the convergence and collision between North China and South China Blocks. The principal tectonic elements including metamorphic basement and its Neoproterozoic to Triassic cover, ophiolitic sutures, nature and ages of granitoid belts, provenance studies and tectonometamorphic studies of metamorphic...
Published on Apr 1, 2011in Geology5.01
Bryan Sell11
Estimated H-index: 11
(SU: Syracuse University),
Scott D. Samson31
Estimated H-index: 31
(SU: Syracuse University)
The Ordovician Millbrig K-bentonite of North America and the Kinnekulle "Big Bed" of Scandinavia have been considered correlative, thus representing one of the largest volcanic eruptions of the Phanerozoic. Whether these two K-bentonites correlate has implications for the paleogeographic reconstructions of Laurentia and Baltica, transoceanic biostratigraphic correlations of graptolites and conodonts, and the possibly global occurrence of the Guttenberg carbon isotope excursion. Trace element ana...
Published on Feb 1, 2011in Ore Geology Reviews3.39
Laimin Zhu9
Estimated H-index: 9
(Northwest University (United States)),
GuoWei Zhang4
Estimated H-index: 4
(Northwest University (United States))
+ 4 AuthorsBen Lee8
Estimated H-index: 8
(Northwest University (United States))
Abstract East Qinling is the largest porphyry molybdenum province in the world; these Mo deposits have been well documented. In West Qinling, however, few Mo deposits have been discovered although granitic rocks are widespread. Recently, the Wenquan porphyry Mo deposit has been discovered in Gansu province, which provides an insight into Mo mineralization in West Qinling. In this paper we report Pb isotope compositions for K-feldspar and sulfides, S isotope ratios for sulfides, the results obtai...
Published on Sep 1, 2010in Journal of Asian Earth Sciences2.76
Hua Yang1
Estimated H-index: 1
(PetroChina),
Wenzheng Zhang3
Estimated H-index: 3
(PetroChina)
+ 3 AuthorsYan Qin2
Estimated H-index: 2
(CAS: Chinese Academy of Sciences)
Abstract The oil source rocks of the Chang 7 member of the Yanchang Formation in the Erdos Basin were deposited during maximum lake extension during the Late Triassic and show a remarkable positive uranium anomaly, with an average uranium content as high as 51.1 μg/g. Uranium is enriched together with organic matter and elements such as Fe, S, Cu, V and Mo in the rocks. The detailed biological markers determined in the Chang 7 member indicate that the lake water column was oxidizing during depos...
Published on Jun 1, 2010in Lithos3.91
Yao-Hui Jiang28
Estimated H-index: 28
(NU: Nanjing University),
Guo-Dong Jin7
Estimated H-index: 7
(NU: Nanjing University)
+ 2 AuthorsPeng Zhao11
Estimated H-index: 11
(NU: Nanjing University)
The Qinling–Dabie–Sulu orogen marks the junction between the North and South China Blocks. However, the exact timing of the final coalescence of the North and South China Blocks in the Qinling orogen is poorly constrained. This paper presents new SHRIMP zircon U–Pb chronology, major and trace elements, and Sr–Nd–Hf isotope data for five early Mesozoic granitic plutons across the Qinling orogen. SHRIMP zircon U–Pb dating shows that four plutons were emplaced in the Carnian (227–218 Ma) of Late Tr...
Published on May 1, 2010in Journal of Asian Earth Sciences2.76
Li-ming Ji3
Estimated H-index: 3
(CAS: Chinese Academy of Sciences),
Kui Yan9
Estimated H-index: 9
(CAS: Chinese Academy of Sciences)
+ 1 AuthorsMin Zhao6
Estimated H-index: 6
(CAS: Chinese Academy of Sciences)
Abstract High abundance but rather low diversity algal fossils were found in the hydrocarbon source rocks of the Ch 7-2–Ch 7-3 section, Triassic Yanchang Formation in the Xifeng area of southwest Ordos Basin, which are mainly composed of prolific Leiosphaeridia and Botryococcus . Botryococcus colonies are of various forms; the majority is nubbly, with some of cluster and cotton shape. The nubbly colonies appear globular, cordiform, ternate petal, obtuse triangle, chrysanthemum shape and so on. M...
Cited By46
Newest
Published on Nov 1, 2019in Marine and Petroleum Geology3.54
Ruiqian Chen (China University of Petroleum), Guangdi Liu11
Estimated H-index: 11
(China University of Petroleum)
+ 1 AuthorsYushun Cao (China University of Petroleum)
Abstract Nitrogen isotope (δ 15 N) analysis has been used to evaluate depositional redox conditions in well-preserved sedimentary systems; however, fewer N-isotope studies have been performed to reconstruct the redox conditions in lacustrine shales. In this paper, we report the δ 15 N data from the Upper Triassic Chang 7 Shale of the Ordos Basin, North China. Sedimentary δ 15 N values are significantly higher in the Chang 7 3 and the lower part of the Chang 7 2 submembers (Zone A; average = 9.4 ...
Published on Jul 1, 2019in Journal of Geodynamics2.81
Guanzhong Shi2
Estimated H-index: 2
(China University of Geosciences),
Cleber J. Soares + 4 AuthorsMenghe Liu
Abstract In order to unravel the Mesozoic sedimentation in response to multistage deformation of the western Ordos fold-thrust belt, combined zircon U-Pb and fission track analyses of single zircon grain are conducted for seven sandstone samples in the Helanshan area. Zircon FT ages are calculated using absolute uranium concentration determined by LA-ICP-MS during the procedure of zircon U-Pb dating. The newly-obtained zircon FT data show age features that are comparable with the previous zircon...
Published on May 22, 2019in Interpretation
Difei Zhao (CUMT: China University of Mining and Technology), Difei Zhao (CUMT: China University of Mining and Technology)+ 4 AuthorsJingshou Liu5
Estimated H-index: 5
(China University of Geosciences)
Published on Aug 1, 2019in Palaeogeography, Palaeoclimatology, Palaeoecology2.62
Rui Zhang , Rui Zhang (Sinopec)+ 5 AuthorsKefeng Du
Abstract The Middle Triassic was a key period that witnessed the evolution of Earth system processes and the commencement of a terrestrial lake in the Ordos Basin, Central China. A high-precision stratigraphic framework is the key to understanding the nature and pattern of critical geological events. Detailed time series analyses of magnetic susceptibility (MS) data were performed on the deep lacustrine shale-dominated Chang 7 Member of the Yanchang Formation from the Y1011 well core. The result...
Published in Geological Journal1.95
Junjie Xu (CAS: Chinese Academy of Sciences), Huaichun Wu22
Estimated H-index: 22
(China University of Geosciences)
+ -3 AuthorsHaiyan Li17
Estimated H-index: 17
(China University of Geosciences)
Published on Jul 1, 2019in Journal of Petroleum Science and Engineering2.89
Hu Li1
Estimated H-index: 1
(SWPU: Southwest Petroleum University),
Hong-ming Tang4
Estimated H-index: 4
(SWPU: Southwest Petroleum University)
+ 6 AuthorsCheng Zhong2
Estimated H-index: 2
(SWPU: Southwest Petroleum University)
Abstract The main target for hydrocarbon exploration of terrestrial strata in Sichuan Basin is the tight gas sandstone reservoir of the Upper Triassic Xujiahe Formation. Xujiahe Formation in YB area is a major discovery of hydrocarbon exploration in recent years, which is characterized as tight with ultralow porosity, ultralow permeability, and intensive heterogeneity. The tectonic fractures have important influence on accumulation and productivity of gas in the area. In the paper, analysis data...
Published on Jul 1, 2019in Palaeogeography, Palaeoclimatology, Palaeoecology2.62
Ziqiang Mao (CAS: Chinese Academy of Sciences), Qingquan Meng8
Estimated H-index: 8
(Lanzhou University)
+ 6 AuthorsMengqi Tan (CAS: Chinese Academy of Sciences)
Abstract The Lunpola Basin plays a key role in determining the elevation history of the central Tibetan Plateau, which is closely related to uplift dynamics and paleoclimatic evolution. However, accurate age constraints on the basin stratigraphy reflecting tectonic, paleo-elevation and climate information have long been vigorously debated, mostly due to a lack of absolute age controls. Here, we found two altered tuff layers in the middle-upper Dingqinghu Formation (Fm.) in the basin stratigraphi...
Published on Jul 1, 2019in Marine and Petroleum Geology3.54
Junfei Chen (China University of Geosciences), Jingli Yao (PetroChina)+ 4 AuthorsXiaozhou Shao (PetroChina)
Abstract There are many reservoirs with low porosity and low permeability in the world, and many large oilfields have been found in these reservoirs. Unlike conventional reservoirs, the genesis of low-porosity and low-permeability reservoirs and the controls of relatively high-porosity and high-permeability zones are still unclear. This study takes the Chang10 1 reservoir sandstones of the Shanbei area in the Ordos Basin, China, a typical low-porosity and low-permeability, as an example. Chang10...
Published on Jun 1, 2019in Ore Geology Reviews3.39
Yin Chen1
Estimated H-index: 1
,
Ruoshi Jin1
Estimated H-index: 1
+ 3 AuthorsLulu Chen1
Estimated H-index: 1
Abstract Large quantities of pyrite have been discovered near the ore-bearing segments of the sandstone-type uranium deposits in the North Ordos Basin. In this study, the electron probe microanalysis, scanning electron microscopy, and isotope geochemical analysis were used to systematically investigate the morphology, composition, and S isotopes of the pyrites in these deposits, and their genetic order relative to the other main altered minerals. Based on the regional tectonic evolutionary seque...