Fluid mixing induced by hydrothermal activity in the ordovician carbonates in Tarim Basin,China

Permian hydrothermal activity in the Tarim Basin may have been responsible for the invasion of hot brines into Ordovician carbonate reservoirs. Studies have been undertaken to explain the origin and geochemical characteristics of the diagenetic fluid present during this hydrothermal event although there is no consensus on it. We present a genetic model resulting from the study of δ¹³C, δ¹⁸O, δ³⁴S, and ⁸⁷Sr/⁸⁶Sr isotope values and fluid inclusions (FIs) from fracture‐ and vug‐filling calcite, saddle dolomite, fluorite, barite, quartz, and anhydrite from Ordovician outcrops in northwest (NW) Tarim Basin and subsurface cores in Central Tarim Basin. The presence of hydrothermal fluid was confirmed by minerals with fluid inclusion homogenization temperatures being >10°C higher than the paleo‐formation burial temperatures both in the NW Tarim and in the Central Tarim areas. The mixing of hot (>200°C), high‐salinity (>24 wt% NaCl), ⁸⁷Sr‐rich (up to 0.7104) hydrothermal fluid with cool (60–100°C), low‐salinity (0 to 3.5 wt% NaCl), also ⁸⁷Sr‐rich (up to 0.7010) meteoric water in the Ordovician unit was supported by the salinity of fluid inclusions, and δ¹³C, δ¹⁸O, and ⁸⁷Sr/⁸⁶Sr isotopic values of the diagenetic minerals. Up‐migrated hydrothermal fluids from the deeper Cambrian strata may have contributed to the hot brine with high sulfate concentrations which promoted thermochemical sulfate reduction (TSR) in the Ordovician, resulting in the formation of ¹²C‐rich (δ¹³C as low as ?13.8‰) calcite and ³⁴S‐rich (δ³⁴S values from 21.4‰ to 29.7‰) H₂S, pyrite, and elemental sulfur. Hydrothermal fluid mixing with fresh water in Ordovician strata in Tarim Basin was facilitated by deep‐seated faults and up‐reaching faults due to the pervasive Permian magmatic activity. Collectively, fluid mixing, hydrothermal dolomitization, TSR, and faulting may have locally dissolved the host carbonates and increased the reservoir porosity and permeability, which has significant implications for hydrocarbon exploration.     

“罗马和平”时期石碑的保护修复

罗马帝国初期的200年(公元前27年~公元2世纪)是罗马的鼎盛时期,开创了经济、文化、军事、艺术前所未有的高峰,被称为"罗马和平"时期。本文保护修复的几件"罗马和平"时期的石碑原本收藏在意大利罗维纳市的Lapidario博物馆,后委托意大利博洛尼亚KRITERION文物修复公司进行保护修复,进行了清洗、补全、封护等保护修复工作。     

1964年中苏第一轮边界谈判的历程及基本经验

20世纪60年代初,随着中苏两国关系的全面恶化,以往一直保持平静的边境地区也开始出现紧张局势。有鉴于此,中方主动提出通过外交谈判来解决边界争端,却被苏方拒绝。一直到1964年年初赫鲁晓夫发起新一轮的"和平攻势"后,苏方才接受中方建议,开始第一轮副部长级的边界谈判。在中苏意识形态论战、两国边界问题的历史纠葛、复杂多变的国际局势等综合因素的影响下,谈判进行得十分艰难,最终也未能签订任何协议,这种情况的出现有其历史必然性。不过,在两国交恶的情况下,中苏第一轮边界谈判所取得的经验为两国最终解决边界问题奠定了一定的基础。     

《坚持四项基本原则》的形成与历史地位

在全面拨乱反正的背景下,理论工作务虚会第一阶段对新中国成立以来的若干重大理论与历史问题进行了热烈讨论,但是会议期间出现了一些不协调的声音,引起中共中央的注意,加之社会上出现的错误思潮,影响了安定团结的局面。在这种情况下,邓小平代表中共中央在全国理论工作务虚会上作了《坚持四项基本原则》的报告,明确提出了"四个坚持"。这个报告在全国理论工作务虚会和随后召开的中央工作会议上引起热烈讨论,各地也很快掀起了一场贯彻学习四项基本原则、进行真理标准讨论"补课"的热潮。随着改革开放事业的发展,四项基本原则作为立国之本的地位被确立起来,并不断被赋予新的时代内涵。     

An analysis of spatial patterns of toponyms in Guangdong,China

The unique geographical environment and the historical waves of immigration of the northern Han Chinese to the Lingnan region have contributed to the development of a complex and unique culture in Guangdong Province. Four ancient ethnic groups, the Zhuang, Cantonese, Hoklo and Hakka, have resided in this area for centuries. As an important part of local culture, toponyms often survive changes in history and can reveal the temporal differences between the past and present in landforms and the spatial differences in the distribution of different ethnic group populations. In this study, two goals were sought: (1) the adoption of spatial smoothing and interpolation methods to reveal the spatial patterns of the Zhuang, Cantonese, Hoklo and Hakka toponyms based on comparisons among the proportions of those who speak various languages and (2) the investigation of the differences among toponymic layers under regional environmental conditions and the influences of geographic factors using an independent samples t-test and a binary logistic regression.     

Crowdsourcing Model Research for the Identification of Post-Earthquake Rescue Objects

The quick and accurate identification of post-earthquake rescue objects can minimize the casualties and property loss caused by earthquakes. With the rapid development of remote sensing technology, rescue objects can be identified through high-resolution remote sensing images. There are two main categories of approaches to identify rescue object through high-resolution images: automatic extraction by a computer and visual judgment by professionals. Although results can be obtained quickly by using automatic extraction, the accuracy of the results is unacceptably low. For visual judgment, the large demands for time and professionals restrict its wide practical application. In this study, we introduce crowdsourcing into the identification of post-earthquake rescue objects. First, we integrate the advantages of the computer and crowdsourcing, which means that the computer takes advantage of the speed of information processing, while crowdsourcing makes full use of human recognition capabilities. Second, we take visual judgment tasks out of the hands of professionals and entrust the tasks to workers in a crowdsourcing platform. Not only are the human resources infinite, but we can also improve the efficiency of identifying rescue objects. Third, we propose a crowdsourcing model that improves the quality of the results and saves human resources. Finally, experimental results demonstrate that our solution is feasible.     

Bayesian Parameter Identification and Model Selection for Normalized Modulus Reduction Curves of Soils

This work develops a procedure that involves the use of Bayesian approach to quantify data scatterness, estimates the optimal values of model parameters, and selects the most appropriate model for the construction of normalized modulus reduction curves of soils. The proposed procedure is then demonstrated using real observation data based on a set of comprehensive resonant column tests on coarse-grained soils conducted in the study.     

Does clean air increase the demand for the consumer city? Evidence from Beijing

Cities offer a large menu of possible employment and leisure opportunities. The gains from such consumer city leisure are likely to be lower on more polluted days. We study the association between daily consumption activity and outdoor air pollution in China and find evidence in favor of the hypothesis that clean air and leaving one's home for leisure trips are complements. Given the high levels of air pollution in cities in the developing world, regulation induced improvement in environmental quality is likely to further stimulate demand for the consumer city.     

What can pollen grains from the Terracotta Army tell us?

The provenance of more than 2200-year-old terracotta warriors and horses in the Qin Shihuang Mausoleum is still a mystery, even though some researchers have inferred that the terracotta figures were produced near the mausoleum. The sporomorphs (pollen and spores) extracted from terracotta fragments of a warrior and a horse and compared with those obtained from soil samples from the Qin Dynasty layer in Pit No. 2 of the Qin Shihuang Mausoleum indicate that the pollen spectrum from the terracotta horse is different from that of the warrior, but similar to the local soil samples. Herbaceous pollen was dominant in the warrior sample, while arboreal pollen predominates in the horse and soil samples. Palynological evidence suggests that the terracotta horses were produced at a locality near the mausoleum, while the warrior came from a site which was further afield.