The Chinese Mars rover Zhurong successfully landed in southern Utopia Planitia on Mars in May 2021. Previous research suggested a Hesperian ocean may have existed in the northern lowland on Mars. Recent research observed water-related features at the Zhurong landing site from in situ data. In this study, we conducted a comprehensive geomorphological analysis of the landing area using remote sensing data, supplemented by in situ observations, and unveiled features consistent with the existence of a nearshore zone in southern Utopia. Different types of water-related geomorphological features were separated by specific topographic contours, suggesting different types of marine environments. The area was subdivided into a foreshore highland-lowland transition unit, a shallow marine unit and a deep marine unit. In situ observations including sedimentary deposit rocks, water-related lamination features, and subsurface sedimentary layers, also indicate past water activities. Results suggested an evolution scenario of the nearshore zone in southern Utopia: (1) Flooding of the Utopia Planitia in Late Noachian around 3.65-3.68 Ga reached the foreshore unit; (2) formation of the shallow and deep marine units after the flooding was completed by about 3.5 Ga and 3.42 Ga in Early Hesperian, respectively; (3) gradual loss of subsurface volatiles during the Amazonian epoch.

The Central Asian Orogenic Belt is the world's largest accretionary orogenic belt, associated with the closure of the Paleo-Asian Ocean (PAO). However, the final closure timing of the eastern PAO remains contentious. The Permian-Triassic sedimentary sequences in the Wangqing area along the Changchun-Yanji suture zone offer important clues into this final closure. New data on petrology, whole-rock geochemistry, zircon U-Pb geochronology and zircon Hf isotopes of sedimentary rocks from the Miaoling Formation and Kedao Group in Wangqing area provide new insights into the final closure of the eastern end of the PAO. The maximum deposition ages of the Miaoling Formation and Kedao Group have been constrained to the Late Permian (ca. 253 Ma) and early Middle Triassic (ca. 243 Ma), respectively. These sedimentary rocks exhibit similar geochemical characteristics, showing low textural and compositional maturities, implying short sediment transport, with all detrital zircons suggesting their origins from felsic igneous rocks. The epsilon Hf(t) values of the Miaoling Formation range from -6.09 to 12.43 and from -2.20 to 7.59 for the Kedao Group, implying these rocks originated from NE China. Considering our new data along with previously published data, we propose that a reduced remnant ocean remained along the Changchun-Yanji suture zone in the early Middle Triassic (ca. 243 Ma), suggesting the final closure of the eastern PAO likely occurred between the latest Middle Triassic and early Late Triassic.

The Mongol-Okhotsk suture belt represents the result of the final closure of the Mongol-Okhotsk Ocean between the Siberian Craton and Erguna Block (also called Amuria), which played an essential role in the formation and tectonic evolution of eastern Eurasia during Mesozoic times. However, the timing of the final closure and subduction polarity of the Mongol-Okhotsk Ocean are still debated. In this study, provenance analysis of Multidimensional scaling and crustal thickness variation based on zircon Eu anomaly were used for the first time to reveal the tectonic evolution of the Mongol-Okhotsk Ocean during Mesozoic times. The results show that the evolution of the Mongol-Okhotsk Ocean can be divided into several stages. From Early Triassic (-245 Ma) onwards, the Mongol-Okhotsk Ocean started to shrink due to southward subduction beneath the Erguna Block. The closure of western segments of the Mongol-Okhotsk Ocean occurred in the Late Triassic, leading to a weakening or cessation of oceanic plate subduction, and the prevalence of an extensional environment during 225-215 Ma. Subsequently, after the Late Triassic (starting at ca. 205 Ma), subduction of the Mongol-Okhotsk Ocean continued until the middle segments closed during Middle Jurassic (-165 Ma). From 165 to 155 Ma, many magmatic arc rocks and metamorphic core complexes formed in the central and western segments of the Mongol-Okhotsk suture belt within a post-orogenic extensional setting. The eastern part of the Mongol-Okhotsk Ocean rapidly closed in a scissor-like manner, resulting in the collision between the Erguna Block and the Siberian Craton during the Late Jurassic (-150-145 Ma). Collision also caused uplift of the southern margin of the Siberian Craton and the sediment deposition in the Mohe Basin. The subsequent crustal shortening associated with the collision led to the formation of nappes and the emplacement of adakites along the northern margin of Greater Xing'an Mountains. Since the Early Cretaceous, the compressional environment transitioned into a postorogenic extensional tectonic environment influenced by the west-directed slab rollback of the Paleo-Pacific Plate and detachment of the subducted Mongol-Okhotsk oceanic plate after closure of the Mongol-Okhotsk Ocean.

辽西地区位于燕山造山带东段,发育大规模的中生代火山-沉积盆地,是研究中生代燕山运动构造体制转换、岩石圈减薄和克拉通破坏的关键地区之一.报道了辽西寺儿堡-白塔盆地晚侏罗世火山岩岩相学、锆石U-Pb年代学、地球化学和锆石Hf同位素组成等资料,确定了其形成时代、岩石成因及构造背景,探讨了晚中生代期间古太平洋板块对华北克拉通东部俯冲后撤作用时间,为进一步认识燕山运动和燕山期岩浆活动的地球动力学机制提供可靠的地质依据.盆地内大范围出露的流纹岩形成时代为153.8～160.3 Ma,在空间上呈NE向展布,具有较高的SiO2、Al2O3和全碱含量,显示准铝质-过铝质和高钾钙碱性特征.样品相对富集大离子亲石元素(LILEs:Rb、Ba、Pb、K等)和轻稀土元素(LREEs),亏损高场强元素(HFSEs:Nb、Ta、P、Ti等)和重稀土元素(HREEs),具明显的Eu负异常和较低的Cr、Co、Ni含量,结合岩浆成因锆石具有负εHf(t)值(-17.8～-23.2)和相对古老的Hf同位素二阶段模式年龄(TDM2=2334～2697 Ma),暗示初始岩浆可能来自于太古代或元古代的古老下地壳的部分熔融.综合研究表明,辽西地区晚侏罗世岩浆构造活动主要受控于古太平洋板块俯冲和后撤.寺儿堡-白塔盆地中流纹岩形成于古太平洋板块俯冲的NW向挤压构造背景,同时,在辽西地区存在大量与古太平洋板块后撤密切相关的变质核杂岩和伸展盆地,暗示区域上伸展体系的存在.因此,认为燕山-辽西地区构造体制于晚侏罗世发生转变,由挤压体系逐渐过渡为伸展体系,为燕山运动的响应.

大兴安岭扎兰屯南部位于中亚造山带东段,兴安地块(XB)与松嫩地块(SB)之间,是探究兴安地块与松嫩地块构造演化过程,乃至中亚造山带东段微地块聚合过程的关键地区.对该地区出露的花岗质糜棱岩进行地质学、地球化学、锆石U-Pb测年分析,以期查明板块俯冲过程中的岩浆作用特征,并尝试限定兴安地块与松嫩地块碰撞拼合时间.LA-ICP-MS锆石U-Pb测年结果表明,花岗质糜棱岩分为两期:Ⅰ期为早泥盆世(～398.8 Ma),Ⅱ期为晚泥盆世末-早石炭世(351.6～365.7 Ma).两期岩石均具有高SiO2(68.20％～77.90％),富碱(K2O+Na2O=6.32％～9.67％),贫镁(MgO=0.22％～0.97％),偏铝质,高钾钙碱性系列的特征.稀土元素分布模式均为右倾[(La/Yb)N=4.33～10.77],Eu负异常(δEu=0.03～0.13),富集LILE,亏损HFSE,具有I型花岗岩的特征.两期花岗质糜棱岩可能为俯冲背景下岛弧岩浆活动形成的I型-分异I型花岗岩.结合区域构造演化和岩石地球化学研究,大兴安岭北段晚古生代早期花岗质岩浆作用与兴安地块与松嫩地块的碰撞拼合作用有关,扎兰屯地区早泥盆世-早石炭世处于古亚洲洋向兴安地块和松嫩地块俯冲的构造背景下,两个地块的最终碰撞拼合时限可能为晚石炭世.

漠河盆地位于蒙古-鄂霍茨克缝合带（MOSB）东段南缘，是研究蒙古-鄂霍茨克洋东段演化的绝佳窗口.本文对漠河盆地东缘出露的绣峰组砂岩进行详细的岩相学、U-Pb锆石定年和主微量元素地球化学分析，综合前人研究成果，限定了蒙古-鄂霍茨克洋乃至中亚造山带东段演化历史.结果表明，绣峰组砂岩碎屑物磨圆度较低、分选差，表现出近源剥蚀的特点；U-Pb锆石定年共获得217个谐和年龄，可划分为3个年龄组，其峰值均与盆地南缘额尔古纳地块的岩浆事件相吻合，其中最年轻的碎屑锆石 206 Pb/ 238 U年龄加权平均值为158±2 Ma（N=5）；样品相对富集大离子亲石元素（LILEs）和轻稀土元素（LREEs），亏损高场强元素（HFSEs）和重稀土元素（HREEs），具有明显的Eu负异常.样品源岩为上地壳长英质岩石，形成于大陆岛弧的构造环境，源区可能为漠河盆地南侧的大陆岛弧、额尔古纳地块以及盆地的古老基底.综上所述，绣峰组的最大沉积年龄为晚侏罗世，物源区构造背景为活动大陆边缘的大陆岛弧环境，形成于晚侏罗世蒙古-鄂霍茨克洋向南俯冲、闭合造山的构造背景下，指示在绣峰组沉积时期（约158 Ma），蒙古-鄂霍茨克洋仍处于俯冲阶段，尚未完全闭合.综合前人研究成果，推断蒙古-鄂霍茨克洋最终闭合的时间可能在晚侏罗世至早白垩世之间.

The Mohe basin is located to the south of the eastern Mongol-Okhotsk suture belt and contains critical strati graphic records and thrust-nappe structures for understanding the closure of the eastern Mongol-Okhotsk Ocean. This paper discusses the formation ages, provenance, and tectonic setting of the Xiufeng and Mohe formations, and further reveals the timing of the final closure of the Mongol-Okhotsk Ocean and the tectonic evolution of the Mohe basin. The weighted mean( 206)Pb/U-238 ages for the youngest zircon of these samples indicate that the maximum depositional ages of the Xiufeng, Mohe and Tamulangou Formations were conservatively estimated at 159 Ma, 150 Ma and 128 Ma, respectively. From Late Triassic to Late Jurassic (150 Ma), the Mongol-Okhotsk Ocean was consumed by bidirectional subduction expressed by subduction under the Siberian Craton and the Erguna Block, respectively. The intense subduction led to the compression of the continental arc and the basement uplift of the Erguna Block, which provided abundant clastic sediments to the Xiufeng-Ershierzhan Formations. During the Late Jurassic-Valanginian (150-135 Ma), the Mongol-Okhotsk Ocean closed rapidly, which finally caused the collision between the Erguna Block and the Siberian Craton. Meanwhile, the southern margin of the Siberian Craton was uplifted and started furnishing sediments into the Mohe-Kaikukang Formations, which may have a bidirectional provenance. The subsequent crustal shortening associated with collision between the Erguna Block and the Siberian Craton led to nappe structures, syn-collisional folds, and nearly N-S-trending reverse and oblique-slip faults occurred along the northwestern margin of the Mohe basin. Between 135 and 128 Ma, the Mohe basin entered the stage of tectonic setting transformation, which is the crucial period for the Mohe basin to transform from compression to extension. Since the Early Barremian (ca. 128 Ma), the compressional environment was transformed into a post-orogenic extensional tectonic environment, and a series of nearly E-W and NE-SW-trending normal faults occurred, which might have been controlled by the slab rollback of the PaleoPacific Plate and detachment of the Mongol-Okhotsk oceanic plate after the closure of the Mongol-Okhotsk Ocean.

This article presents new zircon U–Pb ages, data on whole‐rock major and trace elements for the Early Ordovician to Early Cretaceous granitic rocks exposed in the Mohe Basin of North‐east China, and reveals the tectonic evolution history of the Mohe area during this period. The zircon U–Pb dating results indicate that the magmatic activities from the Early Ordovician to Early Cretaceous in the Mohe area can be divided into six stages, which are ~473, ~281, ~247, ~215, ~130, and ~124 Ma, respectively. The granitic rocks mainly originated by partial melting of a depleted and heterogeneous lower crust, except for the quartz diorites at ~130 Ma, derived from the separated crystallization of mantle‐derived subalkaline basaltic magma. The rock associations and their geochemical features indicate that the granitic rocks of ~247 and ~215 Ma formed in an active continental margin setting, whereas the granitic rocks with formation ages of ~473, ~281, ~130, and ~124 Ma were formed in an extensional tectonic setting. Each stage of magmatic activity is consistent with the magmatism and tectonism of the Erguna Block. Based on the achievements of the previous studies, we put forward a comprehensive tectonic evolution of the Mohe area. From Early Ordovician to Late Permian (473 ~ 252 Ma), the Mohe area was influenced by the Palaeo‐Asian Ocean tectonic domain. Magmatism of Late Permian to Late Jurassic (247 ~ 155 Ma) is mainly due to the subduction of the Mongol–Okhotsk Ocean. During the Late Jurassic, the Erguna Block collided with the Siberian Craton and the southern margin of the Siberian Craton was uplifted and started furnishing sediments into the Mohe Basin. In the Early Cretaceous (~130 Ma), the Mohe area may have been controlled by the Palaeo‐Pacific Ocean and the Mongol–Okhotsk Ocean tectonic domains.

Late Cretaceous granitoid-related deposits with different ore-forming elements show regional discrepancies: Sn polymetallic deposits formed in the southwestern margin of the Yangtze Block, whereas Cu-Mo deposits occurred in the neighbor Yidun arc. In order to figure out the controlling factors of this different mineralization, this study presents a combination of new zircon and apatite data with previously published geochemical data of Sn-related granitoids from Gejiu and Dachang deposits and Cu-Mo-related granitoids from Tongchanggou, Hongshan, and Relin deposits. The Sn-related granitoids are S-type granitoids with epsilon(Nd)(t) values of -10 to -7.6 and two-stage Nd model ages of 1700-1501 Ma, which implies that they were formed by partial melting of Proterozoic crustal materials. The Cu-Mo-related granitoids are I-type granitoids with adakitic features and wide ranges of epsilon(Nd)(t) values (-7.7 to -4.2) and zircon epsilon(Hf)(t) values (-9.6 to -1.3), reflecting the contributions of crustal- and mantlederived materials in the source. Compared with the Cu-Mo-related granitoids, higher whole-rock Sio(2) contents and Rb/Sr ratios, lower Nb/Ta, Zr/Hf, and K/Rb ratios in the Sn-related granitoids together with variations in zircon and apatite trace element ratios affirm that they are more fractionated. The magmas of Cu-Mo-related granitoids however are more oxidized and hydrous. They show higher zircon Eu-N/Eu-N* (average = 0.70), Ce 4+ /Ce 3+ (average = 671), Ce/-/(U ; x Ti) ratios and apatite Eu-N/Eu(N* )ratios, and lower Ti-in-zircon temperature (average = 675) and zircon (Ce/Nd)/Y ratios than those of the Sn-related granitoids (average zircon Eu-N/Eu-N* = 0.09, average Ce4+/Ce3+ ratios = 53, average Ti-in-zircon temperature = 749). The higher Cl content in apatite for the Cu-Mo-related granitoids reflects a Cl-richer magma for the Cu-Mo-related granitoids. Combined with the previous studies on regional contemporaneous magmatic activity and structures, the Sn- and Cu-Morelated granitoids formed in the intraplate and post-collisional extension environments, respectively. Reduced and fractionated crustal-derived magmas facilitate Sn enrichment, while oxidized, hydrous, and Cl-rich magmas with mantle-derived materials promote Cu-Mo mineralization. Accordingly, magma source, fractionation, redox, and volatile conjunctively control the formation of granitoid-related deposits with different ore element assemblages.

陕西靖国军诗群发展与其革命史演进存在着对应关系,以于右任统领全军及义军接受改编为分水岭,划为三个阶段,三段合起来构成一幅完整的诗群史卷:酝酿期(1916—1918年)诗人还没有群体意识,成果也不丰富,但以于右任、党晴梵为代表的诗人已揭开诗群活动的序幕;兴盛期(1918—1921年)重要诗人基本就位,吟唱蔚然成风,深具影响的唐园唱和与《民治园诗》唱和代表了此阶段诗歌活动的主要成就,这也是群体诗史地位得以确立的关键期;衰落期(1921—1922年)诗人风流云散,诗歌活动延续《民治园诗》唱和之余韵,最终在陇川吟唱中落下帷幕.作为民初陕西革命诗史的重要组成部分,对其予以深入考察有助于丰富陕西近现代诗史.

近年,随着《于右任诗词曲全集》编竣及台北故宫博物院军机处档案所藏《半哭半笑楼诗草》抄本之重现,于右任诗歌之收录几臻于完备,为相关研究奠定了良好的文献基础.但事实上,于右任还有不少诗歌散见于晚清民国时期的报刊,基本无人问津.笔者爬罗剔抉,整理点校,终辑得于右任佚诗41首;这些诗歌,乃今所见各种《于右任诗集》未收之作.凡所辑之诗,按创作先后排序,并附简要按语,交代出处与写作时间等.