中国晚泥盆世两种木本石松植物的研究

木本石松植物在晚古生代植物群中一直引人注目，它们是最早在中、晚泥盆世发展乔木和异孢习性的陆生维管植物谱系之一。在这篇报告中，中国两种晚泥盆世（距今约354-370百万年）的木本石松植物被详细地研究了。这两项研究增进了我们对泥盆纪木本石松植物的进化发育生物学的认识。 作者从中国西北部新疆准噶尔盆地上泥盆统的地层中描述了一个新种新疆鳞孢穗Lepidostrobus xinjiangensis sp.nov.，它为我们研究晚泥盆世石松植物的生殖分化和系统发育关系提供了新的认识。这个孢子叶球不同于任何草本石松植物的生殖器官，而与木本石松植物的生殖器官更为相似，它符合鳞孢穗属Lepidostrobus的鉴别性状。它的每个孢子叶由一个楔形的叶柄和一个三角形的叶片构成。孢子叶水平地着生在穗轴上，呈低角度的螺旋排列。叶柄具有侧翼和一个远轴面的脊，其远端延伸为一个上翻的叶片和一个下翻的踵，形成了一种盾状的外貌。孢子囊呈辐向加长、背腹扁的卵球形，具有顶端的纵向开裂。每个孢子囊基部纵向着生在叶柄的近轴面上。在孢子囊中发现了一个柱状的亚孢原组织垫。一个可能的叶舌出现在叶柄近轴面靠孢子囊远端。这个生殖器官是一个小孢子叶球，含石松孢Lycospora型孢子，具有粒状纹饰和赤道凸缘。基于这个鳞孢穗新种，木本石松植物从泥盆纪到石炭纪以来的生殖分化和演化式样在一个系统发育的框架中被讨论了。作者提出，木本石松植物由两性孢子叶球和单孢子叶球所代表的生殖策略到了晚泥盆世已经发展得相当完备，这暗示着系统发育上生有鳞孢穗孢子叶球的木本石松植物比过去所认为得起源要早。 作者重新调查了一个过去描述于中国湖北晚泥盆世（弗拉斯期）黄家磴组地层中的斜方薄皮木Leptophloeum thombicum的树干，并提出关于这个木本石松植物生长结构的新观点。这个树干保存为压扁的硅化化石，具有不均匀渗矿化的初生维管组织和螺旋排列的斜方形叶座。叶座特征符合晚泥盆世广泛分布的植物斜方薄皮木Leptophloeum rhombicum Dawson的鉴别性状。分类上，斜方薄皮木被归入薄皮木科Leptophloeaceae和广义水韭目Isoetales s.l.。这个树干在不同水平的解剖特征证明，斜方薄皮木的个体发育可能符合一种有限的生长方式。结合过去的资料和当前的生长结构分析，作者提出斜方薄皮木具有假单轴分枝的习性，而不是过去所认为的那样长着等二叉分枝的树冠。作者重新复原了这个植物的总体生长形态，它由一个根座式根状茎、一个主干和侧枝三类主要的生长结构单元构成。当这些结果组合了近期的系统发育工作后，它表明斜方薄皮木已经发育了与一些晚泥盆世法门期和石炭纪木本石松植物相似的生长结构，可能代表了早期水韭目植物祖先的生长结构类型之一。

俄罗斯远东和中国湖南晚泥盆世石松类的新发现

在现代的陆地植被当中，石松类为草本植物，在植物界中属于高等植物的低等部分。然而在陆地植物起源和发展演化的早期阶段，石松类是陆地植被的重要成分。石炭纪时期石松类处于最繁盛时期，多生长成为高大乔木，形成森林，是陆地植被的优势类群，也是主要的成煤植物。作为演化历史最长的陆地植物之一，石松类在泥盆纪时期就广泛分布于世界各地，泥盆纪成为石松类演化发展的一个非常重要的时期。研究泥盆纪石松类对认识石松类的起源和发展有重要意义。 本论文是作者在博士期间多个工作之中的两个内容，对采自俄罗斯远东地区的晚泥盆世石松类Haskinsia标本以及采自湖南醴陵的晚泥盆世石松类Lilingostrobus longifolius标本进行了研究。 我们在俄罗斯远东地区的标本中发现了具有三角形叶片的简单叶。泥盆纪石松类Haskinsia属的最典型特征就是其叶由叶柄和三角形或戟形的叶片组成。综合标本的其它特征我们将这些标本归入Haskinsia colophylla这个种中。俄罗斯学者曾在与我们相同的采集地点采集了相似的标本并将其命名为Pseudolepidodendron igrischense，经过仔细对比后我们认为俄罗斯学者的标本也应归并入H. colophylla。同时根据Haskinsia属分布于早泥盆世晚期至晚泥盆世早期的特点，我们对采集地点的地层时代进行了修订，认为其地层时代要比俄罗斯学者认为的晚泥盆世至早石炭世要早。 我们在标本中还首次发现了Haskinsia colophylla这个种的孢子囊。在此之前，Haskinsia 属内的H. colophylla和H. sagittata由于具有相类似的叶而被认为可能是同一个种。由于仅在H. sagittata中发现了孢子囊（椭圆形/卵形）而没有发现H. colophylla的生殖结构，无法确切地区分这两个种。我们在标本中发现了着生于孢子叶腹面的圆形孢子囊。这一发现使我们确认了H. colophylla与H. sagittata的区别，这两个种都是有效种。 我们还对采自湖南醴陵望仙桥水库剖面晚泥盆统岳麓山组地层的部分石松类标本进行了研究。该石松类被命名为Lilingostrobus longifolius。它为木本石松类，茎为二岐分枝，叶在茎上螺旋形排列，叶为长披针形，具有中脉。孢子叶球顶生，呈长锥形，顶端钝圆，孢子叶在孢子叶球上呈紧密的螺旋形排列，每轮约6-8枚。孢子叶分化为孢子叶梗和孢子叶片。孢子叶梗与穗轴近垂直，水平向外延伸后向上弯曲成孢子叶片，叶片至少长45mm，超过孢子叶球长度的一半，孢子叶片与营养叶同型。孢子囊长椭圆形，着生于孢子叶梗的上面。Lilingostrobus longifolius为异型孢子叶球，分为大孢子叶球和小孢子叶球。茎轴具有外始式的初生木质部以及呈放射状的次生木质部。管胞次生壁具有梯纹加厚，加厚的横棒之间有纵向的条状物，即“威廉姆森结构”。Lilingostrobus longifolius具有孢子叶分化明显的孢子叶球因而被归入广义的水韭目。根据其管胞类型和孢子叶球特点，我们认为其可能与Sublepidodendron属亲缘关系较近。 通过对Lilingostrobus longifolius的孢子叶球以及解剖特点的分析，我们认为它代表了晚泥盆世石松类中较为先进的一个类群，这种类群在石炭纪时期得到大规模发展。 结合晚泥盆世其他具有生殖结构的石松类，我们认为晚泥盆世时期石松类的生殖结构类型丰富多样，而且远比中泥盆世石松类生殖结构复杂。这个时期石松类的发展为其在石炭纪的进一步演化奠定了基础。同时，在这个时期石松类植物的叶舌与孢子类型关系中，包括四种类型，即不具叶舌产生单型孢子类型，不具叶舌产生异型孢子类型，具叶舌产生单型孢子类型以及具叶舌产生异型孢子类型。这与现代石松类仅具有两种类型即不具叶舌的类群孢子囊产生同型孢子，而具叶舌的类群孢子囊产生异型孢子有很大的差别。

湖南、广西泥盆纪硅岩地球化学与沉积构造背景

During the Devonian, a complicated carbonate platform-basin configuration was created through transtensional rifting in the context of opening of Devonian South China Sea; extensive bedded chert, commonly interbedded with tuffaceous beds, occurred in the narrow, elongate interplatform basins (or troughs) in South China, where they occurred earlier (Early Devonian) in southern Guangxi and later (early Late Devonian) in northern Guangxi-south central Hunan. In order to unravel the origin and distribution of the bedded chert successions, and their relationships to basement faulting activities during the opening of the Devonian South China Sea, studies of element (major, minor and REE) geochemistry and Rb-Sr, Sm-Nd isotopic systematics are carried out upon the chert deposits. These chert deposits commonly have high SiO2 contents and (average 94.01%) and low TFe2O3 (average 0.55%), together with other geochemical parameters, suggestive of both biogenic and hydrothermal origins. However, Fe/Ti ratio are high along the elongate interplatform basins(troughs) to the northwest along Wuxiangling-Zhaisha-Chengbu, and to the southeast along Xiaodong-Mugui-Xinpu, suggesting relatively intense hydrothermal activities there. They generally contain very low total REE contents (∑REE average 31.21ug/g) with mediate negative Ce anomalies (mean Ce/Ce*=0.83) and low Lan/Cen values (average 1.64), indicating an overall continental margin basin where they precipitated. The northward increases in Ce/Ce* values, particularly along the elongate troughs bounded both to the east and west of the Guangxi-Huanan rift basin, suggest a northward enhancement of terrigenous influences, thereby reflecting a gradual northward propagation of open marine setting. Generally low positive Eu anomalies in the chert, except for the apparently high Eu anomalies in the chert from Chengbu (Eu/Eu* up to 4.6), suggest mild hydrothermal venting activities in general, except for those at Chengbu. The initial 87Sr/86Sr (0) ratios of chert generally vary from 0.712000 to 0.73000 , suggesting influences both from terrigenous influx and seawater. The Nd isotopic model ages (tDM or t2DM) and initial εNd (0) values of chert vary mostly from 1.5 to 2.1 Ga, and from –16 to –21, respectively, implying that the silica sources were derived from the provenances of the Palaeoproterozoic crust relics at depth. The high εNd (0) values of chert (-0.22 to 14.7) in some localities, mostly along the elongate troughs, suggest that silica sources may have been derived from deeper-seated mantle, being channeled through the interplate boundary fault zones extending downwards to the mantle. At Wuxiangling, Nanning, chert occurs extensively from the Emsian through the Frasnian strata, both U/Th ratios and tDM ages of chert reached up to a maximum in the early Frasnian corresponding to the extensive development of chert in South China, pointing to a maximum extensional stage of Devonian South China basin, which is supported by the Ce/Ce* values as is opposed to the previous datasets as the coeval minimum values.

Discovery of Late Cretaceous garnet two-pyroxene granulite in the southern Lhasa terrane, Tibet and its tectonic significances

The Lhasa terrane, located between the Bangonghu-Nujiang suture zone and the Indus-Yalung Tsangpo suture zone in the southern Tibetan Plateau, was considered previously as a Precambrian continental block. Mesozoic and Cenozoic tectonic evolution of the Lhasa terrane is closely related to the subduction of the Tethys ocean and the collision between the Indian and European continents; so it is one of the keys to reveal the formation and evolution of the Tibetan plateau. The garnet two-pyroxene granulite which was found at the Nyingtri rock group of the southeastern Lhasa terrene consists of garnet, clinopyroxene, orthopyroxene, labradorite, Ti-rich amphibolite and biotite, with a chemical composition of mafic rock. The metamorphic conditions were estimated to be at T = 747 similar to 834 degrees C and P = 0.90 similar to 1.35GPa, suggesting a formation depth of 45km. The zircon U-Pb dating for the garnet amphibolite and marble associated with the granulite give a metamorphic age of 85 similar to 90Ma. This granulite-facies metamorphic event together with a contemporaneous magmatism demonstrated that the southern Lhasa terrane has undergone an Andean-type orogeny at Late Mesozoic time.

ISOTOPIC CHARACTERISTICS AND AGE DATING OF THE PUMICE IN OKINAWA TROUGH

The data on the isotope compositions of rubidium, strontium and oxygen in the pumice of Okinawa Trough are reported for the first time. The ages of the pumice were successfully dated with the method of U-series disequilibrium. Then, the material source, crystallization evolution of magma and activity cycles of volcanos are explored. Isotopic data show that pumice magma was originally from the mantle, but had undergone a full crystallization differentiation and had been contaminated to a fair extent by crust-derived materials before the magma was erupted out of the sea floor. According to the dating results available so far, the earliest volcanic eruption in Okinawa Trough occurred about 70,000 a ago and the latest eruption was about 10,000 a B.P. During this period, there were three volcanic eruption cycles which were respectively corresponding to the middle Late Pleistocene, the late Late Pleistocene and the Early Holocene.

THE COMPOUND EYE AS AN INDICATOR OF AGE AND SHRINKAGE IN ANTARCTIC KRILL

Laboratory studies have shown that Antarctic krill (Euphausia superba) shrink if maintained in conditions of low food availability. Recent studies have also demonstrated that E. superba individuals may be shrinking in the field during winter. If krill shrink during the winter, conclusions reached by length-frequency analysis may be unreliable because smaller animals may not necessarily be younger animals. In this study, the correlation between the body-length and the crystalline cone number of the compound eye was examined. Samples collected in the late summer show an apparent linear relationship between crystalline cone number and body-length. From a laboratory population, it appears that when krill shrink the crystalline cone number remains relatively unchanged. If crystalline cone number is little affected by shrinking, then the crystalline cone number may be a more reliable indicator of age than body-length alone. The ratio of crystalline cone number to body-length offers a method for detecting the effect of shrinking in natural populations of krill. On the basis of the crystalline cone number count, it appears from a field collection in early spring that E. superba do shrink during winter.

东准噶尔和尔赛斑岩铜矿特征及其形成的构造背景

Hersai porphyry copper deposit(PCD) of eastern junggar, newly discovered copper deposit, is located at the eastern segment of the Xiemisitai-Kulankazigan-Zhifang-Qiongheba Paleozoic island arc, Eastern Junggar. The Hersai PCD is developed in a intrusive complex, characterized by intensive and multiform hydrothermal alteration, including potassic alteration, silification, chloritization，sericitization，kaolinitization and carbonatization. Granodiorite, grandiorite porphyry, granite and concealed explosion breccia are hosts of the ore bodies containing veinlet and disseminated ore. Ore-bearing granite (ZK107-1-9), granodiorite (ZK107-1-9) and Ore-barren granodiorite (HES2-1) are selected to date zircon U-Pb age by SHRIMP method, and have an age of 429.4±6.4Ma ,413.0±3.4Ma and 411.1±4.8Ma, respectively, showing that they were emplaced from Late Silurian to Early Devonian. In addition, sample ZK107-1-9 has some hydrothermal zircons with a weighted mean 206Pb/238U age of 404.9±3.7Ma which is interpreted to be related to the granodiorite porphyry. Re-Os dating of five molybdenite samples yielded a weighted average model age of 408.0±2.9Ma, indicating the metallogenic epoch of the Hersai PCD. The ore-forming age is close to the petrogenic time of garnodiorite (411-413Ma), this suggests the ore-forming porphyry is most possiblely granodiorite porphyry. Systematic major - trace elements and Rb-Sr-Sm-Nd-Pb-Hf isotopic characteristics were studied. Analysis results show that these intrusives have some interesting and special characteristics, as following:1) containing both calc-alkaline rocks and high potassium calc-alkaline rocks ; 2) have some characteristics of adakite, but not totally, such as much lower La/Yb ratios and no Eu anomaly or just faint Eu anomaly; 3) have an initial 87Sr/86Sr ratios(0.703852-0.704565) similar to that of BSE, positive εNd(t) values between 6.1 and 7.4, the initial 206Pb/204Pb values (17.576-17.912), 207Pb/204Pb values (15.400-15.453) , 208Pb/204Pb values (37.252-37.466) , and high εHf(t) values (10.2-15.4) close to the value of depleted mantle. These geochemical features suggest that these igneous rocks in the Hersai area not only have some characteristics of island arc, but also some characteristics that only appear in the continental margin arc. It is suggested that Hersai PCD is formed in the subduction setting by the partial melting of young crust. These works and advancements mentioned in the paper are helpful to understand the deposit geology, geochemistry and metallogenesis of Hersai PCD. It is also significant to understand mineralization and tectonic setting in the Qiongheba area.

新疆谢米斯台中段地区火山岩特征及其含矿性研究

Central Xiemisitai is located on the northwest edge of the Junggar Basin, bounded on the north by Sawuer Mountain, and southward Junggar Basin. Geotectonically, it is within the Chengjisi-Ximisitai-Santanghu island arc of Late Paleozoic, between Siberian and Junggar plates. The volcanics in this area mainly consist of acidic volcanic lava, rock assemblage of esite, dacite, and rhyolite, and the transitional phase is comparatively developed. Besides, Si2O of volcanics here covers a large range of 53.91-79.28t %, K2O of 1.71-6.94t%, and Na2O of 2.29-5.45t%, which is a set of metaluminous- peraluminous high K calc-alkaline to calc alkaline mid-acidic volcanic series. In addition, the volcanics are potassic to high-potassic assemblage, with slight shoshonite in. The REE curve of volcanics in central Xiemisitai is rightward and smooth, inclining to LREE enrichment, which reveals the characteristics of island-arc volcanics. Through the lithology changing from neutral to acidic, the negative anomaly of Eu is increasing. The volcanics here deplete HFSE such as Nb, Ti, P, etc., but relatively rich in LILE like Rb, K, Th, etc., possessing geochemistry characteristics of arc volcanics, which means that the lava source region is watery, under the meta-somatic contamination of subducted components. Moreover, high Ba and Sr show volcanics in epicontinental arc environment, and their contemporaneous granitoid rocks are also marked with the characteristics of volcanic arc granite. In central Xiemisitai, the volcanics zircon age of volcanic rhyolite is 422.5Ma± 1.9Ma, mid-late Silurian. Only one sample zircon has been measured for the present, not very convincing, so volcanics here might not come from Devonian volcanism. Consequently, further confirming the volcanic age will play a key role in the research on the beginning of volcanism in Xiemisitai area and even North Xinjiang. This area includes three copper mineralization types: a) from andesite fracture; b) from rhyolite fracture broken zone, with the copper mineralization distributed by veins along the fissure; and c) from quartz veins. The mineralization of earth surface in S24 ore spot is intensive, and the primary geochemistry reconnaissance anomaly is fairly good. According to display data, the maximum content of Cu is as high as 0.9% and as low as 0.05%. Also, ore-control fracture structure is having a considerable scale in the strike of fracture both horizontally and vertically downwards, and the result of the geophysics stratagem EH-4 system reveals obvious low-resistivity anomaly. As a result, we believe that the S24 plot is expected to be a volcanic copper deposit target area.

鄂尔多斯盆地西缘中生代构造与地层分析及盆地演化研究

Through the detailed analyses of Mesozoic tectono-stratigraphy and basin formation dynamic mechanism and the styles of different units in the western margin of Ordos Basin(Abbreviated to "the western margin"), while some issues of the pre-Mesozoic in the western margin and central part of Ordos Basin also be discussed, the main views and conclusion as follows: 1. There are three types of depositional systems which are related with syndepositional tectonic actions and different tectonic prototype basins, including: alluvial fan systems, river system (braided river system and sinuosity river system), lacustrine-river delta system and fan delta system. They have complex constitutions of genetic facies. For the tectonic sequence VI, the fan sediments finning upper in the north-western margin and coarse upper in the south-western margin respectively. 2. In order to light the relationship between basin basement subsidence rate and sediment supply and the superposed styles, five categories of depositional systems tracts in different prototype basins were defined: aggrading and transgressive systems tracts during early subsidence stage, regressive and aggrading systems tracts during rapid subsidence, upper transgessive systems tracts during later subsidence stage. Different filling characteristics and related tectonic actions in different stages in Mesozoic period were discussed. 3. In order to determined the tectonic events of the provenance zones and provenance strata corresponding to basins sediments, according the clastics dispersal style and chemical analyses results of sediments in different areas, the provenance characteristics have been described. The collision stage between the "Mongolia block" and the north-China block may be the late permian; The sediments of Mesozoic strata in the north-western margin is mainly from the Alex blocks and north-Qilian Paleozoic orogeny, while the south-western margin from Qinling orogeny. The volcanic debris in the Yan'an Formation may be from the arc of the north margin of north-China block, although more study needed for the origin of the debris. The provenance of the Cretaceous may be from the early orogeny and the metamorphic basement of Longshan group. 4. The subsidence curve and subsidence rate and sedimentary rate in different units have been analyzed. For different prototype basin, the form of the subsidence curves are different. The subsidence of the basins are related with the orogeny of the basins.The beginning age of the foreland basin may be the middle Triassic. The change of basement subsidence show the migration of the foredeep and forebulge into the basin. The present appearance of the Ordos basin may be formed at the late stage of Cretaceous, not formed at the late Jurassic. 5. The structure mode of the west margin is very complex. Structure transfer in different fold-thrust units has been divided into three types: transfer faults, transition structures and intersected form. The theoretic explanations also have been given for the origin and the forming mechanism. The unique structure form of Hengshanpu is vergent west different from the east vergence of most thrust faults, the mechanism of which has been explained. 6. In Triassic period, the He1anshan basin is extensional basin while the Hengshanbu is "forland", and the possible mechanism of the seemingly incompatible structures has been explained. First time, the thesis integrate the Jurassic—early Cretaceous basins of west margin with the Hexi corridor basins and explain the unitive forming mechanism. The model thinks the lateral extrusion is the main mechanism of the Hexi corridor and west margin basins, meanwhile, the deep elements and basement characters of the basins. Also, for the first time, we determine the age of the basalt in Helanshan area as the Cretaceous period, the age matching with the forming of the Cretaceous basins and as the main factor of the coal metamorphism in the Helanshan area. 7. The Neoprotterozoic aulacogen is not the continuation of the Mesozoic aulacogen, while it is another new rift stage. In the Paleozoic, the Liupanshan—southern Helanshan area is part of the back-arc basins of north Qilian ocean. 8. The Helanshan "alacogen" is connected with the north margin of north China block, not end at the north of Zhouzishan area like "appendices". Also, I think the upper Devonian basin as the beginning stage of the extensional early Carboniferous basins, not as a part of the foreland basins of Silurian period, not the collision rift. 9. The controlling factor of the difference of the deformation styles of the north-west margin and the south-west margin is the difference of the basements and adjacent tectonic units of the two parts.