A Different Opinion on the Geological Age of the Longzhaogou and Jixi Groups of Eastern Heilongjiang,China1

Abstract The age of the Longzhaogou and Jixi Groups of coal measures in eastern Heilongjiang were previously considered to be Jurassic or mainly Jurassic. But there occur Middle Barremian- Early Albian Aucellina ( bivalvia) fossils in the Upper Yunshan Formation of the Longzhaogou Group and the Lower Chengzihe Formation of the Jixi Group, and the Qihulin Formation of the Longzhaogou Group yields Early Cretaceous bivalve and ammonite fossils. Consequently, the geological ages of the two groups are mainly, or even all, Early Cretaceous.     

Studies on the Early Cretaceous Longzhaogou and Jixi Groups of eastern Heilongjiang,northeast China,and their bearing on the age of supposedly Jurassic strata in eastern Asia

The coal-bearing Longzhaogou and Jixi Groups in eastern Heilongjiang, northeast China, consist of alternating marine and non-marine deposits containing abundant marine animal and plant fossils. The Jixi Group also yields members of the Johel Fauna that is widely distributed in northern and eastern China. The two groups have been considered as Jurassic or mainly Jurassic in age for a long time. However, recent studies documented that the ammonites, bivalves, dinoflagellates, angiosperms and sporopollens are all of Early Cretaceous rather than Jurassic age. It has been demonstrated that: (1) the Longzhaogou and Jixi Groups and their equivalents, the Johel Group of China and the Transbaikalian Group of Russia, are of Early Cretaceous age, (2) the Barremian-Albian was also a very important period of coal accumulation in northeastern China and perhaps in all of eastern Asia, (3) there existed a large shallow embayment connecting with the Palaeo-Pacific in eastern Heilongjiang, and it was the climate of the embayment that controlled the origin and development of the animal and plant communities of northeastern China during the Early Cretaceous. Correlation between formations in the Jixi and Longzhaogou Groups has also been revised in this paper.     

黑龙江省东部裴德组砾石中放射虫的发现及其意义

裴德组原指分布在黑龙江省东部龙爪沟群下部、中生代海相化石层之下的一套含煤的陆相火山碎屑岩地层,所含植物化石一般认为属于ConiopterisPhoenicopsis植物群的中侏罗世组合。裴德组下部的砾石中发现了放射虫化石,鉴定和对比的结果表明这些砾石来自东部的那丹哈达地体。对佳木斯地体和那丹哈达地体拼贴时限和拼贴地点的进一步分析则建议将“龙爪沟群”解体、裴德组形成的时代修正到白垩纪。     

中国东北中生代地层划分对比之新见

在总结近二十年来有关我国东北地区中生代地层研究诸多新发现与新进展的基础上 ,以生物化石为主要依据 ,以 "海相检验法”及国际性生物地层对比为标准 ,结合同位素年代地层学新资料 ,对东北地区中生代地层的划分及对比 ,提出了新的方案。文中还讨论了三叠系 -侏罗系界线、侏罗系 -白垩系界线及下白垩统 -上白垩统界线的划分以及辽西义县组的时代。同时 ,还首次报道了笔者等对黑龙江东部龙爪沟群研究的最新进展 ,并提出了对龙爪沟群时代及与鸡西群对比的新认识。     

The Upper Jurassic–Lower Cretaceous of eastern Heilongjiang, northeast China: stratigraphy and regional basin history

In eastern Heilongjiang, the Upper Jurassic is marine and restricted to the Suibin and Dong’an areas, where it is characterized faunally by Callovian–Volgian (Tithonian) bivalves and florally by dinoflagellates. The Lower Cretaceous is widely distributed in eastern Heilongjiang, and characterized faunally by Berriasian–Valanginian bivalves, Barremian–Albian ammonites and Aucellina, and florally by dinoflagellates. To the west, the marine facies grade into non-marine beds. Thus, in the east, for example in the Dong’an and Dajiashan areas, near the northwestern Palaeo-Pacific, the Lower Cretaceous is marine; westward, in the Yunshan, Longzhaogou, Peide, and Zhushan areas, marine and non-marine deposits alternate, whereas further west still, e.g. in the Jixi Basin, non-marine facies are intercalated with marine beds. This regional distribution is indicative of a large, shallow embayment opening eastwards to the Palaeo-Pacific; during the Early Cretaceous successive transgressive-regressive events influenced the climate and biota of eastern Heilongjiang and northeastern China. Many of the Lower Cretaceous sections contain abundant coals, demonstrating that in this region the Early Cretaceous was an important coal-forming period. Some non-marine bivalve species are common to the Lower Cretaceous Jixi Group of eastern Heilongjiang, the Jehol Group of western Liaoning and the Transbaikalian Group of Siberia, suggesting that these groups are of comparable Early Cretaceous age.     

Radiolarian-bearing conglomerate from the Hayang Group, the Kyongsang Supergroup, southeastern Korea

The non-marine Cretaceous Kyongsang Supergroup, which is divided into the Sindong, the Hayang and the Yuchon groups, is widely distributed in southeastern Korea. Radiolarian-bearing pebbles are collected from the conglomerates of the Kumidong and the Kisadong formations of the Hayang Group. The age of radiolarian fossils range from Late Permian to Middle Jurassic. In Korea, Permian to Middle Jurassic marine chert beds are not exposed. The directions of paleocurrents of the Kumidong and the Kisadong formations are mainly from the northeast to southwest. During Cretaceous time, the Mino-Tamba Belt, within which Permian to Middle Jurassic chert beds are exposed, is suggested to have been located northeast of the Kyongsang Basin. The radiolarian faunas of the Hayang Group are similar to those of the Mino-Tamba Belt and other associated Mesozoic accretionary belts in Japan (e.g. the Ashio Belt). The provenance of the radiolarian-bearing pebbles collected from the Kumidong and the Kisadong formations is interpreted to be the Mino-Tamba Belt and other associated Mesozoic accretionary belts in Japan.     

我国东北东部侏罗纪的龙爪沟群和鸡西群与其意义

我国东北区的龙瓜沟群和鸡西群中部,由含有侏罗纪化石的海相与非海相岩层组成.龙爪沟群属中,上侏罗统,鸡西群可能全属上侏罗统,其中部的城子河组产有启末利阶的带化石细线雏蛤Buchia tenuistviata（Lahusen）.非海相的热河动物化石群中的软体动物分子与上侏罗统启末利阶海相双壳类化石在城子河组中同组共存,进一步核实了热河动物化石群的侏罗纪年代.     

Turonian Radiolarians from Karnezeika,Argolis Peninsula,Peloponnesus (Greece)

Near Karnezeika a roughly 140 m thick Upper Cretaceous section consists of interbedded pelagic limestones, cherts and coarse polymict breccias including ophiolites and shallow water limestones. At the base, pink pelagic limestones rest on deeply altered and fractured Lower Jurassic Pantokrator Limestone. This first pelagic facies is dated as middle Turonian, based on planktonic Foraminifera. Over 100 m of coarse ophiolite-carbonate breccias, interpreted as a channel or canyon fill in a pelagic environment, document the erosion of the Late Jurassic nappe edifice along the Cretaceous Pelagonian margin. Above these breccias, we mesured 16 m of principally pink and red pelagic limestones and radiolarian cherts, in which we recovered well-preserved radiolarians discussed here. In this interval, the presence of planktonic Foraminfera allows to state a late Turonian to Coniacian age. More than 40 radiolarian species are described and figured in this work. The radiolarian chronostratigraphy established by 10 different authors in 11 publications was compared for this study and used to establish radiolarian ranges. This exercise shows major discrepancies between authors for the radiolarian ranges of the studied assemblage. Nevertheless, a Turonian age can be stated based on a synthesis of cited radiolarian ranges. This age is consistent with the age based on planktonic foraminifera. In combining the ages of both Radiolaria and planktonic Foraminifera, the studied samples can be restricted to the late Turonian. However, the discrepancies of published radiolarian ranges call for an urgent, major revision of the Late Cretaceous radiolarian biochronology. The integration of planktonic foraminifera with radiolarians may greatly enhance biochronologic resolution in sections where both groups occur.     

浙闽赣地区侏罗系——白垩系界线再认识

我国陆相侏罗系—白垩系界线长期存在争议。最近黑龙江东部海相化石的检验使这一问题有所突破;根据与海相层交互的陆相层中各门类化石的对比,又使其它地区(包括浙闽赣地区)的问题也开始解决。众所周知,浙闽赣地区侏罗系—白垩系界线就在建德群(或其相当地层)之中或其顶、底。本文依据与黑龙江东部的对比,并据本区近年来采用多种方法测得的,一批可靠性大的同位素年龄资料,提出了侏罗系—白垩系界线的新认识。     

Aalenian to Cenomanian Radiolaria of the Bermeja Complex (Puerto Rico) and Pacific origin of radiolarites on the Caribbean Plate

The study of the radiolarian ribbon chert is a key in determining the origins of associated Mesozoic oceanic terranes and may help to achieve a general agreement regarding the basic principles on the evolution of the Caribbean Plate. The Bermeja Complex of Puerto Rico, which contains serpentinized peridotite, altered basalt, amphibolite, and chert (Mariquita Chert Formation), is one of these crucial oceanic terranes. The radiolarian biochronology presented in this work is mainly based by correlation on the biozonations of Baumgartner et al. (1995) and O??Dogherty (1994) and indicates an early Middle Jurassic to early Late Cretaceous (late Bajocian?Cearly Callovian to late early Albian?Cearly middle Cenomanian) age. The illustrated assemblages contain about 120 species, of which one is new (Pantanellium karinae), and belonging to about 50 genera. A review of the previous radiolarian published works on the Mariquita Chert Formation and the results of this study suggest that this formation ranges in age from Middle Jurassic to early Late Cretaceous (late Aalenian to early?Cmiddle Cenomanian) and also reveal a possible feature of the Bermeja Complex, which is the younging of radiolarian cherts from north to south, evoking a polarity of accretion. On the basis of a currently exhaustive inventory of the radiolarite facies s.s. on the Caribbean Plate, a re-examination of the regional distribution of Middle Jurassic sediments associated with oceanic crust, and a paleoceanographic argumentation on the water currents, we come to the conclusion that the radiolarite and associated Mesozoic oceanic terranes of the Caribbean Plate are of Pacific origin. Eventually, a discussion on the origin of the cherts of the Mariquita Formation illustrated by Middle Jurassic to middle Cretaceous geodynamic models of the Pacific and Caribbean realms bring up the possibility that the rocks of the Bermeja Complex are remnants of two different oceans.     

西藏南部下鲁硅岩晚侏罗世罩笼虫(放射虫)新材料

下鲁硅岩为藏南日喀则地区雅鲁藏布蛇绿岩南侧的晚侏罗世—早白垩世硅质岩系。本文补充描述了该岩系中 4块标本的罩笼虫亚目放射虫化石 1 6属 2 3种 ,包括 8个新种。加上这些标本原已描述过的 1 8属 3 3种 ,共有 3 4属 56种。所有的属和近一半的种见于北美西部 ,可与那里的晚侏罗世放射虫分带很好地对比 ,它们分别相当于那里牛津期的 2 γ亚带和晚启莫里期—早提索期的 3 β亚带。动物群具特提斯生物地理区特征 ,但与西特提斯的地中海地区同期动物群显然不同 ,可能当时东特提斯与太平洋联系密切。     

黑龙江东部早白垩世生物地层学研究的主要进展

巴列姆期的菊石、巴列姆期—阿尔必期的海相双壳类、早白垩世的沟鞭藻、放射虫和有孔虫等的发现 ,均证实了黑龙江东部含煤地层龙爪沟群、鸡西群和大架山组的时代为早白垩世中、晚期。鸡西群中含有热河或威替姆动物化石群中常见的双壳类化石 ,这一事实似乎暗示着中国热河或俄罗斯威替姆动物化石群为早白垩世时代。早白垩世 ,特别是巴列姆期—阿尔必期 ,沿大架山—云山—虎林-裴德—鸡西一线北东东方向存在着一条向东 (古太平洋 )开口 ,但由东向西变浅的狭长海湾。多次海侵和海泛沿着这一海湾由东向西至鸡西后向南和向北 ,并可能向西扩散。正是这一海湾和海平面的升降控制着东北地区的早白垩世的气候、地理、生物群落的演变、甚至煤的聚集和油的形成     

黑龙江省东部Aucellina(双壳类)的发现

<正> 黑龙江省东部的龙爪沟群分布在虎林、密山、宝清和饶河县境内,鸡西群见于鸡西、穆 棱、勃利、双鸭山、绥滨和集贤等盆地 中。虎林地区的龙爪沟群从下自上分 为裴德组、七虎林组、下云山组、上云 山组(包括曙光组)和珠山组,鸡西盆 地的鸡西群分为滴道组、城子河组(包     

Undications of current action in late Jurassic limestones,radiolarian limestones,saccocoma limestones and associated rocks from the subbetic of SE Spain

In the Vélez Blanco region (province of Almeia), filament limestones occur associated with pellet limestones, crinoidal limestones, radiolarian limestones, Saccocoma limestones and tintinnid limestones. These predominantly Late Jurassic rocks are underlain by Middle Jurassic oolitic limestones and overlain by Cretaceous pelagic limestones and marls.A distinction can be made between long and short filaments. The former are interpreted as undamaged valves, the latter as shell fragments of the pelagic pelecypod Bositra buchi. Bositra valves and fragments have been sorted by weak current (and/or wave) action.In the Saccocoma limestones, evidence for similar sorting of Saccocoma debris has been found.The radiolarian limestones represent a low-energy basin environment, but are not comparable with recent deep-sea radiolarian oozes.Nodular limestone intercalations and hiatuses represent a current- (and/or wave-) swept environment.The occurrence of filament-rich and Radiolaria-bearing, but benthos-poor, intervals within the oolitic limestone indicates that the deposition of such rocks can take place at moderate sea depths.     

Molluscan biostratigraphy and paleomagnetism of Campanian strata, Queen Charlotte Islands, British Columbia: implications for Pacific coast North America biochronology

A previously uncollected fauna of ammonites, bivalves, and other molluscs, associated with radiolarian microfossils, has been newly recognized near Lawn Hill on the east coast of central Queen Charlotte Islands, British Columbia. The regional biostratigraphic zonation indicates that the Lawn Hill fauna is correlative with the Nostoceras hornbyense zonule of the Pachydiscus suciaensis ammonite biozone, recognized in the Nanaimo Group of southeast Vancouver Island. The Nostoceras hornbyense Zone (new) is herein proposed for strata of Pacific coast Canada containing the zonal index. Several molluscan taxa present in the Lawn Hill section are new to British Columbia and the ammonite fauna suggests that the Nostoceras hornbyense Zone is late Campanian in age, supported by radiolarian taxa present in the section. Strata sampled in the Lawn Hill section preserve reversed-polarity magnetization, considered likely correlative with Chron 32r. The presence of the Nostoceras hornbyense Zone on Queen Charlotte Islands is the first recognition of this zone in Canada north of central Vancouver Island and represents the youngest Cretaceous known in this region. Campanian radiolarians identified from the Lawn Hill section are also the first recognized from the Pacific coast of Canada.     

藏北阿木岗群、查桑群和鲁谷组放射虫的发现及有关问题讨论

通常人们一直认为阿木岗(戈木日)群是所谓“羌塘地块”的前寒武纪或前泥盆纪基底,曾发现古生物化石的“中泥盆统”查桑群和“下二叠统”鲁谷组等是其上的晚古生代盖层沉积。本次工作在阿木岗群和鲁谷组中分别发现中-晚三叠世放射虫化石组合;在查桑群中发现二叠纪中-晚期放射虫化石组合。结合野外实际考察和前人研究成果,本文就有关问题作了讨论。     

Discovery of Radiolarian Fossils from the Aiketik Group at the Western End of the South Tianshan Mountains of Chinaand Its Implications

The Aiketik Group, distributed at the western end of the South Tianshan Mountains, China, is an important lithostratigraphic unit involved in the South Tianshan orogen. It is separated from the adjacent rocks by faults. Generally, the geologists ascribed it to the Upper Carboniferous according to Pseudostaffella sp., Profusulinella sp. and Fusulinella sp. found from the limestone and sandy limestone of Aiketik. Our radiolarian fossils were obtained from the chert samples collected from the Haladaok section located at the upper Tuoshihan River. The fossils mainly include Albaillella undulata Deflandre, Albaillella paradoxa Deflandre, Albaillella sp. aff. A. paradoxa Deflandre, Albaillella sp. cf. A. deflandrei Gourmelon, Albaillella sp., Albaillella excelsa Ishiga, Kito and Imoto (?), Belowea variabilis (Ormiston et Lane), Callella cf. C. parvispinosa Won, Entactinia cf. E. tortispina Ormiston et Lane, Entactinia aff. E. tortispina Ormiston et Lane, Entactinia variospina Won, Entactinia sp., Eostylodicty     

Discovery of the Late Triassic (Middle Carnian–Rhaetian) radiolarians in the volcano-sedimentary sequences of the Kocali Complex,SE Turkey: Correlation with the other Tauride units

The Kocali Complex in SE Turkey includes pelagic sediments (pelagic limestones, cherts, etc.), basic volcanic rocks of oceanic crust origin together with platform-derived sediments. Its depositional age was previously assigned as Late Jurassic–Early Cretaceous. In order to study the radiolarian contents of volcano-sedimentary sequences in this complex, six stratigraphic sections have been measured mainly at the NE and NW Adiyaman city.Radiolarian faunas from these stratigraphic sections reveal that the age of these sequences ranges from middle Carnian to Rhaetian. Based on these data, the depositional age of the complex is older than the previously assigned. Lithological characteristics (widespread Triassic basic volcanic rocks associated with pelagic sediments) and radiolarian contents of these sequences have close similarities with the sequences of the Alakircay Nappe of the Antalya Nappes in western and central Taurides.Based on taxonomic studies, 99 taxa have been determined of which one genus (Adiyamanium) and four species (Monocapnuchosphaera kocaliensis, Paronaella speciosa, Ferresium okuyucui and Adiyamanium crassum) are described as new.     

“Cretaceous black flysch” in the Pieniny Klippen Belt, West Carpathians: a case of geological misinterpretation

This is a critical assessment of the paper by Oszczypko et al. (2004: Cretaceous Research 25, 89–113), in which they tried to prove a mid-Cretaceous age for the Szlachtowa (“black flysch”) and Opaleniec Formations, in the Pieniny Klippen Belt, West Carpathians, both of which had previously been shown to be of Jurassic age. We argue that the mid-Cretaceous age assignment is a misinterpretation, primarily resulting from their field samples having been collected from some Cretaceous lithostratigraphic units, tectonically associated with the Jurassic formations, and/or from tectonic contact-breccias involving Jurassic and Cretaceous strata. In addition, we suggest that they have overlooked a number of significant palaeontological papers, published since 1962, which record the presence of in situ ammonites, aptychi, belemnites, thin-shelled bivalves (Bositra), gryphaeids, foraminifera, and ostracod assemblages, all indicating a Jurassic (mainly Aalenian), and not a Cretaceous, age for the Szlachtowa Formation, and also the in situ Jurassic (Bajocian) ammonites and thin-shelled bivalves (Bositra), Bositra-microfacies, and age-diagnostic foraminiferal assemblages of the Opaleniec Formation.Our presentation here of recently published dinocyst data from well-preserved assemblages further supports the Jurassic ages for the Szlachtowa (“black flysch”) and Opaleniec Formations.     

The oldest known metriorhynchid crocodylian from the Middle Jurassic of North-eastern Italy: Neptunidraco ammoniticus gen. et sp. nov.

Metriorhynchidae is a clade of marine-adapted crocodilians known from several Middle Jurassic–Early Cretaceous specimens collected predominantly in South America and Europe, but poorly known in the northern margin of Gondwana. The “Portomaggiore crocodile” is the most complete specimen of an Italian metriorhynchid to date: it consists of a partial skeleton that has been provisionally referred to an unnamed species of Late Jurassic Metriorhynchus or Geosaurus. The specimen is preserved in the reddish, nodular limestone of the Rosso Ammonitico Veronese Formation (Bajocian–Tithonian); new data on microfossil associations constrain the age of the metriorhynchid to the late Bajocian–earliest Bathonian. On the basis of cranial synapomorphies, the “Portomaggiore crocodile” falls as the closest sister-taxon of the Late Jurassic–Early Cretaceous geosaurines, and is referred to Neptunidraco ammoniticus gen. et sp. nov. It is unique among Middle Jurassic metriorhynchids in showing an incipient streamlining of the skull, shared with Late Jurassic and Cretaceous taxa. Since Neptunidraco is the oldest known member of Metriorhynchidae, its phylogenetic position supports the hypothesis that the timing of the initial metriorhynchid and geosaurine diversifications should start in the Bajocian.