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1.
Abstract Radiolarians extracted from marine siliceous sediments from the Bentong-Raub suture zone, Peninsular Malaysia have indicated a range of ages for olistostromal blocks of bedded chert, siliceous argillite and tuffaceous argillite, and chert clasts and lenses within the mélange from the suture zone. Late Devonian (Faniennian), Early Carboniferous (Tournaisian and Viséan) and Early Permian (Wolfcampian and Leonardian) ages are represented by seven radiolarian zones from ten localities along the suture zone. In stratigraphic order these include Holoeciscus 2–3 Assemblage Zones, Albaillella paradoxa Zone, Albaillella dejendrei Zone, Albaillella cartalla Zone, Pseudoalbaillella lomentaria Zone, Albaillella sinuata Zone and Pseudoalbaillella longtanensis Zone. Fifteen genera are represented by 35 species. The range of ages from Late Devonian to Early Permian suggests that an ocean existed between the Sibumasu and East Malaya terranes from at least Late Devonian to late Early Permian time and that closure of the ocean between the two terranes could not have occurred until after late Early Permian time. The range of ages and rock types from different depositional environments, indicate that the Bentong-Raub suture zone includes a disrupted accretionary complex.  相似文献   

2.
Detailed radiolarian biostratigraphy in the Plio-Pleistocene was analyzed by using samples from IODP Site U1340 that was drilled to a core depth of 604 m in the southern Bering Sea. A total of 227 species belonging to 102 genera were identified. Based on the distributions of the radiolarian index species at Site U1340, five radiolarian zones since the Pliocene were established in the southern Bering Sea for the first time, and 25 radiolarian bioevents were recognized. Their ages were estimated on the basis of the age-depth plot that was constructed by the synthetical datum of the effective biostratigraphic and magnetostratigraphic events. The radiolarian zones at Site U1340 were systematically compared with those in its adjacent regions since the late Early Pliocene, which further improved and interpreted the biostratigraphic datum as well as their correlations in the middle-high latitude of the North Pacific. In addition, the comparative results of radiolarian zones show that Botryostrobus aquilonaris Zone emended in this paper is equivalent to the upper part of the same zone defined by Hays, 1970, and Druppatractus irregularis-Dorydruppa bensoni Zone as well as Spongodiscus sp. Zone, newly proposed in this paper, are well correlated with Cycladophora sakaii Zone and Stylatractus universus Zone in the subarctic North Pacific, respectively.  相似文献   

3.
Abstract The Upper Cenozoic sedimentary sequences drilled at Sites 1150 and 1151, Ocean Drilling Program Leg 186, enabled establishment of radiolarian zonation and calibration of the age of bioevents in the forearc area of the northern Japan Islands. The sequences were divided into nine zones from the Pleistocene Botryostrobus aquilonaris Zone to the Upper Miocene Lipmanella redondoensis Zone at Site 1150, and 11 zones from the Pleistocene Stylatractus universus Zone to the Middle Miocene Dendrospyris? sakaii Zone at Site 1151. These zones correlate successfully with the studied sequences of many of deep‐sea cores in the Northwest Pacific Ocean and with some sections of onshore Japan. Of 67 important radiolarian bioevents recognized during the study, 29 Pleistocene to Upper Miocene events were directly tied to the geomagnetic polarity time scale through the well‐defined paleomagnetic polarity records, and 21 Upper Miocene events were calibrated based on the diatom biostratigraphy. Of these events, 24 geographically widespread events were selected to test synchroneity and usefulness as time‐horizons within the mid‐to‐high latitude of the Northwest Pacific, involving eight other offshore and onshore sections. Examination showed that most of the zonal boundary events are synchronous within the considered region, and that many diachronous events, most of which are eliminated from the zonal scheme, are unreliable events linked to rare and sporadic occurrences of the species. Radiolarian biostratigraphy of the studied cores clearly indicates three major hiatuses in the Middle Pleistocene, Late Miocene and late Middle Miocene. The latter two hiatuses can be correlated to two global oceanic hiatuses, NH6 and NH3, respectively.  相似文献   

4.
The hierarchically organized laminae, bundles, bundlesets and superbundlesets which correspond to a sub-Milankovitch, obliquity or precession, eccentricity and long eccentricity cyclothems, respectively, have been distinguished from the Upper Devonian Fras-nian-Famennian (F-F) transitional carbonate successions deposited in the carbonate-basin and slope facies of Guangxi, South China. The durations of cyclothems are 8000-10000a, 16667a or 33333a, 100000a and 400000a, respectively. The ratio of eccentricity to precession, eccentricity to obliquity, and long eccentricity to eccentricity is 1 : 6, 1 : 3 and 1 : 4 in the Devonian, respectively. Orbital cyclostratigraphical studies show that the durations of the conodont falsio-valis Zone, transitans Zone, punctate Zone, Lower hassi Zone, Upper hassi Zone, jamieae Zone, Lower rhenana Zone, Upper rhenana Zone, linguiformis Zone, Lower triangularis Zone, Middle triangularis Zone and Upper triangularis Zone are 0.4, 0.4, 0.4, 0.3, 0.4, 0.2, 0.8, 0.6, 0.8, 0.3, 0  相似文献   

5.
This paper systematically investigated the conodonts from the uppermost Permian to the Lower Triassic at the Dongpan Section, Southern Guangxi, South China, and obtained abundant Late Permian conodonts from the syndepositional limestone lenses of beds 3 and 5-2 at this section. One genus and eight species of conodont P1 element including one new species, Neogondolella dongpanensis sp. nov., have been identified. The feature of conodont fauna indicates that conodonts collected from beds 3 and 5 at the Dongpan Section belong to the Neogondolella yini conodont zone, and correspond to bed 24 at the Meishan Section. Based on these conodont data, we suggest that the Neoalbaillella optima radiolarian zone at the Dongpan Section at least extended to the upper part of the N. yini conodont zone.  相似文献   

6.
Two types of chert are defined in Thailand based on lithology, faunal content, and stratigraphy. 'Pelagic chert' consists of densely packed radiolarian tests in a microcrystalline quartz matrix with no terrigenous material and is found as blocks embedded within sheared matrix. 'Hemipelagic chert' also has a microcrystalline quartz matrix, and contains not only scattered radiolarian tests, but also calcareous organisms such as foraminifers. The pelagic cherts range in age from Devonian to Middle Triassic, whereas hemipelagic chert is only from the Early to the Late Triassic. Lithological and stratigraphic characteristics indicate that the pelagic chert originated in the Paleo-Tethys, whereas the hemipelagic chert accumulated on the eastern margin of the Sibumasu Block. The hemipelagic and pelagic chert are exposed in two north-trending belt-like zones. The western zone includes the hemipelagic chert, as well as glaciomarine and other Paleozoic to Mesozoic successions, overlying a Precambrian basement that consists exclusively of Sibumasu elements. The eastern zone contains pelagic chert and limestone and should be correlated to the Inthanon Zone. The Inthanon Zone is characterized by the presence not only of Paleo-Tethyan sedimentary rocks, but also of Sibumasu Block elements that structurally underlie the Paleo-Tethyan rocks. The boundary between the Sibumasu and Paleo-Tethys zones is a north-trending, low-angle thrust that resulted from the collision of the Sibumasu and Indochina blocks.  相似文献   

7.
The last appearance datum of the radiolarian Kilinora spiralis is recorded above the first appearance datum of the ammonite Ataxioceras (A.) kurisakense in the Todoro Section of the Kurisaka Formation, Southern Kurosegawa Terrane, Shikoku, SW Japan. The constraint by ammonite age prolongs the range of the Kilinora spiralis Zone, a remarkable Jurassic radiolarian zone in Japan-NW Pacific region, into the lower Kimmeridgian. The direct correlation of the Kilinora spiralis zone with the Late Jurassic ammonite faunal succession in the Kurisaka Formation will provide a clue to the still pending chronological difference between European and North American radiolarian zones.  相似文献   

8.
Abundant Triassic radiolarian fossils were obtained from varicolored bedded cherts exposed in the Buruocang section near Jinlu village, Zedong, southern Tibet. The radiolarian‐bearing rocks represent fragmented remnants of the Neotethys oceanic sediments belonging to the mélange complex of the east part of the Yarlung‐Tsangpo Suture Zone. Two new middle Late Anisian radiolarian assemblages recognized from this section named Oertlispongus inaequispinosus and Triassocampe deweveri, respectively, are compared with those known from Europe, Far East Russia, Japan, and Turkey. These Anisian radiolarian fossils are the first reported in southern Tibet and the oldest radiolarian record within the Yarlung‐Tsangpo Suture Zone. They improve time constraints for the evolution of Neotethys in southern Tibet.  相似文献   

9.
Pleistocene radiolarian biostratigraphy in the South China Sea*   总被引：4，自引：0，他引：4  
Based on a quantitative radiolarian analysis, 5 radiolarian zones (NR1-NR5) have been defined at Core. 17957-2 from the South China Sea, considering radiolarian zonations from low latitudes. The absolute age assignment of the radiolarian zones and the ranges of the six marker species is based on the direct correlation with the paleomagnetic and isotopic record, respectively. A comparison of the radiolarian stratigraphic data obtained from Core 17957-2 from the South China Sea with those from the equatorial Pacific and the tropical Indian Ocean shows a close similarity to the ages defined in the equatorial Pacific. The obtained biostratigraphic data provide an excellent tool for further dating of Pleistocene sediments in the China Sea. Project supported by the National Natural Science Foundation of China (Grant No. 49291100) and by the German Federal Ministry for Education, Science, Research and Technology (BMBF) as part of a GermadChinese scientific cooperation program. This is Alfred Wegener Contribution No. 1473.  相似文献   

10.
Atsushi  Matsuoka 《Island Arc》1995,4(2):140-153
Abstract A radiolarian zonal scheme for the entire Jurassic and Lower Cretaceous using biostratigraphic data from both Japanese Island sections and the western Pacific seafloor is documented. The zonation is applicable to low and middle paleolatitude portions of the Paleo-Pacific ocean. Radiolarian bio-events such as the evolutionary first appearance biohorizon, first occurrence biohorizon, and last occurrence biohorizon were used to define zones. The 11 zones proposed are, in ascending order, Parahsuum simplum, Trillus elkhornensis, Laxtorum(?) jurassicum, Tricolocapsa plicarum, Tricolocapsa conexa, Stylocapsa(?) spiralis, Hsuum maxwelli, Pseudodictyomitra primitiva, Pseudodictyomitra carpatica, Cecrops sep-temporatus, and Acanthocircus carinatus zones. Preliminary age assignments for these zones are presented.  相似文献   

11.
Recent works reveal that the size reduction of or- ganisms during the Permian-Triassic transition is of great importance for research on biotic mass extinction and recovery in this period[1,2]. Initially, Urbanek (1993) observed a decrease in the size of Silurian graptolites during the biotic crisis, and used the term “Lilliput Effect” to define the size reduction in sur- viving animal taxa[3]. Subsequently, researchers re- ported a decrease in size of late Devonian conodonts[4], heart urc…  相似文献   

12.
Only a few Paleocene radiolarian assemblages have been reported, while the Early Paleocene zonal schemes remain poorly delineated. The Early Paleocene on-land radiolarians were described in the Hidaka melange belt of Japan and the North Island of New Zeal…  相似文献   

13.
M. Umeda 《Island Arc》1998,7(4):637-646
Five radiolarian zones, from the Upper Silurian to Middle Devonian, are discriminated from the tuffaceous successions of the Joryu and Nakahata Formations of the Yokokurayama Group of the Yokokurayama area and the Konomori area in the Kurosegawa Belt, Southwest Japan. The definition of the zones is based on the first appearance biohorizon of the characteristic species. The zones are the Pseudospongoprunum sagittatum, Futobari solidus, Trilonche (?) sp. A, Glanta fragilis and Protoholoeciscus hindea zones, in ascending order. The preliminary age assignments for the zones are discussed on the basis of the comparison with other previous documented faunas. The age determination of the formations suggests the presence of unconformities and the episodic sedimentation of the tuffaceous strata in the Yokokurayama Group.  相似文献   

14.
The dating of radiolarian biostratigraphic zones from the Silurian to Devonian is only partially understood. Dating the zircons in radiolarian‐bearing tuffaceous rocks has enabled us to ascribe practical ages to the radiolarian zones. To extend knowledge in this area, radiometric dating of magmatic zircons within the radiolarian‐bearing Hitoegane Formation, Japan, was undertaken. The Hitoegane Formation is mainly composed of alternating beds of tuffaceous sandstones, tuffaceous mudstones and felsic tuff. The felsic tuff and tuffaceous mudstone yield well‐preserved radiolarian fossils. Zircon grains showing a U–Pb laser ablation–inductively coupled plasma–mass spectrometry age of 426.6 ± 3.7 Ma were collected from four horizons of the Hitoegane Formation, which is the boundary between the Pseudospongoprunum tauversi to Futobari solidus–Zadrappolus tenuis radiolarian assemblage zones. This fact strongly suggests that the boundary of these assemblage zones is around the Ludlowian to Pridolian. The last occurrence of F. solidus is considered to be Pragian based on the reinterpretation of a U–Pb sensitive high mass‐resolution ion microprobe (SHRIMP) zircon age of 408.9 ± 7.6 Ma for a felsic tuff of the Kurosegawa belt, Southwest Japan. Thus the F. solidus–Z. tenuis assemblage can be assigned to the Ludlowian or Pridolian to Pragian. The present data also contribute to establishing overall stratigraphy of the Paleozoic rocks of the Fukuji–Hitoegane area. According to the Ordovician to Carboniferous stratigraphy in this area, Ordovician to Silurian volcanism was gradually reduced to change the sedimentary environment into a tropical lagoon in the early Devonian. And the quiet Carboniferous environment was subsequently interrupted, throwing it once more into the volcanic conditions in the Middle Permian.  相似文献   

15.
Abstract Main stages of radiolarian taxonomic evolution in the Pacific rim of Russia are discussed. The diversity and distribution of radiolarian assemblages displayed in the studied sections and their geological and tectonic setting have implications regarding paleoecological and paleo-oceanographic conditions as well as paleotectonic reconstructions. Radiolarian events show the close relationship with the tectonic rearrangements in the Pacific and in North America. The attempt to analyze paleo-oceanological aspects and major factors affecting radiolarian events is presented.  相似文献   

16.
Masao  Kametaka  Hiromi  Nagai  Sizhao  Zhu  Masamichi  Takebe 《Island Arc》2009,18(1):108-125
The biostratigraphy of the Middle Permian Gufeng Formation in the northeastern Yangtze platform is examined based on radiolarians. This study is concentrated on the Anmenkou section in the Chaohu area of Anhui Province, China. The Gufeng Formation is divided into the Phosphate Nodule-bearing Mudstone Member (PNMM) and the Siliceous Rock Member (SRM) in ascending order. The former primarily consists of mudstone including abundant phosphate nodules, and the latter consists mainly of alternating beds of chert, siliceous mudstone and mudstone, with intercalations of porous chert. Ammonoids in the mudstone of the lower PNMM are Wordian. Chert, siliceous mudstone and mudstone of the SRM include abundant radiolarians with sponge spicule assemblages suggestive of the Wordian–Capitanian. Albaillellaria are predominant in the lower SRM, while Entactinaria and Spumellaria are predominant in the middle and upper SRM. These radiolarians correspond to three radiolarian assemblage zones: Pseudoalbaillella longtanensis – Pseudoalbaillella fusiformis , Follicucullus monacanthus , and Follicucullus scholasticus – Ruzhencevispongus uralicus . The assemblage of radiolarians and sponge spicule fauna suggests a depositional depth of 150–500 m. The radiolarian fauna of the Gufeng Formation is considered to be representative of the relatively shallow, tropical radiolarian fauna of the Middle Permian eastern Paleotethys.  相似文献   

17.
南海北部陆缘反“S”型构造带及其对地震活动的影响   总被引：3，自引：0，他引：3  
通过地形—地貌、断裂构造、地壳结构、中新生代沉积盆地、第四纪地质特征等分析,认为南海北部陆缘存在滨岸岛链、陆坡北缘和陆坡南缘三条反“S”型构造带,它们形成于晚第三纪,较“新华夏系”和“南海系”晚。上新世末期以来,反“S”型构造带的活动方式,对南海北部陆缘第四纪地质特征影响显著,同时控制了这一区域的地震活动方式和地震带展布,其中,“滨海地震带”和“雷琼地震带”同属于滨岸岛链带,“台西滨外地震带”和“东沙—海南地震带”同属于陆坡北缘带。  相似文献   

18.
Investigation of four sections of Tithonian to Valanginian pelagic limestone have led to refinement of the correlation of calpionellid zones to the magnetic polarity time scale. The correlations are self-consistent but differ slightly from those previously published. The discrepancy with the published correlation from the Bosso section [1] has been resolved by re-evaluation of the biostratigraphy of this sequence.The revised correlation places the base of theChitinoidella Zone in the lower part of polarity chron CM21n, the base of Zone A near the top of CM20n, the A/B boundary at the base of CM18, theB/C boundary in the upper part of CM17, theC/D boundary at the top of CM16 and theD/E boundary at the top of CM14.  相似文献   

19.
A magnetic polarity pattern for Boreal and Sub-Boreal ammonite zones of the Upper Oxfordian to Lower Kimmeridgian was established and confirmed in four British sections, including the proposed Global Boundary Stratotype Section and Point (GSSP) on the Isle of Skye (Scotland) to define the base of the international Kimmeridgian Stage. A coeval pattern for Sub-Mediterranean ammonite zones was compiled from seven sections in Poland, one German section and multi-section composites from France and Spain. The mean paleopole for the European Craton (excluding Spain) at the Oxfordian–Kimmeridgian boundary is 74.2°N, 181.3°E (Α95 = 3.8°). The common magnetic polarity scale enables inter-correlation of ammonite subzones among these three faunal provinces and to the marine magnetic-anomaly M-Sequence. The proposed GSSP at the base of the Pictonia baylei Zone is near the base of an extended interval dominated by reversed polarity, which is interpreted to be Chron M26r. This GSSP level projects to the lower to middle part of the Epipeltoceras bimammatum Subzone, which is the middle subzone of this E. bimammatum Zone in the Sub-Mediterranean standard zonation. In contrast, the traditional placement of the Oxfordian–Kimmeridgian boundary in that Sub-Mediterranean standard zonation (base of Sutneria platynota Zone) is at the base of Chron M25r, or nearly 1 million years younger.  相似文献   

20.
The Tremadocian is the first stage of the Ordovician System and is subdivided into two parts in general. The Upper Tremadocian, spanning a temporal interval of ca. 8 Ma, yields graptolite faunas crucial for biostratigraphic division and correlation in high resolution. Relatively complete successions of Upper Tremadoc graptolite zones have been proposed in Scandinavia, and North and South America. In South China, the coeval graptolite strata are widespread in deep water facies, but the successions of graptolite zones recognized so far are quite incomplete and thus very difficult to be correlated with those in other countries. In recent years, we have sampled bed by bed the Nanba section in the Yiyang area, Hunan Province and, below the Tetragraptus approximatus Zone, identified four Upper Tremadoc graptolite zones in descending order: the Hunnegraptus copiosus Zone, the Araneograptus murrayi Zone, the Aorograptus victoriae Zone and the Adelograptus tenellus Zone. To date, the Nanba section is the only section in China that presents a relatively complete and globally comparable succession of Upper Tremadoc graptolite zones. Therefore, this study not only confirms the existence of some Upper Tremadoc graptolite zones that were never found before in China, but also facilitates a highly resolved division and correlation for the Upper Tremadoc graptolite strata in China. Supported by National Natural Science Foundation of China (Grant No. 40472014)  相似文献   

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