排序方式： 共有18条查询结果，搜索用时 31 毫秒
1.
Bondarenko G. E. Soloviev A. V. Tuchkova M. I. Garver J. I. Podgornyi I. I. 《Lithology and Mineral Resources》2003,38(2):162-176
The South Anyui fold zone (western Chukotka) is considered a suture zone related to closure of the South Anyui oceanic basin and collision of Eurasia with the Chukotka–Arctic Alaska microcontinent in the Early Cretaceous. The existence of a compensatory sedimentation basin (foredeep) during folding in the terminal Jurassic–initial Cretaceous remains debatable. This work presents first data on age estimates of detrital zircons from Upper Mesozoic terrigenous sequences of the South Anyui suture zone obtained by the fission-track method. The distal flysch of presumably Late Jurassic age and the proximal flysch of probably Late Triassic age were sampled in the Uyamkanda River basin. The fission-track dating showed that sandstones from the flysch sections contain detrital zircons of two different-age populations. Young zircon populations from sandstones of distal turbidites in the upper course of the Uyamkanda River (two samples) are 149 ± 10.2 and 155.4 ± 9.0 Ma old (Late Jurassic), whereas those from coarse-grained proximal turbidites sampled in the lower course of the Uyamkanda River (one sample) is 131.1 ± 7.5 Ma old (Early Cretaceous). The data obtained indicate that the Late Mesozoic folding in the South Anyui suture zone was accompanied by the formation of a marginal sedimentary basin. Sediments accumulated in this basin compose tectonic nappes that constitute a fold–thrust structure with the northern vergence. 相似文献
2.
东昆仑及相邻地区中生代-新生代早期构造过程的热年代学记录 总被引：2，自引：0，他引：2
针对东昆仑及相邻地区研究较薄弱的中生代—新生代早期时段的构造过程提供了系列新的热年代学资料.不同热年代学方法综合揭示了东昆仑及相邻地区在中生代—新生代早期至少存在3次明显的热事件记录.第一次大约启动于200Ma的晚三叠世晚期,并可能一直延续到早中侏罗世之交,是一次具有广泛影响并奠定造山带区域构造格架的构造热事件.区域动力背景可能和南部羌塘地块与昆仑地块的碰撞、松潘—甘孜—巴颜喀拉浊积盆地闭合相关.第二次发生在大约130~150Ma的早白垩世,并可能延续到早白垩世末,主要表现为系列区域性NWW-SEE向的挤压性断裂活动,可对应于白垩纪时期拉萨地块沿班公湖—怒江缝合带与欧亚大陆的增生拼贴事件.第三次为大约56~45Ma的古新世,表现为一期伸展抬升.热年代学记录与零星保存的地质记录具有良好的匹配性,并对构造过程提供了更确切的时间限定. 相似文献
3.
Shapiro M. N. Soloviev A. V. Garver G. I. Brandon M. T. 《Lithology and Mineral Resources》2001,36(4):322-336
The mineral composition of sandstones from Cretaceous–Lower Paleocene terrigenous sequences of the western Kamchatka–Ukelayat zone (southern Koryak Upland, western Kamchatka) suggests that the Okhotsk–Chukot volcanogenic belt and fragments of the Uda–Murgal island arc served as the most probable provenance. Fission-track dating of zircon showed that sandstones from this zone contain detrital zircon of several different-age populations. Fission tracks in zircon grains were nor subjected to secondary ignition. The age of young zircon population coincides with the biostratigraphic age of host sequences. Thus, results of dating of detrital zircon grains from sandstones, which did not experience heating above 215–240°C, indicate that this method is appropriate for dating fossil-free terrigenous sequences. The young zircon population in the sandstones is related to erosion of plagiogranite and diorite intrusions of the Uda–Murgal arc and outer zone of the Okhotsk–Chukot volcanic belt exposed at the day surface owing to differential vertical movements and rapid exhumation of blocks. 相似文献
4.
M. Giuditta Fellin Joseph A. Vance John I. Garver Massimiliano Zattin 《Tectonophysics》2006,421(3-4):299-317
New zircon fission-track (ZFT) ages from Corsica record multiple thermal events that can be tied to the structural evolution of the western Mediterranean region. The Corsican zircons have a wide scatter of ZFT grain ages (243–14 Ma), which together define several age domains. Western Corsica consists largely of stable Hercynian basement characterized by ZFT ages in the range 161–114 Ma. We interpret these ages (Late Jurassic–Early Cretaceous) as the product of a long-lived Tethyan thermal event related to continental rifting and subsequent drifting during the separation of the European and African plates and the formation of the Liguro–Piemontese ocean basin. In contrast to Hercynian Corsica, Alpine Corsica (northeast Corsica) experienced widespread deformation and metamorphism in Late Cretaceous(?)–Tertiary time. Dated samples from Alpine Corsica range in age from 112 to 19 Ma and all are reset or partially reset by one or more Alpine thermal events. The youngest ZFT grain ages are from the northernmost Alpine Corsica and define an age population at 24 Ma that indicates cooling after Tertiary thermal events associated with the Alpine metamorphism and the opening of the Liguro–Provençal basin. A less well-defined ZFT age population at 72 Ma is present in both Alpine Corsica and Hercynian basement rocks. The thermal history of these rocks is not clear. One interpretation is that the ZFT population at 72 Ma reflects resetting during a Late Cretaceous event broadly synchronous with the early Alpine metamorphism. Another interpretation is that this peak is related to variable fission-track annealing and partial resetting during the Tertiary Alpine metamorphic event across central to north-eastern Corsica. This partial age resetting supports the presence of a fossil ZFT partial annealing zone and limits the peak temperature in this area below 300 °C, for both the affected pre-Alpine and Alpine units. 相似文献
5.
Thermal modelling of new fission‐track and (U–Th–Sm)/He data from the Fuegian Andes reveals rapid cooling (～12–48 °C Ma?1) during the middle and late Eocene followed by slow cooling ( ～ 1.5 °C Ma?1) to the Recent. We interpret the rapid cooling as a result of exhumation from contractional uplift within the crystalline interior of the orogen. This interpretation is consistent with independent evidence of Eocene shortening, flexural subsidence and provenance changes in the study area, and is approximately coeval with marine geochemical evidence of the onset of Drake Passage opening. In light of the Palaeogene history of Nazca‐South American plate convergence and the differences in shortening magnitudes and exhumation histories between the Fuegian and Patagonian Andes, our data support Eocene development of the Patagonian orocline, which also provides a plausible explanation for early opening of Drake Passage. 相似文献
7.
Integration of zircon color and zircon fission-track zonation patterns in orogenic belts: application to the Southern Alps, New Zealand 总被引：2，自引：0，他引：2
An exhumed crustal section of the Mesozoic Torlesse terrane underlies the Southern Alps collision zone in New Zealand. Since the Late Miocene, oblique horizontal shortening has formed the northeastern–southwestern trending orogen and exhumed the crustal section within it. On the eastern side, rocks are zeolite- to prehnite–pumpellyite-grade greywacke; on the western side rocks, they have the same protolith, but are greenschist to amphibolite facies of the Alpine Schist. Zircon crystals from sediments in east-flowing rivers (hinterland) have pre-orogenic fission-track ages (>80 Ma) and are dominated by pink, radiation-damaged grains (up to 60%). These zircons are derived from the upper 10 km crustal section (unreset FT color zone) that includes the Late Cenozoic zircon partial annealing zone; both fission tracks and color remain intact and unaffected by orogenesis. Many zircon crystals from sediments in west-flowing rivers (foreland) have synorogenic FT ages, and about 80% are colorless due to thermal annealing. They have been derived from rocks that originally lay in the reset FT color zone and the underlying reset FT colorless zone. The reset FT color zone occurs between 250 and 400 °C. In this zone, zircon crystals have color but reset FT ages that reflect the timing of orogenesis. 相似文献
8.
A. V. Solov’ev T. N. Palechek M. N. Shapiro S. A. Johnston J. I. Garver D. M. Ol’shanetskii 《Stratigraphy and Geological Correlation》2007,15(1):112-119
In the Sredinnyi Range of Kamchatka, the Baraba Formation of continental conglomerates is assumed to be of the late Campanian age based on found flora remains, but data of isotopic geochronology suggest the Eocene age of these deposits. New data on radiolarians from cherty pebbles are considered in this work along with results of fission-track dating of zircons from pebbles and matrix of the Baraba conglomerates. Fission-track dates obtained for zircons from matrix approve the Eocene age of the Baraba Formation, and new dates characterizing pebbles are not contradicting this conclusion. The Baraba Formation structural position can hardly be lower, therefore, than that of the Irunei Formation. 相似文献
9.
J. I. Garver 《Contributions to Mineralogy and Petrology》2002,143(6):756-757
10.