共查询到20条相似文献，搜索用时 125 毫秒
1.
AbstractAn interpreted CA–IDTIMS age of 1642.2?±?3.9?Ma for a volcanogenic tuffaceous siltstone from the previously undated Fraynes Formation of the Birrindudu Basin in the northwestern Northern Territory enables a rigorous chronostratigraphic correlation to be made with the economically important Barney Creek Formation of the southern McArthur Basin. This result supports previous interpretations that these geographically widely separated formations are probably linked in the subsurface. It also establishes the stratigraphic interval encompassing the Fraynes and Barney Creek formations as a potential target for greenfields base metals and petroleum exploration programs across the greater McArthur Basin. - KEY POINTS
A new interpreted CA–IDTIMS age provides a chronostratigraphic link between the Fraynes Formation of the Birrindudu Basin and the economically important Barney Creek Formation of the southern McArthur Basin. The Fraynes and Barney Creek formations are probably linked in the subsurface. This stratigraphic level is a potential target for greenfields base metals and petroleum exploration across the greater McArthur Basin.
相似文献
2.
AbstractThe Charters Towers Province, of the northern Thomson Orogen, records conversion from a Neoproterozoic passive margin to a Cambrian active margin, as characteristic of the Tasmanides. The passive margin succession includes a thick metasedimentary unit derived from Mesoproterozoic rocks. The Cambrian active margin is represented by upper Cambrian–Lower Ordovician (500–460?Ma) basinal development (Seventy Mile Range Group), plutonism and metamorphism resulting from an enduring episode of arc–backarc crustal extension. Detrital zircon age spectra indicate that parts of the metamorphic basement of the Charters Towers Province (elements of the Argentine Metamorphics and Charters Towers Metamorphics) overlap in protolith age with the basal part of the Seventy Mile Range Group and thus were associated with extensional basin development. Detrital zircon age data from the extensional basin succession indicate it was derived from a far-field (Pacific-Gondwana) primary source. However, a young cluster (<510?Ma) is interpreted as reflecting a local igneous source related to active margin tectonism. Relict zircon in a tonalite phase of the Fat Hen Creek Complex suggests that active margin plutonism may have extended back to ca 530?Ma. Syntectonic plutonism in the western Charters Towers Province is dated at ca 485–480?Ma, close to timing of metamorphism (477–467?Ma) and plutonism more generally (508–455?Ma). The dominant structures in the metamorphic basement formed with gentle to subhorizontal dips and are inferred to have formed by extensional ductile deformation, while normal faulting developed at shallower depths, associated with heat advection by plutonism. Lower Silurian (Benambran) shortening, which affected metamorphic basement and extensional basin units, resulted in the dominant east–west-structural trends of the province. We consider that these trends reflect localised north–south shortening rather than rotation of the province as is consistent with the north–south paleogeographic alignment of extensional basin successions. - KEY POINTS
Northern Tasmanide transition from passive to active margin tectonic mode had occurred by ca 510?Ma, perhaps as early as ca 530?Ma. Cambro-Ordovician active margin tectonism of the Charters Towers Province (northern Thomson Orogen) was characterised by crustal extension. Crustal extension resulted in the development of coeval (500–460?Ma) basin fill, granitic plutonism and metamorphism with rock assemblages as exposed across the Charters Towers Province developed at a wide range of crustal levels and expressing heterogeneous exhumation. Protoliths of metasedimentary assemblages of the Charters Towers Province include both Proterozoic passive margin successions and those emplaced as Cambrian extensional basin fill.
相似文献
3.
AbstractSilicified fossil macrofloras of the Willalinchina Sandstone, at Stuart Creek in the Billa Kalina Basin of northern South Australia, are most likely early Miocene–early Pliocene with preference for the younger age, based on reinterpretation of published evidence including basin stratigraphy, paleogeography, isotopic and other dating. The macrofloras include Eucalyptus and occur in fluvial channel sandstones. The Willalinchina Sandstone is equated with the Danae Conglomerate Member of the Mirikata Formation, interpreted as older than the Watchie Sandstone, Millers Creek Dolomite Member and Billa Kalina Clay Member, and here regarded as of upper Neogene age. The Billa Kalina Basin lies between Lake Eyre, Torrens and Eucla basins, and has affinities with all three. The Kingoonya Paleochannel, peripheral to the Eucla Basin, joins the southern margin of the Billa Kalina Basin across the Stuart Range Divide, and contains the Garford Formation of mid-Miocene to Pliocene age (palynological dating), here partly equated with the Mirikata Formation. Interpretations of paleolake Billa Kalina and associated paleochannel environments are made, based on a new assessment of stratigraphic and paleogeographic relationships. - KEY POINTS
The Billa Kalina Basin sediments in northern South Australia are equated with the later Neogene ‘upper’ Garford Formation of the Kingoonya Paleochannel, which flowed into the Eucla Basin, and depositional processes are clarified. A variety of consistent age data from adjacent basins and the Kingoonya Paleochannel indicate the Stuart Creek ‘silcrete floras’, associated with the Willalinchina Sandstone channel deposits, are Neogene, probably early Pliocene, but the possibility remains that they may be incised into the Watchie Sandstone and therefore late Pliocene. The Billa Kalina Basin was linked to the Kingoonya Paleochannel through much of its history, with flow disrupted by the Stuart Range Divide, local tectonics, and regional tilting.
相似文献
4.
AbstractTwo north–south-trending belts of high-temperature–low-pressure (HTLP) sub-regional metamorphism have been identified in the New England Orogen of eastern Australia. Metamorphic complexes in the ～1300?km long Early-Permian Inland belt have ages ca 300–290?Ma, and those of the ～400?km long Mid-Permian Coastal belt ca 275–270?Ma. These periods correspond to the beginning and end of an extended (early–mid Permian) phase of subduction rollback and crustal thinning in eastern Australia. This paper describes and incorporates recent work on the Wongwibinda Metamorphic Complex in the southern New England Orogen as a basis for comparison with thirteen other HTLP sub-regional occurrences within the orogen. These are described in as much detail as is currently available. Some outcrops of HTLP rocks in difficult terrain have been subject to limited study and only conditional comparisons can be made. However, a significant number of characteristics shared between the complexes including: their location at the higher-temperature end of broad areas of very low-grade to greenschist facies metamorphic rocks, indicative of tilted crustal blocks; their association with major shear zones; the presence of migmatite at the high-temperature end of a steep metamorphic field gradient; the presence of two-mica granite formed by the melting of the local sedimentary pile; and temporal association with S-type granites; imply a common extension-related mechanism of formation for these HTLP belts. The connection with major faults and shear zones suggests the belts trace major crustal-scale extensional structures that migrated eastwards from ca 300 to 270?Ma. - KEY POINTS
Two previously undocumented belts of HTLP subregional metamorphism are identified within the NEO. Available dating indicates that metamorphism occurred along the belts at the beginning and end of a major early–mid Permian extensional phase in eastern Gondwana/Australia. The characteristics of the HTLP complexes including their association with shear zones indicates they may delineate major loci of extension.
相似文献
5.
AbstractAcropolis is an Fe-oxide–copper–gold prospect ～20?km from Olympic Dam, South Australia, and marked by near-coincident gravity and magnetic anomalies. Prospective Fe-oxide–apatite?±?sulfide veins occur in Mesoproterozoic and Paleoproterozoic volcanic and granitoid host units beneath unmineralised sedimentary formations. We have produced a geological map and history of the prospect using data from 16 diamond drill holes, including LA-ICPMS and high-precision CA-TIMS ages. The oldest unit is megacrystic granite of the Donington Suite ( ca 1850?Ma). A non-conformity spanning ca 250 My separates the Donington Suite and felsic lavas and ignimbrites of the Gawler Range Volcanics (GRV; 1594.03?±?0.68?Ma). The GRV were intruded by granite of the Hiltaba Suite (1594.88?±?0.50?Ma) and felsic dykes (1593.88?±?0.56?Ma; same age as the Roxby Downs Granite at Olympic Dam). The felsic dykes are weakly altered and lack Fe-oxide–apatite–sulfide veins, suggesting that they post-date the main hydrothermal event. If correct, this relationship implies that the main hydrothermal event at Acropolis was ca 1594?Ma and pre-dated the main hydrothermal event at Olympic Dam. The GRV at Acropolis are the same age as the GRV at Olympic Dam and ca 3–7 My older than the GRV exposed in the Gawler Ranges. The gravity and magnetic anomalies coincide with sections through the GRV, Hiltaba Suite and Donington Suite that contain abundant, wide, Fe-oxide veins. The GRV, Hiltaba Suite and Donington Suite are unconformably overlain by the Mesoproterozoic Pandurra Formation or Neoproterozoic Stuart Shelf sedimentary formations. The Pandurra Formation shows marked lateral variations in thickness related to paleotopography on the underlying units and post-Pandurra Formation pre-Neoproterozoic faults. The Stuart Shelf sedimentary formations have uniform thicknesses. - KEY POINTS
Fe-oxide–apatite?±?sulfide veins are hosted by the Gawler Range Volcanics (1594.03?±?0.68?Ma), the Hiltaba Suite granite (1594.88?±?0.50?Ma) and Donington Suite granite (ca 1850?Ma). The age of felsic dykes (1593.88?±?0.56?Ma) interpreted to be post-mineralisation implies that the main hydrothermal event at Acropolis was ca 1594?Ma. The Gawler Range Volcanics at Acropolis are the same age as the Gawler Range Volcanics at Olympic Dam and ca 3 to 7 My older than the Gawler Range Volcanics exposed in the Gawler Ranges.
相似文献
6.
AbstractTwo spectacular cliff lines occur along Australia’s south and west coasts: the Great Southern Scarp (new name) and the Zuytdorp Cliffs. Detailed measurements of their length show that they are exceptionally long and unusually continuous. The Great Southern Scarp is the southern edge of the Nullarbor Plain’s Bunda Plateau; it is cut into shallow marine sediments and extends for 820?km. Once a continuous sea-cliff, local uplift has isolated two sections from the ocean, so it now comprises the Bunda Cliffs (210?km of coastal cliff, 180?km of which is uninterrupted cliff line), Hampton Range (inland; 300?km), Baxter Cliffs (160?km of coastal cliff) and Wylie Scarp (inland; 160?km). The Zuytdorp Cliffs are coastal cliffs cut into eolianite, and extend for 210?km with an uninterrupted section of 120?km. The length of the Great Southern Scarp and the Zuytdorp Cliffs results from an unusual combination of circumstances. They are both composed of poorly jointed, relatively homogenous biogenic calcarenites, presented to high-energy ocean waves by regional uplift. The carbonates are sufficiently well cemented to maintain a steep vertical cliff face, but susceptible to disintegration under direct wave attack. Cliff retreat has been fairly uniform because of the broad spatial scale of both lithology and erosion. The arid climate, absence of nearby non-karstic catchments and karstic nature of the cliffs’ hinterlands has discouraged integrated drainage development, so no significant fluvial systems dissect the cliffs; this is a key factor in cliff edge preservation. In the case of the Great Southern Scarp, these processes have formed the longest continuous cliff line in Australia and probably the world. Referenced against criteria from Australia’s National Heritage List, the cliffs have potentially international/national levels of significance for the rarity of their scale, their demonstration of landscape evolution, and their spectacular beauty. - KEY POINTS
Australia’s longest coastal cliffs, the Bunda (SA) and Zuytdorp (WA) cliffs, are equal in length (210?km, within defined confidence levels). The Bunda Cliffs are part of the Great Southern Scarp (new name), an 820 km-long feature of the Nullarbor Plain that also includes the coastal Baxter Cliffs (160?km in length) and two paleocoastal scarps. The unusual continuity of the cliff lines results from a landscape history specific to the Australian continent, and the Great Southern Scarp is likely to be unusual on a global scale. The Great Southern Scarp and the Zuytdorp Cliffs have potentially national and/or international levels significance for geoheritage values in the criteria of events and processes, rarity and aesthetics.
相似文献
7.
AbstractThe Gangdese batholith, Tibet, records the opening and closing of the Neo-Tethyan ocean and the resultant collision between the Indian and Eurasian plates. The Mesozoic magmatic rocks play a crucial role in understanding the formation and evolution of the Neo-Tethyan tectonic realm. This study focuses on Jurassic intrusive rocks in the Xietongmen area of the southern margin of the Lhasa terrane adjacent to the Yarlung–Tsangpo suture. Zircon U–Pb dating yielded Middle Jurassic dates for ca 170?Ma hornblende gabbro and ca 173?Ma granodiorite intrusions. All of the samples are medium- to high-K calc-alkaline, and the majority are metaluminous and enriched in the large ion lithophile elements and depleted in the high-field-strength elements. This indicates the magma was generated in a subduction-related tectonic setting. The intrusive rocks have high and positive εHf( t) values (hornblende gabbro: 13.3–18.7; granodiorite: 14.2–17.6) that yield Hf model ages younger than 312?Ma. These new data, combined with the results of previous research, suggest that the Jurassic igneous rocks were derived from a metasomatised region of an asthenospheric mantle wedge. Extremely depleted Sr–Nd–Pb–Hf isotope compositions are similar to the Yarlung ophiolite and igneous rocks within other intra-oceanic island arcs. Together with the existence of sandstone that is identified as the product of the oceanic island arc environment, we suggest formation in an intra-oceanic island arc. The new zircon U–Pb dating has yielded Middle Jurassic ages for the ca 170?Ma hornblende gabbro and ca 173?Ma granodiorite phases of the Xietongmen intrusion. Jurassic igneous rocks formed from a metasomatised asthenospheric mantle wedge by northward subduction of the Neo-Tethys oceanic crust beneath the southern margin of the Lhasa terrane. Late Triassic–Jurassic igneous rocks, which are characterised by highly depleted isotopic compositions within the Southern Lhasa sub-terrane, record residual intra-oceanic island arcs in the eastern Tethyan belt.
相似文献
8.
AbstractThe Jurassic–Cretaceous Great Artesian Basin is the most extensive, and largest volume, sedimentary feature of continental Australia. The source of its mud-dominated Cretaceous infill is attributed largely to contemporary magmatism along the continental margin to the east, but the source of its Jurassic infill, dominated by quartz sandstone, remains unconstrained. This paper investigates the question of a Jurassic sediment source for the northern part of the basin. Jurassic uplift and exhumation of the continental margin crustal sector to the east provided the primary Jurassic sediment source. (U–Th)/He data are presented for zircon and apatite from Pennsylvanian to mid Permian granitoids of the Kennedy Igneous Association distributed within the northern Tasmanides between the Townsville and Cairns regions and for coeval granites of the Urannha batholith from the Mount Carlton district (N Bowen Basin), also within the northern Tasmanides. The data from zircon indicate widespread Jurassic exhumation of a crustal tract located to the east of the northern Great Artesian Basin and largely occupied by rocks of the Tasmanides. Detrital zircon age spectra for samples of the Jurassic Hutton and Blantyre sandstones from the northeastern margin of the Great Artesian Basin show their derivation to be largely from rocks of the northern Tasmanides. In combination, the detrital age spectra and (U–Th)/He data from zircon indicate exhumation owing to uplift generating appreciable physiographic relief along the north Queensland continental margin during the Jurassic, shedding sediment westward into the Great Artesian Basin during its early development. A portion of (U–Th)/He data for zircon are consistent with late Permian–mid Triassic exhumation within the Tasmanides, attributable to the influence of the Hunter--Bowen Orogeny. Evidence of Cretaceous and Paleocene exhumation episodes is also indicated for some samples, mainly by apatite (U–Th)/He analysis, consistent with data previously published from fission track studies. Overall, new data from the present study reveal that the exhumation related to Jurassic regional uplift and the subsequent erosional reworking of the northeast Australian continental margin is critical for the evolution and development of the northern side of the Great Artesian Basin in eastern Australia. Apart from this, another two previously suggested Permian–Triassic and Cretaceous exhumation and uplift episodes along the northeast Australian continental margin are also confirmed by the dataset of this study. - KEY POINTS
U–Pb detrital zircon ages of sandstone samples from the northeastern Eromanga Basin reveal Paleozoic (480–280 Ma) and Proterozoic (1800–1400 Ma) age clusters. (U–Th)/He zircon and apatite dating results of granitoids samples from Cairns, Townsville and the Mount Carlton districts are dominated by Jurassic (198–164 Ma) and Permian–Triassic (272–238 Ma) age clusters. Combination of above two datasets proves the regional uplift-driving Jurassic exhumation episode in the northeast Australian continental is vital for the development of the northern Great Artesian Basin.
相似文献
9.
AbstractCambrian deformation associated with the Delamerian Orogeny is most evident in the Delamerian Orogen (southwestern Tasmanides) but has also been documented in the Thomson Orogen (northern Tasmanides). The tectonic evolution of the Thomson Orogen in the context of the Delamerian Orogeny is poorly understood. In particular, tectonostratigraphic relationships between the different parts of the Thomson Orogen (Anakie Inlier, Nebine Ridge, and southern Thomson Orogen) are still unclear. New detrital zircon data from the Nebine Ridge revealed an age spectrum that is consistent with published geochronological data from the Anakie Inlier. These results, in conjunction with petrographic observations and the interpretation of geophysical data, suggest that along the eastern part of the Thomson Orogen, the?～?NNE-trending Nebine Ridge represents the southward continuation of the?～?N–S-trending Anakie Inlier. New detrital zircon geochronological data are also presented for metasedimentary rocks from both sides of the Thomson–Lachlan boundary. The results constrain the maximum age of deposition (Ordovician–Devonian), and show that both sides of the Thomson–Lachlan boundary received detritus from a similar provenance. This might suggest that the Thomson–Lachlan boundary did not play a major role as a crustal-scale boundary prior to the Devonian. We speculate that transpressional deformation along this?～?E–W boundary, during the Early Devonian, was responsible for disrupting the original belt that connected the Delamerian Orogen (Koonenberry Belt) with the eastern Thomson Orogen (Nebine Ridge and Anakie Inlier). - Highlights
The Nebine Ridge is the southward continuation of the Anakie Inlier. The Anakie Inlier and Nebine Ridge represent a northern segment of the Cambrian Delamerian–Thomson Belt. ～E–W-trending crustal-scale structures at the southern Thomson Orogen were active during Devonian.
相似文献
10.
AbstractQuaternary alluvial and colluvial sediments infill major river valleys and form alluvial fans and colluvium-filled bedrock depressions on the range fronts and within the Mount Lofty Ranges of southern Australia. A complex association of alluvial successions occurs in the Sellicks Creek drainage basin, as revealed from lithostratigraphy, physical landscape setting and optically stimulated luminescence (OSL) ages. Correlation of OSL ages with the Marine Oxygen Isotope record reveals that the alluvial successions represent multiple episodes of alluvial sedimentation since the penultimate glaciation (Marine Isotope Stage 6; MIS 6). The successions include a penultimate glacial maximum alluvium (Taringa Formation; 160?±?15?ka; MIS 6), an unnamed alluvial succession (42?±?3.2?ka; MIS 3), a late last glacial colluvial succession within bedrock depressions ( ca 15?ka; MIS 2) and a late last glacial alluvium ( ca 15?ka; MIS 2) in the lowest, distal portion of Sellicks Creek. In addition, the Waldeila Formation, a Holocene alluvium (3.5?±?0.3?ka; MIS 1), and sediments deposited during a phase of Post-European Settlement Aggradation (PESA) are also identified. The age and spatial distribution of the red/brown successions, mapped as the Upper Pleistocene Pooraka Formation, directly relate to different topographic and tectonic settings. Neotectonic uplift locally enhanced erosion and sedimentation, while differences in drainage basin sizes along the margin of the ranges have influenced the timing and delivery of sediment in downstream locations. Close to the Willunga Fault Scarp at Sellicks Creek, sediments resembling the Pooraka Formation have yielded a pooled mean OSL age of 83.9?±?7?ka (MIS 5a) corroborating the previously identified extended time range for deposition of the formation. Elsewhere, within major river valleys, the Pooraka Formation was deposited during the last interglacial maximum (128–118?ka; MIS 5e). In general, alluviation occurred during interglacial and interstadial pluvial events, while erosion predominated during drier glacial episodes. In both cases, contemporaneous erosion and sedimentation continued to affect the landscape. For example, in the Sellicks Creek drainage basin, which lies across an actively uplifting fault zone, late glacial age sediments (MIS 2) occur within the ranges and near the distal margin of the alluvial fan complex. OSL dating of the alluvial successions reported in this paper highlights linkages between the terrestrial and marine environments in association with sea-level (base-level) and climatic perturbations. While the alluvial successions relate largely to climatically driven changes, especially in major river valleys, tectonics, eustasy, geomorphic setting and topography have influenced erosion and sedimentation, especially on steep-sloped alluvial fan environments. - KEY POINTS
Luminescence dating of the Sellicks Creek alluvial fan complex reveals that sedimentation occurred predominantly during the later stages of glacial cycles accompanying lower sea-levels than present. Luminescence dating confirms that the stratigraphically lower portions of the Pooraka Formation are beyond the range of radiocarbon dating. Upper Pleistocene alluvial fan sedimentation at Sellicks Creek correlates with pluvial events in southeastern Australia.
相似文献
11.
AbstractReview and analysis of 1332 gas chromatography (GC) n-alkane traces of oils from the Cooper and Eromanga basins indicate the shape of any GC trace profile is primarily controlled by the degree of organic maturity (early, peak or late) at which the oils were expelled from the parent source rock, rather than indicating the depositional environment, and hence organic composition, of that source rock. The depositional environment of a source rock may still be inferred, however, from the position of the n-alkane maximum on the GC traces of early expulsion oils in association with the pour point of the oil. Departures of GC trace profiles from the standard early, peak or late expulsion profiles can indicate mixing of oils of different maturities, while variations in the GC trace profiles of oils within adjacent reservoir units may indicate phase separation of the parent liquid, or possible seal breach by an accumulation that exceeds the capacity of its overlying seal. - KEY POINTS
GC trace profiles of 1332 oils from across the Cooper and Eromanga basins of central Australia have been reviewed. Organic maturity, rather than organic composition, of the parent source rock controls the shape of any GC trace profile. All early maturity oils display a consistent GC trace profile shape that is different from all peak maturity oils and different again from all late maturity oils. Depositional environment of the source rocks within a basin can be inferred from the relative pour points of the resultant oils.
相似文献
12.
AbstractInformation, mainly from the granitic and silicic volcanic rocks in the Stawell, Bendigo and Melbourne structural zones in the state of Victoria, shows that the sources of both the S- and I-type rocks of the Stawell and Bendigo zones (SBZ) contrast in ages and chemistry with the sources of similar granitic rocks in the Melbourne Zone, consistent with the absence of the mainly Proterozoic Selwyn Block beneath most of the SBZ. Below a mid-crustal décollement in the SBZ, the crust is evidently highly variable and possibly includes thinned Proterozoic crust. There is geochronological evidence for ca 400 and ca 370?Ma granulite-grade metamorphic events here, and, after this double bout of metamorphism, and depletion in the silicic melt component, the constituents of the entire deep crust of the SBZ would have densities similar to those of overlying, much lower-grade Cambrian metabasaltic to boninitic rocks. Thus, granitic magmas may have formed here by partial melting of a variety of rock types, probably with back-arc affinities, with ages that may extend back to the Proterozoic. Therefore, the basement of the SBZ is unlikely to consist solely of thick ocean-floor rocks, as in some current interpretations. - KEY POINTS
The sources of the Devonian granitic rocks of the Stawell and Bendigo zones (SBZ) contrast in ages and chemistry with those of the Melbourne Zone granites. Two Devonian granulite-facies events left the melt-depleted deep SBZ crust with densities similar to those of overlying Cambrian metabasaltic rocks. The SBZ Devonian granitic magmas probably formed by partial melting of heterogeneous Proterozoic to Cambrian arc-related crust, below the mid-crustal décollement.
相似文献
13.
AbstractIn Australian stratigraphic nomenclature, the concept of granitic rock suites has been in formal use for over a decade. The basis for this suite classification of granitic rocks is inconsistent and, in eastern Australian usage, unsound on several levels. We also note that the approach used in Western Australia is different. Granitic intrusions are probably not truly amenable to any strict, comprehensive, lithostratigraphic classification. If these rocks are integrated into such a scheme, group- and supergroup-level units ( i.e. formal suites and supersuites) should not be incorporated. For the present, mappable units should be recognised at the levels of formation and member. The use of granite suites and supersuites in formal stratigraphic hierarchies is not recommended. Instead, granitic bodies could be grouped into individual plutons, which may or may not form parts of larger batholiths. - KEY POINTS
The suite-based classification of granitic bodies, as currently used in the Australian Stratigraphic Units Database, is based on unsound principles, and is not employed in a consistent manner. Granitic intrusive rocks probably cannot be grouped using lithostratigraphic principles that are consistent with either the local or international codes. Granitic bodies can be grouped into batholiths, plutons and members, but the names of these units should, for the moment, remain informal.
相似文献
14.
AbstractAccurate soil-moisture monitoring is essential for water-resource management and agricultural applications, and is now widely undertaken using satellite remote sensing or terrestrial hydrological models’ products. While both methods have limitations, e.g. the limited soil depth resolution of space-borne data and data deficiencies in models, data-assimilation techniques can provide an alternative approach. Here, we use the recently developed data-driven Kalman–Takens approach to integrate satellite soil-moisture products with those of the Australian Water Resources Assessment system Landscape (AWRA-L) model. This is done to constrain the model’s soil-moisture simulations over Australia with those observed from the Advanced Microwave Scanning Radiometer-Earth Observing System and Soil-Moisture and Ocean Salinity between 2002 and 2017. The main objective is to investigate the ability of the integration framework to improve AWRA-L simulations of soil moisture. The improved estimates are then used to investigate spatiotemporal soil-moisture variations. The results show that the proposed model-satellite data integration approach improves the continental soil-moisture estimates by increasing their correlation to independent in situ measurements (～10% relative to the non-assimilation estimates). HighlightsSatellite soil-moisture measurements are used to improve model simulation. A data-driven approach based on Kalman–Takens is applied. The applied data-integration approach improves soil-moisture estimates.
相似文献
15.
AbstractThe shape and structural development of the box-like Parrabel Dome (PD) within the Hastings Block is poorly understood because it has only been weakly cleaved, complexly folded and extensively faulted in comparison to the adjoining blocks. Better characterising this block will provide important controls on the tectonics of the southern New England Orogen. The structural development of the PD and southern Hastings Block (SHB) provides evidence of the degree of rotation, translation and deformation of the Hastings Block, a key terrane within the southern New England Orogen. A major decollement under the Hastings Block–Nambucca Block was suggested to facilitate south-directed deformation caused by the developing Coffs Harbour Orocline. The orientation of bedding and the stratigraphic facing of some fault blocks within the northern Hastings Block (NHB) are consistent with development of the PD, while other fault blocks indicate significant disruption of the NHB prior to, during and after dome development. A deep-seated fault is suggested by the gravity worm analysis consistent with the boundary zone between the PD, NHB-Yarrowitch Block and the east-dipping and younging sequences in the SHB. The eastern limb of the PD underwent clockwise rotation after formation. Fault blocks have been rotated and translated within a restraining bend as the NHB moved post-PD formation northwest along the interface between the NHB and SHB. - KEY POINTS
The Hastings Block was translated and rotated into its current position from the southeastern end of the Tamworth Belt. Gravity worm data indicate a boundary between northern and southern Hastings Block. The Hastings and Nambucca blocks have been detached from the basement Gondwana rocks. Fault block analysis within the Parrabel Dome, northern Hastings Block indicates relocation of some blocks by faulting.
相似文献
16.
AbstractThe sedimentary facies of the Huagang Formation, the major petroleum exploration horizon in the Xihu Depression in the East China Sea Basin, have not been well constrained, owing to limited drilling and core recovery. Interpretations are vague and vary from beach bar, braided river and braided-river delta front sediments. In this paper, the paleosedimentary environments of the Huagang Formation are discussed based on detailed organic and inorganic geochemical analysis and proxies used to interpret the sedimentary facies. Kerogen, dominated by sapropelinite, is mainly of Type I and Type II, and n-Paraffins are dominated by short-chain and medium-chain, with no obvious odd-over-even advantages. The distribution of isoprenoid alkanes and steroids indicates that the organic matter in mudstones is mainly of lacustrine and mixed origins. Elemental ratios of Th/U (4–6), V/Cr (1–4), Ni/Co (3–11) and V/(V?+?Ni) (0.5–0.75) indicate that in the area studied, the Huagang Formation was deposited under anoxic to reduced conditions with some oxygen-enriched horizons. Both inorganic and organic geochemical signatures show that the Huagang Formation was mainly deposited in an aquatic environment but with some minor periods of subaerial exposure. The sequence of the Huagang Formation is characterised by interbedded grey-white thick sandstones and grey-black thin mudstones. Normally graded cycles are widely developed, with rare mudstone in the upper part and scoured surfaces at the base. The cumulative grainsize distribution curve is mainly a two-stage type. The sedimentary facies indicative markers are dominated by braided-river channel deposits and combined with the paleosedimentary environments it is inferred that the sedimentary system in the study area was typical of a braided-river delta front. The cores available were intensively analysed using a hand-held X-ray fluorescence spectrometer to probe the variations in the paleoclimate and show that the braided-river channels were controlled by paleoclimate. During arid climatic settings, the sediments within individual channels were thin, and grainsizes varied significantly; at the base of each channel, basal conglomerates were common. In contrast, under humid climatic settings, thin multi-stage channels were superimposed, and the bottom often developed erosion surface. - KEY POINTS
The paleosedimentary environments are discussed based on detailed organic and inorganic geochemical analysis. The Huagang Formation was deposited in a freshwater lacustrine basin under warm and humid climatic settings. The Huagang Formation is characterised by braided-river delta front facies. The development of braided-river channels was controlled by paleoclimate.
相似文献
17.
AbstractLarge debris flows in steep-sloped ravines debouching to the Rimac River, in metropolitan Lima (Peruvian capital), have resulted in considerable loss of life and property adversely impacting communities in the region. Temporal, spatial and volumetric features of debris flows are difficult to predict, and it is of utmost importance that achievable management solutions are found to reduce the impact of these catastrophic events. The emotional and economic toll of these debris flows on this increasingly densely populated capital city in South America is devastating where communities must live in such inadequate and dangerous conditions. To address this problem, the application of advanced Japanese technology, Sustainable Actions Basin Orientation (SABO), has been investigated using a geomorphological modelling to develop an implementation plan. Rayos de Sol stream basin in Chosica, was selected as a pilot to develop the proposal, as it is considered high risk due to the presence of ancient debris flows and recent flows in 2012, 2015 and 2017. The recurrence of debris flows in this location has resulted in numerous deaths and catastrophic property losses. This study combines geologic and geomorphic mapping and hydraulic and landform evolution numerical modelling. The implementation of a SABO Master Plan based on the multidisciplinary assessment hazard scenarios, will allow the implementation of feasible mitigation actions. The SABO technology has been applied successfully in Japan and other countries in areas with steep short slopes, similar to the conditions surrounding the Peruvian capital. Results from this study will be presented to the Peruvian Government as part of an action plan to manage debris-flow impact. - KEY POINTS
High-risk mass slope failure is linked to poor urban planning in urban developing regions of Lima the capital of Peru. A multidisciplinary study including geotechnical and hydrological analysis, engineering design, and socio-economic research is required to implement a SABO Master Plan, and this basin is pilot study basin. At the present time, a maintenance programme for existing hydraulic structures should be implemented, and a flood risk management plan developed may propose the relocation of some communities and infrastructure.
相似文献
18.
AbstractLongstanding debates on the tectonic setting and provenance of the Lower Cretaceous Lingshandao Formation have hindered basin analysis and tectonic studies of the collision of the Yangtze Craton and the North China Craton, and thus the evolution of the Sulu Orogen. Thin-section analysis, identification of rock particles, cathodoluminescence, heavy minerals and trace-element analysis have, in addition to field investigations, been applied to reconstruct the source area and transport pathways of the sediments that build the Lower Cretaceous Laiyang Group on the Lingshan Island, western Yellow Sea. These analyses indicate that the Laiyang Group consists mainly of material derived from a recycled orogen and from transitional continental sediments. The Laiyang Group on Lingshan Island has been sourced from igneous and metamorphic rocks. Comparing analyses of detrital minerals with rocks from surrounding areas leads to the conclusion that the main source area is the Sulu Orogen that supplied sediment to rift basin rather than a residual basin between the Yangtze Craton and the North China Craton. A recycled orogenic belt is the source area for the Laiyang Group on Linshan Island. Felsic metamorphic and igneous rocks form the most probable sources. The rift basin was filled by sediments supplied from the Sulu Orogen on both sides.
相似文献
19.
Miocene volcanism in the Blue Mountains province of centralOregon produced diverse basaltic rocks. One set of these, thePicture Gorge Formation of the Columbia River Basalt Group,is well known. Others (Bowman Dam, Bear Creek, and Slide Creekflows) are relatively poorly known. Only the Picture Gorge flowsin the center of the province are typical continental floodbasalts. Basaltic rocks with calc-alkaline affinities (evolvedBear Creek flows, Slide Creek basalts) are found to the westand east. Basal Bear Creek flows closely resemble MORB and islandarc tholeiites, despite having erupted on a continental plate.Bowman Dam (formerly ‘Prineville’) basalts are richin K 2O, P 2O 5, and Ba, and poor in Ni, Co, and Cr. Some of thesefeatures may reflect mantle metasomatism or crustal contamination.Thus, several currently debated theories of basalt petrogenesiscan be tested by studying flows erupted during Miocene timesin this relatively small area. Very few, if any, of these basaltic rocks represent primarymantle-derived magmas. Inferred depths of the pre-eruption magmareservoirs in which they were fractionated are shallow in thecenter of the province, deeper to the east and west. The E-W axis of Miocene calc-alkaline rocks in the Blue Mountainsprovince existed simultaneously with a N-S axis of calc-alkalineactivity in the Cascades that paralleled an offshore subductionzone. Current ideas of relationships among tectonic settingsand the compositions of volcanic rocks cannot easily be madeto conform with these facts. 相似文献
20.
AbstractFour economic porphyry Cu–Au deposits and several prospects have been investigated in the Northparkes district, part of the Ordovician to early Silurian Junee–Narromine Belt of the Macquarie Arc, New whole-rock geochemical data from the Northparkes porphyry Cu–Au district, NSW, indicate that the mineralising intrusive complexes exhibit distinct arc signatures that are transitional from high-K calc-alkaline to silica-saturated alkalic. Based on ratios of Sr/Y vs Y ( e.g. Sr/Y > ～20 and Y < ～17?ppm) the mineralising intrusions are interpreted to have crystallised from fractionated hydrous melts indicating the suppression of plagioclase crystallisation in favour of hydrous mineral phases. This interpretation is supported by listric-shaped rare earth element curves and the presence of primary hornblende phenocrysts indicating elevated magmatic water contents. There is an association of mineralising intrusions with a low Zr trend both in the mineralised Northparkes district intrusive rocks and in mineralised porphyry-related intrusive rocks globally. A newly developed fertility indicator ratio Zr/Y ～10% is more accurate at identifying the mineralised rocks at Northparkes than the conventional Sr/Y vs Y fertility indicator diagram, successfully identifying 92% of the mineralising intrusions, mainly owing to the fact that it is less affected by hydrothermal alteration. The insensitivity of Zr–Y to alteration makes this indicator a useful new tool that may lead to enhanced probabilities for future discoveries in the Northparkes district, broader Macquarie Arc and altered rocks globally. - KEY POINTS
Mineralising intrusions in the Northparkes district have distinct Zr vs Y concentrations. The Zr vs Y indicator of magmatic fertility is less sensitive to alteration than Sr-based indicators. The Zr vs Y magmatic fertility indicator identified at Northparkes is not unique and identifies mineralising intrusions in other porphyry fields.
相似文献
|
