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1.
The Callovian–Oxfordian carbonates in the northeastern Amu Darya Basin of southeastern Turkmenistan, are composed of medium-to thick-bedded, mostly grainy limestones with various skeletal (bivalves, brachiopods, echinoderms, foraminifera, corals, and sponge) and non-skeletal grains (intraclasts, ooids, and peloids). The 6 microfacies types recognized in the Callovianand and 18 microfacies types in Oxfordian carbonates are grouped into two depositional phases, ramp and platform. The Callovian carbonates were deposited on a carbonate ramp, which evolved into a depositional platform in the Oxfordian. The main components of the Oxfordian platform margin complex are reefs and shoals. The principal reef builders are corals, algae and sponges. Regional tectonic movements, eustatic sea-level changes and sedimentation rates were the primary controlling factors of facies evolution during the Callovian–Oxfordian time in the northeastern Amu Darya Basin. 相似文献
2.
The Oligocene-Miocene is a key interval that was characterized by a cooling trend associated with a progressive decrease of atmospheric CO2 concentrations that ends in the Present days.In the Central Mediterranean area, during this interval, three main carbonate platform domains developed in the foreland zone of the Apennines: the Latium-Abruzzi-Campana and Apulia domain in the central and south-eastern sectors of the chain and the Hyblea and Pelagian carbonate platforms in the south and south-western sectors. This work analyzes the impact and interplay of global and regional factors controlling the development of different carbonate factories and facies associations over the Chattian and the early Messinian time interval. Three well-studied examples of the central Mediterranean will be used: the Chattian ramp of Malta, the Latium-Abruzzi ramp, and the Bolognano ramp within the northern portion of the Apulian carbonate platform (outcropping on Majella Mountain).The Malta ramp represents the reference model for the heterozoan Oligo-Miocene carbonate factory, since it developed far from terrigenous input, in persistent oligotrophic conditions, and within a tropical climate. In contrast, the evolution of the central Apennine ramps is strictly related to the geodynamic evolution of the Apennines and simultaneously to global oceanographic changes.The Chattian Apennine ramps are affected by a basin conformation that favored the development of dominant currents and related dune fields. Successively, these ramps were exposed to strong Aquitanian volcanism that induced a shift towards an aphotic-dominated carbonate factory. Since the Burdigalian the development of the Apennines has affected the evolution of the investigated ramps through the eastward migration of foredeep systems and related nutrient input. This influence becomes more evident between the Tortonian and Messinian, during which reef-rimmed platforms developed in the rest of the Mediterranean while red algae still dominated in the Apennine ramps. Amongst the global events, the C-cycle perturbation, occurring between the late Burdigalian and Serravallian (Monterey event), leaves a clear sign on the two Apennine ramps. 相似文献
3.
The well-exposed upper Kimmeridgian carbonate ramp near Arroyo Cerezo, Iberian Basin, Eastern Spain, provides an excellent analog to stratigraphically equivalent subsurface reservoirs, such as the carbonate ramps of the Arab-D of the Middle East and the Smackover of the Gulf of Mexico. Critical questions regarding interwell-scale heterogeneity and correlation motifs for low-angle ramp systems can be addressed using continuous exposures that encompass a full range of inner to outer ramp facies. Outcrops in this area provide a complete exposure of the ramp succession in depositional dip direction.At Arroyo Cerezo, a 40-m thick and 1.3-km long, dip-oriented, continuous outcrop has been studied. Lithofacies and bounding surfaces have been mapped on a continuous photomosaic to build a detailed 2D cross-section, complemented by five stratigraphic sections (∼300 m apart) and petrographic analysis. The reconstructed section shows the facies transition from relative proximal- to distal carbonate ramp settings. Carbonate facies associations are grouped according to the dominant carbonate types: buildup-dominated systems and coated-grain dominated systems. Detailed mapping of facies and bounding surfaces documents distinct ramp depositional units with downdip facies changes occurring within the 1.3 km length of the outcrop. The Arroyo Cerezo outcrop indicates that the ramp-facies continuity, when based on a 5–10 km distance well-log correlation, is mostly apparent. Use of detailed spatial and temporal analysis of high-quality outcrop analogs promotes more realistic models for understanding the interwell, meter-scale heterogeneity. And the scale of these depositional heterogeneities, although being below resolution of subsurface tools, governs in fact (along with diagenetic modifications) the fluid flows within a reservoir. The scale of these stratigraphic heterogeneities needs to be considered in order to optimize and enhance hydrocarbon production and last recovery. 相似文献
4.
It is usually very difficult to identify and quantify the relative influence of tectonics, eustasy and climate on carbonate system evolution from sedimentary records. In order to improve our understanding of these mechanisms, we have traced for the first time, the evolution of the eastern Paris Basin platform throughout the entire Jurassic period. This carbonate platform underwent eight successive growth and demise phases, with different depositional profiles ranging from ramps to flat-topped geometries. The eight carbonate growth periods are compared with the standard sea-level curves, local tectonic regimes and recently published oxygen-isotope and/or clay mineralogy databases. Prograding heterozoan facies along ramp profiles mark periods dominated by second-order eustatic sea-level rise, relatively cool sea surface temperatures, and mesotrophic and humid conditions (Hettangian, Pliensbachian, late Oxfordian, Tithonian). During these periods, variable detrital contents in the sedimentary succession hampered the efficiency of shallow-marine carbonate factories. Higher sea surface temperatures, oligotrophic and humid conditions associated with either eustatic sea-level rise or very high local subsidence occurred during the early Bajocian and the mid-Oxfordian. These seawater properties seem to have favoured the aggradation of scleractinian corals forming dome-shaped bioherm buildups. An oolitic and lime-mud carbonate system, deposited during the Bathonian second-order eustatic sea-level fall, is characterised by miliolid-rich micritic facies on a rimmed-ramp under stable, cooler and drier conditions. The second-order maximum flooding associated with a sea surface temperature decline and/or a seawater eutrophication caused at least five carbonate demise periods (i.e. Toarcian, earliest late Bajocian, Callovian/Oxfordian transition, earliest late Oxfordian and Kimmeridgian). 相似文献
5.
M. Berti M. G. Cuzzani G. B. Vai A. Landuzzi M. Taviani P. Aharon 《Geo-Marine Letters》1994,14(2-3):192-200
Evidence of hydrocarbon venting within slumped bodies associated with the siliciclastic, dominantly turbiditic, Marnoso-arenacea Formation (Umbria-Romagna structural domain, Romagna Apennine, northern Italy) is documented with sedimentological, faunal, and geochemical data. Specifically,13C-depleted carbonate concretions and limestones and clusters of chemosynthetic clams (Vesicomyidae) have been identified in the marls of the Le Caselle Olistostrome and other slumped bodies contained within the Early Serravallian section of the Marnoso-arenacea Fm. Most of the olistostrome marls and limestones are extrabasinal and must have slid from a source area located several kilometers southwest of their present position. Thus, they presumably pertain to the Vicchio Marls Formation of the northeastern (outer) Tuscan structural domain, with possible minor contributions from the epi-Ligurian Bismantova Fm. It is suggested that venting of methane in the source area of the olistostromes permitted the establishment of exotic chemosynthetic communities and promoted the precipitation of carbonate concretions and limestones. According to the field evidence, these materials were later subjected to multistep downslope remobilization and were eventually carried into the Marnoso-arenacea basin through gravity mass transport. 相似文献
6.
Subaerial erosion and continental sedimentation interbedded with shallow-water carbonates are unequivocal stratigraphic records to evaluate paleoenvironmental and paleoclimate evolution of emerged landmass.Stratigraphic analysis of the Cretaceous Monte Gallo section of the Mesozoic Panormide carbonate platform, in the northern side of the Palermo Mountains (NW Sicily) records a peculiar continental-derived clays that interrupted the shallow-water carbonate sedimentation. These clays rest, with lenticular geometries, above the tectonically-enhanced subaerial erosional unconformity of the Barremian-Lower Aptian Requienid limestones and are covered by the Upper Cretaceous Rudistid limestone.Sedimentological investigation combined with mineralogical and petrographic results reveal the occurrence of alkaline to saline lake clays deposition in pond-filling depositional environment recording stressed conditions (evaporation) especially in its final living phase. They were formed when a half graben/tilted-block tectonics produced footwall uplift of the Gallo faulted-blocks carbonate platform.Paleoclimate evaluations of the continental-derived clays highlighted that a period of warm-humid conditions, which favoured their formation, interrupted the uniform warm climate conditions highlighting a greenhouse climate phase. 相似文献
7.
Subsurface Upper Triassic sediments of northern Jordan represent part of a regressive evaporitic-clastic succession that marks the shrinkage phase of the Late Triassic basin in the northern parts of the Arabian Plate. Sabkhas developed along the basin margin, whereas, oolitic shoals formed on the deeper parts of the carbonate platform. The basin reached a drewdown stage in the Risha, Palmyra and parts of northern Iraq, where halite was precipitated. Local shales, marls and argillaceous limestones are the major source rocks. The total organic content values of the shales and carbonates range between 0.5–1.9%. The main reservoir rocks are the oolitic limestones with porosities of 8–20% and permeabilities that range between 0.01–80 md. Regional swells and troughs that were cut by normal and strike-slip faulting are the main structural styles in the area. Favourable conditions for hydrocarbon generation and accumulation may be found under the Hauran Basalts in NE Jordan. 相似文献
8.
This work illustrates the evolution the Lower Jurassic shallow-water carbonates known as the Calcare Massiccio Formation in the Central Apennines (Italy). The Calcare Massiccio is characterized by lateral and vertical variability in the facies associations, related to an articulated physiography of the Triassic to Lower Jurassic carbonate platform and to its tectonic evolution. This work documents the depositional environment changes during the platform evolution. Quantitative analysis on samples collected from three stratigraphic sections were performed through the Calcare Massiccio succession allowed up to the overlying Pliensbachian pelagites. Two type of carbonate sedimentation have been recognized: in the peritidal and shallow subtidal environments (Calcare Massiccio A) the carbonate production is dominated by microbial activity, while the carbonate sedimentation in a deeper environment of middle to outer ramp (Calcare Massiccio B), is dominated by a bioclastic sedimentation.The evolution from the Calcare Massiccio A to the B can be interpreted as the product of increase of accommodation that in turn produced a backstepping of carbonate facies belt, the photic microbial dominated peritidal facies developed on the persistent Latium-Abruzzi Platform while the bioclastic carbonate production factory settled on the structural highs resulting from the dismembering of the platform by syn-sedimentary tectonic.The bioclastic carbonate factory was not efficient in filling the available accommodation space produced by Sinemurian extensional tectonic. This inefficiency was amplified by the restricted area available for this factory in the small structural highs. These conditions were sufficient to predispose the platform to the drowning without invoke change in the trophic resource or change in the palaeoceanography. 相似文献
9.
The Apennine Chain provides the first example of stratigraphic (time) and synsedimentary tectonic (space) distribution of the calcari aLucina Miocene equivalents of modern cold-vent carbonates. Chemosynthetic faunal assemblages and related carbonate deposits are found at different stratigraphic levels, with peaks during Langhian-Serravallian and late Tortonian-early Messinian times. A general increase in frequency and volume occurs with time. A genetic link between venting and the Messinian Evaporite event is difficult to demonstrate. However,Lucina limestones are limited to preevaporitic times, and their maximum abundance is reached just before the onset of the Messinian Evaporite accumulation.Lucina limestones occur in almost all tectofacies of the orogen, from backland to foreland. 相似文献
10.
The main reservoir of the Humbly Grove Oilfield comprises variably dolomitic grainstones and packstones representing the Bathonian Great Oolite Group. The Bathonian sequence commences in Lower Fuller's Earth claystones which coarsen upwards into oncolitic claystones and skeletal packstones probably equivalent to the Fuller's Earth Rock. Above is a variable succession of wackestones and thin packstones which have a distinctive sandstone at their base. This sequence is named here the Hester's Copse Formation. The succeeding Great Oolite Limestone is predominantly oolitic and cross-bedded on a variety of scales. It exhibits both coarsening and fining sequences which have locally well-developed capping hardgrounds and burrowed horizons. The Great Oolite Limestone is subdivided into three Members: the lowest (the Humbly Grove Member), and the highest (the Herriard Member) begin with massive shoal oolite deposition, but each then pass upward into more interbedded sequences representing a more transgressive environment. The middle member (the Hoddington) is a thin but widely correlatable wackestone. The overlying Forest Marble commences abruptly in claystones, but there is an upward increase in both the incidence and thickness of discrete oolitic limestones. Both the Great Oolite Limestone and Forest Marble were affected by early fresh-water dissolution and cementation in addition to the localized development of submarine cements. The top of the Great Oolite Group is represented by the Cornbrash. The Lower Cornbrash is a thin micritic limestone while the Upper Cornbrash is a calcareous claystone which passes upwards into the Kellaways Clay. The Bathonian sequence overlies the dolomitic limestones of the Inferior Oolite, the Lower Fuller's Earth claystones being interpreted as a basinal marine mudstone sequence, marking a substantial deepening and transgressive phase at the opening of the Bathonian. These mudstones shoal upwards into the quiet, but photic, water deposits of the Fuller's Earth Rock. The Hester's Copse Formation represents the temporary development of wave-dominated terrigenous shoreface and lagoonal conditions. Renewed transgression established a high-energy, tide-dominated, carbonate shelf upon which the Great Oolite Limestone was deposited as a series of shoal oolites, channels, tidal deltas and spill-overs. Periodic exposure of the carbonate sand-bodies led to the production of early dissolutional and cementation fabrics that post-date (and largely obliterate) submarine cements. The Forest Marble opened with a further phase of deepening, and the temporary establishment of muddy facies. Subsequently discrete tide-dominated ridges and linear channelized oolitic sands prograded into the area. The latest Bathonian is marked by subsidence of the carbonate ramp to the south of the London Platform, the Cornbrash-Kellaways Clay sequence accumulating under progressively deepening waters. 相似文献
11.
The Northern Adriatic Sea is a shallow and very flat shelf area located between the northern Apennines, the southern Alps and the Dinarides; its present day physiography is the result of the filling of a relatively deep Quaternary foredeep basin, developed due to the northeastward migration of the Apennine chain. Multichannel seismic profiles and well data have allowed documenting the stratigraphic architecture, the depositional systems and the physiographic evolution of the Northern Adriatic sea since early Pliocene time. In particular, three main depositional sequences bounded by regional unconformities were recognized. The Zanclean Sequence 1 documents first the drowning of late Messinian incised valleys and then the southward progradation of a shelf-slope system, which is inferred to be related to a tectonic phase of the Apenninic front. The Piacenzian-Gelasian Sequence 2 records a relatively rapid transgressive episode followed by minor southward progradation; the top of the sequence is associated with a major late Gelasian drowning event, linked to the NE-ward migration of the Apennine foredeep. The Calabrian to upper Pleistocene Sequence 3 testifies the infilling of accommodation previously created by the late Gelasian drowning event, and it initially accumulated in deep-water settings and then in shallow-water to continental settings. The upper part of Sequence 3, consisting of the paleo-Po deltaic system, is composed of seven high-frequency sequences inferred to record late Quaternary glacio-eustatic changes. These high-frequency sequences document the stepwise filling of the remaining accommodation, resulting in the development of the modern shelf. 相似文献
12.
This paper presents a detailed seismic analysis of a hitherto undescribed Permian succession interpreted to consist of interbedded anhydrite and carbonate from the northern flank of the Loppa High, western Barents Sea. The Fafner succession forms a locally restricted transgressive unit down-dip on the rotated Loppa High. It is subdivided into four seismic sequences each interpreted to be composed of a basal transgressive anhydrite overlain by highstand carbonates. Fafner seismic sequences 2 and 3 include well-developed buildup complexes which in map view form polygonal patterns.Analysis of attribute maps indicates that the Fafner succession is overprinted by two dissolution systems related to two prominent events of subaerial exposure, creating numerous paleo-sinkholes, breccia-pipes, and collapsed composite cavern systems.The stratigraphical position of the Fafner succession, below the Mid Sakmarian – Artinskian Bjarmeland Group and above the Top Ørn unconformity, resembles that of the Lower Permian Gipshuken Formation on Spitsbergen, and the Fafner succession is thus regarded as its offshore equivalent. 相似文献
13.
S.S. Flint D.M. HodgsonA.R. Sprague R.L. BruntW.C. Van der Merwe J. FigueiredoA. Prélat D. BoxC. Di Celma J.P. Kavanagh 《Marine and Petroleum Geology》2011,28(3):658-674
The Laingsburg depocentre of the SW Karoo Basin, South Africa preserves a well-exposed 1200 m thick succession of upper Permian strata that record the early filling of a basin during an icehouse climate. Uniformly fine-grained sandstones were derived from far-field granitic sources, possibly in Patagonia, although the coeval staging and delivery systems are not preserved. Early condensed shallow marine deposits are overlain by distal basin plain siltstone-prone turbidites and volcanic ashes. An order of magnitude increase in siliciclastic input to the basin plain is represented by up to 270 m of siltstone with thin sandstone turbidites (Vischkuil Formation). The upper Vischkuil Formation comprises three depositional sequences, each bounded by a regionally developed zone of soft sediment deformation and associated 20-45 m thick debrite that represent the initiation of a major sand delivery system. The overlying 300 m thick sandy basin-floor fan system (Unit A) is divisible into three composite sequences arranged in a progradational-aggradational-retrogradational stacking pattern, followed by up to 40 m of basin-wide hemipelagic claystone. This claystone contains Interfan A/B, a distributive lobe system that lies 10 m beneath Unit B, a sandstone-dominated succession that averages 150 m thickness and is interpreted to represent a toe of slope channelized lobe system. Unit B and the A/B interfan together comprise 4 depositional sequences in a composite sequence with an overall basinward-stepping stacking pattern, overlain by 30 m of hemipelagic claystone. The overlying 400 m thick submarine slope succession (Fort Brown Formation) is characterized by 10-120 m thick sand-prone to heterolithic packages separated by 30-70 m thick claystone units. On the largest scale the slope stratigraphy is defined by two major cycles interpreted as composite sequence sets. The lower cycle comprises lithostratigraphic Units B/C, C and D while the upper cycle includes lithostratigraphic Units D/E, E and F. In each case a sandy basal composite sequence is represented by an intraslope lobe (Units B/C and D/E respectively). The second composite sequence in each cycle (Units C and E respectively) is characterized by slope channel-levee systems with distributive lobes 20-30 km down dip. The uppermost composite sequence in each cycle (Units D and F respectively) are characterised by deeply entrenched slope valley systems. Most composite sequences comprise three sequences separated by thin (<5 m thick) claystones. Architectural style is similar at individual sequence scale for comparable positions within each composite sequence set and each composite sequence. The main control on stratigraphic development is interpreted as late icehouse glacio-eustasy but along-strike changes associated with changing shelf edge delivery systems and variable bathymetry due to differential substrate compaction complicate the resultant stratigraphy. 相似文献
14.
The Plio-Pleistocene succession of the Venice area represents part of the infill of a foreland region located between three mountain chains: the Northern Apennines, the Southern Alps and the Dinarides. This structural setting favored the development of a complex stratigraphic architecture of the succession, mostly due to the conveying of sediments from the Southern Alps to the north and the Northern Apennines to the south, in particular since the activation of strong subsidence related to the NE-ward migration of the Apennine foredeep in the early Pleistocene. Accordingly, the studied succession is composed of five third-order sequences mostly controlled by tectonics, the most recent of which display complex patterns due to the interfingering of sedimentary bodies showing contrasting directions of progradation and pinch-out. Despite this, the sequence stratigraphic method still can be applied in the present context, allowing to recognize diagnostic stratal architectures and reconstruct the relative sea-level history of the region. Moreover, the recognized peculiar stratigraphic architecture of the basin fill may serve as an analogue that needs to be taken into account to predict the distribution of porous coarse-grained sedimentary units in similar contexts, aiding for a profitable exploration and production of reservoirs and source/sealing rocks. 相似文献
15.
The southern uplift of the Qiongdongnan Basin is a deepwater area in which no wells have beens drilled. The Miocene-Quaternary strata in the Xisha Islands, which are located 40–100 km to the south, are composed of carbonate reef formations. Paleotectonic and paleogeographic analyses of the basin suggest that the southern uplift experienced favorable geological conditions for the development of carbonate reefs during the Miocene.The high-impedance carbonates have high amplitudes and low frequencies on seismic profiles. The reefs are distributed on paleotectonic highs and are thicker than the contemporaneous formations. A forward model of the variation in carbonate thickness based on lithological and velocity information from wells in nearby regions can simulate the seismic response of carbonates with different thicknesses. We identified several important controlling points for determining the thickness of carbonates from seismic profiles, including the pinchout point,the λ/4 thickness point, and the λ/2 thickness point. We depict a carbonate thickness map in the deepwater area of the southern Qiongdongnan Basin based on this model. The carbonate thickness map, the paleotectonic and paleogeographic background, and the seismic response characteristics of reefs suggest that the carbonates that developed on the southern uplift of the Qiongdongnan Basin during the Miocene were mainly an isolated carbonate platform peninsula and ramp deposits. It consisted of gentle ramp platform, steep slope platform,platform depression, gravity flow, and reef bank facies. 相似文献
16.
A. Milia 《Geo-Marine Letters》1999,19(4):237-244
High-resolution seismic reflection data are used in the identification of the stratigraphic succession filling Naples Bay,
a tectonically active half-graben located in the extensional margin of the eastern Tyrrhenian Sea. The architecture of the
basin infill is characterized by fourth-order depositional sequences correlated to Quaternary eustatic oscillations. These
depositional sequences form aggrading and prograding stacking patterns bounded by tectonically enhanced unconformities. The
changes that the stacking patterns undergo record variations in accommodation space rates. These variations are a result of
the tectonic subsidence produced during the evolution of the half-graben.
Received: 7 July 1998 / Revision received: 29 March 1999 相似文献
17.
P. Cabello O. Falivene M. López-Blanco J. Howell P. Arbués E. Ramos 《Marine and Petroleum Geology》2010
The Eocene Sant Llorenç del Munt fan-delta complex developed in the Ebro foreland basin. The stratigraphy of this succession, about 1000 m thick, has been described as made up of several transgressive–regressive composite sequences, each composed of a stack of fundamental sequences, in turn made up of a transgressive systems tract and an overlying regressive systems tract. Systems tracts are composed of several facies belts: proximal alluvial fan, distal alluvial fan, fan-delta front, carbonate platform, and fan-delta slope and prodelta. 相似文献
18.
A 15-cm-thick carbonate substrate encrusted with ferromanganese oxides from the Vityaz Fracture Zone, Central Indian Ridge was analyzed to reconstruct the paleoceanography of the region. Based on the calcareous nannoplankton assemblage, an early Pliocene age has been assigned to the calcareous substrate. Among the nannoplankton, discoasters outnumber coccoliths and show signs of dissolution. The presence of certain species of benthic Foraminifera such as Uvigerina, Lenticulina, Bulimina and Bolivina, indicates the infringement of the oxygen minimum zone during the deposition of the carbonates. The occurrence of a Reticulofenestra pseudoumbilica zone of early Pliocene age suggests a change in depositional conditions coinciding with the time of formation of the large depositional hiatuses documented in sediment cores from adjacent basins of the western Indian Ocean. These hiatuses resulted from the prevalence of intermediate subsurface currents such as the Somali Current or the Western Boundary Current. 相似文献
19.
20.
High-frequency sequences composed of mixed siliciclastic-carbonate deposits may exhibit either vertical or horizontal changes between siliciclastics and carbonates. Vertical facies shifts occur between systems tracts and define a ‘reciprocal sedimentation’ pattern, typically consisting of transgressive/highstand carbonates and forced regressive/lowstand siliciclastics, although variations from this rule are common. Mixed systems with lateral facies change, usually typifying transgressive and/or highstand systems tracts, may exhibit proximal siliciclastics and distal carbonates or vice-versa, although variations may also occur along depositional strike. The marked variability of mixed siliciclastic-carbonate sequences makes the definition of a universal sequence stratigraphic model impossible, as the composition and geometries of systems tracts may change considerably, and sequence stratigraphic surfaces and facies contacts may vary in terms of occurrence and physical expression. However, some resemblance exists between siliciclastic sequences and mixed sequences showing lateral facies changes between siliciclastics and carbonates. In particular, these mixed sequences display 1) a stratal architecture of the clastic part of the systems tracts that is comparable to that of siliciclastic deposits, 2) a dominant role of the inherited physiography and of erosional processes, rather than carbonate production, in shaping the shelf profile, and 3) a local lateral juxtaposition of siliciclastic sandstones and carbonate bioconstructions due to hydrodynamic processes. These observations are helpful in predicting the location of porous and potential sealing bodies and baffles to fluid flow at the intra-high-frequency sequence scale, and ultimately they are useful for both petroleum exploration and production. 相似文献