scholarly journals Campanian Calciturbidites from Northeast Iraq, Kurdistan Region: Insight into Paleogeography and Source Areas of the Shiranish Formation

2021 ◽  
pp. 1912-1929
Author(s):  
Anhar I. Kamil ◽  
Salam Al-Dulaimi ◽  
Kamal Haji Karim
Keyword(s):  
Foreland Basin ◽  
Source Area ◽  
Turbidity Currents ◽  
Kurdistan Region ◽  
Deep Basin ◽  
Long Distance ◽  
Submarine Channels ◽  
Source Areas ◽  
Thrust Zone ◽  
Carbonate Source

Calciturbidites are similar to siliciclastic turbidites in structure, texture, basin physiography and processes of deposition; nevertheless, their clasts (grains) are carbonate minerals. Turbidity currents transport carbonate grains from carbonate source areas and coastal areas to the deep basins after passing the shelf (peri-platform). These currents are triggered by short-lived catastrophic events, such as tsunamis, earthquakes, marine slides, and typhoons. The Late Cretaceous Zagros Foreland and Hinterland in NE-Iraq (Kurdistan Region) was an active source for the shedding of voluminous sediments to the deep basin of Zagros Foreland Basin. During late Campanian, Shiranish Formation was deposited in the foreland basin; it occurs in the most famous oil fields in the Middle East and represents hemplagite facies (much diluted turbidite facies). Previous studies have not broached the origins of Shiranish Formation, neither in detail or briefly. Conversely, the present study focused on linking the calciturbidite system to the origin of the deposition of the Shiranish Formation via derivation from main carbonate source areas. Along long distance, the sediments crossed the marginal slope, scoring submarine channels and depositing coarse detrital carbonates before reaching the basin plain. On the plain, mostly the fine fractions have settled down and mixed with pelagic sediment. The calciturbidite evidence could be tracked for more than 40 km in the studied area from the slope and outer shelf (present Thrust Zone) to the basin plain (High Folded zone). In several places, channelized detrital laminated limestones are found inside Shiranish Formation and in the most proximal area near Qaladiza town. Bouma sequences are clearly observable with erosional base and A, B, and C divisions. These calciturbidites are keys for picturing Campanian paleogeography and nature of the source area which was consisted of limestone.

scholarly journals Detrital zircon provenance record of the Zagros mountain building from the Neotethys obduction to the Arabia-Eurasia collision, NW Zagros fold-thrust belt, Kurdistan region of Iraq

2021 ◽  
Author(s):  
Renas I. Koshnaw ◽  
Fritz Schlunegger ◽  
Daniel F. Stockli
Keyword(s):  
Detrital Zircon ◽  
Upper Cretaceous ◽  
Foreland Basin ◽  
Source Area ◽  
Late Eocene ◽  
Thrust Belt ◽  
Kurdistan Region ◽  
Angular Unconformity ◽  
Tectonic Processes ◽  
Provenance Data

Abstract. Recognition of new angular unconformity and synthesizing of new detrital zircon U-Pb and (U-Th)/He provenance records, including zircon (U-Th)/(He-Pb) double dating, from the NW Zagros elucidate the basin dynamics of the foreland wedge-top and intermontane units, as well as the tectonic processes in the source terranes in response to different geodynamic phases. In this contribution, we present field observations and detrital zircon provenance data from hinterland basins to reconstruct the basin dynamics and the underlying tectonic controls in the NW Zagros in the Kurdistan region of Iraq. Results reveal that the deposition of the suture zone units of the Red Beds Series (RBS; Suwais Group, Govanda Formation, Merga Group) occurred in an intermontane basin on top of folded Upper Cretaceous units with an angular unconformity. The RBS provenance data point at the Paleogene Walash-Naopurdan-Kamyaran (WNK) arc-related complex as a source area and show substantial decrease of magmatism by ~ 36 Ma, as reflected by the youngest ages peaks. New detrital zircon provenance data from the hinterland wedge-top units of the proto-Zagros foreland basin (the Tanjero, Kolosh, and Gercus Formations) exhibit exclusive derivation from the Upper Cretaceous Neotethys ophiolitic terranes, different from the provenance of the older Lower Cretaceous and Paleozoic units that are dominated by the Paleozoic and Neoproterozoic age spectra. These shifts in provenance between different tectonostratigraphic units argue for sediment route reversal from E to W in response to ophiolite obduction, arrival of the WNK complex and commencement of the continental collision during the late Eocene, followed by deposition of the RBS in the hinterland of the proto-Zagros fold-thrust belt, and paleodrainage connection with the post-collisional Neogene foreland basin.

scholarly journals Heavy-mineral provenance signatures during the infill and uplift of a foreland basin: An example from the Jaca basin (southern Pyrenees, Spain)

2020 ◽  
Vol 90 (12) ◽  
pp. 1747-1769
Author(s):  
Xavier Coll ◽  
David Gómez-Gras ◽  
Marta Roigé ◽  
Antonio Teixell ◽  
Salva Boya ◽  
...  
Keyword(s):  
Foreland Basin ◽  
Source Area ◽  
Late Eocene ◽  
Alluvial Fan ◽  
Heavy Mineral ◽  
Heavy Minerals ◽  
Source Areas ◽  
The North ◽  
Sediment Routing ◽  
Central Pyrenees

ABSTRACT In the Jaca foreland basin (southern Pyrenees), two main sediment routing systems merge from the late Eocene to the early Miocene, providing an excellent example of interaction of different source areas with distinct petrographic signatures. An axially drained fluvial system, with its source area located in the eastern Central Pyrenees, is progressively replaced by a transverse-drained system that leads to the recycling of the older turbiditic foredeep. Aiming to provide new insights into the source-area evolution of the Jaca foreland basin, we provide new data on heavy-mineral suites, from the turbiditic underfilled stage to the youngest alluvial-fan systems of the Jaca basin, and integrate the heavy-mineral signatures with available sandstone petrography. Our results show a dominance of the ultrastable Ap-Zrn-Tur-Rt assemblage through the entire basin evolution. However, a late alluvial sedimentation stage brings an increase in other more unstable heavy minerals, pointing to specific source areas belonging to the Axial and the North Pyrenean Zone and providing new insights into the response of the heavy-mineral suites to sediment recycling. Furthermore, we assess the degree of diagenetic overprint vs. provenance signals and infer that the loss of unstable heavy minerals due intrastratal dissolution is negligible at least in the Peña Oroel and San Juan de la Peña sections. Finally, we provide new evidence to the idea that during the late Eocene the water divide of the transverse drainage system was located in the North Pyrenean Zone, and areas constituted by the Paleozoic basement were exposed in the west-Central Pyrenees at that time. Our findings provide new insights into the heavy-mineral response in recycled foreland basins adjacent to fold-and-thrust belts.

scholarly journals An efficient semi-distributed hillslope erosion model for the subhumid Ethiopian Highlands

2013 ◽  
Vol 17 (3) ◽  
pp. 1051-1063 ◽  
Author(s):  
S. A. Tilahun ◽  
C. D. Guzman ◽  
A. D. Zegeye ◽  
T. A. Engda ◽  
A. S. Collick ◽  
...  
Keyword(s):  
Surface Runoff ◽  
Source Area ◽  
Sediment Concentration ◽  
Erosion Model ◽  
Ethiopian Highlands ◽  
Source Areas ◽  
Blue Nile Basin ◽  
Field Evidence ◽  
Sediment Loss ◽  
Main Variable

Abstract. Erosion modeling has been generally scaling up from plot scale but not based on landscape topographic position, which is a main variable in saturation excess runoff. In addition, predicting sediment loss in Africa has been hampered by using models developed in western countries and do not perform as well in the monsoon climate prevailing in most of the continent. The objective of this paper is to develop a simple erosion model that can be used in the Ethiopian Highlands in Africa. We base our sediment prediction on a simple distributed saturated excess hydrology model that predicts surface runoff from severely degraded lands and from bottom lands that become saturated during the rainy season and estimates interflow and baseflow from the remaining portions of the landscape. By developing an equation that relates surface runoff to sediment concentration generated from runoff source areas, assuming that baseflow and interflow are sediment-free, we were able to predict daily sediment concentrations from the Anjeni watershed with a Nash–Sutcliffe efficiency ranging from 0.64 to 0.78 using only two calibrated sediment parameters. Anjeni is a 113 ha watershed in the 17.4 million ha Blue Nile Basin in the Ethiopian Highlands. The discharge of the two watersheds was predicted with Nash–Sutcliffe efficiency values ranging from 0.80 to 0.93. The calibrated values in Anjeni for degraded (14%) and saturated (2%) runoff source area were in agreement with field evidence. The analysis suggests that identifying the runoff source areas and predicting the surface runoff correctly is an important step in predicting the sediment concentration.

scholarly journals Environment of Deposition and Paleogeography of the Late Cretaceous Glenburn Formation, Eastern North Island, New Zealand

2021 ◽  
Author(s):  
◽  
James McClintock
Keyword(s):  
New Zealand ◽  
Late Cretaceous ◽  
Large Scale ◽  
East Coast ◽  
Three Dimensional ◽  
Depositional Environments ◽  
Tectonic Deformation ◽  
Turbidity Currents ◽  
Submarine Fan ◽  
Submarine Channels

<p>The Glenburn Formation of the East Coast of New Zealand is a Late Cretaceous sedimentary formation consisting of alternating layers of sandstone, mudstone and conglomerate. The Glenburn Formation spans a depositional timeframe of over 10 Ma, is over 1000 m thick, is regionally extensive and is possibly present over large areas offshore. For these reasons, it is important to constrain the paleoenvironment of this unit.  Late Cretaceous paleogeographic reconstructions of the East Coast Basin are, however, hampered by a number of factors, including the pervasive Neogene to modern tectonic deformation of the region, the poorly understood nature of the plate tectonic regime during the Cretaceous, and a lack of detailed sedimentological studies of most of the region’s Cretaceous units. Through detailed mapping of the Glenburn Formation, this study aims to improve inferences of regional Cretaceous depositional environments and paleogeography.  Detailed facies based analysis was undertaken on several measured sections in eastern Wairarapa and southern Hawke’s Bay. Information such as bed thickness, grain size and sedimentary structures were recorded in order to identify distinct facies. Although outcrop is locally extensive, separate outcrop localities generally lie in different thrust blocks, which complicates comparisons of individual field areas and prevents construction of the large-scale, three-dimensional geometry of the Glenburn Formation.  Glenburn Formation consists of facies deposited by sediment gravity flows that were primarily turbidity currents and debris flows. Facies observed are consistent with deposition on a prograding submarine fan system. There is significant variation in facies both within and between sections. Several distinct submarine fan architectural components are recognised, such as fan fringes, fan lobes, submarine channels and overbank deposits. Provenance and paleocurrent indicators are consistent with deposition having occurred on several separate submarine fans, and an integrated regional paleogeographic reconstruction suggests that deposition most likely occurred in a fossil trench following the mid-Cretaceous cessation of subduction along the Pacific-facing margin of Gondwana.</p>

Spatial heterogeneity of debris-flow watershed

2021 ◽  
Author(s):  
Yingjie Yao
Keyword(s):  
Potential Energy ◽  
Debris Flow ◽  
Spatial Autocorrelation ◽  
Gravitational Potential ◽  
Source Area ◽  
Geospatial Analysis ◽  
Gravitational Potential Energy ◽  
Source Areas ◽  
Hypsometric Analysis ◽  
Inflection Points

&lt;p&gt;The intermittent surge is the basic manifestation of viscous debris flow, which emerges universally over the world, especially exemplified by those in Jiangjia Gully (JJG), a valley famous for its high frequency and variety of debris flow surges. It has been found that the surges originate from various sources in the watershed, thus identifying the source areas plays a fundamental role in studying the mechanism and process of surge developing. Advancement of GIS provides an apparent convenience in geospatial analysis of the watershed, which is used as a dominate tool in this paper.&lt;/p&gt;&lt;p&gt;In this study the JJG is divided into 97 tributaries (sub-watershed) and the hypsometric analysis is performed for each, from which derive the height of inflection points and the gravitational potential energy, coupled with the fitted parameters of specific power function. Then the morphology parameters, including slope, roundness, vegetation and soil, are revealed in tributaries. Besides, spatial autocorrelation among tributaries is quantified both globally and locally through Moran&amp;#8217;s I and Getis-Ord G&lt;sub&gt;i&lt;/sub&gt;*, so that the HI spatial distributions are quantified and visualized. In particular, hot spots are conspicuously visible and highlight the geologic meaning of the HI when exploratory spatial data analysis is applied to the data distributions through local indices of spatial autocorrelation.&lt;/p&gt;&lt;p&gt;The results show that H-curves approximately present as S-shaped, and the integral values (HI) range from 0.18 to 0.69 and show positive relationship with both gravitational potential energy and the height of the inflection points. By the HI value, the tributaries are identified as in 5 phases of evolution. The younger tributaries (HI&gt;0.49) make up the majority, which are expected to be the main possible sources for debris flows. Additionally, the slope distribution of tributaries all conform to the extreme distribution while the curves for the upstream, where the HI of tributaries generally manifest higher coupled with larger roundness, tends to skew to the right.&lt;/p&gt;&lt;p&gt;Finally the correlation between possible sources are explored through geospatial analysis. The spatial association in JJG provides an explanation of the debris flow source areas. Global spatial autocorrelation manifests significantly clustered (Moran&amp;#8217;s I shows 0.449, passing the significance test) while tributaries with high HI value concentrate mainly in the Menqian Valley. Moreover, the drainage form of Menqian Valley represents a large possibility of debris flow source area with the respect of that being in Duozhao Valley.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Keywords: &lt;/strong&gt;debris flow source area; hypsometric analysis; topographical characteristics; spatial autocorrelation; evolutionary phases&lt;/p&gt;

The Numidian Sand Event in the Burdigalian Foreland Basin System of the Rif (Morocco) in a source-to-sink perspective

2021 ◽  
Author(s):  
Anas Abbassi ◽  
Paola Cipollari ◽  
Maria Giuditta Fellin ◽  
Mohamed Najib Zaghloul ◽  
Marcel Guillong ◽  
...  
Keyword(s):  
Detrital Zircon ◽  
Large Population ◽  
Foreland Basin ◽  
Source Area ◽  
Western Mediterranean ◽  
Early Miocene ◽  
Calcareous Nannofossils ◽  
External Zone ◽  
Field Evidence ◽  
Basin System

&lt;p&gt;During the Tertiary evolution of the Western Mediterranean subduction system, the orogenic accretion at the Maghrebian margin let the stacking of three main tectonic zones of the Rif fold-and-thrust belt: 1) the Internal Zone; 2) the &amp;#8220;Maghrebian Flysch&amp;#8221; Nappes; and 3) the&amp;#160; External Zone. In this context, a migrating foreland basin system developed between the Maghrebian orogenic belt and the adjacent African Craton.&amp;#160;&lt;/p&gt;&lt;p&gt;A comprehensive reconstruction of the foreland basin system of the Rif Chain for each phase of its accretional history is still missing. In this work, by integrating field observations with quantitative biostratigraphic data from calcareous nannofossils assemblages, sandstone composition, and detrital zircon U-Pb geochronology from selected stratigraphic successions, we reconstruct the foreland basin system that in the early Miocene developed in front of the growing Rif orogen. The analyzed successions are representative of (1) the &amp;#8220;Beliounis Facies&amp;#8221;, made of quartz-arenites and litharenites (Numidian-like &amp;#8220;mixed succession&amp;#8221;), from the Predorsalian Unit; (2) the &amp;#8220;M&amp;#233;rinides Facies&amp;#8221;, made of a Numidian-like &amp;#8220;mixed succession&amp;#8221;, from the &amp;#8220;Maghrebian Flysch Basin&amp;#8221;; and (3) the classical &amp;#8220;Numidian Facies&amp;#8221;, exclusively made of quartzarenites, from the Intrarifian Tanger Unit.&lt;/p&gt;&lt;p&gt;The petrographic analyses and the detrital zircon U-Pb ages show the provenance of the quartzarenites of the &amp;#8220;Numidian Facies&amp;#8221; from the African Craton, whereas the sublitharenites and feldspathic litharenites, of both the &amp;#8220;M&amp;#233;rinides Facies&amp;#8221; and &amp;#8220;Beliounis Facies&amp;#8221;, show provenance from a cratonic area and the growing and unroofing Rif Chain, respectively.&amp;#160;&lt;/p&gt;&lt;p&gt;The Alpine signature of the detrital grains sedimented into the foredeep deposits of the early Miocene orogenic system of the Rif Chain is from the feldspathic litharenites of both the M&amp;#233;rinides Facies and the Beni Ider Flysch. Both show Mesozoic and Cenozoic U-Pb zircon populations, with a large population of zircons centered at ca. 32 Ma. The U and Th concentration, the Th/U ratio, and the REE pattern of this population of zircons suggest a possible source area from Oligocene doleritic rock intrusions, similar to the magmatic dyke swarms (diorite) cropping out in the Malaga region ( SE Spain).&lt;/p&gt;&lt;p&gt;The biostratigraphic analyses pinpoint the same age for the arrival of the quartz grains in the Numidian, M&amp;#233;rinides, and Beliounis deposits, indicating about 1 Myr for their sedimentation (ca. 20-19 Ma, early Burdigalian). Together with field evidence, the biostratigraphic results point to an autochthonous deposition of the Numidian Sandstones on top of the Tanger Unit, allowing to delineate the early Burdigalian foreland basin system of the Rif Chain. The foreland depozone involved the Tanger Unit and received the &amp;#8220;Numidian Facies&amp;#8221; deposits&amp;#160;; the foredeep depozone hosted about 2000 m of the &amp;#8220;M&amp;#233;rinides Facies&amp;#8221; and the Beni Ider Flysch, and developed on the so-called &amp;#8220;Flysch Basin Domain&amp;#8221;; and, finally, the wedge-top depozone, characterized by the &amp;#8220;Beliounis Facies&amp;#8221;, developed on top of the Predorsalian Unit.&lt;/p&gt;&lt;p&gt;The Numidian Sandstones and the Numidian-like deposits analyzed in Morocco show the same age of similar deposits from Algeria, Tunisia, and Sicily, suggesting a comparable early Burdigalian tectono-sedimentary evolution along the southern branch of the Western Mediterranean subduction-related orogen.&lt;/p&gt;

Lower Cretaceous Barents Sea strata: epicontinental basin configuration, timing, correlation and depositional dynamics

2019 ◽  
Vol 157 (3) ◽  
pp. 458-476 ◽  
Author(s):  
Ivar Midtkandal ◽  
Jan Inge Faleide ◽  
Thea Sveva Faleide ◽  
Christopher Sæbø Serck ◽  
Sverre Planke ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Early Cretaceous ◽  
Barents Sea ◽  
Source Area ◽  
High Arctic ◽  
Large Igneous Province ◽  
Long Distance ◽  
Svalbard Archipelago ◽  
Control Factors ◽  
Architectural Patterns

AbstractA comprehensive dataset is collated in a study on sediment transport, timing and basin physiography during the Early Cretaceous Period in the Boreal Basin (Barents Sea), one of the world’s largest and longest active epicontinental basins. Long-wavelength tectonic tilt related to the Early Cretaceous High Arctic Large Igneous Province (HALIP) set up a fluvial system that developed from a sediment source area in the NW, which flowed SE across the Svalbard archipelago, terminating in a low-accommodation shallow sea within the Bjarmeland Platform area of the present-day Barents Sea. The basin deepened to the SE with a ramp-like basin floor with gentle dip. Seismic data show sedimentary lobes with internal clinoform geometry that advanced from the NW. These lobes interfingered with, and were overlain by, another younger depositional system with similar lobes sourced from the NE. The integrated data allow mapping of architectural patterns that provide information on basin physiography and control factors on source-to-sink transport and depositional patterns within the giant epicontinental basin. The results highlight how low-gradient, low-accommodation sediment transport and deposition has taken place along proximal to distal profiles for several hundred kilometres, in response to subtle changes in base level and by intra-basinal highs and troughs. Long-distance correlation along depositional dip is therefore possible, but should be treated with caution to avoid misidentification of timelines for diachronous surfaces.

scholarly journals The Occurrence and Risks of Selected Emerging Pollutants in Drinking Water Source Areas in Henan, China

2019 ◽  
Vol 16 (21) ◽  
pp. 4109 ◽  
Author(s):  
Donghai Wu ◽  
Ying Zhou ◽  
Guanghua Lu ◽  
Kai Hu ◽  
Jingjing Yao ◽  
...  
Keyword(s):  
Drinking Water ◽  
Hazard Index ◽  
Source Area ◽  
Dry Weight ◽  
Water Source ◽  
Triphenylphosphine Oxide ◽  
Drinking Water Source ◽  
Uv Filters ◽  
Source Areas ◽  
Total Concentrations

The occurrence of organic micropollutants (OMPs) in aqueous environments has potential effects on ecological safety and human health. Three kinds of OMPs (namely, pharmaceuticals, ultraviolet (UV) filters and organophosphate esters (OPEs)) in four drinking water source areas in Henan Province of China were analyzed, and their potential risks were evaluated. Among 48 target chemicals, 37 pollutants with total concentrations ranging from 403.0 to 1751.6 ng/L were detected in water, and 13 contaminants with total concentrations from 326.0 to 1465.4 ng/g (dry weight) were observed in sediment. The aqueous pollution levels in Jiangang Reservoir and Shahe Water Source Area were higher than that in Nanwan Reservoir and Baiguishan Reservoir, while the highest total amount of pollutants in sediment was found in Baiguishan Reservoir. Compared with pharmaceuticals and UV filters, OPEs presented higher concentrations in all investigated drinking water source areas. The highest observed concentration was triphenylphosphine oxide (TPPO, 865.2 ng/L) in water and tripentyl phosphate (TPeP, 1289.8 ng/g) in sediment. Moreover, the risk quotient (RQ) analysis implies that the determined aqueous contaminants exhibited high risks to algae and invertebrates, whereas moderate risk to fish was exhibited. The health risk assessment of aqueous OMPs by means of the hazard index (HI) indicates that the risks to adults and children were negligible. These observations are expected to provide useful information for the assessment of water quality in drinking water sources in Henan, China.

scholarly journals How to recognize crescentic bedforms formed by supercritical turbidity currents in the geologic record: Insights from active submarine channels

Geology ◽  
2018 ◽  
Vol 46 (6) ◽  
pp. 563-566 ◽  
Author(s):  
Sophie Hage ◽  
Matthieu J.B. Cartigny ◽  
Michael A. Clare ◽  
Esther J. Sumner ◽  
Daniela Vendettuoli ◽  
...  
Keyword(s):  
Turbidity Currents ◽  
Submarine Channels ◽  
Geologic Record

scholarly journals Rural Households’ Willingness to Accept Compensation Standards for Controlling Agricultural Non-Point Source Pollution: A Case Study of the Qinba Water Source Area in Northwest China

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1251 ◽  
Author(s):  
Xiaoping Li ◽  
Wenxin Liu ◽  
Yan Yan ◽  
Gongyuan Fan ◽  
Minjuan Zhao
Keyword(s):  
Rural Households ◽  
Source Area ◽  
Water Source ◽  
Willingness To Accept ◽  
Point Source Pollution ◽  
Ecological Benefits ◽  
Source Areas ◽  
Compensation Standard ◽  
Non Point Source Pollution ◽  
Willingness To Accept Compensation

Agricultural non-point source pollution (ANSP) has become one of the main sources of pollution in water source areas. An effective solution to this problem is the use of ecological compensation to encourage rural households to adopt agricultural pollution control measures. This study aims to answer two questions: How much compensation should be given to encourage rural households in water source areas to participate in ANSP control? What factors will influence their participation? In this study, paddy rice planting in water source area has been used as an example aiming to answer these questions. This study used the random parameter logit (RPL) model with survey data from 632 rural households in the Qinba water source area to empirically analyze rural households’ willingness to accept compensation for ANSP control and the influencing factors of this willingness. From this information, the compensation standards for ANSP control in a water source area were calculated. The results show that (1) compensation had a significant incentive effect on rural households’ willingness to control ANSP. The marginal compensation standard for reducing the use of fertilizer and pesticide was $3.40/ha and $2.00/ha, respectively. The compensation standard for not applying chemical fertilizer and pesticide at all was $540.23/ha. (2) There was heterogeneity in rural households’ preference for ANSP control compensation policies. Rural households characterized by younger residents, higher family income, higher perception of the ecological benefits, and higher perception of government policy were more willing to participate in the compensation policy. It is suggested that rural households showed a strong preference for ANSP control policies by considering both of their economic losses and ecological benefits. Our study contributes to the literature by enriching the evaluation method in providing references for the compensation of ANSP control policies

Sign in / Sign up

Export Citation Format

Share Document