[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"doc-detail-41005-en":3,"doc-seo-41005-105":29,"detail-sidebar-cat-0-en-105":91},{"code":4,"msg":5,"data":6},0,"success",{"doc_id":7,"user_id":8,"nickname":9,"user_avatar":10,"doc_module":4,"category_id":11,"category_name":12,"doc_title":13,"doc_description":14,"doc_content":15,"file_id":16,"file_url":17,"file_type":18,"file_size":19,"view_count":20,"is_deleted":4,"is_public":20,"is_downloadable":20,"audit_status":20,"page_count":21,"language":22,"language_code":23,"site_id":24,"html_lang":23,"table_of_contents":25,"faqs":26,"seo_title":13,"seo_description":14,"update_tm":27,"read_time":28},41005,1374391974564,"Clementine","https://ap-avatar.wpscdn.com/avatar/14000253aa45c000a9e?x-image-process=image/resize,m_fixed,w_180,h_180&k=1779874745381141002",8,"Research & Report","Formation Age of the Rima Sharp Sinuous Rill on the Moon","Chronological constraints on the Rima Sharp sinuous rill near China’s Chang'e-5 sampling site support reliable interpretation of returned lunar materials. Using crater population studies, crater statistics on rille floors and buffered crater statistics for narrow linear features are applied and cross-compared. Buffered crater statistics yield more trustworthy ages. The proposed sequence of related rilles is Rimae Harpalus → Louville → Sharp → Mairan, with Chang'e-5 basalts mainly sourced from Rima Sharp (~1.7 Ga) and possibly also from Mairan (~1.0 Ga).","A&A 657, A42 (2022)  \n[https://doi.org/10.1051/0004-6361/202142092](https://doi.org/10.1051/0004-6361/202142092)[ ](https://doi.org/10.1051/0004-6361/202142092)© ESO 2022  \n&~~t~~ronomy~~t~~rop~~h~~ys~~i~~cs  \nFormation age of the Rima Sharp sinuous rill on the Moon, source of the returned Chang'e-5 samples  \nLuyuan Xu () 1 , 2 and Le Qiao ()3  \n1 State Key Laboratory of Lunar and Planetary Sciences, Macau University of Science and Technology, Macao, PR China  \n2 CNSA, Macau Center for Space Exploration and Science, Macao, PR China  \n3 Shandong Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, School of Space Science and Physics, Institute of Space Sciences, Shandong University, Weihai, Shandong, 264209, PR China  \ne-mail: [leqiao.geo@gmail.com](leqiao.geo@gmail.com)  \nReceived 26 August 2021 / Accepted 3 November 2021  \nABSTRACT  \nContext. In December 2020, China's Chang'e-5 spacecraft successfully returned 1731 g of lunar samples to Earth. Rima Sharp, oneof the longest sinuous rilles on the Moon, lies very near (\u003C20 km) to the Chang'e-5 sampling site and is very likely to be the source of the returned samples. Constraining its formation age would provide key references for the ongoing sample analyses.  \nAims. Our intent is to obtain the accurate formation ages of Rima Sharp and related lunar rilles through crater population studies and to assess their implications for the Chang'e-5 sample analyses and interpretations.  \nMethods. We utilized two separate techniques to measure and analyze craters that were formed after the formation of the studied sinuous rilles: the conventional crater statistics for the rille floors and the buffered crater statistics that are specialized in the dating of narrow linear features. We were able to carefully compare the results derived from the two methods and estimate the formation ages of these rilles.  \nResults. We suggest that the buffered crater statistic method produces more reliable ages for the studies rilles than the conventional method. The formation sequence of sinuous rilles around the Chang'e-5 site is proposed as follows, in chronological order: Rimae Harpalus, Louville, Sharp, and Mairan. The basalt samples returned by Chang'e-5 are likely to have mainly been sourced from Rima Sharp, with an estimated age of 􀀘 1.7 Ga based on the crater N(1) value (spatial density of craters 􀀆1 km in diameter) of (2:10 􀀆 0:20) 􀀂 10􀀀3 km􀀀2 and the new crater chronology function (CF) . The other, younger rille, Rima Mairan, which was formed 􀀘 1.0 Ga (N(1) =(1:17 􀀆 0:20) 􀀂 10􀀀3 km􀀀2 and with the same CF), may also contribute to the basaltic deposits at the landing site. These crater count statistics and dating results can be coordinated with the radio-isotopic age of Chang'e-5 samples for a recalibration of lunar impact flux and the crater population dating method.  \nKey words. Moon – planets and satellites: surfaces – planets and satellites: physical evolution  \n1. Introduction and background  \nOn the 1st of December (UTC) 2020, China's Chang'e-5 lunar sample return spacecraft successfully landed on the northeastern Oceanus Procellarum (43.06􀀎 N, 51.92􀀎 W; Wang et al. 2021) and returned 1731 g of samples to Earth on 16 December 2020 . The landing site was later officially named Statio Tianchuan by the International Astronomical Union (IAU) (Fig. 1) . The landing site is located in a mare unit (termed Em4/P58; 􀀘 37 000 km2 in area) with an estimated age ranging from 􀀘 1–2 Ga, based on previous crater count dating studies (Hiesinger et al. 2003 ; Morota et al. 2011 ; Qian et al. 2018, 2021a,c; Wu et al. 2018 ; Jia et al. 2020 ; Qiao et al. 2021b) . This makes it among the youngest mare basalt units on the Moon (Hiesinger et al. 2003 ; Morota et al. 2011) and much younger than any returned lunar basalt samples or lunar meteorites (Qiao et al. 2021a) . Geological knowledge concerning the provenance of these samples is essential for ongoing sample analyses and interpretations.  \nAt 􀀘 17 ","cbCaidS4sLo1tpML","https://ap.wps.com/l/cbCaidS4sLo1tpML","pdf",24478770,1,9,"English","en",105,"# Abstract\n# Introduction and background\n## Chang'e-5 mission and landing site context\n## Sinuous rilles near the sampling area: Rima Sharp, Rima Mairan, Rima Harpalus, Rima Louville","[{\"question\":\"Why is constraining the formation age of Rima Sharp important for Chang'e-5 sample analysis?\",\"answer\":\"Rima Sharp lies very close to the Chang'e-5 sampling site and is likely the source of the returned samples. Accurate formation ages provide key references for interpreting the sample analyses.\"},{\"question\":\"What crater-dating approaches were used to estimate the rilles’ ages?\",\"answer\":\"Two techniques were applied: conventional crater statistics for rille floors and buffered crater statistics designed for dating narrow linear features. Results from both methods were carefully compared.\"},{\"question\":\"Which method was judged more reliable, and what age sequence of rilles is proposed?\",\"answer\":\"Buffered crater statistics produced more reliable ages. The chronological sequence proposed is Rimae Harpalus, Louville, Sharp, and Mairan, with Sharp estimated around ~1.7 Ga and Mairan around ~1.0 Ga.\"}]",1783317793,23,{"code":4,"msg":30,"data":31},"ok",{"site_id":24,"language":23,"slug":32,"title":13,"keywords":33,"description":14,"schema_data":34,"social_meta":86,"head_meta":88,"extra_data":90,"updated_unix":27},"formation-age-of-the-rima-sharp-sinuous-rill-on-the-moon","",{"@graph":35,"@context":85},[36,53,68],{"@type":37,"itemListElement":38},"BreadcrumbList",[39,43,47,50],{"item":40,"name":41,"@type":42,"position":20},"https://docshare.wps.com","Home","ListItem",{"item":44,"name":45,"@type":42,"position":46},"https://docshare.wps.com/document/","Document",2,{"item":48,"name":12,"@type":42,"position":49},"https://docshare.wps.com/document/research-report/",3,{"item":51,"name":13,"@type":42,"position":52},"https://docshare.wps.com/document/formation-age-of-the-rima-sharp-sinuous-rill-on-the-moon/41005/",4,{"url":51,"name":13,"@type":54,"author":55,"headline":13,"publisher":57,"fileFormat":60,"inLanguage":23,"description":14,"dateModified":61,"datePublished":62,"encodingFormat":60,"isAccessibleForFree":63,"interactionStatistic":64},"DigitalDocument",{"name":9,"@type":56},"Person",{"url":40,"name":58,"@type":59},"DocShare","Organization","application/pdf","2026-07-13","2026-07-06",true,{"@type":65,"interactionType":66,"userInteractionCount":20},"InteractionCounter",{"@type":67},"ViewAction",{"@type":69,"mainEntity":70},"FAQPage",[71,77,81],{"name":72,"@type":73,"acceptedAnswer":74},"Why is constraining the formation age of Rima Sharp important for Chang'e-5 sample analysis?","Question",{"text":75,"@type":76},"Rima Sharp lies very close to the Chang'e-5 sampling site and is likely the source of the returned samples. Accurate formation ages provide key references for interpreting the sample analyses.","Answer",{"name":78,"@type":73,"acceptedAnswer":79},"What crater-dating approaches were used to estimate the rilles’ ages?",{"text":80,"@type":76},"Two techniques were applied: conventional crater statistics for rille floors and buffered crater statistics designed for dating narrow linear features. Results from both methods were carefully compared.",{"name":82,"@type":73,"acceptedAnswer":83},"Which method was judged more reliable, and what age sequence of rilles is proposed?",{"text":84,"@type":76},"Buffered crater statistics produced more reliable ages. The chronological sequence proposed is Rimae Harpalus, Louville, Sharp, and Mairan, with Sharp estimated around ~1.7 Ga and Mairan around ~1.0 Ga.","https://schema.org",{"og:url":51,"og:type":87,"og:title":13,"og:site_name":58,"og:description":14},"article",{"robots":89,"canonical":51},"index,follow",{"doc_id":7,"site_id":24},{"code":4,"msg":5,"data":92},[93,97,101,105,110,115,120,123,127,130,134],{"id":20,"doc_module":4,"doc_module_name":45,"category_name":94,"show_sort_weight":95,"slug":96},"Story & Novel",90,"story-novel",{"id":46,"doc_module":4,"doc_module_name":45,"category_name":98,"show_sort_weight":99,"slug":100},"Literature",80,"literature",{"id":52,"doc_module":4,"doc_module_name":45,"category_name":102,"show_sort_weight":103,"slug":104},"Exam",70,"exam",{"id":106,"doc_module":4,"doc_module_name":45,"category_name":107,"show_sort_weight":108,"slug":109},5,"Comic",60,"comic",{"id":111,"doc_module":4,"doc_module_name":45,"category_name":112,"show_sort_weight":113,"slug":114},6,"Technology",50,"technology",{"id":116,"doc_module":4,"doc_module_name":45,"category_name":117,"show_sort_weight":118,"slug":119},7,"Healthcare",40,"healthcare",{"id":11,"doc_module":4,"doc_module_name":45,"category_name":12,"show_sort_weight":121,"slug":122},30,"research-report",{"id":21,"doc_module":4,"doc_module_name":45,"category_name":124,"show_sort_weight":125,"slug":126},"Religion & Spirituality",20,"religion-spirituality",{"id":125,"doc_module":4,"doc_module_name":45,"category_name":128,"show_sort_weight":125,"slug":129},"World Cup","world-cup",{"id":131,"doc_module":4,"doc_module_name":45,"category_name":132,"show_sort_weight":131,"slug":133},10,"Lifestyle","lifestyle",{"id":135,"doc_module":4,"doc_module_name":45,"category_name":136,"show_sort_weight":106,"slug":137},19,"General","general"]