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The presence and distribution of preserved organic matter on the surface of Mars can provide key information about the Martian carbon cycle and the potential of the planet to host life throughout its history. Several types of organic molecules have been previously detected in Martian meteorites1and at Gale crater, Mars2–4. Evaluating the diversity and detectability of organic matter elsewhere on Mars is important for understanding the extent and diversity of Martian surface processes and the potential availability of carbon sources1,5,6. Here we report the detection of Raman and fluorescence spectra consistent with several species of aromatic organic molecules in the Máaz and Séítah formations within the Crater Floor sequences of Jezero crater, Mars. We report specific fluorescence-mineral associations consistent with many classes of organic molecules occurring in different spatial patterns within these compositionally distinct formations, potentially indicating different fates of carbon across environments. Our findings suggest there may be a diversity of aromatic molecules prevalent on the Martian surface, and these materials persist despite exposure to surface conditions. These potential organic molecules are largely found within minerals linked to aqueous processes, indicating that these processes may have had a key role in organic synthesis, transport or preservation.

Although Mars today does not have a core dynamo, magnetizations in the Martian crust and in meteorites suggest a magnetic field was present prior to 3.7 billion years (Ga) ago. However, the lack of ancient, oriented Martian bedrock samples available on Earth has prevented accurate estimates of the dynamo's intensity, lifetime, and direction. Constraining the nature and lifetime of the dynamo are vital to understanding the evolution of the Martian interior and the potential habitability of the planet. The Perseverance rover, which is exploring Jezero crater, is providing an unprecedented opportunity to address this gap by acquiring absolutely oriented bedrock samples with estimated ages from ∼2.3 to >4.1 Ga. As a first step in establishing whether these samples could contain records of Martian paleomagnetism, it is important to determine their ferromagnetic mineralogy, the grain sizes of the phases, and the forms of any natural remanent magnetization. Here, we synthesize data from various Perseverance instruments to achieve those goals and discuss the implications for future laboratory paleomagnetic analyses. Using the rover's instrument payload, we find that cored samples likely contain iron oxides enriched in Cr and Ti. The relative proportions of Fe, Ti, and Cr indicate that the phases may be titanomagnetite or Fe‐Ti‐Cr spinels that are ferromagnetic at room temperature, but we cannot rule out the presence of non‐ferromagnetic ulvöspinel, ilmenite, and chromite due to signal mixing. Importantly, the inferred abundance of iron oxides in the samples suggests that even <1 mm‐sized samples will be easily measurable by present‐day magnetometers. Mars today does not have a magnetic field, but laboratory studies of Martian meteorites and spacecraft observations of the Martian crust indicate that Mars's metallic core once generated a magnetic field, known as a core dynamo. Although the dynamo seems to have been active prior to ∼3.7 billion years ago, its strength, direction and lifetime are largely unknown. Determining these characteristics is important for understanding the evolution of the Martian core and to test the theory that the magnetic field played a key role in making ancient Mars habitable. The Perseverance rover is providing a unique opportunity to answer these questions by acquiring bedrock samples that may span the full lifetime of the field. However, to establish whether these samples could tell us about the ancient dynamo, it is important to show they contain minerals with a special property known as ferromagnetism that allows them to record and retain records of the ancient magnetic field. Here, we present evidence the samples contain iron oxide minerals, many of which are known to be ferromagnetic. As such, we expect that future laboratory studies of these samples following their return to Earth will provide powerful constraints on the history of Mars's magnetic field. Iron oxides with titanium and chromium components are present in lithologies sampled by the Perseverance rover on MarsThese iron oxides may contain magnetizations from ancient Martian magnetic fieldsReturned samples of these lithologies will constrain the history and characteristics of the Martian dynamo Iron oxides with titanium and chromium components are present in lithologies sampled by the Perseverance rover on Mars These iron oxides may contain magnetizations from ancient Martian magnetic fields Returned samples of these lithologies will constrain the history and characteristics of the Martian dynamo

The Mars 2020 Perseverance rover has explored fluvio‐lacustrine sedimentary rocks within Jezero crater. Prior work showed that igneous crater floor Séítah and Máaz formations have mafic mineralogy with alteration phases that indicate multiple episodes of aqueous alteration. In this work, we extend the analyses of hydration to targets in the Jezero western fan delta, using data from the SHERLOC (Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals) Raman spectrometer. Spectral features, for example, sulfate and hydration peak positions and shapes, vary within, and across the crater floor and western fan. The proportion of targets with hydration associated with sulfates was approximately equal in the crater floor and the western fan. All hydrated targets in the crater floor and upper fan showed bimodal hydration peaks at ∼3,200 and ∼3,400 cm−1. The sulfate symmetric stretch at ∼1,000 cm−1coupled with a hydration peak at ∼3,400 cm−1indicate that MgSO4·nH2O (2 < n≤ 5) is a likely hydration carrier phase in all units, perhaps paired with low‐hydration (n≤ 1) amorphous Mg‐sulfates, indicated by the ∼3,200 cm−1peak. Low‐hydration MgSO4·nH2O (n= 1–2) are more prevalent in the fan, and hydrated targets in the fan front only had one peak at ∼3,400 cm−1. While anhydrite co‐occurs with hydrated Mg‐sulfates in the crater floor and fan front, hydrated Ca‐sulfates are observed instead at the top of the upper fan. Collectively, the data imply aqueous deposition of sediments with formation of salts from high ionic strength fluids and subsequent aridity to preserve the observed hydration states. The Mars 2020 Perseverance rover has explored a fan delta deposit in the Jezero crater where a lake was present in the past. In this work, we use the SHERLOC (Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals) Raman spectroscopy instrument on the rover to determine the minerals that contain water in the form of H2O and/or OH. These hydrated minerals are indicators of interactions of rock with water and inform us how the environmental conditions and the habitability of Jezero crater evolved over time. Hydrated Mg‐sulfates MgSO4·nH2O (2 < n≤ 5) are observed in both the crater floor and the western fan. Mg‐sulfates of lower hydration degree (n= 1–2) are more commonly found in the western fan, particularly the fan front. Hydrated Ca‐sulfate is found only close to the top of the fan. These changes in sulfate degree of hydration and/or cations from the floor to the fan are evidence of multiple past fluid events and chemistries at Jezero crater. MgSO4·nH2O (2 < n≤ 5) are found in the Jezero fan and floor while low‐hydration MgSO4·nH2O (n= 1–2) are more commonly found in the fanHydrated Ca‐sulfates are found only in the upper fanThe diverse phases imply salt formation from high ionic strength fluids and subsequent aridity to preserve the observed hydration states MgSO4·nH2O (2 < n≤ 5) are found in the Jezero fan and floor while low‐hydration MgSO4·nH2O (n= 1–2) are more commonly found in the fan Hydrated Ca‐sulfates are found only in the upper fan The diverse phases imply salt formation from high ionic strength fluids and subsequent aridity to preserve the observed hydration states

The Mars 2020 Perseverance rover has examined and sampled sulfate‐rich clastic rocks from the Hogwallow Flats member at Hawksbill Gap and the Yori Pass member at Cape Nukshak. Both strata are located on the Jezero crater western fan front, are lithologically and stratigraphically similar, and have been assigned to the Shenandoah formation. In situ analyses demonstrate that these are fine‐grained sandstones composed of phyllosilicates, hematite, Ca‐sulfates, Fe‐Mg‐sulfates, ferric sulfates, and possibly chloride salts. Sulfate minerals are found both as depositional grains and diagenetic features, including intergranular cement and vein‐ and vug‐cements. Here, we describe the possibility of various sulfate phases to preserve potential biosignatures and the record of paleoenvironmental conditions in fluid and solid inclusions, based on findings from analog sulfate‐rich rocks on Earth. The samples collected from these outcrops, Hazeltop and Bearwallow from Hogwallow Flats, and Kukaklek from Yori Pass, should be examined for such potential biosignatures and environmental indicators upon return to Earth. Images and compositional data of Mars rocks taken by the Mars 2020 Perseverance Rover at Hogwallow Flats and Yori Pass in Jezero crater show an abundance of sulfate minerals. The goal of this study was to describe the characteristics of these rocks with close‐up views of places where these rocks were abraded to expose fresh rock surface, and to make preliminary interpretations of any preservation potential of any possible environmental and biosignature data. We found sand and silt grains with a variety of colors, some of which are sulfate minerals. We also found sulfate mineral crystals between and cross‐cutting the grains. The sulfate sand and silt grains may have originally grown as chemical sediments in past salty lakes, and the sulfate crystals found between and cross‐cutting the grains formed from past salty groundwater. Sulfate mineral grains and crystals on Earth contain fluid and solid inclusions, which are remnant water, air and other gases, other minerals, and microorganisms and organic compounds. From this knowledge of terrestrial sulfate minerals, we suggest that samples of Hogwallow Flats and Yori Pass, if returned to Earth, should be investigated for fluid and solid inclusions to be evaluated for any enclosed past Martian water, gas, minerals, and possible biosignatures. We describe sub‐mm scale observations for abrasion patches Berry Hollow and Uganik Island at Hogwallow Flats and Yori Pass on the western fan front in Jezero craterThese are sulfate‐rich clastic rocks with various diagenetic features that suggest sulfate‐rich surface waters and groundwaterEnvironmental data, such as parent water temperatures and compositions, and any potential biosignatures, may have been preserved We describe sub‐mm scale observations for abrasion patches Berry Hollow and Uganik Island at Hogwallow Flats and Yori Pass on the western fan front in Jezero crater These are sulfate‐rich clastic rocks with various diagenetic features that suggest sulfate‐rich surface waters and groundwater Environmental data, such as parent water temperatures and compositions, and any potential biosignatures, may have been preserved

Sulfur plays a major role in martian geochemistry and sulfate minerals are important repositories of water. However, their hydration states on Mars are poorly constrained. Therefore, understanding the hydration and distribution of sulfate minerals on Mars is important for understanding its geologic, hydrologic, and atmospheric evolution as well as its habitability potential. NASA's Perseverance rover is currently exploring the Noachian‐age Jezero crater, which hosts a fan‐delta system associated with a paleolake. The crater floor includes two igneous units (the Séítah and Máaz formations), both of which contain evidence of later alteration by fluids including sulfate minerals. Results from the rover instruments Scanning Habitable Environments with Raman and Luminescence for Organics and Chemistry and Planetary Instrument for X‐ray Lithochemistry reveal the presence of a mix of crystalline and amorphous hydrated Mg‐sulfate minerals (both MgSO4·[3–5]H2O and possible MgSO4·H2O), and anhydrous Ca‐sulfate minerals. The sulfate phases within each outcrop may have formed from single or multiple episodes of water activity, although several depositional events seem likely for the different units in the crater floor. Textural and chemical evidence suggest that the sulfate minerals most likely precipitated from a low temperature sulfate‐rich fluid of moderate pH. The identification of approximately four waters puts a lower constraint on the hydration state of sulfate minerals in the shallow subsurface, which has implications for the martian hydrological budget. These sulfate minerals are key samples for future Mars sample return. The history of water on Mars is a puzzle that is of interest to scientists as well as the general public. Mars currently has water in the form of ice at the poles, trace amounts of gas in the atmosphere, and an unknown amount beneath the surface as ground water, bound in minerals, and in ice. However, there is strong evidence that ancient Mars may have had long‐lived streams, rivers, and lakes. There is still much to learn about what Mars was like and how it transformed over time. One approach is to study the inventory of water at different times. In this work, we report the presence of hydrated magnesium sulfate (similar to Epsom salts) and dehydrated calcium sulfate that were formed by water flowing through cracks in volcanic rocks at the bottom of the 3.8‐billion‐year‐old Jezero crater. These hydrated minerals trap water within themselves and record the history of how and when they formed. Returning samples of these minerals to Earth would allow researchers to explore the history of Mars' water and climate, and possibly evidence of ancient life with the most sensitive instruments possible. Sulfate phases detected by Scanning Habitable Environments with Raman and Luminescence for Organics and Chemistry and PIXL in igneous units consists of crystalline/amorphous Mg‐sulfate minerals with 3–5 waters and anhydrous Ca‐sulfate mineralsHydration of sulfate minerals sets a lower constraint on how much subsurface water is stored in sulfate mineralsThe sulfate minerals of Jezero crater floor were deposited in moderate pH, likely at low temperature, and during several episodes Sulfate phases detected by Scanning Habitable Environments with Raman and Luminescence for Organics and Chemistry and PIXL in igneous units consists of crystalline/amorphous Mg‐sulfate minerals with 3–5 waters and anhydrous Ca‐sulfate minerals Hydration of sulfate minerals sets a lower constraint on how much subsurface water is stored in sulfate minerals The sulfate minerals of Jezero crater floor were deposited in moderate pH, likely at low temperature, and during several episodes

The Mars 2020 Perseverance rover landed in Jezero crater on 18 February 2021. After a 100‐sol period of commissioning and the Ingenuity Helicopter technology demonstration, Perseverance began its first science campaign to explore the enigmatic Jezero crater floor, whose igneous or sedimentary origins have been much debated in the scientific community. This paper describes the campaign plan developed to explore the crater floor's Máaz and Séítah formations and summarizes the results of the campaign between sols 100–379. By the end of the campaign, Perseverance had traversed more than 5 km, created seven abrasion patches, and sealed nine samples and a witness tube. Analysis of remote and proximity science observations show that the Máaz and Séítah formations are igneous in origin and composed of five and two geologic members, respectively. The Séítah formation represents the olivine‐rich cumulate formed from differentiation of a slowly cooling melt or magma body, and the Máaz formation likely represents a separate series of lava flows emplaced after Séítah. The Máaz and Séítah rocks also preserve evidence of multiple episodes of aqueous alteration in secondary minerals like carbonate, Fe/Mg phyllosilicates, sulfates, and perchlorate, and surficial coatings. Post‐emplacement processes tilted the rocks near the Máaz‐Séítah contact and substantial erosion modified the crater floor rocks to their present‐day expressions. Results from this crater floor campaign, including those obtained upon return of the collected samples, will help to build the geologic history of events that occurred in Jezero crater and provide time constraints on the formation of the Jezero delta. The Mars 2020 Perseverance rover, along with the Ingenuity Helicopter technology demonstration, landed in Jezero crater, Mars on 18 February 2021. Here, we detail results from the first science campaign of the mission, the purpose of which was to explore the enigmatic Jezero crater floor. By the end of the campaign, Perseverance traversed more than 5 km, created seven abrasion patches, and sealed a total of nine samples and a witness tube for return to Earth. Analysis of the rocks in the crater floor revealed two distinct geologic formations, named the Máaz and Séítah formations. Both formations were determined to be igneous in origin, the former likely from a series of lava flows and the latter formed from a slowly cooling melt or magma body. The composition of the Máaz and Séítah formation rocks also indicate that they experienced significant alteration from water in the past, consistent with Jezero crater having once been filled with water. Results from Perseverance's Jezero crater floor campaign, including those obtained upon return of the collected samples to Earth, will help build the geologic history of Jezero crater and reveal its past habitability. The Máaz and Séítah formations are igneous, with Séítah representing olivine‐rich cumulates and Máaz representing separate lava flowsCrater floor rocks have been variably altered to produce carbonates and other alteration minerals during multiple aqueous episodesPost‐emplacement processes tilted these rocks near the Máaz‐Séítah contact, and erosion produced varied textures and olivine‐rich regolith The Máaz and Séítah formations are igneous, with Séítah representing olivine‐rich cumulates and Máaz representing separate lava flows Crater floor rocks have been variably altered to produce carbonates and other alteration minerals during multiple aqueous episodes Post‐emplacement processes tilted these rocks near the Máaz‐Séítah contact, and erosion produced varied textures and olivine‐rich regolith

The goals of NASA's Mars 2020 mission include searching for evidence of ancient life on Mars, studying the geology of Jezero crater, understanding Mars' current and past climate, and preparing for human exploration of Mars. During the mission's first science campaign, the Perseverance rover's SHERLOC deep UV Raman and fluorescence instrument collected microscale, two‐dimensional Raman and fluorescence images on 10 natural (unabraded) and abraded targets on two different Jezero crater floor units: Séítah and Máaz. We report SHERLOC Raman measurements collected during the Crater Floor Campaign and discuss their implications regarding the origin and history of Séítah and Máaz. The data support the conclusion that Séítah and Máaz are mineralogically distinct igneous units with complex aqueous alteration histories and suggest that the Jezero crater floor once hosted an environment capable of supporting microbial life and preserving evidence of that life, if it existed. The goals of NASA's Mars 2020 mission include searching for evidence of ancient life on Mars, studying the geology of Jezero crater, understanding Mars' current and past climate, and preparing for human exploration of Mars. During the mission's first science campaign, SHERLOC (Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals), one of Perseverance rover's spectroscopic instruments, collected microscale, two‐dimensional images that displayed mineral and organic molecule detections on 10 natural (unabraded) and abraded targets on two different Jezero crater floor geological units: Séítah and Máaz. We report SHERLOC mineral detections made during the Crater Floor Campaign and discuss their implications regarding the origin and history of Séítah and Máaz. The mineral detections support the conclusion that Séítah and Máaz are igneous units with different mineral compositions and distinct histories of alteration by fluids. The detections further suggest that the Jezero crater floor was once home to an environment capable of supporting microbial life and preserving evidence of that life, if it ever existed. The floor of the Jezero crater hosts distinct igneous units with differing aqueous alteration historiesSHERLOC Raman mineral class detections indicate that the Jezero crater floor was once a habitable environmentSome Crater Floor Campaign samples may contain salts known to preserve biosignatures in terrestrial analog environments The floor of the Jezero crater hosts distinct igneous units with differing aqueous alteration histories SHERLOC Raman mineral class detections indicate that the Jezero crater floor was once a habitable environment Some Crater Floor Campaign samples may contain salts known to preserve biosignatures in terrestrial analog environments