Remote detection of a lunar granitic batholith at Compton-Belkovich.

Granites are nearly absent in the Solar System outside of Earth. Achieving granitic compositions in magmatic systems requires multi-stage melting and fractionation, which also increases the concentration of radiogenic elements1. Abundant water and plate tectonics facilitate these processes on Earth, aiding in remelting. Although these drivers are absent on the Moon, small granite samples have been found, but details of their origin and the scale of systems they represent are unknown2. Here we report microwave-wavelength measurements of an anomalously hot geothermal source that is best explained by the presence of an approximately 50-kilometre-diameter granitic system below the thorium-rich farside feature known as Compton-Belkovich. Passive microwave radiometry is sensitive to the integrated thermal gradient to several wavelengths depth. The 3-37-gigahertz antenna temperatures of the Chang'e-1 and Chang'e-2 microwave instruments allow us to measure a peak heat flux of about 180 milliwatts per square metre, which is about 20 times higher than that of the average lunar highlands3,4. The surprising magnitude and geographic extent of this feature imply an Earth-like, evolved granitic system larger than believed possible on the Moon, especially outside of the Procellarum region5. Furthermore, these methods are generalizable: similar uses of passive radiometric data could vastly expand our knowledge of geothermal processes on the Moon and other planetary bodies.

Mixed-methods evaluation of a face-to-face educational intervention for health and social care professionals to deliver family-centred cancer supportive care when a parent with dependent children is at end of life.

OBJECTIVE: To deliver and evaluate an educational intervention to equip health and social care professionals (professionals) on how best to support parents at end of life with cancer concerning their dependent children (<18). METHODS: An evidence-based and theory-driven face-to-face educational intervention was developed and evaluated using three levels of Kirkpatrick's Model of Evaluation. Pre-test, post-test surveys were completed immediately before-and-after the intervention using a validated self-efficacy scale and single-item questions evaluating perceived usefulness and relevance (levels one/two). Qualitative interviews ≥ 3-months post-intervention explored if, and how the intervention impacted professionals' practice (level three). Fourteen sessions were delivered at oncology settings to 347 professionals between 2021 and 2023. Two hundred seventy four professionals completed the pre-test survey, with 239 completing the post-test survey. Fourteen professionals were interviewed between three-and 19-months post-intervention. RESULTS: Quantitative findings demonstrated a statistically significant improvement in self-efficacy post-educational intervention (p < 0.001). Qualitative data highlighted professionals gained new approaches to progress end of life conversations with parents, despite some familial resistance to sharing the reality of the situation with children. Positive intervention content shaping clinical practice included the bereaved parent's lived experience, communication framework and roleplay videos. Some professionals considered a booster session and opportunities to practice conversations necessary to further consolidate learning into practice. CONCLUSIONS: Evidence and theory-driven education can positively impact professionals' provision of family-centred cancer care. Future studies should explore the impact of this educational intervention on familial outcomes. Alongside a sustainable delivery of this intervention, advanced communication skills programmes should incorporate parent-child end of life conversations.

Obstacles and facilitators to communicating with children about their parents' mental illness: a qualitative study in a sub-district of Mpumalanga, South Africa.

BACKGROUND: Given that common mental disorders are one of the leading causes of disease burden worldwide, it is likely that many children are growing up with a parent or other adult within their family who has anxiety or depression. Parents with a mental illness may not consider it appropriate to discuss their illness with their child, and consequently an absence of communication may lead to stigmatization, shame, misunderstanding their parents' symptoms, and even blaming themselves. There is a scarcity of research exploring the experiences and perceptions of healthcare professionals about communication with children of parents with mental illness in low-resource and African contexts. METHODS: A qualitative study using semi-structured interviews with healthcare professionals (n = 15) was conducted within the Bushbuckridge sub-district of Mpumalanga Province, South Africa. Data were analysed using Thematic Analysis. RESULTS: Four themes were identified relating to the obstacles around communication with children. These included: (1) finding an appropriate language to describe mental illness, as well as the prevailing cultural explanations of mental illness (2) the stigma associated with mental illness (3) the perceived role of children in society and (4) mental health services and staff skills. Two themes that addressed facilitators of communication about parental mental illness were identified: (1) the potential to increase mental health awareness amongst the broader community through social media, the internet, and general psychoeducation (2) healthcare professionals' concerns for the wellbeing and future mental health of patients' children, as well as their hopes for increased mental health awareness amongst future generations. CONCLUSIONS: This study provides insight into healthcare professionals' attitudes and perceptions about talking to patients and families within their community about mental illness. The results provide recommendations about possible ways to promote sharing information about a parent's mental illness with children at an individual and community level. Future research should focus on the collaborative creation of culturally sensitive psychoeducational resources and evidence-based guidelines. This must be supported by systemic and organisational change in order for professionals to successfully facilitate conversations with patients who are parents, and their children.

Trusting relationships between patients with non-curative cancer and healthcare professionals create ethical obstacles for informed consent in clinical trials: a grounded theory study.

BACKGROUND: Clinical trial participation for patients with non-curative cancer is unlikely to present personal clinical benefit, which raises the bar for informed consent. Previous work demonstrates that decisions by patients in this setting are made within a 'trusting relationship' with healthcare professionals. The current study aimed to further illuminate the nuances of this relationship from both the patients' and healthcare professionals' perspectives. METHODS: Face-to-face interviews using a grounded theory approach were conducted at a regional Cancer Centre in the United Kingdom. Interviews were performed with 34 participants (patients with non-curative cancer, number (n) = 16; healthcare professionals involved in the consent process, n = 18). Data analysis was performed after each interview using open, selective, and theoretical coding. RESULTS: The 'Trusting relationship' with healthcare professionals underpinned patient motivation to participate, with many patients 'feeling lucky' and articulating an unrealistic hope that a clinical trial could provide a cure. Patients adopted the attitude of 'What the doctor thinks is best' and placed significant trust in healthcare professionals, focusing on mainly positive aspects of the information provided. Healthcare professionals recognised that trial information was not received neutrally by patients, with some expressing concerns that patients would consent to 'please' them. This raises the question: Within the trusting relationship between patients and healthcare professionals, 'Is it possible to provide balanced information?'. The theoretical model identified in this study is central to understanding how the trusting professional-patient relationship influences the decision-making process. CONCLUSION: The significant trust placed on healthcare professionals by patients presented an obstacle to delivering balanced trial information, with patients sometimes participating to please the 'experts'. In this high-stakes scenario, it may be pertinent to consider strategies, such as separation of the clinician-researcher roles and enabling patients to articulate their care priorities and preferences within the informed consent process. Further research is needed to expand on these ethical conundrums and ensure patient choice and autonomy in trial participation are prioritised, particularly when the patient's life is limited.

'I didn't know what was in front of me'-Bereaved parents' experience of adapting to life when a co-parent of dependent children has died with cancer.

OBJECTIVE: It is not clear how the bereaved parent navigates life with the children after a co-parent has died. The objective of this study is to explore bereaved parents' experience of managing life when a co-parent of dependent children has died with cancer. METHODS: Twenty-one in-depth interviews were conducted with bereaved parents when a co-parent died with cancer. Data were analysed thematically. RESULTS: Bereaved parents highlighted how their children was their key focus after the death of a co-parent with cancer, as they effortfully strived to be a 'perfect parent'. While some bereaved parents struggled to adapt to the role as a sole parent, others described the importance of maximising social networks to help with the practical aspects of parenting. However, most bereaved parents described intense feelings of loneliness as they navigated parenting alone. To help navigate this post-bereavement period, parents considered it important for their children to openly talk about the deceased parent. Also, meeting others who have experienced similar situations was helpful for the bereaved parent and children, providing hope for the future. Results are discussed under two themes: (1) adapting to life without the parent, and (2) a desire to keep the memory alive of the parent that died with cancer. CONCLUSIONS: Bereaved parents should be encouraged to practice self-care when a co-parent has died from cancer so they can appropriately meet the needs of their children. Bereaved parents should be reassured that showing emotion in front of the children is helpful and could facilitate better grief experiences for the whole family.

'There's something about admitting that you are lonely' - prevalence, impact and solutions to loneliness in terminal illness: An explanatory sequential multi-methods study.

BACKGROUND: Loneliness is a prevalent societal issue and can impact on a person's physical and mental health. It is unclear how loneliness impacts on end of life experiences or how such feelings can be alleviated. AIM: To explore the perceived prevalence, impact and possible solutions to loneliness among people who are terminally ill and their carers in Northern Ireland through the lens of health and social care professionals. DESIGN: An explanatory multi-method study. SETTING/PARTICIPANTS: An online survey (n = 68, response rate 30%) followed by three online focus groups with palliative and end of life care health and social care professionals (n = 14). Data were analysed using descriptive statistics and thematic analysis. RESULTS: Loneliness was perceived by professionals as highly prevalent for people with a terminal illness (92.6%) and their carers (86.8%). Loneliness was considered a taboo subject and impacts on symptoms including pain and breathlessness and overall wellbeing at end of life. Social support was viewed as central towards alleviating feelings of loneliness and promoting connectedness at end of life. Four themes were identified: (1) the stigma of loneliness, (2) COVID-19: The loneliness pandemic (3) impact of loneliness across physical and mental health domains and (4) the power of social networks. CONCLUSION: There is a need for greater investment for social support initiatives to tackle experiences of loneliness at end of life. These services must be co-produced with people impacted by terminal illness to ensure they meet the needs of this population.

Young parents' experiences of pregnancy and parenting during the COVID-19 pandemic: a qualitative study in the United Kingdom.

Young parents (aged 16-24 years) in the perinatal period are at an increased risk of poor mental health especially during the COVID-19 pandemic, due to multiple risk factors including social and economic instability. COVID-19 related restrictions had profound implications for the delivery of perinatal care services and other support structures for young parents. Investigating young parents' experiences during the pandemic, including their perceived challenges and needs, is important to inform good practice and provide appropriate support for young parents.Qualitative interviews were conducted with young parents (n = 21) during the COVID-19 pandemic in the United Kingdom from February - May 2021. Data were analysed using thematic analysis.Three key themes were identified to describe parents' experiences during the COVID-19 pandemic. Parents reported specific COVID-19 related anxieties and stressors, including worries around contracting the virus and increased feelings of distress due to uncertainty created by the implications of the pandemic. Parents described feeling alone both at home and during antenatal appointments and highlighted the absence of social support as a major area of concern. Parents also felt their perinatal care had been disrupted by the pandemic and experienced difficulties accessing care online or over the phone.This study highlights the potential impact of the COVID-19 pandemic on young parents, including their mental wellbeing and the perinatal support they were able to access. Insights from this study can inform the support and services offered to families going forward. Specifically, the findings emphasise the importance of (a) supporting both parents during perinatal appointments, (b) providing parents with mental health support early on and (c) finding ways to facilitate communication pathways between professionals and parents.

Challenges and opportunities for perinatal health services in the COVID-19 pandemic: a qualitative study with perinatal healthcare professionals.

BACKGROUND: Perinatal healthcare professionals (PHCPs) provide essential support to all parents in the perinatal period, including young parents aged 16-24, who are at an increased risk of morbidity and mortality. Little is known about the impact of COVID-19 restrictions on the provision of perinatal services, and on perinatal healthcare professionals, caring for young parents in the UK. METHODS: A UK based qualitative study using semi-structured interviews with perinatal healthcare professionals (n = 17). Data were analysed using thematic analysis. RESULTS: Two themes were identified describing perinatal healthcare professionals' perceptions of providing care to young parents during the pandemic. Perinatal healthcare professionals perceived that young parents' needs were amplified by the pandemic and that pandemic-related changes to the service, such as the use of telemedicine to replace face-to-face interactions, did not manage to successfully mitigate the increased feelings of anxiety and isolation experienced by young parents. Concerns were raised by perinatal healthcare professionals that these changes reduced young parent's access to vital support for themselves and their child and may contribute to exacerbating pre-existing inequalities. CONCLUSIONS: This study provides insight into the impact of the COVID-19 pandemic on the provision of perinatal care to young parents. Perinatal mental health professionals felt these negative impacts could be overcome by using a blended approach of technology and face-to-face interactions allowing regular contact with young parents and facilitating the exchange of vital information, while maintaining access to opportunities for social interactions with other parents. Findings from this study could be used to future-proof services against further COVID-19 restrictions.

Immediate bereavement experiences when a parent of dependent children has died of cancer: Funeral directors' perspectives.

When a parent of dependent children dies, families are often unsure if and how children could be part of the immediate bereavement period. Children excluded can be more susceptive to negative outcomes. In-depth interviews explored funeral directors' (N = 23) experiences of providing a service to families in the immediate bereavement period, when a parent dies from cancer. Findings highlighted funeral directors can have an important role in guiding families through the distressing immediate bereavement period. Recommendations are discussed surrounding a pastoral role of the funeral director in the immediate bereavement period.

Providing care to parents dying from cancer with dependent children: Health and social care professionals' experience.

OBJECTIVE: Parents often feel ill-equipped to prepare their dependent children (<18 years old) for the death of a parent, necessitating support from professionals. The aim of this study is to explore health and social care professionals' (HSCPs) experiences and perceptions of providing supportive care to parents regarding their children, when a parent is dying from cancer. METHODS: Semi-structured qualitative interviews were conducted with 32 HSCPs, including nurses, allied health professionals, social workers and doctors from specialist or generalist roles, across acute or community sectors. RESULTS: HSCPs' perceptions of the challenges faced by many families when a parent is dying from cancer included: parental uncertainties surrounding if, when and how to tell the children that their parent was dying, the demands of managing everyday life, and preparing the children for the actual death of their parent. Many HSCPs felt ill-equipped to provide care to parents at end of life concerning their children. The results are discussed under two themes: (1) hurdles to overcome when providing psychological support to parents at end of life and (2) support needs of families for the challenging journey ahead. CONCLUSIONS: There appears to be a disparity between HSCPs' awareness of the needs of families when a parent is dying and what is provided in practice. HSCPs can have a supportive role and help equip parents, as they prepare their children for the death of their parent. Appropriate training and guideline provision could promote this important aspect of end of life care into practice.

'Don't forget the children': a qualitative study when a parent is at end of life from cancer.

PURPOSE: Preparation for end of life is one of the greatest challenges faced by parents with cancer who have dependent children (< 18 years old), with requirement for support from professionals. The aim of this study is to explore how parents can be best supported in relation to their children, when a parent is at end of life from cancer. METHODS: This is an interpretive qualitative study, using 79 semi-structured interviews with parents at end of life (n3), bereaved parents (n21), health and social care professionals (HSCPs) (n32) and funeral directors (n23). Data were analysed thematically and triangulated. RESULTS: Parents are central to preparing their children for the death of a parent. Striving for everyday ordinariness, maximising social networks, maintaining hope and making preparations for the future are helpful for families when a parent is at end of life. Most HSCPs were unaware of the challenges faced by parents at end of life, and psychosocial support was often left outside the caring realm. As a result, funeral directors noted complexities faced by the families after the death. Results are discussed under four themes: (1) communication with the children as a process, (2) coping throughout the unfolding end of life experience, (3) tension and complexities at end of life and (4) preparing for the future. CONCLUSIONS: Parents should be reassured that by involving the children early in the end of life experience when the ill-parent is 'well enough' to parent enables them to be actively involved in supporting their child through one of the greatest life changing event. A number of recommendations are discussed for professionals.

'Living in parallel worlds' - bereaved parents' experience of family life when a parent with dependent children is at end of life from cancer: A qualitative study.

BACKGROUND: When a parent of dependent children (<18 years old) is at end of life from cancer, this has a profound impact on the family. Children less prepared for the death of a parent are more susceptive to poorer psychosocial adjustment in later life. There is a lack of understanding from the literature surrounding what support parents require, and how they navigate this end of life experience. AIM: To explore bereaved parents' experience and needs for families when a parent is at end of life from cancer with dependent children. DESIGN: In-depth, semi-structured qualitative interviews were conducted with 21 bereaved mothers and fathers, identified from the general public, a family support service and hospice. Data were analysed thematically. RESULTS: Parents often live in 'parallel worlds' throughout the end of life period. In one world, 'living in the moment', cherishing the ordinariness of family life, remaining hopeful treatment will prolong life, whilst adapting as the illness unfolds. The other world presents as 'intermitted glimpses that death is approaching', shadowed with painful emotional concerns surrounding their children and the future. At the end, death rapidly approaches, characterised as suddenly 'falling off the cliff'; placing significant demands on the well-parent. CONCLUSIONS: Amidst challenges, clinicians should provide parents with clear information surrounding a poor prognosis, so families can plan and prepare for parental death. There is a need for healthcare professionals to engage, encourage and equip parents, as they prepare their children throughout the end of life experience for the inevitable death of a parent.

Are public health measures and individualised care compatible in the face of a pandemic? A national observational study of bereaved relatives' experiences during the COVID-19 pandemic.

BACKGROUND: COVID-19 public health restrictions have affected end-of-life care experiences for dying patients and their families. AIM: To explore bereaved relatives' experiences of quality of care and family support provided during the last days of life; to identify the impact of factors associated with perceived support. DESIGN: A national, observational, open online survey was developed and disseminated via social media, public fora and professional networks (June-September 2020). Validated instruments and purposively designed questions assessed experiences. Analysis used descriptive statistics, logistic regression and thematic analysis of free-text responses. PARTICIPANTS: Individuals (⩾18 years) who had experienced the death of a relative/friend (all care settings) within the United Kingdome during the COVID-19 pandemic. RESULTS: Respondents (n = 278, mean 53.4 years) tended to be female (n = 216, 78%); over half were 'son/daughter' (174, 62.6%) to the deceased. Deceased individuals (mean 81.6 years) most frequently died in their 'usual place of care' (n = 192, 69.3%). Analysis established five conceptual themes affecting individualised care: (1) public health restrictions compounding the distress of 'not knowing'; (2) disparate views about support from doctors and nurses; (3) challenges in communication and level of preparedness for the death; (4) delivery of compassionate care; (5) emotional needs and potential impact on grief. Male respondents (OR 2.9, p = 0.03) and those able to visit (OR 2.2, p = 0.04) were independently associated with good perceptions of family support. CONCLUSION: Despite public health restrictions, individualised care can be enabled by proactive, informative communication; recognising dying in a timely manner and facilitating the ability to be present before death.

A qualitative study of bereaved relatives' end of life experiences during the COVID-19 pandemic.

BACKGROUND: Meeting the needs of relatives when a family member is dying can help facilitate better psychological adjustment in their grief. However, end of life experiences for families are likely to have been deleteriously impacted by the COVID-19 crisis. Understanding how families' needs can be met during a global pandemic will have current/future relevance for clinical practice and policy. AIM: To explore relatives' experiences and needs when a family member was dying during the COVID-19 pandemic. DESIGN: Interpretative qualitative study using semi-structured interviews. Data were analysed thematically. SETTING/PARTICIPANTS: A total of 19 relatives whose family member died during the COVID-19 pandemic in the United Kingdom. RESULTS: In the absence of direct physical contact, it was important for families to have a clear understanding of their family member's condition and declining health, stay connected with them in the final weeks/days of life and have the opportunity for a final contact before they died. Health and social care professionals were instrumental to providing these aspects of care, but faced practical challenges in achieving these. Results are presented within three themes: (1) entering into the final weeks and days of life during a pandemic, (2) navigating the final weeks of life during a pandemic and (3) the importance of 'saying goodbye' in a pandemic. CONCLUSIONS: Health and social care professionals can have an important role in mitigating the absence of relatives' visits at end of life during a pandemic. Strategies include prioritising virtual connectedness and creating alternative opportunities for relatives to 'say goodbye'.

Health and social care professionals' experiences of providing end of life care during the COVID-19 pandemic: A qualitative study.

BACKGROUND: Health and social care professionals' ability to address the needs of patients and their relatives at end of life is likely to have been impacted by the COVID-19 pandemic. AIM: To explore health and social care professionals' experiences of providing end of life care during the COVID-19 pandemic to help inform current/future clinical practice and policy. DESIGN: A qualitative interview study. Data were analysed using thematic analysis. SETTING/PARTICIPANTS: Sixteen health and social care professionals working across a range of clinical settings in supporting dying patients during the first wave (March-June 2020) of the COVID-19 pandemic in the United Kingdom. RESULTS: Participants reported emotional and practical challenges to providing end of life care during the pandemic, including increases in patient numbers, reduced staffing levels and relying on virtual platforms for sensitive, emotive conversations with relatives. Participants were central to promoting connections between patients and their families at end of life and creating opportunities for a final contact before the death. However, the provision of support varied as a consequence of the pressures of the pandemic. Results are discussed under two themes: (1) challenges and facilitators to providing end of life care, and (2) support needs of relatives when a family member was dying during the COVID-19 pandemic. CONCLUSION: There is a need for flexible visiting arrangements at end of life during a pandemic. A systems-level approach is necessary to promote the wellbeing of health and social care professionals providing end of life care during and after a pandemic.

Structure and evolution of the lunar Procellarum region as revealed by GRAIL gravity data.

The Procellarum region is a broad area on the nearside of the Moon that is characterized by low elevations, thin crust, and high surface concentrations of the heat-producing elements uranium, thorium, and potassium. The region has been interpreted as an ancient impact basin approximately 3,200 kilometres in diameter, although supporting evidence at the surface would have been largely obscured as a result of the great antiquity and poor preservation of any diagnostic features. Here we use data from the Gravity Recovery and Interior Laboratory (GRAIL) mission to examine the subsurface structure of Procellarum. The Bouguer gravity anomalies and gravity gradients reveal a pattern of narrow linear anomalies that border Procellarum and are interpreted to be the frozen remnants of lava-filled rifts and the underlying feeder dykes that served as the magma plumbing system for much of the nearside mare volcanism. The discontinuous surface structures that were earlier interpreted as remnants of an impact basin rim are shown in GRAIL data to be a part of this continuous set of border structures in a quasi-rectangular pattern with angular intersections, contrary to the expected circular or elliptical shape of an impact basin. The spatial pattern of magmatic-tectonic structures bounding Procellarum is consistent with their formation in response to thermal stresses produced by the differential cooling of the province relative to its surroundings, coupled with magmatic activity driven by the greater-than-average heat flux in the region.

Challenges and support needs of parents and children when a parent is at end of life: A systematic review.

BACKGROUND: Preparing children for the death of a parent is challenging. Parents are often uncertain if and how to communicate and support their children. Many parents feel it is protecting their children by not telling them about the prognosis. Children less prepared for parental death from a terminal illness are more susceptive to later adversities. To facilitate coping and moderate for such adversities, there is a need to gain insight and understand the experience and challenges confronted by families. AIM: This review synthesised evidence on the experiences of parents and children when a parent is at end of life to discern their challenges, support needs and factors that facilitated good practice. DESIGN: Mixed-methods systematic review. DATA SOURCES: Four electronic databases (CINAHL, PubMed, PsycINFO and Ovid MEDLINE) using MeSH terms and word searches in October 2018. Studies were not limited by year of publication, language or country. Grey literature searches were also completed on Google Scholar and OpenGrey. RESULTS: In all, 7829 records were identified; 27 qualitative and 0 quantitative studies met the inclusion criteria. Eight descriptive themes were identified, further categorised into two broad themes: (1) barriers and facilitators in sharing the news that a parent is dying and (2) strategies to manage the changing situation. CONCLUSION: Lack of understanding in relation to the parent's prognosis, denial and feeling ill-equipped were suggested as barriers for parents to share the news with their children. Engagement with social networks, including extended family relatives and peers, and maintaining routines such as attending school were suggested supportive by parents and children. Findings are limited primarily to White, middle-class two-parent families. A number of areas for future research are identified.

The Borealis basin and the origin of the martian crustal dichotomy.

The most prominent feature on the surface of Mars is the near-hemispheric dichotomy between the southern highlands and northern lowlands. The root of this dichotomy is a change in crustal thickness along an apparently irregular boundary, which can be traced around the planet, except where it is presumably buried beneath the Tharsis volcanic rise. The isostatic compensation of these distinct provinces and the ancient population of impact craters buried beneath the young lowlands surface suggest that the dichotomy is one of the most ancient features on the planet. However, the origin of this dichotomy has remained uncertain, with little evidence to distinguish between the suggested causes: a giant impact or mantle convection/overturn. Here we use the gravity and topography of Mars to constrain the location of the dichotomy boundary beneath Tharsis, taking advantage of the different modes of compensation for Tharsis and the dichotomy to separate their effects. We find that the dichotomy boundary along its entire path around the planet is accurately fitted by an ellipse measuring approximately 10,600 by 8,500 km, centred at 67 degrees N, 208 degrees E. We suggest that the elliptical nature of the crustal dichotomy is most simply explained by a giant impact, representing the largest such structure thus far identified in the Solar System.

Meridiani Planum and the global hydrology of Mars.

The Opportunity Mars Exploration Rover found evidence for groundwater activity in the Meridiani Planum region of Mars in the form of aeolian and fluvial sediments composed of sulphate-rich grains. These sediments appear to have experienced diagenetic modification in the presence of a fluctuating water table. In addition to the extensive secondary aqueous alteration, the primary grains themselves probably derive from earlier playa evaporites. Little is known, however, about the hydrologic processes responsible for this environmental history-particularly how such extensive evaporite deposits formed in the absence of a topographic basin. Here we investigate the origin of these deposits, in the context of the global hydrology of early Mars, using numerical simulations, and demonstrate that Meridiani is one of the few regions of currently exposed ancient crust predicted to have experienced significant groundwater upwelling and evaporation. The global groundwater flow would have been driven primarily by precipitation-induced recharge and evaporative loss, with the formation of the Tharsis volcanic rise possibly playing a role through the burial of aquifers and induced global deformation. These results suggest that the deposits formed as a result of sustained groundwater upwelling and evaporation, rather than ponding within an enclosed basin. The evaporite formation coincided with a transition to more arid conditions that increased the relative impact of a deep-seated, global-scale hydrology on the surface evolution.