Built From the Crater Up – Site Museums in Geosciences Communication and Outreach

15 What is the role of site museums and geological sites in geosciences communication, education and outreach? Natural history and site museums contribute to learning, outreach and educational programs, with geological sites in National Parks, GeoParks and UNESCO heritage sites attracting large numbers of visitors, as well as scholars and students. Here, we examine the role and potential of a museum and research center in Yucatan, Mexico built around studies of the Chicxulub asteroid 20 impact and the Cretaceous/Paleogene boundary mass extinction. The impact ranks among major single events shaping Earth’s history, triggering global climatic change and wiping out ~76% of species. The crater, with a ~200 km rim diameter, is the best preserved of the three large terrestrial multi-ring impact structures, being a natural laboratory for investigating impact dynamics, crater formation and planetary evolution. The crater and impact deposits are not exposed at the surface, 25 being covered by carbonate sediments after its formation, which presents a challenge for outreach and educational programs. The Chicxulub museum and center have a core mission to serve as a hub for multi-disciplinary research on the impact, planetary sciences, climate change and life evolution, as well as educational, outreach and science communication programs. It fulfills a recognized task for dissemination and communication of geosciences. After decades of studies, 30 the Chicxulub impact and mass extinction remain under intense scrutiny and the new facilities built inside the crater, play a major role in expanding those efforts. https://doi.org/10.5194/gc-2020-13 Preprint. Discussion started: 14 April 2020 c © Author(s) 2020. CC BY 4.0 License.

southern Gulf of Mexico (Fig. 3), was first identified in oil exploration surveys and drilling 65 programs by Petroleos Mexicanos (Pemex) (Penfield and Camargo, 1981). It has a ~200 km rim diameter and a peak-ring and multi-ring morphology (Fig. 4); the structure has been investigated by an array of geophysical/geological surveys and drilling programs (Figs. 5,6).
The K/Pg boundary is marked globally by the impact ejecta layer, characterized by the iridium and platinum group elements derived from the impacting body ( Fig. 7; Schulte et al., 2010). The impact 70 and its effects on Earth's climate and evolution of life have been intensively studied (Alvarez et al., 1980;Mukhopadhyay et al., 2001;Schulte et al., 2010;Lowery et al., 2018). Impact had massive immediate, medium and longer-term global effects on the climate and environment, providing important lessons for understanding the effects of human-made greenhouse emissions.
Although the mechanisms for the extinction and subsequent species diversification remain under 75 scrutiny, studies of this mass extinction uncover general principles governing species/clade resilience and evolvability in response to rapid climate and environmental changes. CCSRAS research rests on multi-disciplinary and international cooperation to tackle these issues.

Chicxulub Center
The CCSRAS is housed over an area of ~19 square kilometers located in the central sector of the 80 Yucatan Science City ("Parque Científico Tecnológico de Yucatán" -PCYTY) in the state of Yucatan, southern Mexico (Fig. 2). CCSRAS is a joint project between the National University of Mexico, the National Council of Science and Technology and the Ministry of Science and Higher Education of Yucatan.
The project developed over the course of a decade, first emerging with the aim to establishing a 85 site museum dedicated to the Chicxulub impact, its effects on the planet and showcase the research past and present to better understand the world around us. The first phase of the Chicxulub Science Museum was completed in 2011 within the Yucatan Science City, housed in the Central Library The Grand Museum Chicxulub exhibition was coordinated by Enrique Ortiz Lanz and has attracted large number of visitors, including students and researchers (Fig. 9). The exhibition provided an introduction to comets, asteroids and meteorites, early observations, myths and interpretations of https://doi.org/10.5194/gc-2020-13 Preprint. Discussion started: 14 April 2020 c Author(s) 2020. CC BY 4.0 License. meteorite falls and cometary showers, which later evolved as part of the studies of the planetary system. It included exhibits of the fossil record, particularly during the Mesozoic and evolution of 95 the dinosaurs, marine microorganisms, ammonites and flying and marine reptiles, which went extinct with the Chicxulub impact. The crater studies are presented within the context of the oil exploration in southern Mexico and the geological characteristics of the Yucatan peninsula. The surface geological processes, including the groundwater flow and fracturing are influenced by the buried crater, which can be traced by the ring of cenotes and semicircular topographic depression 100 over the crater rim. Chicxulub exhibition was awarded the 2013 Miguel Covarrubias Prize from the National Institute of Anthropology and History. Related programs at the museum have included conferences, seminars and symposia, with progress reports of studies and drilling projects.
Around the initial aim, plan for a larger facility in addition to the museum exhibits was born in 105 2015, which rapidly expanded to have laboratories, offices and the core repository of material from successive drilling programs. The PCYTY houses academic institutions and start-ups researchoriented firms, including the Yucatan State University, National University, National Council of Science and Technology research centers, CINVESTAV Center for Research and High Education, National Hydrocarbon Core Repository and apartment blocks for visiting scholars and students. 110

Chicxulub Science Museum
Studies on large meteorite impacts, dinosaurs, mass extinctions and life evolution attract the interest of wide audiences, opening interesting possibilities for science communication. The museum exhibits are organized around the studies of the Solar System, impact cratering, evolution of planetary surfaces, impact, crater formation, impact effects on climate and life-support systems, 115 extinction of organisms, biotic turnover and life evolution. Exhibits aim to present, inform, engage and entertain visitors on the Earth and planetary sciences through studies on the Chicxulub impact, life evolution, K/Pg turnover and related inter-and multidisciplinary research.
Exhibits on the Universe hall introduce to the origin and evolution of the Universe, formation of stars and galaxies, the Milky Way galaxy, planetary system formation and the Solar System. The Exhibits on Chicxulub crater give an introduction to the impact and impact effects. Chicxulub is the best preserved of the three large impact structures in the terrestrial record, being a natural 135 laboratory for investigating impact dynamics, crater formation and planetary surface evolution in the Solar System. The crater is presently located half on land and half offshore, with geometric center at Chicxulub Puerto on the coastline; it has a peak-ring and multi-ring morphology, which characterizes complex craters on the Moon and other Solar System bodies.
Hall on the End-Cretaceous extinction and life evolution introduces to the meteorite impact end 140 effects on life-support systems, linking the impact processes with the mass extinction. Exhibits introduce the fossil record, geological processes, the geological time scales and concepts of deep time and life evolution. The mass extinction marks a major boundary from the Mesozoic to the Cenozoic. In the geological record the boundary is marked by the Chicxulub ejecta layer.
Interactive exhibits are used to introduce species communities and diversification after the impact 145 and macro-evolutionary trends.
Exhibits present challenging themes such as extinction of species, emergence of species, macroevolution and global climate change (Sepkoski, 1998;Jablonski, 2006Jablonski, , 2008. Experiences in Science Museums and Museums of Natural History emphasise roles of teachers and museum staff in interacting with visitors, particularly with school groups and students. In this regard, 150 exhibits on asteroid impact effects on life support systems permit to address present day extinctions and global warming. and lunar and sun eclipses were associated with catastrophes, diseases, warfare and social unrest.
How they were presented in the framework of the end of the Mesozoic era and mass extinction was subject of discussion.
Chicxulub Museum takes advantage of the research programs, laboratories and core repository, providing up to date information on studies and drilling projects. Plan is to also host temporary 160 exhibits on studies of Yucatan peninsula, Gulf of Mexico-Caribbean Sea, mineral and energy resources, climate change and biodiversity.

CCSRAS Research
CCSRAS has a core repository and six laboratories for core analyses, sample preparation, petrography, micropaleontology, geochemistry and physical properties. Laboratories are equipped 165 with analytical instruments, including core scanners, X-ray fluorescence system, gamma-ray core logging system, magnetic susceptibility meters, electrical resistivity meter, petrographic microscopes, laser particle analyser and an electronic scanning microscope (e.g., Fig. 10). The core repository has storage space for core samples and for conducting experiments, including low-speed impacts. It has facilities for slim-core logging and geophysical field equipment, including electrical 170 resistivity, gravity and magnetic meters.
The crater and ejecta deposits are not exposed at the surface, making drilling an indispensable tool to sample the impact lithologies and pre-and post-impact sedimentary rocks. Initial drilling was carried out by Pemex oil company, with intermittent core recovery providing samples of the carbonates, impact breccias and melt that were key for confirming the impact age, corresponding 180 to the K/Pg boundary (Hildebrand et al., 1991;Sharpton et al., 1992). Subsequent drilling programs https://doi.org/10.5194/gc-2020-13 Preprint. Discussion started: 14 April 2020 c Author(s) 2020. CC BY 4.0 License. incorporated continuous core recovery and geophysical logging (Urrutia-Fucugauchi et al., 2004, 2011, with tens of thousands of core samples distributed to groups in different countries, which has allowed to expand the research on the crater and K/Pg boundary. Impact resulted in global effects on the climate and life support systems triggering a mass 185 extinction in the marine and continental environments (Alvarez et al., 1980;Schulte et al., 2010;Lowery et al., 2018). Recent studies are shedding light on the likelihood of taxa becoming extinct as in the case of arboreal birds after forests disappeared (Field et al. 2018). Mass extinction coinciding with the impact was followed by radiations in numerous taxa including mammals (Dos Reis et al. 2012), worm lizards (Longrich et al. 2015) and birds (Field et al., 2018). Further 190 investigations of factors driving species extinction and radiations are crucial to understand the effects of human-induced changes.
The CCSRAS conducts research relevant to communities at the Yucatan peninsula, which is characterized by karstic terrains, with low elevations and smooth relief (Fig. 2). The city of Merida, located ~30 km away from the coastline, is just a few meters above sea level. The platform is an 195 extensive low-inclination shallow ramp, which records the sea-level fluctuations during the Late Pleistocene glaciation and the Holocene. The region is in the trajectory of hurricanes and tropical storms, with a thin soil cover and no surface waters, being vulnerable to coastal erosion, marine intrusion, aquifer contamination and to global warming with changes of precipitation, sea level, cloud coverage and evaporation. 200 The buried crater structure exerts a strong influence in surface geological processes including groundwater flow, subsidence, fracturing, coastal and karst processes. The density and distribution of karstic structures are related to dissolution and in turn to fracturing, topography, rainfall and groundwater flow. The sinkhole distribution correlates with the buried crater, notably with the cenote ring located over the crater rim. Surface fracturing is related to the stress/strain state, with 205 the regional tectonics and differential subsidence of fractured breccias and carbonates, inside and surrounding the crater. Coastline morphology and processes are related to the buried structure, marked by the correlation at the intersections with the crater rings. The crater is marked on the surface by a gravity and magnetic semi-circular concentric pattern (Fig. 4), associated with the basement uplift, peak-ring and impactite deposits. 210 https://doi.org/10.5194/gc-2020-13 Preprint. Discussion started: 14 April 2020 c Author(s) 2020. CC BY 4.0 License.

Discussion
The Chicxulub museum has been designed in a broad context, focusing on the Chicxulub impact and crater, and also including life evolution, impact dynamics and cratering on planetary scales.
As a site museum, it joins other museums located in impact craters (e.g., Pösges, 2005). natural and physical sciences are developing (e.g. Reiss, 2004, 2006). Plans include field trips to K/Pg boundary sites (e.g., Fig. 7), with nearest sites in Campeche, Quintana Roo and Belize. Exhibits of boundary sites are complemented in videos and computer simulations, which illustrate how ejecta was emplaced at distant locations. 245 The crater and proximal ejecta deposits are not exposed at the surface, which is a challenge in comprehending the huge dimensions and characteristics. We found that visitors have difficulties understanding how and why dinosaurs went extinct, dynamics of asteroid impacts and crater formation, sequence of events, other species affected, what happened with the mammals, why and how some mammal species did not go extinct, how some species went extinct while others do not. 250 The crater size and relation of buried structure and the ring of cenotes generate questions, with difficulties following the sequence of events. For instance, many visitors consider that impact formed the cenotes, though they acknowledge the crater lies deep beneath, covered by young rocks and that the cenotes are much younger surface features. The origin of the crater also generates confusion, though there are exhibits on the impacts, craters on the Moon and other bodies, 255 asteroids, etc., some visitors have difficulty understanding volcanic craters and volcanoes as different geological processes.
Presenting and understanding geological time, evolution and fossil record are not easy tasks.
Museums have developed a wide range of approaches Reiss, 2004, 2006;Mujtada et al., 2018). Results show mixed responses and the complex interactions, which have been discussed 260 and evaluated in different contexts. Exhibits on dinosaurs attract more interest than displays on other groups. Widespread interest in dinosaurs comes from their large sizes and diversity, including predators like the T Rex and raptors as well as the feathered dinosaurs. The dinosaurs were a highly successful group during the Mesozoic, occupying the ecosystems in the continental land masses including the polar regions (Sereno, 1999;Barret et al., 2009) flying reptiles, ammonites and many other groups went extinct helps to appreciate macroevolutionary traits, species interdependency, how species evolve and interact, how ecosystems develop and function and how species relate and react to environmental and climatic conditions (Jablonski, 2005(Jablonski, , 2008Bambach, 2006;Barrett et al., 2009). 275 The End-Cretaceous mass extinction is the fifth and last large extinction event recognized in the geologic record (Alvarez et al., 1980;Emiliani et al., 1981;Bambach, 2006). Exhibits on the other major extinction events and the extinction rates for genera, families and species during the Phanerozoic in the marine and land realms allow to present macroevolution and changes through time (Sepkoski, 1998;Jablonski, 2005Jablonski, , 2008. Paleogeographic reconstructions document the 280 evolving distribution of continents and oceans, with assemblage of the Pangea supercontinent and its breakup and drift apart. The changing ocean-continent distribution, ocean circulation, climate and landscapes form the backdrop for life evolution. Impact affected the climate and environment at global scales, with a sharp sudden period of darkness and cooling caused by the fine dust ejecta in the stratosphere. This impact winter was 285 followed by a global warming caused by the massive injection of carbon dioxide and other greenhouse gases (Alvarez, 1997;Schulte et al., 2010). The deposition of the fine ejecta resulted in severe changes in the sea surface water chemistry, affecting the marine organisms. The warm climates of the Cretaceous were followed by a cooling trend during the Cenozoic, with the formation of the ice polar caps and the Late Pleistocene glaciation (Zachos et al., 2008). Evolution 290 of the different genera, families and species correlates with the long term climate evolution and changing paleogeographic and climate evolution during the Cenozoic. unprecedented detail into the events before, during and after the impact and mass extinction, which allow for a narrative of events, integrating evidence in a multidisciplinary approach.
CCSRAS has a research approach, displaying new results and challenges, with exhibits, displays and virtual experiences (Louw and Crowley, 2013). It provides an attractive forum, although its 305 potential still needs to be further developed. In particular, we require to implement an evaluation of the programs, visitor experiences and ways to engage with teachers and students. Museums that house research and educational departments permit to keep up to date advances. Needed is a closer and better structured relationship with other actors in the science park and state education system.
We require a strategic plan for science communication, with a wider scope and well defined 310 priorities Nield, 2013: Stewart andLewis, 2017). societies. The museums of science are linked to development of modern societies and key components, fulfilling a recognized task for "effective dissemination and communication of the (geo)sciences to decision makers and society" (Arattano et al., 2018;Stewart and Lewis, 2017;Illingworth et al., 2018).
Knowledge among the general public of the Earth System characteristics and processes, principles 340 of species evolution and extinctions and the power of human activities to transform our planet and impact on other species is critical to address the geo-environmental hazards (Stewart and Lewis, 2017;Illingworth et al., 2018). The CCSRAS combines features of natural history museums and research facilities, with exhibits that cover from hypervelocity impacts, high pressure/temperature processes and rheological properties to the delicate balance of geological processes and life. The 345 Yucatan peninsula, known as the cradle of the Maya civilization that reached high levels of development, offers additional advantages for the project. The CCSRAS aims to become a multidisciplinary hub for academics and students, expanding the capabilities for research, outreach and science communication programs of the PCYTY.    (Sharpton et al., 1993), showing the concentric semi-circular pattern, with the central gravity high and gravity rings marking the peak-ring and multi-ring morphology. (inset) Schematic structural model of Chicxulub crater, showing the basin, central uplift, terrace zone, melt sheet, breccias and target Cretaceous sediments (Collins et al.,380 2008).