ABSTRACT A comprehensive correlation chart of Pennsylvanian–Eocene stratigraphic units in Mexico, adjoining parts of Arizona, New Mexico, south Texas, and Utah, as well as Guatemala, Belize, Honduras, and Colombia, summarizes existing published data regarding ages of sedimentary strata and some igneous rocks. These data incorporate new age interpretations derived from U-Pb detrital zircon maximum depositional ages and igneous dates that were not available as recently as 2000, and the chart complements previous compilations. Although the tectonic and sedimentary history of Mexico and Central America remains debated, we summarize the tectonosedimentary history in 10 genetic phases, developed primarily on the basis of stratigraphic evidence presented here from Mexico and summarized from published literature. These phases include: (1) Gondwanan continental-margin arc and closure of Rheic Ocean, ca. 344–280 Ma; (2) Permian–Triassic arc magmatism, ca. 273–245 Ma; (3) prerift thermal doming of Pangea and development of Pacific margin submarine fans, ca. 245–202 Ma; (4) Gulf of Mexico rifting and extensional Pacific margin continental arc, ca. 200–167 Ma; (5) salt deposition in the Gulf of Mexico basin, ca. 169–166? Ma; (6) widespread onshore extension and rifting, ca. 160–145 Ma; (7) arc and back-arc extension, and carbonate platform and basin development (ca. 145–116 Ma); (8) carbonate platform and basin development and oceanic-arc collision in Mexico, ca. 116–100 Ma; (9) early development of the Mexican orogen in Mexico and Sevier orogen in the western United States, ca. 100–78 Ma; and (10) late development of the Mexican orogen in Mexico and Laramide orogeny in the southwestern United States, ca. 77–48 Ma.

ABSTRACT The Cretaceous-Paleocene (K/P) boundary intervals are rarely preserved in successions of shallow-water limestones. Here, we describe a shallow rocky shore on the active orogenic wedge of the eastern Alps (Austria) fringed by a carbonate platform that was largely cannibalized by erosion. We compared this succession with similar nearshore environments globally, as well as the deep sea, to gain a better understanding of the environmental response to the K/P boundary transition. In the eastern Alps, Cretaceous and Paleocene lithofacies across the K/P boundary transition are separated by a hardground that formed during subaerial exposure and that terminates Upper Maastrichtian limestone with planktic foraminiferal assemblages deposited at neritic depth during zone CF3 (ca. 66.500 Ma). Above the hardground, there are beachrocks with early Danian zone P1a(1) assemblages, which indicate the hardground spans about ~600 k.y. of nondeposition and/or erosion. During the early Danian, the marine transgressive fringe fluctuated between “shoreface to emersion” environments, depositing limestones rich in bryozoans, rhynchonellids, coralline algae, and rare planktic foraminifera along with abraded, bored, and/or encrusted clasts eroded from older rocks. Repeated short subaerial exposure is marked by vadose diagenesis and hardgrounds, including an ~1.5 m.y. interval between magnetochrons C29n to C28n and planktic foraminiferal zones P1b to P1c(2). Comparison with platform carbonate sequences from Croatia, Oman, Madagascar, Belize, and Guatemala, as well as nearshore siliciclastic environments of southern Tunisia, Texas, and Argentina, across the K/P boundary transition revealed surprisingly similar deposition and erosion patterns, with the latter correlative with sea-level falls and repeated subaerial exposure forming hardgrounds. Comparison with deep-sea depositional patterns revealed coeval but shorter intervals of erosion. This pattern shows a uniform response to the K/P boundary transition linked to climate and sea-level changes, whether in shallow nearshore or deep-sea environments, with climate change tied to Deccan volcanism in magnetochrons C29r-C29n.

Abstract Central America is a small and culturally homogeneous region that, since the 1990s, has experienced economic and political integration of its six countries, which share the same threats of volcanic eruptions, disastrous earthquakes and tsunamis. The Pacific coastline of 1700 km is common for Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica and Panama, and the Pacific subduction zone has the potential for creating huge tsunamis that threaten this coast. In addition to the natural hazard, the growing tourist industry is expanding its infrastructure along the Pacific beaches, which again enhances the exposure and tsunami risk. Even though the 1992 tsunami disaster in Nicaragua did not severely hit the tourist beaches, it raised the risk awareness, and special attention is now given to ‘slow’ earthquakes that may be modest in shaking while still having a large tsunami potential. The tsunami hazard mapping is well advanced in Nicaragua, Costa Rica and El Salvador, and initiatives are ongoing to improve the mapping in all countries. National systems for early warning were established in Nicaragua and El Salvador, while the other four countries rely on rapid information from the Pacific Tsunami Warning Center. Mitigation measures and information campaigns are presently conducted on a national basis in all countries, but a regional centre for early tsunami warning and coordinated information campaigns (CATAC) is expected to become operational in the near future.

Efforts to improve water quality and quantity, and sanitation in the world are impeded by a variety of technical and socioeconomic issues often unfamiliar to well-motivated individuals. Sustainable technological improvement can be thwarted by the lack of consideration of regional norms, customs, mores, and traditions, and by the absence of feasibility assessment and coordination with the community both before and during instatement of local improvements. Specifically, the absence of coordination means not fully allowing users to define their needs, resources, issues, and maintainable solutions, and not understanding local and regional power dynamics and the ability of the community to provide long-term project stewardship. Other mistakes can include: a lack of long-term planning; inadequate scientific and engineering design and construction; lack of anticipation of contingencies and complicating issues and lack of adaptive management to deal with these unforeseen events; use of inappropriate technology; absence of educational efforts (both for the community to understand and provide stewardship for the project, and for the education of those installing the facilities in the community); lack of follow-up; and lack of technical expertise and leadership. There is no single approach to water and sanitation development that fits all situations. However, avoiding common pitfalls can bring these important resources to villages worldwide, and in the process empower communities, reduce sickness and mortality, and improve the human condition.

Collapse of masonry buildings still accounts for most earthquake casualties in developing countries, even though effective earthquake-resistant building techniques are available. The amateur builders and local contractors who are responsible for most housing and small-scale commercial construction are typically unaware of these techniques, or they believe that prohibitively expensive engineering design and materials are required. However, the principal technique—confined masonry—is highly effective for nonengineered buildings of less than three stories, and it involves only modest changes in customary building practices. I developed a 2 hour workshop to teach local builders in Guatemala earthquake-resistant construction techniques. Simple graphics with minimal captions and photographs of local buildings were used to show basic design principles, and to illustrate best versus poor practices. Printed manuals (in Spanish and illustrated for a low-literacy audience) were provided, for later reference and the possibility of wider dissemination. The most challenging aspect of this project was developing a working relationship with a local organization willing and able to assist with scheduling, publicity, and generally connecting me with appropriate audiences. My experience suggests that effective teaching is the most critical tool for providing meaningful assistance with a range of geologic and environmental challenges. Expert knowledge, fluency in local languages, and years of local experience are all useful but can be provided or developed through relationships with local partners. Targeted education addressing specific community needs can be highly effective for increasing resilience to natural hazards, and it represents a more-efficient and lower-cost alternative to many other forms of development aid.