GSA Today Science Articles: Hot Topics and Recurring Themes, 1998 to 2008

GSA Today science articles: Hot topics and recurring themes, 1998 to 2008

Kristen E. Asmus, GSA Today Managing Table 1. 50 common keywords from GSA Today science article abstracts, 1998–2008 Editor, [email protected] Year 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 No. of science articles 10 11 12 12 10 9 8 10 9 10 10 for each year (111 total) Keywords (no. of articles) INTRODUCTION Antarctic (7) 3 1 1 1 – – – – 1 – – Over the past 10 years, GSA Today Archean (14) 2 – 2 2 2 1 – 2 1 – 2 Basin (20) – 2 3 3 4 – – 1 3 1 3 has printed 111 peer-reviewed science Cambrian/ articles, which were selected by the sci- Precambrian (9) 2 – 2 1 1 – – – 1 – 2 ence editors for their timeliness, acces- Carbon/radiocarbon (13) 2 2 1 – 2 1 1 1 2 1 – sibility to a broad audience of geoscien- CO2 (8) 1 1 – – – 2 2 1 – – 1 tists, and focus on current topics in the Climate (20) 1 3 3 3 2 2 1 – 2 3 – Coast (8) – 1 1 1 1 – 1 – 1 2 – earth sciences. GSA Today is posted on- Continent (29) 4 2 2 4 2 4 1 3 2 3 2 line from 1995 to present, and all sci- Cretaceous (11) – 1 1 2 2 1 – 2 – 2 – ence articles are open-access via link at Crust (33) 3 1 4 5 4 4 1 3 2 2 4 www.geosociety.org/pubs/. Deformation (16) 1 – 2 5 2 2 1 1 – 1 1 The purpose of this review is to pro- Earthquake (13) – – 3 1 3 2 – – 2 – 2 Environment (19) 1 2 4 1 1 – 1 1 2 2 4 vide readers with a perspective on those Erosion/eroded (12) – 1 – – 1 2 – 2 2 3 1 issues and topics that have shaped our Evolution of Earth (13) 1 – – 3 1 1 1 3 – 2 1 community over the past decade as well Evolution of life (14) 2 2 4 1 2 – – 1 – 1 1 as the future evolution of the earth sci- Extinction (8) 1 – 2 1 1 – 1 1 – – 1 ences. I first recount the topics most Fault/faulting (13) – 1 3 1 1 3 2 – – 1 1 Fossil/assemblage (10) 2 1 2 1 2 – – – 1 – 1 commonly addressed in GSA Today Geomorphology (7) – 1 – 1 – – 1 2 – 1 1 through a review of key words (see Glacial/glaciation (13) 3 – 1 1 1 2 1 1 1 – 2 Table 1), followed by abstracts and Global warming/ 1 2 2 – 1 2 1 – 1 2 1 comments on one or two science arti- climate change (13) Greenhouse (7) 1 1 1 – – 2 1 – 1 – – cles from each of the past 10 years. The Hazards (7) – – 1 1 1 1 2 – 1 – – list of papers is a personal one; selec- Human/ 1 – 1 1 1 – 2 2 1 2 1 tion was based on what seemed to me anthropogenic (12) Image/imaging (11) 2 – 2 1 – – 2 2 1 1 – to be key issues and on the success of Isotope/isotopic (14) 1 1 2 1 1 1 – 2 3 2 – the papers in communicating to the Landscape (9) 2 – – – 1 1 – 2 1 1 1 broadest audience possible. Lithosphere (18) 1 – 1 3 3 2 – 1 2 2 3 Table 1 records the top 50 key words Magma (17) 1 – 1 4 3 1 2 3 – 1 1 in abstracts from 1998 to 2008. In order Mantle (23) 1 – 2 4 6 1 – 3 1 2 3 to have made the top-50 list, a word Marine (18) 2 2 3 2 3 – 1 – 1 1 3 Mineral (10) – 1 1 3 – 1 1 1 1 1 – would have had to appear in at least Models/modeling (27) 1 4 3 6 1 4 2 – 1 3 2 seven of the 111 abstracts. Key words Mountain (11) 1 1 – 2 3 – – – 2 – 2 from Presidential Addresses were not in- Ocean/oceanic (29) 2 4 3 2 4 2 – 1 4 2 5 cluded in Table 1 because most do not Orogeny/orogenic (14) 1 2 1 1 2 3 – 1 1 1 1 Proterozoic/ have abstracts. Neoproterozoic (16) 4 1 2 3 3 – – 1 1 – 1 The geological terms used most often Rocks (21) 3 1 1 5 1 2 1 – 3 4 – were sediments (36 times), crust (33), Sea level (15) 1 – 3 1 3 1 2 1 1 2 – and water (32), with references to sur- Sediments (36) 2 2 4 6 5 – 2 3 3 4 5 face/surficial processes (29) , ocean/oce- Seismic (23) 1 1 4 2 4 1 4 1 3 1 1 Strata/stratigraphic (22) 3 1 – 2 3 1 – 1 4 5 2 anic (29), and models/modeling (27) fol- Subduction (14) 1 – 1 4 2 1 – 2 1 1 1 lowing close behind. Words that usually Surface/surficial (29) 2 2 4 4 3 2 1 2 5 2 2 come to mind when one thinks of geol- Tectonic (24) 3 3 3 3 2 1 – 2 3 3 1 ogy didn’t have enough hits to make the Temperature/°C (16) 2 2 1 – 3 2 1 1 2 – 2 list, like dinosaurs (two), soil (four), re- Terrane (9) 2 1 – 1 2 – – 1 – 1 1 Water (32) 3 3 3 3 4 2 4 4 3 2 1 sources (three), or gems (zero). “Moun- Note: Key words counted only once per abstract. The April 1998 GSA Today included four related tain” had just 11 occurrences in the ab- science articles; key words for that month are from the titles only. Presidential Address articles are not stracts; the mountains referenced most included in these totals as most do not include an abstract.

GSA Today, v. 19, no. 1, doi: 10.1130/1052-5173(2009)19[41:GTSAHT]2.0.CO;2

GSA TODAY, January 2009 41 often were the Himalaya (five articles) Gas hydrates: Greenhouse Energy and Minerals at www.nsf.gov/ and the Rockies (four articles); Yucca nightmare? Energy panacea or about/congress/106/bhaq990525.jsp. Mountain was the focus of two articles. pipe dream? The most-often-mentioned location out- Bilal U. Haq (Nov. 1998, v. 8, no. 11, 1999 side of the United States was the Antarctic, p. 1–6; ftp://rock.geosociety.org/pub/ Hurricanes Dennis and Floyd: Coastal with seven articles (see the April 1998 is- GSAToday/gt9811.pdf). effects and policy implications sue for a four-part treatment of the Antarc- Abstract: Recent interest in methane Robert S. Young et al. (Dec. 1999, v. 9, tic Sirius Group). Canada was also a popu- hydrates has resulted from the recogni- no. 12, p. 1–7; ftp://rock.geosociety.org/ lar location of study, with five occurrences, tion that they may play important roles in pub/GSAToday/gt9912.pdf). and China and Tibet combined were fea- the global carbon cycle and rapid climate Abstract: Tropical systems Dennis and tured in eight abstracts. change through emissions of methane Floyd impacted eastern North Carolina in from marine sediments and permafrost 1999, the fourth and fifth storms in three A TEN-YEAR RETROSPECTIVE into the atmosphere, and in causing mass years to make landfall in this area. All five failure of sediments and structural changes storms were very similar in strength (wind 1998 on the continental slope. Their presumed speed); however, the effects on the coast Environmental change, geoindica- large volumes are also considered to be were quite different. In addition to ab- tors, and the autonomy of nature a potential source for future exploitation solute storm strength, morphological Antony R. Berger (Jan. 1998, v. 8, of methane as a resource. Natural gas hy- changes to the natural environment were no. 1, p. 3–8; ftp://rock.geosociety.org/ drates occur widely on continental slope controlled by the forward speed of the pub/GSAToday/gt9801.pdf). and rise, stabilized in place by high hy- storms, orientation of the shoreline rela- Abstract: Geological indicators of rap- drostatic pressure and frigid bottom-tem- tive to storm track, underlying geology, id environmental change provide a con- perature conditions. Change in these impacts of recent storms, and associated ceptual framework for assessing changes conditions, either through lowering of rainfall. Damage to buildings was a func- in the abiotic components of landscapes sea level or increase in bottom-water tion of the placement of structures with and ecosystems resulting from natural temperature, may trigger the following respect to the shoreline and the removal processes or human actions. The appli- sequence of events: dissociation of the of weaker buildings by previous storms. cation of geoindicators to monitoring of hydrate at its base, weakening of sedi- On the basis of these observations, we landscape conditions, particularly in ment strength, major slumping, and re- recommend a new Hurricane Impact state-of-the-environment reporting and lease of significant quantities of methane Scale, which will allow prediction of pos- long-term ecosystem research, can help in the atmosphere to affect enhanced sible storm impacts and comparisons of earth scientists to contribute more effec- greenhouse warming. Thus, gas-hydrate coastal impacts in other Hurricanes. tively to these interdisciplinary efforts. breakdown has been invoked to explain Each additional Hurricane demon- Geoindicators may also help to remind the abrupt nature of glacial terminations, strates that our society does not have a policymakers and the general public of pronounced 12C enrichments of the glob- forward-looking plan for dealing with the reality of natural change and the al carbon reservoir such as that during coastal storms. Instead, we typically re- common difficulty of distinguishing it the latest Paleocene thermal maximum, pair and rebuild in place, and continue from human modifications. and the presence of major slides and the upward spiral of property damage in Note slumps in the stratigraphic record associ- storms. Although the dollar amount of Berger’s Table 1 lists 27 “geoindicators” ated with periods of sea-level lowstands. property damage will be low from these of environmental change, with the caveat The role of gas hydrates in controlling storms, the public must bear the cost of that they be modified and amended as climate change and slope stability cannot cleanup and repair of infrastructure. necessary over time. Berger is clear that be assessed accurately without a better Note both natural and anthropogenic change understanding of the hydrate reservoir Published more than five years before should be scrutinized, writing that “anthro- and meaningful estimates of the amount Hurricane Katrina, this article cites the les- pogenic stress on the environment … is of methane it contains. Lack of knowl- sons to be learned from the “the legacy rightly the central concern … [but] natural edge also hampers the evaluation of of Bertha, Fran, Bonnie, Dennis, and change and its effects on land and the bio- the resource potential of gas hydrates, Floyd” (p. 6): (1) the need for a proactive sphere tend to be overlooked” (p. 5). In underscoring the need for a concerted plan for dealing with coastal storms rather his final paragraph (p. 7), Berger calls for research effort on this issue of signifi- than “the typical response [of] cleanup and geoscientists to develop “better ways to cant scientific importance and societal complete rebuilding, maintaining the sta- assess changes to the landscape, whatever relevance. tus quo”; and (2) a new Hurricane Impact the cause” because “society must not only Note Scale that includes the cost to local citizens reduce unsustainable human activities but This is the only GSA Today article in of infrastructure repair. must also adjust to natural fluctuations.” the past ten years that deals directly with Recommended reading: See “Katrina’s a potential energy resource (methane hy- unique splay deposits in a New Orleans drates) as well as climate change. You neighborhood” (v. 16, no. 9, p. 4–10; ftp:// can still read Haq’s 25 May 1999 testi- rock.geosociety.org/pub/GSAToday/ mony on these issues before the House gt0609_NWS.pdf) and “Submergence of Committee on Science Subcommittee on

42 JAnuary 2009, GSA TODAY ancient Greek cities off Egypt’s Nile extraordinarily difficult to attribute the 4. Identify “geologic, chemical, or bio- delta—A cautionary tale” (Jan. 2004, v. 14, warming trend to any particular forcing logic parameters or a suite of param- no. 1, p. 4–10; ftp://rock.geosociety.org/ function with sufficient certainty to satis- eters that can indicate the health or pub/GSAToday/gt0401.pdf). fy policy makers” (p. 5). The “Recom- biodiversity of an ecosystem” as well mendations and Conclusions” section as come up with systems to “moni- 2000 (p. 6) warns, “We will not truly be able to tor or measure” these parameters in Evaluating global warming: attribute global warming to greenhouse order to understand “the effective- A post-1990s perspective gas increases until the climate has al- ness of our … efforts at restoration David S. Gutzler (Oct. 2000, v. 10, ready warmed a great deal relative to or remediation” (p. 44); no. 10, p. 1–7; ftp://rock.geosociety.org/ pre-twentieth century temperatures,” and 5. Build “complex computer models of pub/GSAToday/gt0010.pdf). ends with a call for the geoscience com- natural systems that can forecast Abstract: Globally averaged surface-air munity to advance “our ability to model impending disasters” (p. 44); and temperature warmed approximately the climate system with sufficient confi- 6. “Refocus society’s desire for abso- 0.5 °C during the twentieth century, and dence to assuage skepticism and debate lute guarantees from science and the rate of warming has accelerated con- on those issues.” replace it with an acceptance that siderably since about 1980. Proxy climate most solutions are uncertain and data suggest that current global tempera- 2001 will carry some level of risk and also tures are warmer than at any time in the Grand challenges in earth and some level of environmental conse- last millennium. As this trend persists, the environmental sciences: Science, quences” (p. 45). likelihood increases that the warming is stewardship, and service for the Further, under the heading “What due at least in part to anthropogenic in- twenty-first century Should We Do?” Zoback calls on the puts of atmospheric greenhouse gases. Mary Lou Zoback (Dec. 2001, v. 11, earth science community to become ac- There is no debate over the measured in- no. 12, p. 41–47; ftp://rock.geosociety. tive participants in “one of the grandest creases in greenhouse gas concentrations, org/pub/GSAToday/gt0112-presAddr.pdf). scientific, technological experiments of or the anthropogenic origin of these in- Note the twenty-first century … [to] tackle creases, or the direct radiative effect of in- This millennial Presidential Address safe, long-term isolation of high-level ra- creased greenhouse gas concentrations. from GSA’s 2000 Annual Meeting in Reno, dioactive waste” (p. 46). Public debate and policy development Nevada, USA, presents six challenges on global warming are stuck, however, in for geoscientists in the coming decades. 2002 part because it remains exceedingly diffi- There is no abstract; what follows is a brief Eocene meridional weather patterns cult to specifically attribute current global summary. reflected in the oxygen isotopes of warming to increases in greenhouse gases, Zoback begins, “A measure of our fu- Arctic fossil wood or to make confident predictions of the ture success as earth scientists will depend A. Hope Jahren and Leonel Silveira rate and spatial variability of future warm- on our ability to help our global society Lobo Sternberg (Jan. 2002, v. 12, no. 1, ing. Attribution and prediction of global find and implement effective solutions to p. 4–9; ftp://rock.geosociety.org/pub/ warming both depend on large-scale mod- environmental problems,” (p. 41) and then GSAToday/gt0201.pdf). eling, and the complexities associated with presents six “Grand Challenges in Earth Abstract: The spectacularly preserved simulating the climate system are so great and Environmental Science”: Metasequoia wood excavated from the that conclusive attribution and prediction 1. Answer the question, “Are steady Fossil Forest site of Axel Heiberg Island will probably not be reached for some increases in global temperature … (Canadian High Arctic) provides a unique 18 time. These uncertainties tend to over- in the past 150 years simply an window into the δ O value of Eocene shadow the higher degree of certainty as- expression of natural variability, or meteoric water via the analysis of fossil sociated with observational evidence for are they a direct result of mankind’s cellulose. Seventeen fossilized Meta global warming. The scientific community activities that have resulted in an sequoia individuals yielded cellulose 18 should acknowledge that the attribution increase in greenhouse gases?” with δ O (Vienna standard mean ocean and prediction problems will not be re- (p. 41); water [VSMOW]) values ranging from solved to the satisfaction of policy makers 2. Understand “biogeochemical cycles 17.1‰ to 21.4‰ and with a mean value in the near future, and should instead such as the carbon or nitrogen of 19.9‰—strikingly low compared to work toward establishing new paradigms cycle,” which is “fundamental to modern trees of all latitudes. Using es- for partnership with policy makers, with understanding how larger natural tablished biosynthetic relationships for greater emphasis on observations of past systems, such as the global climate plant cellulose, we reconstructed the 18 and present climate change. system, function” (p. 42); δ O (VSMOW) value of Eocene mete- Note 3. Recognize “that actions of man have oric water to be −15.1‰ on Axel Heiberg Gutzler notes that the six warmest deliberately or inadvertently perturbed Island—a value similar to previous deter- years out of a 120-year period from 1880 natural systems” (p. 43), including minations of Eocene terrestrial water to 1999 “all occurred in the 1990s” (p. 1; urban weather (see Zoback’s Fig. 4, using varied paleoenvironmental indica- see also his Fig. 2, p. 4) and writes, “The p. 44, depicting urban sprawl for tors. A wholly temperature-based inter- debate over detection of climate change Atlanta, Georgia, USA) and local, pretation of these isotopic results would is drawing to a close … [but] it remains regional, and global water cycles; predict a mean annual temperature of

GSA TODAY, January 2009 43 −2.7 °C, but this is incompatible with ex- keys to dynamics. Slabs sinking broad- specific impacts of human activities (e.g., tremely high forest productivity. Instead, side from retreating hinges drive both mining, logging, and urbanization) vary a calculation of isotopic fractionation in subducting and overriding plates and among regions and watersheds, as well moisture transported from the Pacific force seafloor spreading in both shrinking as between different channel reaches in Ocean north across North America ex- and expanding oceans. An Antarctica- the same watershed. Consequently, rec- plains the simultaneous arrival of warm fixed framework depicts prediction-con- ognizing and diagnosing the nature and air and isotopically depleted moisture in firming “absolute” plate motions that causes of differences between historical the Eocene Arctic; we suggest that these make kinematic sense, whereas hotspot and contemporary fluvial and watershed meridional weather patterns were caused and no-net-rotation frames do not. Plumes conditions and processes can require by the absence of a Polar Front during from deep mantle, subduction into deep careful evaluation of both historical and the ice-free Eocene. mantle, and bottom-up convective drive spatial contexts. In order to be most ef- do not exist. fective, the contribution of geomorpho- Note Note logical insights to salmon recovery efforts This is the only paleontological and requires both assessment protocols com- climatological study in GSA Today focus- Hamilton’s overview perfectly summa- rizes what makes his GSA Today article mensurate with providing adequate ing on a species of Earth’s flora rather knowledge of context, and experienced than fauna. unique (p. 11): “The Earth described here differs profoundly from that accepted as practitioners well versed in adapting dogma in most textbooks and research general theory to local settings. The sub- stantial influences of watershed process- 2003 papers.” Be sure to read Hamilton’s four es on salmon habitat and salmon abun- An alternative Earth “major stages in Earth evolution” on pag- dance indicate the need to incorporate Warren B. Hamilton (Nov. 2003, v. 13, es 11–12, and check out the Comment insights from geology and geomorphol- no. 11, p. 4–12; ftp://rock.geosociety. and Reply on this article, published ogy into salmon recovery efforts. org/pub/GSAToday/gt0311.pdf). March 2004, by linking to them at www. Abstract: The standard Earth of geo- geosociety.org/pubs. dynamics and geochemistry is rational- ized from assumptions that the mantle is compositionally inverted—still-unfrac- tionated lower mantle beneath volatile- depleted upper mantle—and that material circulates easily from bottom to top. Multidisciplinary data better fit a less- volatile and less-radioactive planet wherein depleted lower mantle, fraction- ated early and irreversibly, is decoupled from upper mantle plus crust that evolve and circulate separately. Early Archean fractionation produced global(?) felsic crust and refractory upper mantle. Later Archean granite-and-greenstone upper crust formed atop this ancient crust, which remained hot and weak; distinct continents and oceans did not exist, and upper mantle was much hotter than now. Figure 1. Nov. 2004 cover; drawing by Ray Troll. Figure 2. Jan. 2005 cover: Incidences of lead Plate tectonics began ca. 2.0 Ga when poisoning in children in Indianapolis, Indiana, continents could stand above oceans and USA, from 1992 to 1994. oceanic lithosphere could cool to sub- 2004 duction-enabling density and thickness. Geology, geomorphology, and the 2005 Upper mantle has since become more restoration ecology of salmon Urban lead poisoning and medical fertile and new increments of continental David R. Montgomery (Nov. 2004, v. 14, geology: An unfinished story crust more mafic as continental crust has no. 11, p. 4–12; ftp://rock.geosociety.org/ Gabriel M. Filippelli et al. (Jan. 2005, been progressively diminished by recy- pub/GSAToday/gt0411.pdf). v. 15, no. 1, p. 4–11; ftp://rock.geosociety. cling into cooling mantle. Plate circula- Abstract: Natural and anthropogenic org/pub/GSAToday/gt0501.pdf). tion is driven by subduction, which is influences on watershed processes affect Abstract: The intersection between enabled by density inversion produced the distribution and abundance of salmon geological sciences and human health, by sea-water cooling from the top of across a wide range of spatial and tem- termed medical geology, is gaining signifi- oceanic lithosphere, is self-organized, poral scales, from differences in species cant interest as we understand more com- and is confined to upper mantle. The use and density between individual pools pletely coupled biogeochemical systems. matching rates of hinge rollback and of and riffles to regional patterns of threat- An example of a medical geology prob- advance of fronts of overriding plates are ened, endangered, and extinct runs. The lem largely considered solved is that of

44 JAnuary 2009, GSA TODAY lead (Pb) poisoning. With aggressive re- Abstract: On 29 August 2005, storm tween the aquifers in the limestones and moval of the major sources of Pb to the surge from Hurricane Katrina entered the overpressured mud in overlying units. As environment, including Pb-based paint, drainage canals in the northern part of this was not protected by steel casing, leaded gasoline, and lead pipes and sol- the city of New Orleans, Louisiana, USA. the pressure induced hydraulic fractur- der, the number of children in the United Although the floodwalls and levees on ing, and fractures propagated to the sur- States affected by Pb poisoning has been these canals were not overtopped, the face, where pore fluid and some- en reduced by 80%, down to a current level surge resulted in three levee breaches trained sediment started to erupt. Flow of 2.2%. In contrast to this national aver- that flooded 80% of the city. The south- rates remain high (7000–150,000 m3 per age, however, about 15% of urban chil- ern breach on the London Avenue Canal day) after 173 days of continuous erup- dren exhibit blood Pb levels above what resulted in a blast of water that displaced tion (at the time of this writing), indicat- has been deemed “safe” (10 µg per decili- a house in front of the breach and buried ing that the aquifer volume is probably ter); most of these are children of low parts of the neighborhood with up to 1.8 significant. A continued jet of fluid, driv- socioeconomic-status minority groups. We m of sandy sediment derived from remo- en by this aquifer pressure, has caused have analyzed the spatial relationship be- bilization of subsurface late-Holocene erosion and entrainment of the overpres- tween Pb toxicity and metropolitan road- marsh and beach deposits. These depos- sured mud. As a result, we predict a cal- ways in Indianapolis and conclude that Pb its are a rare but spectacular example of dera will form around the main vent with contamination in soils adjacent to road- crevasse splay deposits in an urban envi- gentle sag-like subsidence of the region ways, the cumulative residue from the ronment. Approximately 26,380 m3 of covered by the mud flow and surround- combustion of leaded gasoline, is being material, varying in size from fine sand to ing areas. The eruption demonstrates remobilized. Developing strategies to re- gravel-size clay balls, along with various that mud volcanoes can be initiated by move roadway Pb at the source is a matter human-made objects, was deposited fracture propagation through significant of public health and social justice, and mostly as planar strata, with some small- thicknesses of overburden and shows constitutes perhaps the final chapter in and medium-scale cross-strata showing that the mud and fluid need not have this particular story of medical geology. climbing bed forms that were deposited previously coexisted, but can be “mixed” Note on and around obstacles, such as cars within unlithified sedimentary strata. GSA’s Geology and Health Division and houses. This unique splay deposit Note was established in the spring of 2005, has no preservation potential, and this This is the first major scientific article shortly after the publication of this arti- paper reports the first (and probably published on the event, which buried cle, but this remains a unique topical only) results from the study of its mor- four villages in eastern Java, Indonesia. contribution to GSA Today. phology and sedimentology. See a follow-up article in the August 2008 Note issue of Geology, “Triggering of the Lusi 2006 Written by a team from New Orleans’ mud eruption: Earthquake versus drilling Katrina’s unique splay deposits in a Tulane University, this is one of the first initiation” by M. Tingay et al. You’ll also New Orleans neighborhood geoscience papers published about the find pictures and extended coverage in Stephen A. Nelson and Suzanne F. aftermath of Hurricane Katrina. It in- May 2008’s Geoscientist (v. 18, p. 24–27). Leclair (Sept. 2006, v. 16, no. 9, p. 4–10; cludes a map drawn during post-hurri- ftp://rock.geosociety.org/pub/GSAToday/ cane field work that illustrates the extent Is agriculture eroding civilization’s gt0609_NWS.pdf). of the splay deposits in a neighborhood foundation? near the London Avenue Canal breach as David R. Montgomery (Oct. 2007, well as photos taken Feb. 2006 of re- v. 17, no. 10, p. 4–9; ftp://rock.geosociety. maining deposits. org/pub/GSAToday/gt0710.pdf). Abstract: Recent compilations of data 2007 from around the world show that soil Birth of a mud volcano: East Java, erosion under conventional agriculture 29 May 2006 exceeds both rates of soil production Richard J. Davies et al. (Feb. 2007, and geological erosion rates by from sev- v. 17, no. 2, p. 4–9; ftp://rock.geosociety. eral times to several orders of magnitude. org/pub/GSAToday/gt0702.pdf). Consequently, modern agriculture—and Abstract: On 29 May 2006, an erup- therefore global society—faces a funda- tion of steam, water, and, subsequently, mental question over the upcoming cen- mud occurred in eastern Java in a loca- turies. Can an agricultural system capable tion where none had been previously of feeding a growing population safe- documented. This “pioneer” mud erup- guard both soil fertility and the soil itself? tion (the first to occur at this site)- ap Although the experiences of past societies pears to have been triggered by drilling provide ample historical basis for concern of overpressured porous and permeable about the long-term prospects for soil con- Figure 3. Sept. 2006 cover: Car exhumed from the limestones at depths of ~2830 m below servation, data compiled in recent studies post–Hurricane Katrina levee breach sedimentary the surface. We propose that the bore- indicate that no-till farming could reduce deposits in New Orleans, Louisiana, USA. hole provided a pressure connection be- erosion to levels close to soil production

GSA TODAY, January 2009 45 Vancouver Sun, and more. As of this writing (November 2008), five of the six “GSA Today in the News” articles listed on the GSA Today home page at www. gsajournals.org are related to this article, and it has been on our list of the top-five most-viewed GSA Today articles since its publication.

A geological and geophysical context for the Wenchuan earthquake of 12 May 2008, Sichuan, People’s Republic of China B.C. Burchfiel et al.(July 2008, v. 18, no. 7, p. 4–11; ftp://rock.geosociety.org/ pub/GSAToday/gt0807.pdf). Abstract: On 12 May 2008, a magni- Figure 4. Oct. 2007 cover: U.S. Dept. of Agricul- Figure 5. Feb. 2008 cover: Shanghai, People’s tude 7.9 earthquake ruptured the Long- ture image from 13 May 1936 of Dallas, South Republic of China, 2007. men Shan margin of the eastern Tibetan Dakota, USA. plateau. This event occurred within the context of long-term uplift and eastward rates. Similarly, organic farming methods may be discussed on stratigraphic enlargement of the plateau. The area has have been shown to be capable of pre- grounds. A case can be made for its con- numerous geological features not typical serving—and in the case of degraded sideration as a formal epoch in that, of active convergent mountain belts, in- soils, improving—soil fertility. Conse- since the start of the Industrial Revolu- cluding the presence of a steep moun- quently, agricultural production need not tion, Earth has endured changes suffi- tain front (>4 km relief) but an absence necessarily come at the expense of either cient to leave a global stratigraphic sig- of large-magnitude low-angle thrust soil fertility or the soil, even if recent pro- nature distinct from that of the Holocene faults; young high topography (post ca. posals to rely on conventionally grown or of previous Pleistocene interglacial 15 Ma) and thickened crust but low glob- corn for biofuels exemplify how short- phases, encompassing novel biotic, sed- al positioning system (GPS) shortening term social and economic trade-offs can imentary, and geochemical change. rates (<3 mm/yr); and no coeval foreland de-prioritize soil conservation. Like the These changes, although likely only in subsidence. In our interpretation, crustal issues of climate change and loss of bio- their initial phases, are sufficiently dis- thickening beneath the eastern Tibetan diversity, ongoing global degradation tinct and robustly established for sugges- plateau occurred without large-scale and loss of soil present fundamental so- tions of a Holocene-Anthropocene shortening of the upper crust but instead cial challenges in which the slow pace boundary in the recent historical past to is caused by ductile thickening of the of environmental change counter-intui- be geologically reasonable. The bound- deep crust in a weak (low-viscosity) lay- tively makes solutions all the more dif- ary may be defined either via Global er. Late Cenozoic shortening across the ficult to adopt. Stratigraphic Section and Point (“golden Longmen Shan could be as little as 10–20 Note spike”) locations or by adopting a nu- km, with folding and faulting mainly ac- David Montgomery (also author of merical date. Formal adoption of this commodating differential surface uplift 2004’s “Geology, geomorphology, and term in the near future will largely de- between the plateau and the Sichuan Ba- the restoration ecology of salmon” [v. 14, pend on its utility, particularly to Earth sin. The earthquake of 12 May probably no. 11, p. 4–12]) was awarded a MacAr- scientists working on late Holocene suc- reflects long-term uplift, with slow con- thur Fellowship in September 2008 for cessions. This datum, from the perspec- vergence and right-slip, of the eastern exceptional achievement and promise. tive of the far future, will most probably plateau relative to the Sichuan Basin. approximate a distinctive stratigraphic GPS-determined rates in the vicinity of 2008 boundary. the 12 May event suggest an average re- Are we now living in the Note currence interval of ~2,000–10,000 yr. Anthropocene? This article received an exceptional Note Jan Zalasiewicz and 20 others amount of media attention, as well as in- The rapid date to publication of this ar- (Feb. 2008, v. 18, no. 2, p. 4–8; terest from both Parliament (UK) and the ticle after the Sichuan earthquake shows ftp://rock.geosociety.org/pub/GSAToday/ U.S. House of Representatives. Articles the editorial flexibility ofGSA Today in ad- gt0802.pdf). appeared in Science Daily, Discovery- dressing timely events of geologic impor- Abstract: The term Anthropocene, Channel.com, The Australian, Telegraph. tance. This article was received on 4 June proposed and increasingly employed to co.uk, NationalGeographic.com, the 2008, peer-reviewed, and accepted on denote the current interval of anthropo- Christian Science Monitor, Wired, Money 7 June 2008, going to press just three genic global environmental change, Times, the Edmonton Journal, the weeks later. This article has remained one

46 JAnuary 2009, GSA TODAY of the top-five most viewed GSA Today other themes or stand-out articles that articles since its publication. may have been missed. Letters to the editor are welcome and can be sent via CONCLUSIONS post to GSA Today, P.O. Box 9140, I invite readers to have a look at the Boulder, CO 80301-9140, USA, or by past ten years of GSA Today articles (or e-mail to [email protected]. Please even farther—GSA Today is online keep your letter to 300 words or fewer. beginning from 1995, and copies of GSA Today reserves the right to edit articles are available back to 1991) and letters for space and clarity. comment on the selections herein or on

GSA TODAY’S RECURRING THEMES Jan./Feb. GSA Bulletin Over the past 10 years, GSA Today has also published a few articles with • Raiding the lost Arc recurring themes. All articles are open access at www.geosociety.org/pubs. • Shuttle diplomacy in the Archean • Martian deformation is thin-skinned • Crack relaxes New England granites JELLY SANDWICHES & CRÈME BRÛLÉE See the April 2008 issue of Geology (v. 36, no. 4, p. 331–334; doi: 10.1130/ G24424A.1) for another article in this “series”: “Toasting the jelly sandwich: The effect of shear heating on lithospheric geotherms and strength,” by Ebbe H. Hartz and Yuri Y. Podladchikov. Strength of the continental lithosphere: December Geosphere Time to abandon the jelly sandwich? • SHRIMP-y systematics at Angel Lake James Jackson (Sept. 2002, v. 12, no. 9, p. 4–10; ftp://rock.geosociety.org/ • Piggybacking across the basin • Extended evolution of the south pub/GSAToday/gt0209.pdf). Balkan system The long-term strength of continental lithosphere: • Playful paleoevents in southwestern sediments “jelly sandwich” or “crème brûlée”? E.B. Burov and A.B. Watts (Jan. 2006, v. 16, no. 1, p. 4–10; ftp://rock. GSA’s online journal. geosociety.org/pub/GSAToday/gt0601.pdf).

GRAND CANYON SAND JAnuary GEOLOGY ISSN 0091-7613 JANUARY 2009 VOL. 37 NO. 1 P. 1–96 Floods and sandbars in the Grand Canyon • An orogen looks at forty • Trying to reason with Ivo Lucchitta and Luna B. Leopold (Apr. 1999, v. 9, no. 4, p. 1–7; ftp:// earthquake season rock.geosociety.org/pub/GSAToday/gt9904.pdf). • Fault tango in Tibet Is there enough sand? Evaluating the fate of Grand Canyon sandbars • Lahontan breeze

An Orogen Looks at Forty, p. 11 Scott A. Wright et al. (Aug. 2008, v. 18, no. 8, p. 4–10; ftp://rock.geosociety. Trying to Reason with Earthquake Season, p. 23 Fault Tango in Tibet, p. 31 Lahontan Breeze, p. 55 org/pub/GSAToday/gt0808.pdf). November ENVIRONMENTAL & ENGINEERING GEOSCIENCE • Graduate drains landslides What Drove The Phanerozoic Climate? • Leaky pavement? Environmental & Celestial driver of Phanerozoic climate? • Designing debris deflectors Engineering Geoscience NOVEMBER 2008 VOLUME XIV, NUMBER 4 Nir J. Shaviv and Ján Veizer (July 2003, v. 13, no. 6, p. 4–10; ftp://rock. • Soil amplifies quake waves geosociety.org/pub/GSAToday/gt0307.pdf). • Fissures follow failure CO2 as a primary driver of Phanerozoic climate Dana L. Royer et al. (Mar. 2004, v. 14, no. 1, p. 4–10; ftp://rock.geosociety. org/pub/GSAToday/gt0403.pdf).

CAN YOU INTERPRET THIS? Both of the following articles include a “mystery graphic” to be interpreted by the reader. Check them out online. Experimental stratigraphy Chris Paola et al. (July 2001, v. 11, no. 7, p. 4–9; ftp://rock.geosociety.org/ To subscribe, contact pub/GSAToday/gt0107.pdf). [email protected], or call What do you think this is? “Conceptual uncertainty” +1-888-443-4472, or +1-303-357-1000, option 3. in geoscience interpretation C.E. Bond et al. (Nov. 2007, v. 17, no. 11, p. 4–10; ftp://rock.geosociety.org/ Look for open access articles and more at pub/GSAToday/gt0711.pdf). www.gsajournals.org

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