Detectives and geology in fiction - 1: Holmes and Thorndyke

In the early years - the so called 'Golden Age' - of mystery fiction, there were a number of towering figures - the 'great detectives'. However, only two of them included geology among their concerns. Their abilities and achievements are here compared and assessed.     

Quaternary changes in level of the upper Taylor Glacier, Antarctica: implications for paleoclimate and East Antarctic Ice Sheet dynamics

Glacial drifts perched alongside outlet glaciers that drain through the Transantarctic Mountains constrain inland polar plateau ice elevations. The Taylor Glacier, which heads in the Taylor Dome (a peripheral dome of the East Antarctic Ice Sheet), drains East Antarctic ice into the Dry Valleys sector of Transantarctic Mountains and terminates in central Taylor Valley, about 24 km west of the Ross Sea. Five gravel-rich drifts (including 39 distinct moraine ridges) fringe a lateral lobe of the Taylor Glacier in the lower Arena Valley, Quartermain Mountains, southern Victoria Land. ³He and ¹⁰Be exposure age dating (from Brook et al . 1992), together with Arena Valley stratigraphy and soil morphologic data, provide chronologic control for these drifts and constrain maximum Quaternary thickening of the inland Taylor ice dome to less than 160 m. These minor Quaternary expansions of Taylor Glacier were out-of-phase with outlet glaciers that pass through the Transantarctic Mountains and terminate in the Ross Sea north and south of the Dry Valleys region. Textural analyses suggest that drift deposition occurred from cold-based ice, even though Taylor Glacier advances most likely occurred during global interglaciations. The thermal regime of former Taylor Glacier ice lobes, the character of geomorphic features superimposed on individual drifts, the chemical composition of soils developed on Taylor drifts, and the stability of in situ moraine ridges on steep valley walls suggest that the present cold-desert climate in Arena Valley has persisted for at least the last 2.2 Ma.     

Gould Pond, Maine: late-glacial transitions from marine to upland environments

Gould Pond sediments are unusual in North America in that they include a continuous record of change from marine to freshwater conditions during the late-glacial period, with a wide array of micro- and macrofossils deposited during a period of high sedimentation rate. Marine waters, much colder than those in the present Gulf of Maine, covered the site at the time of deglaciation (c. 13,200 BP). Plants characteristic of modem tundra grew on nearby uplands. Marine recession, due to isostatic rebound of the land, occurred from c . 12,800–12,200 BP. The lake water was completely freshened by 12,000 BP. A sparse shrub-herb tundra became established around Gould Pond as marine waters receded. Subsequent to 11,300 BP, sedges and other herbs became more abundant, and willow and Dryas less abundant, signifying increased warmth and decreased frost action. At least six tree species, all now common in the area, arrived around Gould Pond between c . 10,800 and 10,500 BP. This rapid transition was coincident with the most rapid major non-anthropogenic change of vegetation at sites across eastern North America during the postglacial period.     

Photointerpretation of Tertiary structures in platform cover strata of interior Oscar II Land, Spitsbergen

A structural map of Oscar II Land compiled using black and white, stereo-pair air photos and other available information sources suggests the existence of three structural zones within the deformed platform cover strata. The western zone consists of basement involved overthrusts of complex geometry in the north large-scale folds of platform cover strata with a stepped, down to the east profile in the south. The central zone consists primarily of folds within Kapp Starostin Fm. and overlying Triassic strata that likely formed above a subhorizontal décollement within Gipshuken Fm. strata. Farther to the east thrusts emplace Permian Kapp Starostin Fm. strata over Triassic strata. This zone probably represents stratigraphic climb of the basal decollement. Conservative estimates of shortening for the central and eastern zones are in the 15-25% range. The contribution of the western zone structures to overall Tertiary shortening depends on the geometry of faults underlying the stepped folds and is uncertain at present.
Changes along strike are in part due to differential levels of erosion and changes in transport direction, but also probably important was variable thickness of the platform cover strata involved (less to the north) and the availability of incompetent horizons along which thrust-fiats could form. Two areas with anomalous structural trends may represent oblique ramps.     

The latest vertebrates are the earliest

The teeth, or elements, ofconodonts are among the most important Palaeozoic microfossils. Despite this, the biological relationships of conodonts have long remained enigmatic. Recent evidence of their soft anatomy, and of the ultrastructure of the elements, has finally revealed that they are vertebrates. These discoveries push vertebrate origins firmly back into the Cambrian and add a large cohort of specialists to the ranks of the vertebrate palaeontologists.     

A storm-related origin for the Jurassic Brentskardhaugen Bed of Spitsbergen, Norway

The laterally persistent but thin, Jurassic age (Bathonian-Callovian) Brentskardhaugen bed is poorly sorted (often with mud to cobble size), and is crudely normally and/or reversely graded without internal discontinuities. These traits may indicate a short-lived depositional event, and are inconsistent with an origin as a basal, transgressive gravel lag formed in a terrestrial or shoreline setting. Mega-storm events on a shallow marine shelf with an underlying condensed section may account for the poor sorting, grading, stratigraphic position and remanie character of the bed.     

Within-valley asymmetry and related problems of Neoglacial lateral moraine development at certain Jotunheimen glaciers, southern Norway

A difference in the size of Neoglacial lateral moraines on either side of a valley axis (within-valley asymmetry of lateral moraine development) is described. Analysis of clast roundness has revealed subangular material in latero-terminal and terminal moraines; lateral moraines, however, exhibit a compositional gradient of increasing angularity with distance from the former glacier snout. Comparisons with clasts of known origin suggest that this 'roundness gradient' may be explained with reference to either or both of two hypotheses: (1) a variable proportion of supraglacial (or englacial) to subglacial transported material; and (2) the variable composition of regolith incorporated by a push mechanism from the valley sides. Within-valley asymmetry is inferred to result where the supply of debris to lateral moraines from these sources is unequal either side of a valley axis. Both interpretations are also consistent with the relatively large size of latero-terminal sections of end moraines. In order to account for the discrepancy between moraine size and apparent debris supply rates, it is suggested that the largest lateral moraines may have been formed over a longer time scale than the 'Little Ice Age', and that reworking of deposits may have occurred. The supply of debris to the north-facing lateral moraine at Nordre Illåbreen has been so great that it has developed into a rock glacier; this suggests the possibility that subglacial material and valley-side regolith, as well as supraglacial material, contributes to the formation of ice-cored rock glaciers.     

Assessing the completeness of the deglacial-marine stratigraphic record on west Spitsbergen by accelerator mass spectrometry radiocarbon dating

The record of Quaternary glaciations of coastal areas is frequently preserved as a raised deglacial-emergence sequence. Detailed radiocarbon dating of foraminifera and marine macrofossils from a representative deglacial sequence on west Spitsbergen document two periods of sedimentation at c . 11,400 BP and at 9500 BP that together span < 500 years. The incompleteness of this record (< 25%), the highly episodic nature of sedimentation, the dominance of local glacial and environmental effects and the presence of allochthonous foraminifera inhibits ascertaining the relation between deglaciation of Svalbard/Barents Sea and changes in thermohaline circulation in the Norwegian Sea. The Late Weichselian and older deglacial sequences on west Spitsbergen have a similar sedimentologic succession. Thus, one possibility is that older raised-marine deglacial sequences on Svalbard and other Arctic areas may represent similar brief intervals, potentially confounding correlations across the Arctic and with well established events (i.e. the Eemian Interglacial) at lower latitudes.     

THE LEGENDARY “REDISCOVERY” OF GEORGE PERKINS MARSH

The conventional narrative regarding the American reception of George Perkins Marsh, author of Man and Nature (1864), is that his work and ideas were “lost,”“forgotten,” or “neglected” until Lewis Mumford “rediscovered” him and introduced him to geographers at the University of California‐Berkeley through The Brown Decades (Mumford [1931] 1955) and until Carl Sauer made him known to the profession at large beginning in 1938. This article upends the conventional narrative by looking at earlier references to Marsh's later versions of Man and Nature, which were published as The Earth as Modified by Human Action from 1874 to 1907. Analysis reveals that a number of geographers and historians cited these editions between 1875 and the early 1950s. Examining the legend of loss and rediscovery suggests the value of methods utilized in reception studies for research on the history of geography.