The origins of marine and non-marine boulder deposits: a brief review

Abstract

We identify 14 mechanisms, marine and non-marine, one man made, that result and could result in the formation of boulder deposits after reviewing issues associated with clast shape, size and classification. Four of these mechanisms: storm deposits; waterspouts; cliff collapse; and catastrophic flooding below sea level, may produce deposits stretching for significant distances along shorelines which could be confused with historical or prehistoric tsunami deposits. However, recent debate has more specifically focused on parameters that can be employed in the distinction between coarse-grained tsunami and storm deposits, both of which can occur in the same location. We argue that features such as size, areal distribution and clast shape are not uniquely characteristic of either deposit. Rather, a wide variety of parameters, which reflect the period and the frequency of the transporting waves, need to be taken into account. Such analyses may be aided by profiles which evaluate the variation in modeled flow velocities with distance from the shoreline. Finally, we compare and contrast characteristics of coarse grained tsunami deposits with those of northeast Atlantic storm deposits that may aid in the identification of the transporting wave.

Automatic Characterization of Boulders on Planetary Surfaces From High‐Resolution Satellite Images

“…Mass‐wasting events such as landslides, rockfalls, and debris flows can break down damaged bedrock into boulders (Shobe et al., 2021). Similarly, glaciers (Darvill et al., 2015), rivers and floods (Elfström, 1987), as well as storms, hurricanes, and tsunamis (Dewey et al., 2021), can erode bedrock under the action of a shearing fluid.…”

“…As the shape, size, and orientation distributions of boulders often relate to their formation process, they offer a unique opportunity to decipher the geologic history of the diverse planetary surfaces in our solar system (e.g., Lapôtre et al., 2020). For example, boulders have been used to identify the geological processes shaping planetary landscapes (Bickel et al., 2020; Dewey et al., 2021; Lapôtre et al., 2016; Lapôtre & Lamb, 2018; Pajola et al., 2021; Xiao et al., 2013), infer the past existence of multiple glaciations on Mars (Levy et al., 2021), determine the direction of glacier flows (Darvill et al., 2015), and estimate erosion rate (Basilevsky et al., 2013; Watkins et al., 2019). Last but not least, quantitative characterizations of boulders are critical to landing‐site selection and hazard assessment for landed missions (Golombek et al., 2012, 2017; Pajola et al., 2017).…”

An erg landscape mystery: An exotic boulder in Jurassic aeolian‐fluvial deposits, Grand Staircase Escalante National Monument, Utah, USA

“…These Jurassic units have been well studied for their structure, tectonics, stratigraphy, sedimentology, and palaeontology. However, this paper focuses on a previously unreported, anomalous feature, a meter‐scale exotic boulder (>256 mm: Dewey et al, 2021; Wentworth, 1922) of weakly bedded carbonate and siltstone in a carbonate mudstone matrix that is embedded in and eroding out of host‐rock sandstone close to the interfingering transition between the Lower Jurassic fluvial Tenney Canyon Tongue of the Kayenta Formation (Fm) and aeolian Lamb Point Tongue of the Jurassic Navajo Sandstone (Ss), in Grand Staircase Escalante National Monument, east of Johnson Canyon, Utah (Figure 1). The term exotic boulder is used here to imply an anomalous boulder that differs from the host rock, and lacks any obvious transport mechanism of how it was incorporated into the surrounding rock.…”

The Imprint of Recent Meteorological Events on Boulder Deposits along the Mediterranean Rocky Coasts

“…However, CBDs produced by high-energy waves have some peculiar characteristics (see Section 2). Thus a geomorphological survey is usually enough to recognize their origin with high confidence [3][4][5]. Boulder production and deposition by wave quarrying are strictly related to coastal erosion and flooding hazard.…”