Proefschrift--Groningen. / "Literatuur": p. 238-271.

A study of the origin of the boulder fields at Shek Lung Tsai, Ma On Shan has been carried out because of the mystery surrounding their origin, which has yet to be formally investigated. The objective of the study was to give a descriptive analysis of the geometry of the boulders, and to examine if they are jointed columns like those of the High Island Formation in Sai Kung, by obtaining data on aspect ratio and interfacial angles. Data has been obtained from the boulders and is presented in the form of a table detailing their individual measurements. The data has been interpreted in relation to the concept that Y-intersections and hence interfacial angles of 120˚ are indicative of columnar-jointed rocks. It is concluded that there is a possibility of the boulders being cooling-jointed columns, and their failure may have been triggered by a tilting of southeastern Hong Kong to the east was as much as 30˚ in the Quaternary. / published_or_final_version / Applied Geosciences / Master / Master of Science

Proefschrift--Groningen. / "Literatuur": p. 238-271.

Thesis (Ph.D.)--University of Wollongong, 2005. / Typescript. Bibliographical references: p. 275-293.

Analysis of impact craters and their ejecta addresses someunanswered questions about the lunar surface. First I estimatethe regolith depth on the south farside of the Moon to be about40 m, which is significantly deeper than the nearside regolith,estimated to be 3-16 m. This result is obtained by studyinghundred meter diameter flat floored craters, using the method ofQuaide and Oberbeck (J. Geophys. Res., 1968, 73, 5247-5270). This measurement has implications for the formation of the lunarregolith, and for interpretation of samples returned in thefuture by astronauts or automated sample return missions.Next, I report the discovery of a method that distinguishesbetween primary and distant secondary craters in high resolutionplanetary images. For a given crater size, the largest bouldersof secondary craters are significantly larger than those ofprimary craters. The ability to identify distant secondarycraters will help constrain primary production rates of smallcraters and improve surface age determination of small areasbased on small crater counts.Third, I characterize the distributions of boulders ejected from18 lunar impact craters. I find that in large craters, thelargest boulders are preferentially ejected at low velocities(closer to the crater), whereas the largest boulders from smallcraters are ejected over a wider range of ejection velocities. Also, for a given crater size, deeper regolith reduces themaximum ejection velocity attained by a boulder ejected from acrater. I show that this is a logical result of the streamlinesof excavation in an impact when there are no coherent boulders inthe regolith. Cumulative plots of the boulders have slopessteeper than -2, as do secondary craters. This result isexpected because ejecta fragments produce secondary craters.Finally, I describe the morphology of some lunar crater walllandslides that strongly resemble martian gullies, despite thelack of geologically active water on the Moon today or in thepast. The lunar features indicate that alcove-channel-apronmorphology, attributed on Mars to seepage of liquid water, canalso form via a dry landslide mechanism. Therefore alcove-channel-apron morphology is not diagnostic of water carvedgullies.

Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 54-58). Also available on the World Wide Web.

Geomorphologists have long observed the influence of lithology on landscape form and evolution. However, the specific mechanisms by which this is accomplished are not well characterized. Here, I investigate the role of lithology in landscape evolution processes across spatial and temporal scales and geomorphic domains, to progress our understanding of the basic controls on the processes which shape Earth's surface. These investigations were carried out within the Valley and Ridge province of the Appalachian Mountains, where contrasts in strength of underlying lithologies (juxtaposed by Alleghanian deformation) exert a clear, dominant control on the fabric of the landscape, providing an excellent opportunity to study the influence of lithology on a variety of landscape evolution processes. First, I assess the geomorphic function of boulders found on hillslopes and channels in the Valley and Ridge province of the Appalachians, which are sourced from resistant lithologies capping ridgelines. High-resolution UAV surveys and field mapping of boulder distributions and characteristics reveal that boulders are abundant on hillslopes and highly concentrated in channels, often trap sediment upslope, and appear to be long-lived. These observations suggest that boulders act as armor for hillslopes and channels, shielding weaker underlying units from erosion and inhibiting fluvial incision, and therefore play an important role in preserving topography in the Valley and Ridge landscape, highlighting a specific mechanism by which lithology exerts an influence on topography in this setting. Second, I investigate the relative importance of rock strength and discontinuity spacing in setting fluvial bedrock erodibility by comparing knickpoint and non-knickpoint bedrock, which correspond to end-member erodibility cases, and assess how lithology impacts knickpoint expression. Detailed field surveys of 21 lithologic knickpoints, surrounding non-knickpoint reaches, and corresponding bedrock properties reveal three key outcomes: 1) discontinuity spacing is a stronger predictor of knickpoint occurrence, and therefore more significant in setting bedrock erodibility in this setting, confirming quantitatively the hypothesis that discontinuities exert a dominant control on fluvial erodibility, 2) knickpoint expression is a function of the unique combination of characteristics within a given stratigraphic interval, and therefore highly complex and specific to local conditions, implying that knickpoint morphology should be interpreted with extreme caution, and 3) because all 21 study knickpoints occur within the same unit, inter-unit heterogeneity must be accounted for before lithologic influence on channel profile convexities can be ruled out, rather than comparing to geologic map contacts. These findings represent an important contribution towards a more functional understanding of the influence of lithology on fluvial bedrock incision processes. / Doctor of Philosophy / It has long been observed that underlying geology has a strong impact on the shape of the surrounding landscape and influences the erosional processes that act within that landscape. However, though the importance of rock type in shaping landscapes is recognized, the specific mechanisms by which this is accomplished are not well understood. The work presented here investigates the role of rock type and rock properties in landscape evolution processes in both hillslope and river environments within the Valley and Ridge Province of the Appalachian Mountains. This setting is ideally suited for investigating the role of rock type on landscape evolution processes because of the wide variation in rock types present in this setting, which exert a strong influence on local topography (e.g., strong rocks form ridges while weak rocks underlie valleys). First, I mapped the distribution of large boulders on local Valley and Ridge slopes and mountain streams to assess the potential for these boulders to play a role in preserving local topography. Results show that boulders are sourced from resistant rock types found along ridgelines, and are abundant on hillslopes and highly concentrated in channels. Boulders also trap sediment upslope and appear to remain in place for long periods of time. These observations suggest boulders play an important role in slowing erosion of weaker rock types underlying hillslopes and channels, and therefore aid in preserving topography in this setting. Second, I conducted detailed surveys of local small-scale waterfalls and surrounding flat river reaches and compared properties of the bedrock between these locations to better understand how bedrock properties influence erodibility. In this setting, waterfalls often signify strong underlying bedrock relative to the rock beneath flat river reaches, so comparing bedrock properties between these areas should give insight into how properties like rock strength and bed thickness impact how erodible the bedrock is. Results show that bed thickness is the most important variable impacting bedrock erodibility in this setting, and that waterfall appearance is a product of the unique combination of bedrock properties within a given area. These results are important for improving our ability to model natural landscapes and erosional processes, and for developing a more complete understanding for the relationships between rock type and river morphology.

Several laterally extensive candidate tsunami deposits are preserved along coastlines facing the eastern Java Trench, indicating it has experienced mega-thrust earthquakes in the past. We investigated 37 coastal sites in Bali, Lombok, Sumba and Timor islands, many of which preserve course sand and pebble layers that overlie sharp basal contacts with scour marks into the mud, fine upward in grain size, and have bimodal grain size distributions. Other unique features are the common occurrence of marine fossils and concentrations of heavy minerals. The occurrence of these high-energy deposits interlayered with clay-rich units indicates the coarse clastics are anomalous because they were deposited in what is normally a very low-energy depositional environment. The lateral extent and paucity of thin, coarse clastic layers with marine organisms are inconsistent with local stream flood event, and the proximity to the equator of the sites diminishes the possibility of marine flood events from cyclones. The sparse, but consistent, the occurrence of at least two candidate tsunami deposits at depths of 1 and 2 meters over 950 km along the strike of the Java Trench may reveal that mega-thrust earthquakes have occurred there and generated giant tsunamis in the recent past.Five widely scattered imbricated boulder deposits are also found on Bali, Lombok, and Sumba. The boulders consist of slabs of hardpan up to 2.5 m in length and 80 cm thick that was torn from a near-shore seabed and stacked on top of one another. Some of the boulders were carried over the erosional coastal bank and deposited up to 100 meters inland. Comparisons with imbricated boulder ridges formed during the 1994 tsunami in east Java indicate that these deposits are from one or multiple tsunamis sourced by the Java Trench.Experiments in effective ways to communicate and implement tsunami disaster mitigation strategies have led us to train local communities about the 20-20-20 rule. If coastal communities experience more than 20 seconds of shaking from an earthquake, even if it is not intense, they should evacuate the coast. The time delay between the earthquake and arrival of tsunami waves is around 20 minutes, which is the time window for evacuation. Some tsunami waves may be as high as 20 meters, which is the target elevation for evacuation. Adopting the 20-20-20 rule could save thousands of lives throughout the region, especially in Bali where nearly 1 million people inhabit likely tsunami inundation zones.

Thesis (PhD)--Macquarie University, School of Earth Sciences, 1981. / Bibliography: leaves 218-233. / Introduction -- Methods -- Boulder size -- Boulder morphology -- Boulder roundness -- Beach form -- Boulder movement -- Process inference from studies of coastal protection structures -- Summary and conculsion. / Five boulder beaches along the central New South Wales coast were selected for the study of their sedimentary properties, form, and sediment transport. Each beach is aligned obliquely to the approaching waves and is composed of local sediment. One beach, which appears to have little or no recent sediment input, is considered to be a closed sediment system and the other four beaches, which appear to have recent sediment supply, are considered to be open sediment systems. -- On the open system beaches, boulder size fines towards the embayment in the direction of transport, and on all beaches size fines up-beach (contrasting with the up-beach coarsening of pebble and cobble beaches). During transport, breakage and chipping diminish boulder size, and the products of these forms of abrasion constitute a subordinate fine population causing the distribution of size to be positively skewed, contrasting with most fine-sediment beaches which exhibit negative size skewness. -- More boulders are oblate than prolate, but this may reflect geology rather than coastal weathering processes. In contrast to pebble beaches, no longshore or up-beach shape zoning exists, and boulder shapes are believed to be largely determined by geology. Boulder shape is not related to boulder size. Sphericity varies little within each beach and nowhere does it increase seaward as is common for pebble and cobble beaches. -- Boulder roundness tends to increase longshore towards the embayment, and decrease up-beach. The relationships between boulder roundness and size may be influenced by sediment supply. Roundness and shape of boulders do not appear to be related. -- Overall beach form is consistent and no rhythmic features could be identified. Surface packing or armouring occurs on all beaches and may contribute to beach stability. Foreshore slopes tend to be concave upward and range between 7° and 12°, significantly lower than the slopes of >= 24° predicted in the literature for boulder-sized sediment. This anomaly may be explained by the fact that only very high-energy waves, which produce low beach slopes, are competent to transport boulders. -- Boulder mobility is evident on all beaches and was monitored on one beach. Wave competency appears to determine the maximum size of transported boulders, and a competency model is proposed in which it is predicted that there exists a power relationship between transported particle diameter and significant wave height. Since boulder beaches and rubble coastal protection structures have environmental and compositional similarities, beach-boulder movement is examined in the light of engineering studies of protection-structure stability. Two no-damage design formulae were found to over-predict the movement of the smaller-sized beach sediment and underpredict the movement of the larger-sized sediment. This effect may be due to the packing of beach boulders. -- Up-beach fining, positive size skewness, the absence of shape zoning, much particle breakage, the absence of sphericity grading, and low foreshore slope are all characteristics of the five studied boulder beaches which contrast markedly with the characteristics of pebble and cobble beaches. These findings, combined with the development of a reasonable predictive transport model, suggest that the studied boulder assemblages are organized and distinct coastal deposits, which may properly be termed beaches. / Mode of access: World Wide Web. / 309 leaves ill. (some col.), maps

Detta examensarbete handlar om att följa upp skuthantering i Aitik och dess ekonomiska påverkan, Aitik är en dagbrottsgruva som ligger i Gällivares kommun. Skut är ett bergblock som är större än 1 m3 och är ett återkommande problem då de orsakar störningar i produktionsflödet. Totalt genomfördes tre fältstudier som inriktades på lastning, skutknackning och kross. Ett utav målen var att undersöka om det är lönsamt att låta Aitiks entreprenör knacka skut, detta genom att jämföra kostnaden som entreprenören fakturerar mot att hantera skuten som gråberg vilket medför en deponiförlust av kopparvärdet. Hantering av skut kan ske på två olika sätt, hantering vid upplag och hantering vid salva. Dessa två metoder jämförs för att se vilken som är mest lönsam. Ett annat mål var att undersökahur stor inverkan skut har i krossen då de orsakar stopp, och därefter jämföra dessa stopporsaker mot krossoperatörens inrapporterade stopporsak, vilket denne gör i Aitiks Sogetisystem. Studien åskådliggör att det inte är lönsamt att låta entreprenören hantera skut vid kopparhalten 0,06 %. För kopparhalter kring 0,1 % bör vidare undersökningar genomföras om det är lönsamt eller ej. Vid 0,2 % och över är det lönsamt med skuthantering från entreprenören. Skuthantering vid upplag är den mest lönsamma metoden så länge dieselpriset understiger 10 kr per liter. Skut har en stor negativ inverkan på produktionseffektiviteten i krossen. Totalt orsakades 86 minuter stopp i krossen på grund av skut under två skift. Detta motsvarar ca 400 000 kr i produktionsförlust, vid produktionseffektiviteten 4041 ton per timme vilket var den verkliga effektiviteten hos krossen under det ena skiftet. Olikheter påträffades vid jämförelse mellan dokumenterade stopporsaker och operatörernas stopporsaker i Sogeti. Vid uppföljande studier bör hänsyn tas till kostnader för truckslitage i beräkningar av skuthantering, då detta kan påverka resultatet. Fler fältstudier bör utföras för att få ett mer tillförlitlig resultat. / This thesis is about following up the handing of boulders and its economic impact. Aitik is an open-pit mine located near Gällivare in Norrbotten. According to Aitik, a boulder is a rough stone that is larger than 1 m3, and they are a recurrent problem because boulders cause a disturbance in the production flow. A total of three field studies were done which focused on loading, boulder breaking and crushing. The goal was to investigate if it was going to be profitable to let Aitik´s entrepreneur handle boulders using a hydraulic breaker, thus comparing the invoice from Aitik´s entrepreneur compared to handling the boulders as waste rock, which entails a landfill loss of the copper value. The handling of boulders can occur in two different ways, handling at stockpile or handling at burst. These two methods are compared with each other to see which one is the most profitable. Beyond this it was also examined on how much of an impact boulders have in the crushing section when they cause a stop, and thereafter compare these stops against the reported stoppage from the operators which is done in Aitiks Sogetisystem. The study illustrates that it is not profitable to let Aitik´s entrepreneur handle boulders at the copper content 0,06 %. Copper concentrations around 0,1 % should be further analyzed whether it is profitable or not. At 0,2 % and above it is profitable to let Aitik´s entrepreneur handle the boulders. Handling boulders at stockpile is the most profitable method as long as the fuel cost is below 10 SEK per liters. Boulders have a large negative impact on the production efficiency in the crushing section. In two shifts there were a total of 86 minutes stop in the crusher caused by boulders, this corresponds to about 400 000 SEK in production loss at a production efficiency of 4041 tons per hour, which was the actual efficiency during one of the shifts. Differences occurred among the documented stop causes and the stop causes made by the operators in Sogeti. For further studies, a regard should be made occurring costs of truck wear due to boulder handling as this may affect the results. Also perform more field studies in order to get a more reliable result.