نتایج جستجو برای: boulders

تعداد نتایج: 736  

Journal: :Geological Magazine 1888

2017
Kiran Liversage

Disturbances in ecological systems can cause new resources to become available and can free the resources held by strongly competitive species. In intertidal boulder fields, wave-action causes disturbance by overturning boulders and freeing space for re-colonisation. In this study, mensurative experiments showed that boulder disturbance may also cause new biogenic-habitat resources to become av...

2015
Yun Jiang Jianghui Ji Jiangchuan Huang Simone Marchi Yuan Li Wing-Huen Ip

Boulders are ubiquitously found on the surfaces of small rocky bodies in the inner solar system and their spatial and size distributions give insight into the geological evolution and collisional history of the parent bodies. Using images acquired by the Chang'e-2 spacecraft, more than 200 boulders have been identified over the imaged area of the near-Earth asteroid Toutatis. The cumulative bou...

Journal: :Icarus 2021

Boulders on the surfaces of planets, satellites and small bodies, as well their geological associations, provide important information about surface processes. We analyzed all available images Mercury that have sufficient resolution quality to detect boulders, we mapped boulders observed. The lower size limit detectable was ~5 m. All found are associated with fresh impact craters hundreds meter...

2017
Kiran Liversage Kirsten Benkendorff

Most species of Ischnochiton are habitat specialists and are almost always found underneath unstable marine hard-substrata such as boulders. The difficulty of experimenting on these chitons without causing disturbance means little is known about their ecology despite their importance as a group that often contributes greatly to coastal species diversity. In the present study we measured among-b...

2009
Jason P. Briner

Cosmogenic exposure dating of moraines during the last two decades has vastly improved knowledge on the timing of glaciation worldwide. Due to a variety of geologic complications, such as moraine degradation, snow cover, bedrock erosion and isotopic inheritance, samples from multiple large boulders (>1– 2 m) often lead to the most accurate moraine age assignments. However, in many cases, large ...

2016
Josh Walter Borella Mark Quigley Louise Vick

Human modification of natural landscapes has influenced surface processes in many settings on Earth. Quantitative data comparing the distribution and behavior of geologic phenomena before and after human arrival are sparse but urgently required to evaluate possible anthropogenic influences on geologic hazards. We conduct field and imagery-based mapping, statistical analysis, and numerical model...

2016
Robert Williams Angelo P. Pernetta Julia A. Horrocks

House Geckos in the genus Hemidactylus are highly successful colonizers of regions beyond their native range, often resulting in displacement of native gecko species through competitive interactions for daytime refuge (crevices) and prey resources. We report on data collected from night time surveys undertaken in April-May 2014 on Barbados, West Indies, that focused on the distribution and abun...

2005
MICHAEL WAGREICH

Middle Miocene alluvial fans in the intramontane Fohnsdorf Basin of the Eastern Alps originated along normal faults and linked strike-slip faults in a continental half-graben setting. The fans display considerable facies differences. Debris flows of the Rachau fan are characterized by a sandy matrix and large boulders, whereas debris flows of the Apfelberg fan are characterized by higher silt a...

2017
Kiran Liversage Kirsten Benkendorff KIRAN LIVERSAGE

35 36 The rock type of hard-substrata marine habitats can affect numerous benthic invertebrates, but 37 little is known of the effects on molluscan assemblages, for example, the chitons often found 38 under intertidal boulders. We compared chiton assemblage composition, abundance, species 39 richness, and patterns of frequency distribution in ten boulder-fields containing either hard 40 metamor...

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