Digital surface model, hillshade and Lambertian reflectance model of the rock glaciers Oelgrube and Aeusseres Hochebenkar (Oetztal Alps, Tyrol, Austria)

With full-waveform (FWF) lidar systems becoming increasingly available from different commercial manufacturers, the possibility for extracting physical parameters of the scanned surfaces in an area-wide sense, as addendum to their geometric representation, has risen as well. The mentioned FWF systems digitize the temporal profiles of the transmitted laser pulse and of its backscattered echoes, allowing for a reliable determination of the target distance to the instrument and of physical target quantities by means of radiometric calibration, one of such quantities being the diffuse Lambertian reflectance. The delineation of glaciers is a time-consuming task, commonly performed manually by experts and involving field trips as well as image interpretation of orthophotos, digital terrain models and shaded reliefs. In this study, the diffuse Lambertian reflectance was compared to the glacier outlines mapped by experts. We start the presentation with the workflow for analysis of FWF data, their direct georeferencing and the calculation of the diffuse Lambertian reflectance by radiometric calibration; this workflow is illustrated for a large FWF lidar campaign in the Ötztal Alps (Tyrol, Austria), operated with an Optech ALTM 3100 system. The geometric performance of the presented procedure was evaluated by means of a relative and an absolute accuracy assessment using strip differences and orthophotos, resp. The diffuse Lambertian reflectance was evaluated at two rock glaciers within the mentioned lidar campaign. This feature showed good performance for the delineation of the rock glacier boundaries, especially at their lower parts.

Carbonate, organic carbon and nitrogen, bitumen and rock-eval pyrolysis at DSDP Leg 79 Holes

The lipids and kerogens of 15 sediment samples from Site 547 (ranging from Pleistocene to Early Jurassic/Triassic) and 4 from Site 545 (Cretaceous) have been analyzed. A strong terrestrial contribution of organic matter was found, and significant autochthonous inputs were also present, especially at Site 545. Both strongly reduced and highly oxidized sediments have been found in the Cenozoic and Jurassic samples of Site 547. On the contrary, all the Cretaceous sections of Sites 547 and 545 are anoxic. Sediments from anoxic paleoenvironments are immature and have a high content of sterenes, diasterenes, steradienes, hopenes, and ßß hopanes. Samples from oxic paleoenvironments are mainly mature and their content of hopenes and steriod structures is below the detection level. Nevertheless, their hopane distributions have the immature ßß homologs as the predominant molecular markers. For Site 545 the most abundant molecular markers are ring A monoaromatic steranes, and their presence is attributed to microbial and chemical transformations during early diagenesis.

Magnetic measurements performed on sediments from the Bay of Seine seafloor (France) from 2011 to 2013

Impact and monitoring of dredge spoils are an important environmental issue. This investigation aims to map two dredge-spoil dispersals in the Bay of Seine by using an innovative application of well-established environmental magnetic proxies. Low-field magnetic susceptibility measurements were performed on discrete samples from dredge sediments and from the Bay of Seine seafloor before & after dumping. The fingerprinting of the dispersion of dredge-dumped sediments is efficient due to the higher susceptibility of the dredge sediments with respect to the background. Besides, terrestrial input is also monitored in our susceptibility maps. Dilution of the susceptibility signal allows an estimation of the resilience of the sedimentary environment on a six-month survey. This susceptibility signal is controlled by the ferromagnetic fraction of the sediment. A constant magnetic mineralogy carried by magnetite is observed in the study area, thus a qualitative parameter for magnetic grain size was selected that shows an in-progress resilience pattern over the survey.

Age determination on rock samples from Svalbard

A linear, N-S-trending belt of elliptical, positive magnetic anomalies occurs in central Nordaustlandet, northeast Svalbard. They extend from the Caledonian and older complexes in the vicinity of Duvefjorden, southwards beneath the western margin of Austfonna and the offshore areas covered by Carboniferous and younger strata, to the vicinity of Edge¯ya. One of the strongest anomalies occurs in inner Duvefjorden where it coincides with a highly magnetic quartz monzonite-granite pluton at Djupkilsodden. U-Pb and Pb-Pb zircon dating of this post-tectonic pluton defines an age of c. 415 Ma, this being based on the Pb-Pb analyses of three specimens (Pb-Pb ages of 414±10 Ma, 411±10 Ma and 408±10 Ma) and a U-Pb discordia with an upper intercept at 417+18/-7 Ma. Neighbouring felsic plutons in central Nordaustlandet, including the Rijpfjorden and Winsnesbreen granites, lack magnetic signatures in their exposed parts, but have a similar Caledonian age. The central Nordaustlandet magnetic anomalies appear to be part of a circa 300 km long linear belt of late Silurian or early Devonian post-tectonic plutonism that characterizes the Caledonian basement of eastern Svalbard. Felsic intrusions of similar age further west in Spitsbergen are likewise both highly magnetic (Hornemantoppen batholith) and largely non-magnetic (Newtontoppen batholiths / Chydeniusbreen granitoid suite). They all appear to have been intruded at the end of the main period of Caledonian terrane assembly of the northwestern Barents Shelf.