Certain alteration minerals are used to identify the hydrothermally altered rocks. In volcanic rocks, mainly potassic, phyllic (sericitic), propylitic, argillic alteration and silicification are observed. The role of remote sensing in alteration mapping is the differentiation of the minerals that are unique for different alteration types. In this study, Landsat TM 5 images are used. General alt...

Rifted continental margins are the product of stretching, thinning and ultimate break-up of a continental plate into smaller fragments, and the rocks lying beneath them store a record of this rifting process. Earth scientists can read this record by careful sampling and with remote geophysical techniques. These experimental studies have been complemented by theoretical analyses of continental e...

We examined the potential use of lead (Pb) isotopes to source archaeological materials from the Maya region of Mesoamerica. The main objectives were to determine if: 1) geologic terrains throughout the Maya area exhibit distinct lead isotope ratios (206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb), and 2) a combination of lead and strontium ratios can enhance sourcing procedures in the Mesoamerica re...

New geochemical data including Sm/Nd isotopic data show evidence for an early Paleozoic arc/back-arc complex in the Nashoba terrane of southeastern New England. The Nashoba terrane lies between rocks of Ganderian affinity to the northwest and Avalonian affinity to the southeast. It consists of early Paleozoic mafic to felsic metavolcanic and metasedimentary rocks that were intruded by intermedi...

•80 data have been obtained on 7 of the 17 intrusive centers of diorite and granodiorite (Miocene?) that lie along a N-S belt about 50 km west of the High Cascades. Whole-rock $ values (per mil relative to SMOW) in the intrusive stocks are: -[-2.3 to -t-4.9 (South Umpqua River), -0.7 to -t-3.8 (Bohemia mining district), -t-4.3 to -t-4.6 (Vida stock), -0.2 to -t-5.5 (Nimrod stock), --1.7 to -}-0...

Maars are monogenic volcanic edifices of peculiar morphology with a wide circular crater surrounded by a low gentle rim of erupted pyroclastic material. Craters of maars are deeply incised into underlying rocks (frequently down to the aquifer), which explains their frequent partial or complete water infill. Owing to their morphological peculiarities, maars are easily identifiable in air photos.

A bidimensional empirical mode decomposition (BEMD) program on a MATLAB platform was effectively used to handle gravity signals for the Tongshi gold field. This yielded a two-dimensional intrinsic mode function (IMF3) image that meticulously depicts the spatial distribution relationship between various gold deposits and the different geological units of the gold field. By combining the IMF3 ima...

0019-1035/$ see front matter 2010 Elsevier Inc. A doi:10.1016/j.icarus.2010.12.014 ⇑ Fax: +1 480 965 8102. E-mail address: [email protected] The surface of Mercury contains ancient volcanic features and signs of pyroclastic activity related to unknown magmatic volatiles. Here, the nature of possible magmatic volatiles (H, S, C, Cl, and N) is discussed in the contexts of formation and evolution of...

Soils in ice-free areas of Livingston Island have been forming since the last deglaciation in a maritime warmer climate that is more humid than in interior Antarctica. A soil survey was carried out on Byers and Hurd peninsulas to characterize the soils and investigate the processes. Soils were sampled on two different substrates, mudstones and volcanic rocks in Byers Peninsula