Mineralization consists of megascopic and microscopic molybdenite, pyrite, minor chalcopyrite and rare bornite.
|
|
In this project, we are observing morphological features that are preserved or created during early post-mortem decomposition of modern megascopic algae.
|
|
The term "megascopic" is a synonym. "Macroscopic" may also refer to a "larger view", namely a view available only from a large perspective (a hypothetical "macroscope"). A macroscopic position could be considered the "big picture".
|
|
Diskagma ("disc-like fragment") is a genus of problematic fossil from a Paleoproterozoic (2200 million years old) paleosol from South Africa, and significant as the oldest likely eukaryote and earliest evidence for megascopic life on land. Reconstruction of Diskagma buttonii.
|
|
When a solid solution becomes unstable—due to a lower temperature, for example—exsolution occurs and the two phases separate into distinct microscopic to megascopic lamellae. This is mainly caused by difference in cation size. Cations which have a large difference in radii are not likely to readily substitute.Nesse, William D. (2000).
|
|
Myxomitodes (Greek "slime thread like") is a genus of problematic fossil from the Paleoproterozoic (1900 million years old) Stirling Range Formation of Western Australia, and is significant as a very old megascopic fossil, and thus eukaryote. It is a trace fossil and thus evidence of activity, rather than a body fossil. Detail of levees in flaring portion of trail of Myxomitodes stirlingensis.
|
|
Megascopic cross-cutting relationships are features like igneous dikes, as mentioned above, which would be seen on an outcrop or in a limited geographic area. Microscopic cross-cutting relationships are those that require study by magnification or other close scrutiny. For example, penetration of a fossil shell by the drilling action of a boring organism is an example of such a relationship.
|
|
Thus, they are not always 'planar' in the strictest sense and may violate the rule of being perpendicular to the regional stress field, due to local influences. This is a megascopic version of what may occur around porphyroblasts. Often, fine observation of foliations on outcrop, hand specimen and on the microscopic scale complements observations on a map or regional scale.
|
|
If an alkali feldspar grain with an intermediate composition cools slowly enough, K-rich and more Na-rich feldspar domains separate from one another. In the presence of water, the process occurs quickly. Megascopic antiperthite Perthite feldspar from Dan Patch pegmatite, Black Hills, South Dakota When megascopically developed, the texture may consist of distinct pink and white lamellae representing exsolved white albite (NaAlSi3O8) in pink microcline. The intergrowths in perthite have a great variety of shapes.
|
|
This is one of the reasons why the Nuuk area is extraordinary and also because the particular climate zone for the area limits the vegetation which makes it possible to observe impressive km-scale megascopic textures. The bedrock around Nuuk consists of two major lithologic packages, the dark melanocratic Amitsoq gneiss, which is intruded by and complexly folded into the younger leucocratic Nuuk gneiss. This western gneiss complex is approximately 3600 million years old. The Isua Greenstone Belt in the Isukasia area, southwest Greenland, is extraordinary in that it contains some of the oldest bedrock on the planet, approximately 3800 million years old.
|
|
Searlesite is a sodium borosilicate mineral, with the chemical formula NaBSi2O5(OH)2. It was discovered in 1914 at Searles Lake, California, and was named to honor John W. Searles (16 November 1828 - 7 October 1897), California pioneer, who drilled the well that yielded the first known Searlesite. Searlesite is usually found disseminated in fine-grained lacustrine strata and often associated with altering volcanic ash. It may be a minor component of borate deposits, but it is rarely found concentrated or in megascopic crystals and so has not been developed as an ore mineral of boron.
|
|
The lower boundary of the Vendian was suggested to be defined at the base of the Varanger (Laplandian) tillites. In: (82mb) The Vendian in its type area consists of large subdivisions such as Laplandian, Redkino, Kotlin and Rovno regional stages with the globally traceable subdivisions and their boundaries, including its lower one. The Redkino, Kotlin and Rovno regional stages have been substantiated in the type area of the Vendian on the basis of the abundant organic-walled microfossils, megascopic algae, metazoan body fossils and ichnofossils. The lower boundary of the Vendian could have a biostratigraphic substantiation as well taking into consideration the worldwide occurrence of the Pertatataka assemblage of giant acanthomorph acritarchs.
|
|