The western hemisphere is dominated by the Tharsis region red and brown. Tall volcanoes appear white. Valles Marineris blue is the long gash-like feature to the right. The Elysium province is at the upper right edge. Areas north of the dichotomy boundary appear as shades of blue on both maps. The northern and southern hemispheres of Mars are strikingly different from each other in topography and physiography. This dichotomy is a fundamental global geologic feature of the planet. Simply stated, the northern part of the planet is an enormous topographic depression. In contrast, the lowlands north of the dichotomy boundary have few large craters, are very smooth and flat, and have other features indicating that extensive resurfacing has occurred since the southern highlands formed. The third distinction between the two hemispheres is in crustal thickness.
Two versions of each set of lecture notes are shown in the table below. The first is in html format, optimized for viewing on the Web at screen resolutions greater than x You can print this version directly from your Web browser, but there is no guarantee that the pages will break where they are supposed to, since each person’s browser can be set up differently margins, fonts, font sizes, etc.
Metamorphic Rocks The weight of a mountain creates enough pressure to recrystallize rock, thus creating metamorphic rocks.
Christopher , with an area of km2 and a population of 36, , comprises a chain of overlapping volcanic centers 28 km long and elongated NW-SE along the axis of the Active Arc of the Lesser Antilles. Baker described how volcanism migrated along the axis of the island with the centers becoming progressively younger towards the north west. The youngest and only active volcano is Mt.
Misery which forms the north-west end of the island. Morphologically the island can be regarded as comprising four distinct components. Oldest is the Salt Pond Peninsula — a chain of eroded Pelean domes at the south-east end believed to have been active around 2. Also forming a component of this oldest part of the island are eroded remnants of other volcanic centers at Canada Hills and Conaree Hills on the south-east side of the island.
Little is known about the geology of these hills but this oldest part of the island is 16km long and a distinct and separate part from the three younger stratovolcanoes that comprise the bulk of St. The middle part of the island comprises two tropical jungle covered eroded stratovolcanoes — the South East Range and the Middle Range — believed to be 1 to 2 million years old Rex cited in Baker The stratovolcano of Mt Liamugia is believed to be less than 1 million years old.
Colorado Geology Photojournals
Yellowstone Park Foundation Yellowstone National Park covers 2, , acres, which is roughly the size of the state of Connecticut. The park is comprised primarily of high, forested, volcanic plateaus that have been eroded over – the millennia by glaciation and stream flow and that are flanked on the north, east, and south by mountains. The elevation of the park averages 8, feet, ranging from 5, feet in the north, where the Gardner River drains from the park, to 11, feet in the east, at the summit of Eagle Peak in the Absaroka Range.
Take a complete tour of Yellowstone National Park as our Narrator Cathy Coan guides you to all the wonders of the park including all the geyser basins, wildlife, waterfalls and much more. We previously sold travel packets but these packets, maps and trail guides are all available at the park for free or minimal charge.
A geyser is a hot spring with the intriguing habit of tossing underground water into the air.
Volcanic Sand – Christmas Lake, Oregon This sand from a dune near Christmas Lake, Oregon likely contains particles of ejecta produced by the eruption of Mount Mazama about years ago, which formed the caldera known today as Crater Lake.
Sand Sand isn’t a boring material if you know what you are looking at! Highly rounded sand grains from the Gobi Desert of Mongolia. Wind-blown sand sustains repeated tiny impacts as it bounces along Earth’s surface. These impacts gradually abrade sharp protrusions from the grains and give their surface a “frosted” luster. The width of this view is approximately 10 millimeters. The white grains are coral fragments, and the gray-black grains are pieces of basalt.
If you think the grains have a “gemmy” appearance, olivine is the mineral name of a gemstone known as “peridot. Thinking About Sand Sand is a common material found on beaches, deserts, stream banks, and other landscapes worldwide. In the mind of most people, sand is a white or tan, fine-grained, granular material. However, sand is much more diverse – even beyond the pink sand beaches of Bermuda or the black sand beaches of Hawaii.
These are just a few of the many types of sand. Pink Coral Sand – Bermuda Some of the beaches of Bermuda have a light pink color caused by fragments of pink coral in the sand.
St. Kitts Geology
Down to Earth Surface conditions of the planets Venus and Mars are compared with those of Earth, and scenes of Earth’s living landscapes lead into a discussion of how unique Earth truly is. Major topics addressed in the series, including plate tectonics, natural resources, seismology, and erosion, are introduced in this program.
However, this notion changed dramatically over time, especially after the invention of the telescope. This program traces the development of astronomical theory with discussions of the discoveries of Copernicus, Galileo, Kepler, and Newton. Unique characteristics of Earth are also discussed. This program introduces the topic of geophysics, exploring methods of studying what lies beneath Earth’s surface.
The lava does not flow as far as the other two types, so their diameters are not as great as the other types.
Upon encountering a new site, the archaeologist immediately requires information about its age in order to set it in context with other sites. In research into our heritage the conservationist or architect may be able to date the general period of a building he is working with from either the situation, materials of construction, type of timber joints or other stylistic features. Almost certainly the century or portion of a century when it was built may be assigned with some certainty.
However, as more and more work is done and increasing numbers of structures with complex constructional phases are encountered, the general features may not be sufficient to give the accuracy in dating that is currently required. If research into other sources of information also fails to throw light on the building’s history, resort may be made to the various scientific methods of dating.
This article outlines three of the most important methods currently used for dating buildings or, in a complex situation, the order of construction within the building. Each method has a distinct role in the investigation of historic buildings.
Rock Identification Made Easy
Nickel is vital as an alloy to stainless steel, and it plays a key roll in the chemical and aerospace industries. Leading producers are Canada, Norway, and Russia. Phosphate rock Primarily a sedimentary rock used to produce phosphoric acid and ammoniated phosphate fertilizers, feed additives for livestock, elemental phosphorus, and a variety of phosphate chemicals for industrial and home consumers.
The majority of U. These elements commonly occur together in nature and are among the scarcest of the metallic elements. Platinum is used principally in catalytic converters for the control of automobile and industrial plant emissions; in jewelry; in catalysts to produce acids, organic chemicals, and pharmaceuticals; and in dental alloys used for making crowns and bridges.
Coal barges on the Finow Canal at Eberswalde, Germany.
The wide range of glacial types across the Antarctic Peninsula has resulted in a range of responses. The response of land-terminating glaciers across the Antarctic Peninsula is particularly interesting, because land-terminating glaciers respond in a linear fashion to changes in temperature and precipitation. Land-terminating glaciers on James Ross Island and nearby land have been observed to be shrinking[ ], and this has resulted in several campaigns to monitor long-term glacier mass balance in the region[5, 6].
Studies of glaciers are limited to either a short temporal scale era of satellite observations or are limited to small numbers of glaciers field-based measurements. Aims and Objectives It is important to characterise the centennial-scale behaviour of small land-terminating glaciers in this region, in order to understand these short-term variations.
Over a 7-week field season in January-March , Jonathan Carrivick, Bethan Davies and Neil Glasser investigated prominent moraines in front of small land-terminating glaciers. Our objectives were, Holistic geological descriptions of the topography, sedimentology and geomorphology of the prominent ice-cored moraines; Interpretation of the character and behaviour of those glaciers while they were at this relatively advanced position, and; Quantification of the geometric changes to these glaciers during the Late Holocene.
The Ulu Peninsula comprises large areas of Cretaceous sandstone and mudstone, overlain by multiple layers of basalt and hyaloclastite. Radiocarbon dates on organic remains on James Ross Island suggest that the Ulu Peninsula became ice-free following the Last Glacial Maximum by around years ago, with a glacial readvance that finished around years ago.
Ulu Peninsula has several small cirque glaciers with pronounced ice-cored moraines, which relate to a more recent glacier readvance. ASTER image from We investigated six glaciers on Ulu Peninsula: A differential GPS dGPS Leica GPS was used in realtime kinematic mode for topographical surveys and to precisely determine the location and elevation of glacier margins, glacier snout positions and moraine crests.
Relative dating Cross-cutting relations can be used to determine the relative ages of rock strata and other geological structures. Methods for relative dating were developed when geology first emerged as a natural science. Geologists still use the following principles today as a means to provide information about geologic history and the timing of geologic events. The principle of uniformitarianism states that the geologic processes observed in operation that modify the Earth’s crust at present have worked in much the same way over geologic time.
In geology, when an igneous intrusion cuts across a formation of sedimentary rock , it can be determined that the igneous intrusion is younger than the sedimentary rock. Different types of intrusions include stocks, laccoliths , batholiths , sills and dikes.
In practice, the measurements may resolve differences of about 20 or 30 years.
It has a maximum sediment thickness of over 15 m concentrated in two NW trending depocentres. Deposition in the basin commenced during an Early Ordovician phase of extension and rapid subsidence. Rifting was followed by a prolonged sag stage characterised by widespread evaporitic and playa conditions in the Late Ordovician and Silurian. The second basin phase was initiated by minor folding, regional uplift and erosion in the earliest Devonian and embraces laterally extensive, aeolian and terrestrial deposits.
The third phase incorporates major extension, rifting and rapid subsidence in the mid-Devonian. The sag stage following this extension was interrupted by at least two extensional tectonic pulses marked by influxes of conglomerates along the northern margins of the basin. The fourth basin phase was initiated by mid-Carboniferous compression and inversion of Devonian normal faults.
This phase is marked by syntectonic fluvial deposits.
How Carbon-14 Dating Works
See Article History Rock, in geology , naturally occurring and coherent aggregate of one or more minerals. Such aggregates constitute the basic unit of which the solid Earth is comprised and typically form recognizable and mappable volumes. Rocks are commonly divided into three major classes according to the processes that resulted in their formation. These classes are 1 igneous rocks, which have solidified from molten material called magma; 2 sedimentary rocks, those consisting of fragments derived from preexisting rocks or of materials precipitated from solutions; and 3 metamorphic rocks, which have been derived from either igneous or sedimentary rocks under conditions that caused changes in mineralogical composition , texture, and internal structure.
These three classes, in turn, are subdivided into numerous groups and types on the basis of various factors, the most important of which are chemical, mineralogical, and textural attributes.
In a rock these general properties are determined by averaging the relative properties and sometimes orientations of the various grains or crystals.
See my copyright notice for fair use practices. Select the photographs to display the original source in another window. Links to external sites will be displayed in another window. Terrestrial planets have hard surfaces that can be re-shaped by several different processes: Impact Cratering There are still small chunks of rock orbiting the Sun left over from the formation of the solar system.
Some of them have orbits that cross the orbits of the planets and moons. When they get close enough to a planet or moon, they will be pulled in by the large body’s gravity and strike the surface at a speed of at least the escape velocity of the planet or moon, i. At such speeds, the projecticle explodes on impact and carves out a round bowl-shaped depression on the surface. This process is impact cratering.
How can you distinguish an impact crater from a volcanic crater?
Mineralogy As a discipline, mineralogy has had close historical ties with geology. Minerals as basic constituents of rocks and ore deposits are obviously an integral aspect of geology. The problems and techniques of mineralogy, however, are distinct in many respects from those of the rest of geology, with the result that mineralogy has grown to be a large, complex discipline in itself.
These include basalt ; andesite ; dacite ; rhyolite ; ignimbrite ; diorite ; granite ; peridotite ; gabbro ; and tonalite, trondhjemite, and granodiorite TTG.
Skip to Archean Backstop, 2. Here, I sketch the big picture in Colorado, as best I can put it together, from past to present. Subsequent sections will flesh out the details, also in chronological order. The mobile belt added to the continent during this time is known as the Colorado Province. Despite a long-standing intracontinental location, it’s been unstable ever since. The assembly of the Colorado Province resembled in some respects the Early Proterozoic assembly of northeast Australia, which has changed little since then and therefore has a history much easier to unravel than Colorado’s oft-overprinted story.
Buffalo Mountain Around 1. Colorado intrusive rocks with radiometric dates in the 1. Just Add Granite and Stir Mount Evans from Denver A large number of granitic intrusions , ductile shear zones, differential basement uplifts and rifts peppered the Colorado Province , along with the rest of the continent, in the Berthoud orogeny at 1. Colorado’s many intrusive rocks with radiometric dates in the 1. The Berthoud and Grenville orogenies appear to have occurred in response to convergent plate interactions playing out far to the south.
The many granitic intrusions at 1.