Chapter 1: Geologic History of the Southwestern US:
... a common ancestor and thus certain anatomical similarities, including long ankle bones and erect limbs. ...
... a common ancestor and thus certain anatomical similarities, including long ankle bones and erect limbs. ...
Mercury - GEOCITIES.ws
... kilometres in length and as much as three kilometres high. Many of these scarps cut through surfaces and topographic features (Figure 3), while in other areas they are themselves covered. These relationships permit both the relative age and possible origins of the scarps to be studied. The morpholog ...
... kilometres in length and as much as three kilometres high. Many of these scarps cut through surfaces and topographic features (Figure 3), while in other areas they are themselves covered. These relationships permit both the relative age and possible origins of the scarps to be studied. The morpholog ...
Lecture 3 Page 1 - University of Surrey
... To summarise the geological history of the Moon: the initial impact with Earth probably occurred about 4.5 billion years ago the newborn Moon’s surface was probably molten for a long period, due to heat released from the impact, and the decay of radioactive isotopes As the Moon cooled, low dens ...
... To summarise the geological history of the Moon: the initial impact with Earth probably occurred about 4.5 billion years ago the newborn Moon’s surface was probably molten for a long period, due to heat released from the impact, and the decay of radioactive isotopes As the Moon cooled, low dens ...
Calculating the Radiometric Ages of USGS samples
... a tree burned in the violent eruption of Mount Mazama which created Crater Lake. This eruption blanketed several States with ash, providing Y=no/nt = 0.447880803 geologists with an excellent time zone. Charcoal Sample collected from the "Marmes Man" site in southeastern Washington. This rock shelter ...
... a tree burned in the violent eruption of Mount Mazama which created Crater Lake. This eruption blanketed several States with ash, providing Y=no/nt = 0.447880803 geologists with an excellent time zone. Charcoal Sample collected from the "Marmes Man" site in southeastern Washington. This rock shelter ...
... Is the floor of SPA basin a mixture of half mantle and half lower crust, as Lucey prefers, or all lower crust, as Pieters prefers? Why do the two approaches not agree? Well, actually, they do not disagree all that much. For one thing, the technique used by Pieters and co-workers cannot detect olivin ...
Teacher’s Guide THE MOON GATEWAY TO THE SOLAR SYSTEM W
... immense impact basins. So, although the Moon does not have many volcanic craters, it did experience volcanic activity. Close examination of the relationships between the highlands and the maria shows that this activity took place after the highlands formed and after most of the cratering took place. ...
... immense impact basins. So, although the Moon does not have many volcanic craters, it did experience volcanic activity. Close examination of the relationships between the highlands and the maria shows that this activity took place after the highlands formed and after most of the cratering took place. ...
Precambrian geology and the Bible: a harmony
... instead of being a boiling ocean of magma, was cool enough to have water, continents and exhibited conditions that could have supported life. This also challenges common views of an early Earth with intense meteorite bombardment, and an origin of the Moon by a Mars-sized body impacting the Earth bla ...
... instead of being a boiling ocean of magma, was cool enough to have water, continents and exhibited conditions that could have supported life. This also challenges common views of an early Earth with intense meteorite bombardment, and an origin of the Moon by a Mars-sized body impacting the Earth bla ...
Megaregolith evolution and cratering cataclysm models—Lunar
... swept up (Wetherill 1975, 1977). I will refer to these ideas as the “megaregolith evolution” hypothesis. A new round of work on early cratering and the cataclysm model was inspired by Ryder (1990), who emphasized that Apollo lunar samples show no impact melts before about 4.0 Gyr. Ryder inferred tha ...
... swept up (Wetherill 1975, 1977). I will refer to these ideas as the “megaregolith evolution” hypothesis. A new round of work on early cratering and the cataclysm model was inspired by Ryder (1990), who emphasized that Apollo lunar samples show no impact melts before about 4.0 Gyr. Ryder inferred tha ...
Neoproterozoic Conglomerate and Breccia in the Formation of
... Gulch (OZlu) is over 30 m thick. The basal bed is a massive boulder conglomerate that contains clasts of OZll. The conglomerate is overlain by latest Neoproterozoic and earliest Cambrian marine sandstone and siltstone that contains trace fossils. Individual sand grains in OZlu contain planar deforma ...
... Gulch (OZlu) is over 30 m thick. The basal bed is a massive boulder conglomerate that contains clasts of OZll. The conglomerate is overlain by latest Neoproterozoic and earliest Cambrian marine sandstone and siltstone that contains trace fossils. Individual sand grains in OZlu contain planar deforma ...
Chapter 24: The Mesozoic and Cenozoic Eras
... that developed an upright posture about 228 million years ago. Even though our understanding of these rulers of the Mesozoic land has changed, our fascination with dinosaurs has remained. Dinosaurs came in all sizes, from the very small to the extraordinarily large, and all were terrestrial. You can ...
... that developed an upright posture about 228 million years ago. Even though our understanding of these rulers of the Mesozoic land has changed, our fascination with dinosaurs has remained. Dinosaurs came in all sizes, from the very small to the extraordinarily large, and all were terrestrial. You can ...
The Oldest Rocks on Earth
... to Inukjuak, where they have loaded canoes with camping gear and laboratory equipment and trekked along the coast of the bay to the belt itself. Their goal: to prove just how old the rocks are. One team, headed by University of Colorado geologist Stephen J. Mojzsis, is certain that the age is 3.8 bi ...
... to Inukjuak, where they have loaded canoes with camping gear and laboratory equipment and trekked along the coast of the bay to the belt itself. Their goal: to prove just how old the rocks are. One team, headed by University of Colorado geologist Stephen J. Mojzsis, is certain that the age is 3.8 bi ...
Earth History
... K-T Boundary Mass Extinction Boundary clay layer is highly enriched in Iridium (Ir), an element rare on Earth and abundant in meteorites. Ir enrichment in K-T boundary clay worldwide. Evidence for an impact includes a thin layer of plankton-free clay that separates plankton-rich chalk at the K-T bou ...
... K-T Boundary Mass Extinction Boundary clay layer is highly enriched in Iridium (Ir), an element rare on Earth and abundant in meteorites. Ir enrichment in K-T boundary clay worldwide. Evidence for an impact includes a thin layer of plankton-free clay that separates plankton-rich chalk at the K-T bou ...
Geologic History - Teacher Friendly Guides
... periods all enjoy official status, with the latter pair being more commonly used in the US. ...
... periods all enjoy official status, with the latter pair being more commonly used in the US. ...
Shock metamorphism of siliceous volcanic rocks of the El`gygytgyn
... (PFs) and planar deformation features (PDFs) in quartz by universal stage analysis. Additional PDF orientation measurements (on sample E963-12) were performed in Vienna in 2003. The presence of high-pressure polymorphs of silica was determined by X-ray diffractometry on insoluble fractions of shocke ...
... (PFs) and planar deformation features (PDFs) in quartz by universal stage analysis. Additional PDF orientation measurements (on sample E963-12) were performed in Vienna in 2003. The presence of high-pressure polymorphs of silica was determined by X-ray diffractometry on insoluble fractions of shocke ...
Zircon U-Pb grain ages clustering at several ages between 92 and
... • Very high U (1000-15,000 ppm). • Very low Th/U (<0.01). • Hi U/Ce ratios. • Very high Hf, 13k-26k ppm. • Heavy-REE depleted. • Deep negative Eu anomalies. ...
... • Very high U (1000-15,000 ppm). • Very low Th/U (<0.01). • Hi U/Ce ratios. • Very high Hf, 13k-26k ppm. • Heavy-REE depleted. • Deep negative Eu anomalies. ...
Document
... useful set would be (1) Cosmic history, (2) Earth history, (3) Life history and (4) Human history, while a more detailed subdivision would be (1) Big-Bang history, (2) Cosmic history, (3) Earth History, (4) Life history, (5) Human prehistory and (6) Human written history (Alvarez et al. 2009). It is ...
... useful set would be (1) Cosmic history, (2) Earth history, (3) Life history and (4) Human history, while a more detailed subdivision would be (1) Big-Bang history, (2) Cosmic history, (3) Earth History, (4) Life history, (5) Human prehistory and (6) Human written history (Alvarez et al. 2009). It is ...
Impact resistance of Illinois limestones and
... (scleroscope hardness), and Gilbert (1954) determined the scleroscope hardness of single crystals of the Mohs' scale minerals. A "cloudburst" machine developed by Herbert (19 29) subjects the surface of a material to a rain of hard steel balls falling from a known height. Studies have been made of m ...
... (scleroscope hardness), and Gilbert (1954) determined the scleroscope hardness of single crystals of the Mohs' scale minerals. A "cloudburst" machine developed by Herbert (19 29) subjects the surface of a material to a rain of hard steel balls falling from a known height. Studies have been made of m ...
Reconstruction of subducted oceanic crust based on accreted
... arc whose activity ceased in the earliest Cretaceous (ca. 140 Ma). In the Late Cretaceous, the subducted parts were ca. 100 Ma. Spreading centers must have subducted during the early Paleogene (i.e. 40-60 Ma) resulting in the in-situ MORB. These suggest that the oceanic basement had an age gap more ...
... arc whose activity ceased in the earliest Cretaceous (ca. 140 Ma). In the Late Cretaceous, the subducted parts were ca. 100 Ma. Spreading centers must have subducted during the early Paleogene (i.e. 40-60 Ma) resulting in the in-situ MORB. These suggest that the oceanic basement had an age gap more ...
ttu_gs0001_000468
... by streams. Some rocks were once lava flows or beds of cinders and ash thrown out of ancient volcanoes; others are portions of large masses of oncemolten rock that cooled very slowly far beneath the Earth's surface. Other rocks were so transformed by heat and pressure during the heaving and buckling ...
... by streams. Some rocks were once lava flows or beds of cinders and ash thrown out of ancient volcanoes; others are portions of large masses of oncemolten rock that cooled very slowly far beneath the Earth's surface. Other rocks were so transformed by heat and pressure during the heaving and buckling ...
Notes- Relative and Absolute Dating
... We can measure how much of the element is left Tells us how much time has passed since the rock formed. ...
... We can measure how much of the element is left Tells us how much time has passed since the rock formed. ...
Relative and Absolute Dating 2013
... We can measure how much of the element is left Tells us how much time has passed since the rock formed. ...
... We can measure how much of the element is left Tells us how much time has passed since the rock formed. ...
Rocks from space - Oxford University Museum of Natural History
... of tektite, found across Europe from an impact in southern Germany 14 million years ago. ...
... of tektite, found across Europe from an impact in southern Germany 14 million years ago. ...
Oldest rocks, earliest life, heaviest impacts, and the Hadean
... and chemical sediments, such as banded iron-formation. These enclaves must be at least 3.82-Ga old. This extraordinary terrain has not been studied much, and only a few geologists have visited the area. After so much intense current interest in, and exploration of, the ancient surfaces of Moon and M ...
... and chemical sediments, such as banded iron-formation. These enclaves must be at least 3.82-Ga old. This extraordinary terrain has not been studied much, and only a few geologists have visited the area. After so much intense current interest in, and exploration of, the ancient surfaces of Moon and M ...
Planetary Materials Research at APL
... diameter of about 85 km. The impact occurred around 35.5 million years ago when an asteroid some 4 km in diameter struck off what was then the eastern coast of North America in several hundred meters of ocean. The impact had an energy equivalent of 200–300 gigatons of TNT and formed the crater in a ...
... diameter of about 85 km. The impact occurred around 35.5 million years ago when an asteroid some 4 km in diameter struck off what was then the eastern coast of North America in several hundred meters of ocean. The impact had an energy equivalent of 200–300 gigatons of TNT and formed the crater in a ...
chemical composition and origin of the shock metamorphic rocks of
... and also the abundances of Al, Fe, Ca, K were determined in this way. The results are presented in Table 1 as the calculated arithmetic mean values of each rock type. The standard deviations indicate the difference of composition in each rock group. In order to depict the compositional variations of ...
... and also the abundances of Al, Fe, Ca, K were determined in this way. The results are presented in Table 1 as the calculated arithmetic mean values of each rock type. The standard deviations indicate the difference of composition in each rock group. In order to depict the compositional variations of ...
Chicxulub crater
The Chicxulub crater (/ˈtʃiːkʃʉluːb/; Mayan pronunciation: [tʃʼikʃuluɓ]) is an impact crater buried underneath the Yucatán Peninsula in Mexico. Its center is located near the town of Chicxulub, after which the crater is named. The age of the Chicxulub asteroid impact and the Cretaceous–Paleogene boundary (K–Pg boundary) coincide precisely. The crater is more than 180 kilometers (110 miles) in diameter and 20 km (12 mi) in depth, making the feature one of the largest confirmed impact structures on Earth; the impacting bolide that formed the crater was at least 10 km (6 mi) in diameter.The crater was discovered by Antonio Camargo and Glen Penfield, geophysicists who had been looking for petroleum in the Yucatán during the late 1970s. Penfield was initially unable to obtain evidence that the geological feature was a crater, and gave up his search. Through contact with Alan Hildebrand, Penfield obtained samples that suggested it was an impact feature. Evidence for the impact origin of the crater includes shocked quartz, a gravity anomaly, and tektites in surrounding areas.The age of the rocks marked by the impact shows that this impact structure dates from roughly 66 million years ago, the end of the Cretaceous period, and the start of the Paleogene period. It coincides with the K-Pg boundary, the geological boundary between the Cretaceous and Paleogene. The impact associated with the crater is thus implicated in the Cretaceous–Paleogene extinction event, including the worldwide extinction of non-avian dinosaurs. This conclusion has been the source of controversy. In March 2010, 41 experts from many countries reviewed the available evidence: 20 years' worth of data spanning a variety of fields. They concluded that the impact at Chicxulub triggered the mass extinctions at the K–Pg boundary. In 2013 a study compared isotopes in impact glass from the Chicxulub impact with the same isotopes in ash from the boundary where the extinction event occurred in the fossil record; the study concluded that the impact glasses were dated at 66.038±0.049 Ma, and the deposits immediately above the discontinuity in the geological and fossil record was dated to 66.019±0.021, the two dates being within 32,000 years of each other, or almost exactly the same within experimental error.