Lynx rufus (Schreber, 1777) - bobcat near Castle Rock, Kansas, USA. (13 June 2013)
Mammals are the dominant group of terrestrial vertebrates on Earth today. The group is defined based on a combination of features: endothermic (= warm-blooded), air-breathing, body hair, mother's milk, four-chambered heart, large brain-to-body mass ratio, two teeth generations, differentiated dentition, and a single lower jawbone. Almost all modern mammals have live birth - exceptions are the duck-billed platypus and the echidna, both of which lay eggs.
Mammals first appear in the Triassic fossil record - they evolved from the therapsids (mammal-like reptiles). Mammals were mostly small and a minor component of terrestrial ecosystems during the Mesozoic. After the Cretaceous-Tertiary mass extinction at 65 million years ago, the mammals underwent a significant adaptive radiation - most modern mammal groups first appeared during this radiation in the early Cenozoic (Paleocene and Eocene).
Three groups of mammals exist in the Holocene - placentals, marsupials, and monotremes. Other groups, now extinct, were present during the Mesozoic.
The bobcat is an uncommon, medium-sized cat that ranges throughout America, Mexico, and southern Canada.
Classification: Animalia, Chordata, Vertebrata, Mammalia, Carnivora, Felidae
Locality: above chalk bluffs near Castle Rock, ~24 air-kilometers south-southeast of the town of Quinter, eastern Gove County, western Kansas, USA
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See info. at:
en.wikipedia.org/wiki/Bobcat
Tags: Lynx rufus bobcat bobcats mammal mammals Castle Rock Gove County Kansas
Lapis lazuli (lazuritic gneiss) from the Precambrian of Afghanistan. (~7.3 centimeters across at its widest)
Blue = lazurite
Whitish = calcite
Brassy gold specks = pyrite (click on the photo to zoom in and see these)
Lapis lazuli is one of the most gorgeous rocks I’ve ever seen. The highest quality lapis lazuli in the world is from northeastern Afghanistan (northern Kuran Wa Munjan District, southern Badakhshan Province). Lapis lazuli is both Latin & Persian for “heaven stone”, or “sky stone”, or “blue stone”. This rare rock is dominated by the deep-blue mineral lazurite, which is a sodalite-group feldspathoid - (Na,Ca)8(AlSiO4)6(SO4,S,Cl)2. Commonly, whitish streaks of calcite (CaCO3) and brass-colored specks of pyrite (FeS2) are present. Lazurite is essentially the most intensely-blue mineral known (azurite is also consistently intense blue). The intensity of the blue color in lazurite has been attributed to the sulfur and calcium content.
Lapis lazuli is known from elsewhere in the world, but northeastern Afghanistan is the classic locality. Afghani material has been reportedly mined for at least 7000 years. In ancient times, lapis lazuli was referred to as “sapphire”. Pliny the Elder's 37-volume work Naturalis Historiae, or Natural History, written in about the 70s A.D., refers to Afghani lapis lazuli as “sappiri”, and notes that it has glistening dots of gold in it - see his book 37.
Afghani lapis lazuli comes from the Sar-e-Sang Deposit, which consists of ~1-8 meter thick and ~20-450 meter long, north-south trending veins, lenses, and layers of lapis lazuli hosted in high-grade marbles. Stratigraphically, this is the marble member of the Sakhi Formation, Anglich Group, Sar-e-Sang Series. This material is Late Archean to early Paleoproterozoic in age (?) (2.4 to 2.7 billion year metamorphic dates come from Pamir in adjacent Tajikhistan). The lapis lazuli rocks appear to be the result of retrograde metamorphism and/or metasomatism (alaskite granite & pegmatite & basic dike intrusions are nearby). They occur along the eastern limb of the Kokcha Anticline, and are part of the Fayzabad Metamorphic Massif in the South Badakhshan Block.
The lapis lazuli mines of northeastern Afghanistan are some of the most difficult-to-access localities in the world, occurring along steep slopes of deeply carved, narrow river canyons in the northern flanks of the western Hindu-Kush Mountains. The Sar-e-Sang Mining District (apparently synonymous with “Firgamu Mines”) occurs about 1500 feet above river water level. The mines are above the lowermost reaches of the Sar-e-Sang River, a west-flowing tributary of the Kokcha River. This stretch of the Kokcha River is quite isolated. The nearest villages are Koran-o-Munjan (to the south) and Robat-e-Payan (to the north). Fayzabad, the nearest sizable town, is about 100 km to the north-northwest of the Sar-e-Sang Mines.
Location of Sar-e-Sang Mine adits: approximately 36° 12.2’ to 36° 14.14’ North latitude, 70° 47.85’ to 70° 48.63’ East longitude.
Access to the Sar-e-Sang Mines is only via narrow foot trails in a barren, but harshly beautiful landscape. Regarding this area, British Army Lieutenant John Wood famously said in 1837: “If you do not wish to die, avoid the Valley of Kokcha.”
Tags: lapis lazuli Afghanistan Sar-e-Sang Deposit Sakhi Formation Precambrian lazurite calcite pyrite
Seirocrinus subangularis (Miller, 1821) - fossil crinoid from the Jurassic of Germany. (CM 34210, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania, USA)
Crinoids (sea lilies) are sessile, benthic, filter-feeding, stalked echinoderms that are relatively common in the marine fossil record. Crinoids are also a living group, but are relatively uncommon in modern oceans. A crinoid is essentially a starfish-on-a-stick. The stick, or stem, is composed of numerous stacked columnals, like small poker chips. Stems and individual columnals are the most commonly encountered crinoid fossils in the field. Intact, fossilized crinoid heads (crowns, calices, cups) are unusual. Why? Upon death, the crinoid body starts disintegrating very rapidly. The soft tissues holding the skeletal pieces together decay and the skeleton falls apart.
The specimen seen here is from the famous Holzmaden Lagerstätte, a Jurassic-aged soft-bodied fossil deposit in Germany. The deposit consists of marine black shales and has produced many complete vertebrate skeletons, many of which have a carbonized halo/outline of skin. The latter is seen in sharks, bony fish, crocodilians, pterosaurs, plesiosaurs, and ichthyosaurs. Many female ichthyosaurs are fossilized with embryos in their bodies, or in the apparent act of giving birth. An alternative interpretation of the latter is that such fossils represent post-mortem abortions due to compression from burial in sediments. The Holzmaden deposit also has fossil logs with encrusting crinoids, plus ammonites & belemnites (both cephalopods) with soft tissues preserved - including ink sacs, tentacles, and hooks.
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From museum signage:
Holzmaden
Fossils from a Jurassic sea
The bottom waters of the seas covering southern Germany during the Early Jurassic often lacked oxygen, so when a dead organism sank to the seabed, there were few bacteria around to decompose it. These conditions are the main reason for the exquisite preservation of Holzmaden's fossils, which include rarely preserved soft tissues such as ichthyosaur fins and cephalopod ink sacs. Such finds have revealed fundamental aspects of these animals' anatomy and behavior that could not have been determined from hard parts alone.
As in the Triassic, crinoids (“sea lilies”) remained abundant in Jurassic seas, and were more diverse than today. Unlike all modern crinoids, which live anchored to the seafloor, Seirocrinus probably drifted the open ocean attached to floating logs. This crinoid reached gigantic sizes, with stalks stretching up to 65 feet (20 meters) long.
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Classification: Animalia, Echinodermata, Crinoidea, Articulata, Isocrinida, Pentacrinitidae
Stratigraphy: Holzmaden Lagerstätte, Posidonia Shale, Toarcian Stage, upper Lower Jurassic
Locality: unrecorded/undisclosed site at or near the town of Holzmaden, southwestern Germany
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See info. at:
en.wikipedia.org/wiki/Crinoid
Tags: Seirocrinus subangularis fossils crinoids fossil crinoid Posidonia Shale Jurassic Holzmaden Germany
Aratus pisonii (Milne-Edwards, 1837) - mangrove tree crab in Florida, USA (January 2016).
The crustaceans are a large group of arthropods that inhabit marine, marginal marine, freshwater, and terrestrial habitats. The crustaceans include crabs, lobsters, shrimp, crayfish, barnacles, ostracods, and other organisms. The oldest fossil crustaceans are in the Cambrian. The group experienced a significant radiation in the oceans during the Mesozoic Marine Revolution.
The mangrove tree crab seen here occupies mangrove swamp environments. It usually lives among red mangroves - Rhizophora mangle (en.wikipedia.org/wiki/Rhizophora_mangle). At low tide, the crabs are near or on the ground. During high tide, they ascend tree trunks, often to relatively high levels. Mangrove tree crabs are omnivorous - they are principally herbivores, feeding on mangrove foliage, but are also detritovores, scavengers, and predators on small invertebrates and some protists.
Classification: Animalia, Arthropoda, Crustacea, Malacostraca, Decapoda, Brachyura, Sesarmidae
Locality: tree along boardwalk to Mangrove Overlook, Ding Darling National Wildlife Refuge, Sanibel Island, southwestern Florida, USA
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More info. at:
en.wikipedia.org/wiki/Crustacean
and
en.wikipedia.org/wiki/Aratus_pisonii
Tags: Aratus pisonii mangrove tree crab Ding Darling National Wildlife Refuge Sanibel Island Florida crustacean crabs crustaceans Crustacea Brachyura Decapoda mangroves Rhizophora mangle
(image provided by the Alaska Volcano Observatory; original photo taken by Lee Cooper from a Canadian coast guard vessel)
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Shishaldin Volcano is a subduction zone stratovolcano on Unimak Island in the Aleutian Islands of Alaska. Minor lava eruptions in the summit crater started on 12 July 2023. Twelve episodes of explosive ash eruptions have occurred since then, on 14 July, 15 July, 18 July, 22-23 July, 25-26 July, 4 August, 14-15 August, 25 August, 5 September, 15 September, 24 to 25 September, and 3 October 2023. Seen here is ash erupting from Shishaldin on 14 July 2023.
The Aleutian Arc is a subduction zone formed as the Pacific Plate dives underneath the North American Plate (this area is sometimes called the Bering Plate). The diving plate in subduction zones releases water at depth, which causes partial melting of overlying mantle rocks. The low-density melt rises and eventually reaches the surface, forming volcanoes. All subduction zones have volcanoes and frequent seismicity. Volcanoes in such settings tend to have explosive ash eruptions. Rocks and tephra deposits at subduction zone volcanoes are usually intermediate in composition - typically andesitic to dacitic.
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Info. at:
en.wikipedia.org/wiki/Mount_Shishaldin
and
en.wikipedia.org/wiki/Aleutian_Arc
Tags: July 2023 Shishaldin Volcano stratovolcano stratovolcanoes composite volcanoes Aleutian Arc Aleutians Alaska ash eruption eruptions