Texas contains a wide variety of geologic settings. The state's stratigraphy has been largely influenced by marine transgressive-regressive cycles during the Phanerozoic, with a lesser but still significant contribution from late Cenozoic tectonic activity, as well as the remnants of a Paleozoic mountain range.
The Roxbury Conglomerate, also informally known as Roxbury puddingstone, is a name for a rock formation that forms the bedrock underlying most of Roxbury, Massachusetts, now part of the city of Boston. The bedrock formation extends well beyond the limits of Roxbury, underlying part or all of Quincy, Canton, Milton, Dorchester, Dedham, Jamaica Plain, Brighton, Brookline, Newton, Needham, and Dover. It is named for exposures in Roxbury, in the Boston area. It is the Rock of the Commonwealth in Massachusetts.
The San Juan Basin is a geologic structural basin located near the Four Corners region of the Southwestern United States. The basin covers 7,500 square miles and resides in northwestern New Mexico, southwestern Colorado, and parts of Utah and Arizona. Specifically, the basin occupies space in the San Juan, Rio Arriba, Sandoval, and McKinley counties in New Mexico, and La Plata and Archuleta counties in Colorado. The basin extends roughly 100 miles (160 km) N-S and 90 miles (140 km) E-W.
The Fountain Formation is a Pennsylvanian bedrock unit consisting primarily of conglomerate, sandstone, or arkose, in the states of Colorado and Wyoming in the United States, along the east side of the Front Range of the Rocky Mountains, and along the west edge of the Denver Basin.
The geology of Kansas encompasses the geologic history and the presently exposed rock and soil. Rock that crops out in the US state of Kansas was formed during the Phanerozoic eon, which consists of three geologic eras: the Paleozoic, Mesozoic and Cenozoic. Paleozoic rocks at the surface in Kansas are primarily from the Mississippian, Pennsylvanian, and Permian periods.
The Bend Arch–Fort Worth Basin Province is a major petroleum producing geological system which is primarily located in North Central Texas and southwestern Oklahoma. It is officially designated by the United States Geological Survey (USGS) as Province 045 and classified as the Barnett-Paleozoic Total Petroleum System (TPS).
The Pennsylvanian Pottsville Formation is a mapped bedrock unit in Pennsylvania, western Maryland, West Virginia, Ohio, and Alabama. It is a major ridge-former in the Ridge-and-Valley Appalachians of the eastern United States. The Pottsville Formation is conspicuous at many sites along the Allegheny Front, the eastern escarpment of the Allegheny or Appalachian Plateau.
The Illinois Basin is a Paleozoic depositional and structural basin in the United States, centered in and underlying most of the state of Illinois, and extending into southwestern Indiana and western Kentucky. The basin is elongate, extending approximately 400 miles (640 km) northwest-southeast, and 200 miles (320 km) southwest-northeast.
The geology of Massachusetts includes numerous units of volcanic, intrusive igneous, metamorphic and sedimentary rocks formed within the last 1.2 billion years. The oldest formations are gneiss rocks in the Berkshires, which were metamorphosed from older rocks during the Proterozoic Grenville orogeny as the proto-North American continent Laurentia collided against proto-South America. Throughout the Paleozoic, overlapping the rapid diversification of multi-cellular life, a series of six island arcs collided with the Laurentian continental margin. Also termed continental terranes, these sections of continental rock typically formed offshore or onshore of the proto-African continent Gondwana and in many cases had experienced volcanic events and faulting before joining the Laurentian continent. These sequential collisions metamorphosed new rocks from sediments, created uplands and faults and resulted in widespread volcanic activity. Simultaneously, the collisions raised the Appalachian Mountains to the height of the current day Himalayas.
The Grand Canyon Supergroup is a Mesoproterozoic to a Neoproterozoic sequence of sedimentary strata, partially exposed in the eastern Grand Canyon of Arizona. This group comprises the Unkar Group, Nankoweap Formation, Chuar Group and the Sixtymile Formation, which overlie Vishnu Basement Rocks. Several notable landmarks of the Grand Canyon, such as the Isis Temple and Cheops Pyramid, and the Apollo Temple, are surface manifestations of the Grand Canyon Supergroup.
The Lower Permian Esplanade Sandstone is a cliff-forming, resistant sandstone, dark red, geologic unit found in the Grand Canyon. The rock unit forms a resistant shelf in the west Grand Canyon, south side of the Colorado River, at the east of the Toroweap Fault, down-dropped to west, southeast of Toroweap Overlook, and west of Havasupai. The red, sandstone shelf, The Esplanade is about 20-mi long. At Toroweap Overlook region, Toroweap Valley with Vulcan's Throne, Uinkaret volcanic field, the resistant Esplanade Sandstone is described in access routes exploring the Toroweap Lake area.
Dedham granite is a light grayish-pink to greenish-gray, equigranular to slightly porphyritic, variably altered, granite south and west of Boston, named for the town of Dedham, Massachusetts.
The Eastern Frontal Fault System is a megaregional system of oblique and thrust faults cross-cutting Colombia from Ecuador in the south to Venezuela in the north. The system from south to north covers ten out of 32 departments of Colombia; Nariño, Putumayo, Cauca, Huila, Caquetá, Cundinamarca, Meta, Boyacá, Casanare and Arauca. The Eastern Frontal Fault System underlies and affects the capitals of Putumayo, Mocoa, Caquetá, Florencia, Meta, Villavicencio and Casanare, Yopal. The fault system has a total length of 921.4 kilometres (572.5 mi) with a cumulative length of the faults of 1,821.8 kilometres (1,132.0 mi) and runs along an average northeast to southwest strike of 042.1 ± 19 bordering and crossing the Eastern Ranges of the Colombian Andes. The fault system forms the boundary between the North Andes microplate and the South American Plate.
The Hoppin Formation named for Hoppin Hill in North Attleborough, Massachusetts, contains Early Cambrian fossils associated with the explosion of multi-cellular life, beginning 539 million years ago at the start of the Phanerozoic Eon. The bottom rock units of the formation are arkose quartzite, conglomerate and sandstone. The quartzite lies on top and was sourced from the underlying Dedham Granite. Upper units in the formation include green and red slate shale, calcareous nodules and layers of red, argillite limestone.
The Bellingham Conglomerate is one of several Pennsylvanian stratigraphic units in eastern Massachusetts. It is mainly conglomerate and greywacke, exclusive to the Bellingham Basin. The conglomerate has granite and quartzite pebbles in a mica matrix, sourced from the neighboring Blackstone Group and Milford Granite. The two main rock types are interbedded with chlorite phyllite which contains minerals such as muscovite, quartz, zoisite, magnetite and chloritoid.
The Mattapan Volcanic Complex is a suite of Proterozoic felsic volcanic rocks in the U.S. state of Massachusetts. It is situated at the edge of the Boston Basin into the Blue Hills and lying unconformably atop the Dedham Granite. The complex is overlain by the Roxbury Conglomerate. In terms of its petrology, the rock types and compositions in the Mattapan Volcanic Complex are very similar to the Lynn Volcanic Complex and include ancient rhyolite and rhyodacite flows, some of which have porphyry characteristics, welded ash flows, tuff, breccia, extrusion domes and breccia pipes.
The Bloody Bluff fault is the boundary between the Milford-Dedham zone and the Nashoba zone in eastern Massachusetts. It runs between Westborough, Massachusetts and Lynnfield, Massachusetts. In the south, into Connecticut, the component Lake Char fault is poorly exposed. The Bloody Bluff fault zone is 3.2 kilometers wide in Framingham, Massachusetts and forms the five kilometer wide Burlington mylonite zone to the north. Rocks along the fault have experienced both ductile and brittle deformation.
The Middleton Basin is a small sedimentary basin, in northeastern Massachusetts, containing Late Triassic and Early Jurassic red beds. Estimated to be 5.7 kilometers long and at most half a kilometer wide, it is one of the smallest basins in the state and is closely associated with the Newbury basins.
The geology of Rhode Island is based on nearly one billion year old igneous crystalline basement rocks formed as part of the microcontinent Avalonia that collided with the supercontinent Gondwana. The region experienced substantial folding associated with its landlocked position during the Alleghanian orogeny mountain building event. The region accumulated sedimentary rocks, including small deposits of coal. The region was covered with thick Atlantic Coastal Plain sediments, with the erosion of the Appalachians and the creation of the Atlantic Ocean throughout the past 200 million years. These surficial sediments and soils were substantially reworked by the Pleistocene glaciations. The state's geology is part of the broader geology of New England.
