The Cameroon Volcanic Line (CVL) is a significant geological feature stretching from the Atlantic Ocean into continental Africa, characterised by a chain of volcanoes that provides valuable insights into the Earth’s dynamic processes. In simple terms, it’s a long line of both active and extinct volcanoes and associated landforms that cuts across Cameroon and extends offshore. This unique alignment of volcanic activity isn’t just a pretty sight; it offers scientists a window into the mantle plumes and tectonic forces shaping our planet, making it a hotspot for geological research and a fascinating natural wonder.<\/p>\n
The Cameroon Volcanic Line is a remarkable geological entity, notable for its linear arrangement and its considerable reach. It’s essentially a roughly 1,600 km long chain of volcanic centres, making it one of the most prominent volcanic lines in the world. This extensive stretch isn’t confined to land; it boasts both an oceanic and a continental segment, presenting a compelling geological puzzle.<\/p>\n
Starting from the Atlantic Ocean, the CVL’s oceanic segment is marked by several volcanic islands. These islands are essentially the tops of much larger submarine volcanoes that have breached the ocean’s surface.<\/p>\n
At the southernmost end of the oceanic segment lies Annob\u00f3n, a small island that is politically part of Equatorial Guinea. Geologically, it’s a clear manifestation of the CVL, composed predominantly of basaltic lavas. Its volcanic origins are evident in its rugged topography and the presence of numerous small craters and volcanic cones. While its current volcanic activity is quiescent, the island’s formation is directly linked to the same magmatic processes driving the entire line.<\/p>\n
Further north, S\u00e3o Tom\u00e9 and Pr\u00edncipe form another pair of islands along the CVL. These are larger and more populated volcanic islands, also part of Equatorial Guinea. S\u00e3o Tom\u00e9, the larger of the two, is dominated by Pico de S\u00e3o Tom\u00e9, an extinct volcano that is the highest point on the island. Both islands exhibit classic shield volcano morphology, characterised by gentle slopes formed by highly fluid lava flows. The volcanic rocks here are primarily alkali basalts, similar to those found throughout the CVL. Erosion has heavily sculpted these islands, creating dramatic landscapes of steep valleys and sharp peaks.<\/p>\n
Moving northwards, Bioko, part of Equatorial Guinea, represents a significant volcanic centre. It’s a large, roughly triangular island, home to Mount Malabo (formerly Pico de Santa Isabel), which is the highest point on the island and a stratovolcano. Bioko shows evidence of relatively recent volcanic activity, though currently dormant. The island’s fertile volcanic soils support lush rainforests and extensive agriculture, a common characteristic of volcanic islands. The volcanic rocks here are a mix of basalts, trachybasalts, and phonolites, indicative of a more evolved magmatic system compared to the purely basaltic Annob\u00f3n.<\/p>\n
While not as prominent as the larger islands, there are also smaller islets and submarine features within the oceanic segment that contribute to the overall linearity of the CVL. These smaller expressions further underscore the continuous nature of the magmatic system beneath the ocean floor. Their petrology is consistent with the larger islands, providing a coherent picture of the offshore volcanic activity.<\/p>\n
Once it reaches the mainland, the CVL continues its trajectory through Cameroon, forming a distinct chain of volcanoes that stretches for hundreds of kilometres inland. This continental portion is perhaps the most well-known and extensively studied part of the line.<\/p>\n
Dominating the coastline and standing as the tallest peak in West Africa, Mount Cameroon (Fako) is the most active volcano on the entire CVL. It’s a massive stratovolcano, rising directly from the coast. Its frequent eruptions, though generally effusive (lava flows rather than explosive), make it a constant focus of monitoring and research. The sheer volume of lava it has produced has built up its impressive edifice. Its slopes are covered in tropical rainforest, transitioning to grassland and then barren volcanic rock at higher elevations. The rocks are primarily basalts and hawaiites.<\/p>\n
North-east of Mount Cameroon, the Rumpi Hills are another significant volcanic complex. While not as high as Mount Cameroon, they are a collection of eroded volcanic cones and lava flows. Their activity is considered extinct, but their morphology clearly indicates their volcanic origin. The Rumpi Hills represent an older, more deeply eroded part of the continental CVL.<\/p>\n
The Koup\u00e9 Massif is a prominent volcanic structure known for its rich biodiversity and cultural significance. It’s an extinct volcanic complex, heavily forested and home to unique flora and fauna. Geologically, it showcases a range of volcanic rocks, indicating a more complex eruptive history than simple basaltic flows.<\/p>\n
Further inland, the Manengouba Mountains are a major volcanic edifice characterised by two large caldera structures: Lac Manengouba and Lac Bambuluwe. These calderas indicate past explosive eruptions, a departure from the effusive nature of Mount Cameroon. The area is known for its beautiful crater lakes and fertile soils, making it an important agricultural region.<\/p>\n
The CVL continues into the Bamenda Highlands, a vast plateau punctuated by numerous volcanic cones and lava flows. This region is home to several prominent volcanic mountains, including Mount Oku, the second-highest peak in Cameroon. Mount Oku is a large stratovolcano with a significant caldera, Lac Oku, within its summit. The Oku Massif is particularly important for its carbonatite intrusions, which are unusual igneous rocks. The volcanic activity in this region is considered extinct, but the landscape is clearly shaped by its volcanic past.<\/p>\n
The continental segment culminates in the Adamawa Plateau, a broad, high-lying region in central Cameroon. While less dramatic than the coastal volcanoes, the Adamawa Plateau is also dotted with numerous volcanic cones and lava flows, albeit more eroded and less pronounced. These scattered volcanic features demonstrate the continued influence of the CVL’s underlying magmatic system across a vast area. The volcanic rocks here are also predominantly basaltic, though with some phonolites and trachytes.<\/p>\n
Understanding the tectonic setting of the Cameroon Volcanic Line is crucial to comprehending its existence. Unlike typical volcanic arcs found at convergent plate boundaries (where plates collide) or mid-ocean ridges (where plates pull apart), the CVL doesn’t fit neatly into these classic models. It’s generally considered to be a ‘hotspot’ volcano chain, driven by a mantle plume.<\/p>\n
The prevailing hypothesis for the formation of the CVL involves a mantle plume. Imagine a buoyant column of abnormally hot rock rising from deep within the Earth’s mantle. When this plume reaches the base of the lithosphere (the Earth’s rigid outer layer), it causes melting, generating magma. This magma then ascends through weaknesses in the crust, leading to volcanic eruptions on the surface.<\/p>\n
A common characteristic of mantle plume volcanism is that the plume itself is thought to remain relatively stationary in the mantle, while the overlying tectonic plate moves over it. This motion leaves a trail of volcanoes on the plate, with the oldest volcanoes being furthest from the current position of the plume and the youngest (and often most active) volcanoes being directly above it.<\/p>\n
For the CVL, seismic studies have indicated the presence of anomalous structures in the mantle beneath the line, consistent with a rising plume. Geochemical analysis of the volcanic rocks also supports a mantle plume origin, showing distinct isotopic signatures that differ from typical mid-ocean ridge or subduction zone basalts. The age progression of volcanism along the CVL, though somewhat debated and complex, broadly suggests a hotspot track, with older volcanoes generally found at the northeastern end of the continental segment and younger, more active ones like Mount Cameroon near the oceanic segment.<\/p>\n
The African Plate is largely considered an intraplate setting, meaning it’s not at a major plate boundary. However, the plate is not entirely stable and experiences various stress fields due to its interactions with surrounding plates. These stresses can create fractures and weaknesses in the continental crust, providing pathways for magma generated by the mantle plume to reach the surface.<\/p>\n
The presence of the West African Rift System, though distinct from the CVL, indicates that the African continent is under extensional stress in various places. While the CVL isn’t a direct rift, the existing fault systems and crustal weaknesses in the region likely play a role in localising the ascent of magma from the plume. The linear arrangement of the volcanoes suggests some form of crustal control, where the magma exploits pre-existing lines of weakness or propagates along a major structural discontinuity.<\/p>\n
The interaction between the deep-seated mantle plume and the overlying continental and oceanic lithosphere is a complex geological interplay. The differing thicknesses and compositions of the continental versus oceanic crust influence how magma ascends and what type of volcanic structures are formed. For instance, the thicker continental crust might lead to more differentiated magmas and more explosive eruptions, while the thinner oceanic crust often results in more effusive basaltic volcanism.<\/p>\n
The volcanoes of the Cameroon Volcanic Line exhibit a range of eruptive styles, from relatively gentle lava flows to more powerful, explosive events. The type of eruption is largely dictated by the magma’s composition, gas content, and viscosity.<\/p>\n
As mentioned, Mount Cameroon is the most active volcano on the CVL, and its eruptions are predominantly effusive. This means that magma (known as lava once it reaches the surface) flows relatively gently from vents, rather than exploding violently.<\/p>\n
The lava erupted by Mount Cameroon is primarily basaltic, which is low in silica and therefore has a relatively low viscosity (it’s quite fluid). This fluidity allows the lava to flow easily over distances, forming the characteristic gentle slopes of a shield volcano. While not as destructive as explosive eruptions, these lava flows can still engulf villages, agricultural land, and infrastructure, making monitoring crucial. Eruptions often occur from flank vents, creating new cones and lava channels.<\/p>\n
Sometimes, Mount Cameroon exhibits strombolian activity, which involves moderate explosions that throw incandescent bombs and scoria into the air. These are relatively small-scale explosive events compared to plinian eruptions but can still pose localised hazards. The explosions are driven by the intermittent release of gas bubbles from the magma.<\/p>\n
While Mount Cameroon is mostly effusive, other volcanoes along the CVL show evidence of past, more explosive activity, particularly those in the continental segment.<\/p>\n
The presence of large calderas, such as those at Manengouba and Oku, is clear evidence of significant past explosive eruptions. A caldera forms when a volcano erupts so violently that the magma chamber beneath it empties, causing the overlying volcanic edifice to collapse inwards. These types of eruptions are typically associated with more viscous, silica-rich magmas (e.g., rhyolites, trachytes, phonolites) that trap gases more effectively, leading to immense pressure build-up. While these volcanoes are currently dormant, their history indicates a potential for such events.<\/p>\n
Several maar lakes are also found along the CVL, particularly in the western highlands. Maars are broad, low-relief volcanic craters formed by explosive eruptions that occur when rising magma interacts with groundwater (phreatomagmatic eruptions). These interactions produce steam explosions that excavate craters, which often fill with water to form lakes. While smaller in scale than caldera-forming events, maars represent another form of explosive volcanism.<\/p>\n
Beyond visible eruptions, the CVL is also associated with passive gas emissions, which can sometimes pose unique hazards.<\/p>\n
One of the most infamous examples is Lake Nyos, a crater lake within the CVL. In 1986, a limnic eruption occurred at Lake Nyos, which involved the sudden release of a massive cloud of carbon dioxide (CO2) from the lake. The CO2, a heavy gas, flowed down valleys, asphyxiating over 1,700 people and thousands of livestock in nearby villages. This event was caused by CO2-rich spring water saturating the bottom layers of the lake, which then suddenly overturned, releasing the dissolved gas.<\/p>\n
Following the Lake Nyos disaster, similar concerns arose for other crater lakes in the CVL, notably Lake Monoun (which had a smaller limnic eruption in 1984). Mitigation efforts have since been implemented, primarily involving the installation of degassing pipes to continually release CO2 from the bottom of these lakes in a controlled manner, preventing future catastrophic build-ups. This is a critical ongoing safety measure in the region.<\/p>\n
The geological evolution of the Cameroon Volcanic Line spans millions of years, and the study of its rocks (petrology) provides invaluable clues about the processes occurring deep within the Earth.<\/p>\n
While the general ‘hotspot track’ model often implies a clear age progression from older to younger volcanoes along the line, the CVL presents a more complex picture.<\/p>\n
In the continental segment, there’s a broad trend of decreasing age from the northeast (e.g., Adamawa Plateau, dating back to around 60-70 million years ago, Ma) towards the southwest (e.g., Mount Cameroon, with activity in the last few million years to present). However, this isn’t a perfectly linear progression, and there’s often evidence of renewed activity in older volcanic centres, or simultaneous activity along different parts of the line. This complexity suggests that the interaction between the plume, crustal structures, and regional stress fields isn’t always straightforward.<\/p>\n
The oceanic segment shows a similar trend, with the oldest volcanic islands (Annob\u00f3n) being further south and progressively younger islands to the north (S\u00e3o Tom\u00e9, Pr\u00edncipe, Bioko), leading up to Mount Cameroon. The youngest activity is consistently found around Bioko and Mount Cameroon, suggesting that the current focus of the mantle plume might be beneath this region or that the African Plate is moving in a way that brings this segment over the plume.<\/p>\n
The volcanic rocks found along the CVL are predominantly alkaline in nature, which is characteristic of intraplate volcanism and mantle plume activity. However, there’s a significant diversity in rock types, indicating varying degrees of magmatic differentiation and crustal interaction.<\/p>\n
The most common rock types are basalts and their more evolved relatives, hawaiites. These are mafic (rich in magnesium and iron) and relatively low in silica, reflecting their origin from partial melting of the mantle. Basalts form the bulk of the lava flows, especially from Mount Cameroon and the shield volcanoes of the oceanic islands.<\/p>\n
As magma ascends and differentiates within crustal magma chambers, it can evolve to become more silica-rich and alkaline, leading to the formation of trachytes and phonolites. These rocks are commonly found in the more evolved volcanic centres, such as the calderas of Manengouba and Oku, and some of the continental stratovolcanoes. Their presence often correlates with more explosive eruptive styles due to higher viscosity and gas content.<\/p>\n
A particularly unusual and geologically interesting rock type found in some areas of the CVL, especially around the Oku Massif, are carbonatites. These are igneous rocks composed of more than 50% carbonate minerals, which is highly unusual as most igneous rocks are silicate-based. Carbonatites are thought to originate from very deep mantle sources and are often associated with mantle plumes and rifting environments. Their presence provides crucial insights into the unusual composition of the mantle source beneath the CVL.<\/p>\n
As magma rises through the Earth’s crust, it can interact with the surrounding rocks (crustal assimilation) and undergo processes of differentiation.<\/p>\n
Magma chambers within the crust allow for fractional crystallisation, where different minerals crystallise out of the melt at various temperatures and pressures. This process changes the composition of the remaining liquid magma, leading to a progression from basaltic to more evolved compositions like trachyte and phonolite.<\/p>\n
Magma can also mix with other magmas or assimilate parts of the surrounding crust. In the continental segment, where the crust is thicker and more varied, this interaction can significantly alter the final composition of the erupted lavas. This complexity in petrology helps scientists unravel the journey of the magma from the mantle to the surface.<\/p>\n
<\/p>\n
| Metric<\/th>\n | Description<\/th>\n | Value \/ Detail<\/th>\n<\/tr>\n<\/thead>\n |
|---|---|---|
| Location<\/td>\n | Geographical extent of the volcanic line<\/td>\n | From the Gulf of Guinea islands to the interior of Cameroon<\/td>\n<\/tr>\n |
| Length<\/td>\n | Approximate length of the volcanic line<\/td>\n | Approximately 1,600 km<\/td>\n<\/tr>\n |
| Age<\/td>\n | Estimated geological age of volcanic activity<\/td>\n | From Late Cretaceous (~90 million years ago) to Recent<\/td>\n<\/tr>\n |
| Volcanic Features<\/td>\n | Types of volcanic formations along the line<\/td>\n | Stratovolcanoes, basaltic lava flows, volcanic islands<\/td>\n<\/tr>\n |
| Notable Volcanoes<\/td>\n | Key volcanoes along the line<\/td>\n | Mount Cameroon, Mount Manengouba, Mount Oku<\/td>\n<\/tr>\n |
| Elevation<\/td>\n | Highest peak elevation on the volcanic line<\/td>\n | Mount Cameroon: 4,040 metres<\/td>\n<\/tr>\n |
| Volcanic Activity<\/td>\n | Recent volcanic eruptions<\/td>\n | Mount Cameroon last erupted in 2012<\/td>\n<\/tr>\n |
| Tectonic Setting<\/td>\n | Geological context of the volcanic line<\/td>\n | Located along a major fault zone related to the African plate<\/td>\n<\/tr>\n |
| Significance<\/td>\n | Importance of the volcanic line<\/td>\n | Influences regional biodiversity, climate, and human settlement<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n The Cameroon Volcanic Line, with its active and potentially active volcanoes, poses several hazards to the communities living within its vicinity. However, it also offers significant benefits, shaping both the landscape and human activity.<\/p>\n Volcanic Hazards<\/h3>\nUnderstanding and mitigating volcanic hazards is paramount for public safety and sustainable development in the region.<\/p>\n Lava Flows<\/h4>\nAs seen with Mount Cameroon, lava flows are a primary hazard. While typically slow-moving and allowing for evacuation, they can destroy everything in their path: homes, roads, and agricultural land. Monitoring systems and early warning protocols are crucial for communities living on the flanks of active volcanoes.<\/p>\n Ashfall<\/h4>\nExplosive eruptions, though less common along the CVL, can produce ashfall. Volcanic ash, consisting of pulverised rock and glass, can contaminate water supplies, damage crops, and cause respiratory problems. It can also disrupt air travel and accumulate on roofs, potentially causing structural collapse.<\/p>\n Lahars (Mudflows)<\/h4>\nRainfall on volcanic slopes, especially after an eruption when loose ash and debris are plentiful, can trigger lahars. These are destructive mudflows that can travel rapidly down valleys, sweeping away everything in their path. The steep, often forested slopes of CVL volcanoes make them susceptible to lahars.<\/p>\n Gas Emissions<\/h4>\nThe Lake Nyos and Lake Monoun incidents tragically highlighted the danger of sudden CO2 releases. While degassing pipes are in place, continuous monitoring of dissolved gas levels in these and other crater lakes remains essential. Other volcanic gases, such as sulfur dioxide (SO2), can also be released, affecting air quality and human health, especially near active vents.<\/p>\n Earthquakes<\/h4>\nVolcanic activity is often accompanied by seismic activity. Magma moving beneath the surface can generate earthquakes, which can range from imperceptible tremors to more significant shaking. While usually not as powerful as tectonic earthquakes, they can still cause damage to structures.<\/p>\n Benefits and Opportunities<\/h3>\nDespite the hazards, the volcanic landscape of the CVL also provides numerous benefits.<\/p>\n Fertile Soils<\/h4>\nVolcanic soils are notoriously fertile due to their rich mineral content. This makes the regions around CVL volcanoes prime agricultural land, supporting a wide range of crops and contributing significantly to the local economy and food security. The volcanic highlands are often densely populated because of this fertility.<\/p>\n Geothermal Energy Potential<\/h4>\nThe underlying heat associated with the mantle plume and volcanic activity presents a potential for geothermal energy. Tapping into this heat source could provide a clean and sustainable source of electricity for Cameroon, reducing reliance on fossil fuels. While currently underexploited, this remains a significant long-term opportunity.<\/p>\n Tourism and Recreation<\/h4>\nThe dramatic volcanic landscapes, crater lakes, and unique biodiversity attract tourists and researchers alike. Mount Cameroon is a popular hiking destination, and the scenic beauty of the Bamenda Highlands and other volcanic areas offers opportunities for ecotourism, supporting local businesses and employment.<\/p>\n Scientific Research<\/h4>\nThe Cameroon Volcanic Line is a natural laboratory for geologists, volcanologists, and geophysicists. Its unusual tectonic setting, diverse petrology, and active volcanism provide invaluable opportunities to study mantle plumes, magma generation, crustal interaction, and volcanic hazards, advancing our understanding of Earth’s dynamic processes. The ongoing monitoring of Mount Cameroon and the lake degassing efforts at Nyos and Monoun are themselves significant scientific and engineering endeavours.<\/p>\n <\/p>\n FAQs<\/h2>\n<\/p>\n What is the Cameroon Volcanic Line?<\/h3>\nThe Cameroon Volcanic Line is a chain of volcanoes and volcanic activity that stretches from the Gulf of Guinea in the west to the northeast region of Cameroon. It is a geologic feature that has shaped the landscape and geology of the region.<\/p>\n How many active volcanoes are there along the Cameroon Volcanic Line?<\/h3>\nThere are around 30 active volcanoes along the Cameroon Volcanic Line. These volcanoes have varying levels of activity, with some being more active than others. Mount Cameroon is one of the most well-known and active volcanoes in the region.<\/p>\n What causes the volcanic activity along the Cameroon Volcanic Line?<\/h3>\nThe volcanic activity along the Cameroon Volcanic Line is primarily caused by the movement of tectonic plates beneath the Earth’s surface. The line is located at a boundary where the African Plate is slowly splitting apart, leading to the formation of magma chambers and volcanic eruptions.<\/p>\n Is the volcanic activity along the Cameroon Volcanic Line a threat to the local population?<\/h3>\nYes, the volcanic activity along the Cameroon Volcanic Line poses a threat to the local population living in the vicinity of the active volcanoes. Eruptions can lead to lava flows, ash clouds, and pyroclastic flows, which can cause damage to property and endanger lives.<\/p>\n How does the Cameroon Volcanic Line contribute to the region’s geology and biodiversity?<\/h3>\nThe Cameroon Volcanic Line has played a significant role in shaping the region’s geology by creating unique landforms and volcanic features. The volcanic soil in the area is fertile and supports diverse plant and animal species, contributing to the region’s biodiversity.<\/p>\n","protected":false},"excerpt":{"rendered":" The Cameroon Volcanic Line (CVL) is a significant geological feature stretching from the Atlantic Ocean into continental Africa, characterised by […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"yoast_wpseo_title":["Cameroon\u2019s Volcanic Line Explained\r"],"yoast_wpseo_metadesc":["The Cameroon Volcanic Line (CVL) is a significant geological feature stretching from the Atlantic Ocean into continental Africa, characterised by a.."],"rank_math_title":["Cameroon\u2019s Volcanic Line Explained\r"],"_rank_math_title":["Cameroon\u2019s Volcanic Line Explained\r"],"rank_math_description":["The Cameroon Volcanic Line (CVL) is a significant geological feature stretching from the Atlantic Ocean into continental Africa, characterised by a.."],"_rank_math_description":["The Cameroon Volcanic Line (CVL) is a significant geological feature stretching from the Atlantic Ocean into continental Africa, characterised by a.."],"aioseo_title":["Cameroon\u2019s Volcanic Line Explained\r"],"_aioseo_title":["Cameroon\u2019s Volcanic Line Explained\r"],"aioseo_description":["The Cameroon Volcanic Line (CVL) is a significant geological feature stretching from the Atlantic Ocean into continental Africa, characterised by a.."],"_aioseo_description":["The Cameroon Volcanic Line (CVL) is a significant geological feature stretching from the Atlantic Ocean into continental Africa, characterised by a.."],"seopress_titles_title":["Cameroon\u2019s Volcanic Line Explained\r"],"_seopress_titles_title":["Cameroon\u2019s Volcanic Line Explained\r"],"seopress_titles_desc":["The Cameroon Volcanic Line (CVL) is a significant geological feature stretching from the Atlantic Ocean into continental Africa, characterised by a.."],"_seopress_titles_desc":["The Cameroon Volcanic Line (CVL) is a significant geological feature stretching from the Atlantic Ocean into continental Africa, characterised by a.."],"genesis_title":["Cameroon\u2019s Volcanic Line Explained\r"],"_genesis_title":["Cameroon\u2019s Volcanic Line Explained\r"],"genesis_description":["The Cameroon Volcanic Line (CVL) is a significant geological feature stretching from the Atlantic Ocean into continental Africa, characterised by a.."],"_genesis_description":["The Cameroon Volcanic Line (CVL) is a significant geological feature stretching from the Atlantic Ocean into continental Africa, characterised by a.."],"sq_title":["Cameroon\u2019s Volcanic Line Explained\r"],"_sq_title":["Cameroon\u2019s Volcanic Line Explained\r"],"sq_description":["The Cameroon Volcanic Line (CVL) is a significant geological feature stretching from the Atlantic Ocean into continental Africa, characterised by a.."],"_sq_description":["The Cameroon Volcanic Line (CVL) is a significant geological feature stretching from the Atlantic Ocean into continental Africa, characterised by a.."],"wds_title":["Cameroon\u2019s Volcanic Line Explained\r"],"_wds_title":["Cameroon\u2019s Volcanic Line Explained"],"wds_metadesc":["The Cameroon Volcanic Line (CVL) is a significant geological feature stretching from the Atlantic Ocean into continental Africa, characterised by a.."],"_wds_metadesc":["The Cameroon Volcanic Line (CVL) is a significant geological feature stretching from the Atlantic Ocean into continental Africa, characterised by a.."]},"categories":[12],"tags":[],"class_list":["post-31915","post","type-post","status-publish","format-standard","hentry","category-history"],"yoast_head":"\n |