A Geomorphological Approach to Geodiversity and Geotourism in Uttarakhand Himalaya, India: A Pilot Survey

<p>Himalaya is the greatest heritage of India. The objective of this paper is to present a view of the geomorphological heritage of the Himalaya.Uttarakhand<strong> </strong>state (77°35’5”-81°2’25” E and 28°43’45”-31°8’18’’N, Area: 53,066 sq.km.)<strong> </strong>lies almost wholly within the realm of the Himalaya and is a distinct geographical entity. The state is a land of vast geological and topographic diversities and a realm with rich geo-wealth and geoheritage. Geological and geomorphological features occurring in different parts of Uttarakhand Himalaya are part of the natural assets and are precious state heritage (geoheritage), worthy of conservation. Apart from rock monuments and fossil parks, geomorphological features or geomorphosites have great potential to exert a pull on tourists. These sites have noteworthy impact on the geoscience education and research. Geotourism is growing rapidly all over the world and Himalaya region is no exception to this. To promote geotourism in the Himalayan State of Uttarakhand, comprehensive information about geomorphosites should be made available to the tourists by way of websites. For this, first a peer-reviewed state inventory of geomorphosites and their classification, mapping and assessment is required. Geodiversity in Uttarakhand State can best be understood in the form of the rise of Himalayan mountains from the bed of Tethys Sea which gave rise to four distinct tectonic units largely varying in lithology and structure. The relief was fragmented into four major morphosculptural units which signify the mountainous part of the state: viz. i. the Tethys zone or the Trans-Himalaya ii. the Greater Himalaya iii. the Lesser Himalaya and iv. the Siwalik. Apart from this mountainous region of the State, there is  outlying region of the state, which incompasses : iv. Bhabhar and Tarai (a sub-montane tract) - a landscape feature along the foothills, v. Dun Valleys – valleys of tectonic origin and vi. Plains of North India - the lowest part in Uttarakhand with an altitude of 200 m. These geological units recognised on the basis of evolutionary history, stratigraphic sequences and component rock units and reveal identical topographic and climatic characteristics. These units are separated by various tectonic boundaries. Apart from geodiversity, the geomorphological diversity can be assessed in the form of towering snow peaks, awe-inspiring horned peaks with natural grandeur, widely distributed stretches of wide and fertile valleys, valleys of tectonic origin-canoe shaped longitudinal valleys, lofty snow capped peak surrounded by several small and big snowfields, glaciers and lakes, mountain passes and  elevated zones packed in a series of multi-level distinctive waterfalls. Thus, being the youngest mountain of the world, this Himalayan State has geotouristic potential from the point of view of its geomorphological heritage.</p><p><strong> </strong><strong>Keywords: </strong>Himalaya<strong>, </strong>geodiversity , geomorphological heritage, geomorphosites, geotourism.  </p>

The Isua (Greenland) relict stromatolites cannot be confidently interpreted as original sedimentary structures

<p>The biogenicity of proposed stromatolite structures from Eoarchean (ca. 3.71 Ga) rocks of the Isua Supracrustal Belt (ISB) in West Greenland is under debate. Our 2020 publication argues against biogenicity for the proposed stromatolites. The subsequent Comment to our work challenged some of our fundamental arguments for a tectonic origin to the structures. This Comment has been an opportunity for us to elaborate on these structures and further refine and solidify our initial conclusion that they represent the expected outcome of the tectonic deformation displayed in the ISB. This dialogue between groups is essential as the consequence of these structures being biogenic would move the date for complex microbial communities 200 million years closer to Earth's formation, to a time when Earth’s surface would have been even less habitable. Here we reexamine our four key observations that support our tectonic origin. First, we report detailed field characterization and structural analysis to show that the structures are linear inverted ridges aligned with azimuths of local and regional fold axes and parallel to linear structures; they were never primary linear, deformation-parallel stromatolites or deformed conical stromatolites. Second, our combined major element (e.g., Ca, Mg, Si) scanning μXRF maps fail to reveal internal laminations for the cores of these structures, but other authors argue layers are present. In the instance where layers appear to be preserved, we argue that an amorphous core is still present.  Also, layering on its own is inconclusive of a biogenic origin as relict internal laminations could be preserved. Third, the gross morphology of these structures being nearly identical in morphology and dimensions to clearly tectonic structures only tens of meters away is a more reliable indicator of a tectonic versus biogenic origin than internal laminations. Lastly, discontinuous field relationships and absence of primary sedimentary structures that could serve as way-up indicators preclude confident assignment of these outcrops as being structurally overturned, as originally argued. Collectively, our results reinforce that the Isua structures are the expected result of a tectonic fabric that preserves no fine-scale primary sedimentary structures and were probably never stromatolites.</p>

Multi-level fluid monitoring to understand the origin of transients

<p>Anomalies in timeseries are frequently reported in the context of earthquake precursor studies. The state of knowledge can be summarized as follows: (i) significant anomalies exist, (ii) seismo-tectonically induced anomalies might exist, (iii) anomalies of non-tectonic origin exist and may look very similar to tectonic ones. Thus, presumably only a fraction of all reported precursors is real in the sense that they are of seismo-tectonic origin. A key problem in earthquake prediction research is to understand the origin of an anomaly and thus the separation of internal and external drivers like e.g. rainfall.  </p><p>State-of-the-art fluid monitoring techniques allow for a high temporal resolution compared to the low-resolution discrete sampling approach used in the last decades. A unique approach will allow to monitor ascending fluids along a vertical profile in a set of drillings from a depth of a few hundred metres to the surface. This setup can provide hints on the origin of temporal variations related to the opening of fault-valves, admixture of crustal fluids to a background mantle-flow or the release of hydrogen during fault rupturing. Gas migration velocities can thus be measured directly from the arrival times of anomalies at different depth levels. In addition, potential admixtures of mantle fluids with crustal or meteoric fluids during the ascent to the Earth’s surface can be quantified.</p><p>A prototype of a multi-level gas monitoring system has been implemented at a mofette. Mofettes are gas emission sites where CO2 ascends through long-lived, narrow channels from the deep crust and possibly the Earth’s upper mantle and thus provide natural windows to magmatic processes at depth. The primary objective of our research on mofettes is to clarify physical links between fluid properties, their pathways and the relation to swarm earthquakes. The Hartoušov mofette field with an estimated daily CO<sub>2</sub> flux between 23 and 97 t over an area of about 350,000 m<sup>2</sup> has been chosen as a key site in the frame of the ICDP project: “Drilling the Eger Rift: Magmatic fluids driving the earthquake swarms and the deep biosphere.” It is located in the Cheb Basin, which terminates the Czech part of the Eger Rift to the West and is known for recurring earthquake swarms and mantle degassing. Gas and isotope compositions will be continuously analyzed in-situ at different depth levels (30 m, 70 m, 230 m) reached by three adjacent boreholes.</p>

Early exhumation of the Beni Bousera granulites and peridotites at the northern margin of the westernmost Tethys (Rif belt, Morocco); new constraints from overlying marbles

<p>The West Mediterranean Alpine belts of the Rif and its northern counterpart, the Betics, are famous for the subcontinental peridotites exposed in their Internal zones (Alboran Domain), the Beni Bousera (BB) and Ronda massifs, respectively. The Beni Bousera Marbles (BBMs) here described are known for long in the northern Rif, but remained overlooked so far. Since <em>Kornprobst (1974)</em>, these marbles have been considered as simple intercalations within the kinzigites (migmatitic granulites) envelope of the BB peridotite. Based on the integration of field mapping, structural and petrology investigations and supported by SHRIMP U-Th-Pb geochronology, we present a new interpretation of these marbles and infer geodynamic implications at the local and regional scale. The field data show that the BBMs form minor, dismembered units within a ~30 to 300 m-thick mylonitic contact zone between the kinzigites and the overlying gneisses of the Filali Unit (Filali-Beni Bousera Shear Zone, FBBSZ). They display bedding structures marked by more or less siliceous marbles and some mica-rich or conglomeratic beds. The FBBSZ includes secondary ductile thrusts that determine kinzigite horses carried NW-ward over the marbles. Within the latter, NNE-trending folds are conspicuous. Brittle, northward-dipping normal faults crosscut the FBBSZ ductile structures. An unconformable contact, either of stratigraphic or tectonic origin, onto the kinzigites can be locally observed. The petrological investigation allows us to define pebbles and/or detrital grains, including K-feldspar, quartz, garnet, and zircon in these high-grade marbles. Peak mineral assemblage consists of forsterite, Mg-Al-spinel, phlogopite, and geikielite (MgTiO3) in dolomite marbles, phlogopite, scapolite, diopside, and titanite in calcite marbles. This characterizes a peak HT-LP metamorphism at ~700-750°C, 4-8 kbar. The BBMs compare with the Triassic carbonates deposited over the crustal units of the Alpujarrides-Sebtides. The detrital cores of the zircon grains from the BBMs yield two U-Th-Pb age clusters of ~270 Ma and ~340 Ma, distinct from the 290-300 Ma age of the zircon grains from the kinzigites (<em>Rossetti et al., 2020</em>), and supporting a Triassic age of the protoliths; the zircon rims yield ~21 Ma ages. The BBMs protoliths may have been deposited onto the kinzigites or carried later as extensional allochthons over a detachment in the frame of the incipient formation of the Alboran Domain continental margin, which is dated from the late Liassic-Dogger in the “Dorsale calcaire” detached units (<em>Chalouan et al., 2008</em>). Thus, the Beni Bousera mantle rocks would have been exhumed at shallow depth during the early rifting events responsible for the birth of the Maghrebian Tethys, i.e., as early as the Triassic-late Liassic.</p><p><strong>Keywords:</strong> BBMs/ FFBSZ/ HT-LP metamorphism/ SHRIMP U-Th-Pb geochronology / hyperextended margin/ mantle rocks exhumation / Gibraltar Arc</p><p><strong>References </strong>:</p><p>Please use this link for access to the cited references:  https://www.docdroid.net/hPSheTG/references-farah-et-al-2021-vegu-pdf </p><p> </p><p> </p><p> </p>

Determining the Tectonic Origin of the Gara and Mateen Anticlines Using Geomorphological and Structural Forms, Iraqi Kurdistan Region

Gara and Mateen are 2 major anticlines in the northern part of the Iraqi Kurdistan Region, located in the vicinity of the town Amadiyah. Both anticlines are oriented in an almost east–west (E–W) trend with a steep southern limb. The length and width of the Gara and Mateen anticlines are 87 km and 63 km, and 11 km and 9.5 km, respectively. The 2 anticlines are separated by a wide and shallow syncline filled by the Tertiary rocks of the Pliocene–Pleistocene age. The oldest exposed rocks in the Gara and Mateen anticlines are from the Triassic age. The carapace of both anticlines is built up by the Bekhme and Qamchuqa formations. The geomorphological and structural features were studied through satellite images and geological maps. Based on these studies, it was found that both anticlines show clear geomorphological and structural features that indicate their lateral growth. Among those features are water and wind gaps, different shapes of valleys that indicate lateral growth, abandoned alluvial fans, whale-back shapes, en-echelon plunges, and multiple dome anticlines. Furthermore, the rate of upward movements was calculated using neotectonic data. In addition, the rate of river and stream incisions was calculated on the basis of the height of the river terrace levels.

Planetary fracturing and lineaments revealed in the Kovdor magnetite–apatite ore deposit by open pit mining

The analysis of the studies into fracturing of Zhelezny pitwall rock mass over the period from 1989 to 2019 proves that planetary fracturing is represented by faults, carbonatite dykes and single fractures oriented in the same direction as the prevailing regional lineaments on the Kola Peninsula. Planetary fracturing is assumed as a system of regular-oriented fractures. The planetary fracturing also includes lineaments of tectonic origin. The scientists think the faults registered in the pitwall rock mass and codirectional with the lineaments will accompany mining operations down to the full depth of the pit, up to the full extraction of magnetite–apatite ore reserves. While preparing this article, the authors have collected, generalized and analyzed the data of geological and structural mapping implemented by VIOGEM’s experts over the period from 1989 to 2019. VIOGEM’s procedure of geological and structural mapping ensures continuous documentation of extensional tectonics at high referencing accuracy (to 50 cm), as well as determination of inaccessible azimuths and angles of fractures by remote assessment of their orientations in pit walls using a laser scanner and photographic techniques to study the structure of hard rock mass and the behavior of permanent benches.